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            "page_number": 2,
            "text": "Cisco Press\n800 East 96th Street\nIndianapolis, Indiana 46240 USA\nCisco Press\nEnd-to-End Network Security \nDefense-in-Depth\nOmar Santos\n"
        },
        {
            "page_number": 3,
            "text": "ii\nEnd-to-End Network Security \nDefense-in-Depth\nOmar Santos\nCopyright© 2008 Cisco Systems, Inc.\nPublished by:\nCisco Press\n800 East 96th Street \nIndianapolis, IN 46240 USA\nAll rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic \nor mechanical, including photocopying, recording, or by any information storage and retrieval system, without \nwritten permission from the publisher, except for the inclusion of brief quotations in a review.\nPrinted in the United States of America\nFirst Printing   August 2007\nLibrary of Congress Cataloging-in-Publication Data:\nSantos, Omar.\n  End-to-end network security : defense-in-depth / Omar Santos.\n       p. cm.\n  ISBN 978-1-58705-332-0 (pbk.)\n 1.  Computer networks—Security measures.  I. Title. \n  TK5105.59.S313 2007\n  005.8—dc22\n2007028287\nISBN-10: 1-58705-332-2\nISBN-13: 978-1-58705-332-0\nWarning and Disclaimer\nThis book is designed to provide information about end-to-end network security. Every effort has been made to \nmake this book as complete and as accurate as possible, but no warranty or fitness is implied.\nThe information is provided on an “as is” basis. The authors, Cisco Press, and Cisco Systems shall have \nneither liability nor responsibility to any person or entity with respect to any loss or damages arising from \nthe information contained in this book or from the use of the discs or programs that may accompany it.\nThe opinions expressed in this book belong to the author and are not necessarily those of Cisco Systems.\nTrademark Acknowledgments\nAll terms mentioned in this book that are known to be trademarks or service marks have been appropriately \ncapitalized. Cisco Press or Cisco Systems, Inc. cannot attest to the accuracy of this information. Use of a term in \nthis book should not be regarded as affecting the validity of any trademark or service mark.\n"
        },
        {
            "page_number": 4,
            "text": "iii\nFeedback Information\nAt Cisco Press, our goal is to create in-depth technical books of the highest quality and value. Each book is crafted \nwith care and precision, undergoing rigorous development that involves the unique expertise of members from the \nprofessional technical community.\nReaders’ feedback is a natural continuation of this process. If you have any comments regarding how we could \nimprove the quality of this book or otherwise alter it to better suit your needs, you can contact us through e-mail at \nfeedback@ciscopress.com. Please make sure to include the book title and ISBN in your message.\nWe greatly appreciate your assistance.\nCorporate and Government Sales\nThe publisher offers excellent discounts on this book when ordered in quantity for bulk purchases or special sales \nwhich may include electronic versions and/or custom covers and content particular to your business, training goals, \nmarketing focus, and branding interests. For more information, please contact: \nU.S. Corporate and Government Sales    \n1-800-382-3419\ncorpsales@pearsontechgroup.com\nFor sales outside the United States, please contact: \nInternational Sales\ninternational@pearsoned.com\nPublisher\nPaul Boger\nAssociate Publisher\nDave Dusthimer\nCisco Representative\nAnthony Wolfenden\nCisco Press Program Manager\nJeff Brady\nExecutive Editor\nBrett Bartow\nManaging Editor\nPatrick Kanouse\nDevelopment Editor\nBetsey Henkels\nProject Editor\nJennifer Gallant\nCopy Editor\nKaren A. Gill\nTechnical Editors\nPavan Reddy\nJohn Stuppi\nEditorial Assistant\nVanessa Evans\nBook and Cover Designer\nLouisa Adair\nComposition\nICC Macmillan Inc.\nIndexer\nKen Johnson \nProofreader\nAnne Poynter\n"
        },
        {
            "page_number": 5,
            "text": "iv\nAbout the Author\nOmar Santos is a senior network security engineer and Incident Manager within the Product Security \nIncident Response Team (PSIRT) at Cisco. Omar has designed, implemented, and supported numerous \nsecure networks for Fortune 500 companies and the U.S. government, including the United States \nMarine Corps (USMC) and the U.S. Department of Defense (DoD). He is also the author of many \nCisco online technical documents and configuration guidelines. Before his current role, Omar was a \ntechnical leader within the World Wide Security Practice and Cisco Technical Assistance Center (TAC), \nwhere he taught, led, and mentored many engineers within both organizations. He is an active member \nof the InfraGard organization. InfraGard is a cooperative undertaking that involves the Federal Bureau \nof Investigation and an association of businesses, academic institutions, state and local law enforcement \nagencies, and other participants. InfraGard is dedicated to increasing the security of the critical \ninfrastructures of the United States of America. \nOmar has also delivered numerous technical presentations to Cisco customers and partners, as well as \nexecutive presentations to CEOs, CIOs, and CSOs of many organizations. He is also the author of the \nCisco Press books: Cisco Network Admission Control, Volume II: NAC Deployment and Troubleshooting, \nand Cisco ASA: All-in-One Firewall, IPS, and VPN Adaptive Security Appliance.\n"
        },
        {
            "page_number": 6,
            "text": "v\nAbout the Technical Reviewers\nPavan Reddy, CCIE No. 4575, currently works as a consulting systems engineer for Cisco specializing \nin network security. Pavan has been collaborating with customers and partners on the design and \nimplementation of large-scale enterprise and service provider security architectures for nearly ten years. \nBefore joining Cisco, Pavan worked as a network security engineer in the construction and financial \nindustries. Pavan also holds a bachelor of science degree in computer engineering from Carnegie Mellon.\nJohn Stuppi, CCIE No. 11154, is a network consulting engineer for Cisco. John is responsible for \ncreating, testing, and communicating effective techniques using Cisco product capabilities to \nprovide identification and mitigation options to Cisco customers who are facing current or expected \nsecurity threats. John also advises Cisco customers on incident readiness and response methodologies \nand assists them in DoS and worm mitigation and preparedness. John is a CCIE and a CISSP, and he \nholds an Information Systems Security (INFOSEC) Professional Certification. In addition, John has a \nBSEE from Lehigh University and an MBA from Rutgers University. John lives in Ocean Township, \nNew Jersey with his wife Diane and his two wonderful children, Thomas and Allison.\n"
        },
        {
            "page_number": 7,
            "text": "vi\nDedications\nI would like to dedicate this book to my lovely wife, Jeannette, and my two beautiful children, Hannah \nand Derek, who have inspired and supported me throughout the development of this book.\nI also dedicate this book to my parents, Jose and Generosa. Without their knowledge, wisdom, and \nguidance, I would not have the goals that I strive to achieve today.\n—Omar\nAcknowledgments\nI would like to acknowledge the technical editors, Pavan Reddy and John Stuppi. Their superb technical \nskills and input are what make this manuscript a success. Pavan has been a technical leader and \nadvisor within Cisco for several years. He has led many projects for Fortune 500 enterprises and service \nproviders. He was one of the key developers of the Cisco Operational Process Model (COPM). John \nhas also led many implementations and designs for Cisco customers. His experience in worldwide \nthreat intelligence provides a unique breadth of knowledge and value added.\nMany thanks to my management team, who have always supported me during the development of \nthis book. \nI am extremely thankful to the Cisco Press team, especially Brett Bartow, Andrew Cupp, Betsey \nHenkels, and Jennifer Gallant for their patience and continuous support.\nFinally, I would like to acknowledge the great minds within the Cisco Security Technology \nGroup (STG), Advanced Services, and Technical Support organizations.\n"
        },
        {
            "page_number": 8,
            "text": "vii\n"
        },
        {
            "page_number": 9,
            "text": "viii\nContents at a Glance\nForeword\nxix\nIntroduction\nxx\nPart I\nIntroduction to Network Security Solutions\n3\nChapter 1\nOverview of Network Security Technologies\n5\nPart II\nSecurity Lifecycle: Frameworks and Methodologies\n41\nChapter 2\nPreparation Phase\n43\nChapter 3\nIdentifying and Classifying Security Threats\n99\nChapter 4\nTraceback\n141\nChapter 5\nReacting to Security Incidents\n153\nChapter 6\nPostmortem and Improvement\n167\nChapter 7\nProactive Security Framework\n177\nPart III\nDefense-In-Depth Applied\n209\nChapter 8\nWireless Security\n211\nChapter 9\nIP Telephony Security\n261\nChapter 10\nData Center Security\n297\nChapter 11\nIPv6 Security\n329\nPart IV\nCase Studies\n339\nChapter 12\nCase Studies\n341\nIndex\n422\n"
        },
        {
            "page_number": 10,
            "text": "ix\nContents\nForeword\nxix\nIntroduction\nxx\nPart I\nIntroduction to Network Security Solutions\n3\nChapter 1\nOverview of Network Security Technologies\n5\nFirewalls\n5\nNetwork Firewalls\n6\nNetwork Address Translation (NAT)\n7\nStateful Firewalls\n9\nDeep Packet Inspection\n10\nDemilitarized Zones\n10\nPersonal Firewalls\n11\nVirtual Private Networks (VPN)\n12\nTechnical Overview of IPsec\n14\nPhase 1\n14\nPhase 2\n16\nSSL VPNs\n18\nIntrusion Detection Systems (IDS) and Intrusion Prevention Systems (IPS)\n19\nPattern Matching\n20\nProtocol Analysis\n21\nHeuristic-Based Analysis\n21\nAnomaly-Based Analysis\n21\nAnomaly Detection Systems\n22\nAuthentication, Authorization, and Accounting (AAA) and Identity Management\n23\nRADIUS\n23\nTACACS+\n25\nIdentity Management Concepts\n26\nNetwork Admission Control\n27\nNAC Appliance\n27\nNAC Framework\n33\nRouting Mechanisms as Security Tools\n36\nSummary\n39\n"
        },
        {
            "page_number": 11,
            "text": "x\nPart II\nSecurity Lifestyle: Frameworks and Methodologies\n41\nChapter 2\nPreparation Phase 43\n Risk Analysis\n43\nThreat Modeling\n44\nPenetration Testing\n46\nSocial Engineering\n49\nSecurity Intelligence\n50\nCommon Vulnerability Scoring System\n50\nBase Metrics\n51\nTemporal Metrics\n51\nEnvironmental Metrics\n52\nCreating a Computer Security Incident Response Team (CSIRT)\n52\nWho Should Be Part of the CSIRT?\n53\nIncident Response Collaborative Teams\n54\nTasks and Responsibilities of the CSIRT\n54\n Building Strong Security Policies\n54\nInfrastructure Protection\n57\nStrong Device Access Control\n59\nSSH Versus Telnet\n59\nLocal Password Management\n61\nConfiguring Authentication Banners\n62\nInteractive Access Control\n62\nRole-Based Command-Line Interface (CLI) Access in Cisco IOS\n64\nControlling SNMP Access\n66\nSecuring Routing Protocols\n66\nConfiguring Static Routing Peers\n68\nAuthentication\n68\nRoute Filtering\n69\nTime-to-Live (TTL) Security Check\n70\nDisabling Unnecessary Services on Network Components\n70\nCisco Discovery Protocol (CDP)\n71\nFinger\n72\nDirected Broadcast\n72\nMaintenance Operations Protocol (MOP)\n72\nBOOTP Server\n73\nICMP Redirects\n73\nIP Source Routing\n73\nPacket Assembler/Disassembler (PAD)\n73\nProxy Address Resolution Protocol (ARP)\n73\n"
        },
        {
            "page_number": 12,
            "text": "xi\nIDENT\n74\nTCP and User Datagram Protocol (UDP) Small Servers\n74\nIP Version 6 (IPv6)\n75\nLocking Down Unused Ports on Network Access Devices\n75\nControl Resource Exhaustion\n75\nResource Thresholding Notification\n76\nCPU Protection\n77\nReceive Access Control Lists (rACLs)\n78\nControl Plane Policing (CoPP)\n80\nScheduler Allocate/Interval\n81\nPolicy Enforcement\n81\nInfrastructure Protection Access Control Lists (iACLs)\n82\nUnicast Reverse Path Forwarding (Unicast RPF)\n83\nAutomated Security Tools Within Cisco IOS\n84\nCisco IOS AutoSecure\n84\nCisco Secure Device Manager (SDM)\n88\nTelemetry\n89\nEndpoint Security\n90\nPatch Management\n90\nCisco Security Agent (CSA)\n92\nNetwork Admission Control\n94\nPhased Approach\n94\nAdministrative Tasks\n96\n Staff and Support\n96\nSummary\n97\nChapter 3\nIdentifying and Classifying Security Threats\n99\nNetwork Visibility\n101\nTelemetry and Anomaly Detection\n108\nNetFlow\n108\nEnabling NetFlow\n111\nCollecting NetFlow Statistics from the CLI\n112\nSYSLOG\n115\nEnabling Logging (SYSLOG) on Cisco IOS Routers and Switches\n115\nEnabling Logging Cisco Catalyst Switches Running CATOS\n117\nEnabling Logging on Cisco ASA and Cisco PIX Security Appliances\n117\nSNMP\n118\nEnabling SNMP on Cisco IOS Devices\n119\nEnabling SNMP on Cisco ASA and Cisco PIX Security Appliances\n121\nCisco Security Monitoring, Analysis and Response System (CS-MARS)\n121\n"
        },
        {
            "page_number": 13,
            "text": "xii\nCisco Network Analysis Module (NAM)\n125\nOpen Source Monitoring Tools\n126\nCisco Traffic Anomaly Detectors and Cisco Guard DDoS Mitigation \nAppliances\n127\nIntrusion Detection and Intrusion Prevention Systems (IDS/IPS)\n131\nThe Importance of Signatures Updates\n131\nThe Importance of Tuning\n133\nAnomaly Detection Within Cisco IPS Devices\n137\nSummary\n139\nChapter 4\nTraceback\n141\nTraceback in the Service Provider Environment\n142\nTraceback in the Enterprise\n147\nSummary\n151\nChapter 5\nReacting to Security Incidents\n153\nAdequate Incident-Handling Policies and Procedures\n153\nLaws and Computer Crimes\n155\nSecurity Incident Mitigation Tools\n156\nAccess Control Lists (ACL)\n157\nPrivate VLANs\n158\nRemotely Triggered Black Hole Routing\n158\nForensics\n160\nLog Files\n161\nLinux Forensics Tools\n162\nWindows Forensics\n164\nSummary\n165\nChapter 6\nPostmortem and Improvement 167\nCollected Incident Data\n167\nRoot-Cause Analysis and Lessons Learned\n171\nBuilding an Action Plan\n173\nSummary\n174\nChapter 7\nProactive Security Framework 177\nSAVE Versus ITU-T X.805\n178\n"
        },
        {
            "page_number": 14,
            "text": "xiii\nIdentity and Trust\n183\nAAA\n183\nCisco Guard Active Verification\n185\nDHCP Snooping\n186\nIP Source Guard\n187\nDigital Certificates and PKI\n188\nIKE\n188\nNetwork Admission Control (NAC)\n188\nRouting Protocol Authentication\n189\nStrict Unicast RPF\n189\nVisibility\n189\nAnomaly Detection\n190\nIDS/IPS\n190\nCisco Network Analysis Module (NAM)\n191\nLayer 2 and Layer 3 Information (CDP, Routing Tables, CEF Tables)\n191\nCorrelation\n192\nCS-MARS\n193\nArbor Peakflow SP and Peakflow X\n193\nCisco Security Agent Management Console (CSA-MC) Basic \nEvent Correlation\n193\nInstrumentation and Management\n193\nCisco Security Manager\n195\nConfiguration Logger and Configuration Rollback\n195\n Embedded Device Managers\n195\nCisco IOS XR XML Interface\n196\nSNMP and RMON\n196\nSyslog\n196\nIsolation and Virtualization\n196\nCisco IOS Role-Based CLI Access (CLI Views)\n197\nAnomaly Detection Zones\n198\nNetwork Device Virtualization\n198\nSegmentation with VLANs\n199\nSegmentation with Firewalls\n200\nSegmentation with VRF/VRF-Lite\n200\nPolicy Enforcement\n202\nVisualization Techniques\n203\nSummary\n207\n"
        },
        {
            "page_number": 15,
            "text": "xiv\nPart III\nDefense-In-Depth Applied 209\nChapter 8\nWireless Security\n211\nOverview of Cisco Unified Wireless Network Architecture\n212\nAuthentication and Authorization of Wireless Users\n216\nWEP\n216\nWPA\n218\n802.1x on Wireless Networks\n219\nEAP with MD5\n221\nCisco LEAP\n222\nEAP-TLS\n223\nPEAP\n223\nEAP Tunneled TLS Authentication Protocol (EAP-TTLS)\n224\nEAP-FAST\n224\nEAP-GTC\n225\nConfiguring 802.1x with EAP-FAST in the Cisco Unified Wireless Solution\n226\nConfiguring the WLC\n226\nConfiguring the Cisco Secure ACS Server for 802.1x and EAP-FAST\n229\nConfiguring the CSSC\n233\nLightweight Access Point Protocol (LWAPP)\n236\nWireless Intrusion Prevention System Integration\n239\nConfiguring IDS/IPS Sensors in the WLC\n241\nUploading and Configuring IDS/IPS Signatures\n242\nManagement Frame Protection (MFP)\n243\nPrecise Location Tracking\n244\nNetwork Admission Control (NAC) in Wireless Networks\n245\nNAC Appliance Configuration\n246\nWLC Configuration\n255\nSummary\n259\nChapter 9\nIP Telephony Security 261\n Protecting the IP Telephony Infrastructure\n262\nAccess Layer\n266\nDistribution Layer\n273\nCore\n275\nSecuring the IP Telephony Applications\n275\nProtecting Cisco Unified CallManager\n276\nProtecting Cisco Unified Communications Manager Express (CME)\n277\nProtecting Cisco Unity\n281\n"
        },
        {
            "page_number": 16,
            "text": "xv\nProtecting Cisco Unity Express\n287\nProtecting Cisco Personal Assistant\n289\nHardening the Cisco Personal Assistant Operating Environment\n289\nCisco Personal Assistant Server Security Policies\n291\nProtecting Against Eavesdropping Attacks\n293\nSummary\n295\nChapter 10\nData Center Security 297\nProtecting the Data Center Against Denial of Service (DoS) Attacks and Worms\n297\nSYN Cookies in Firewalls and Load Balancers\n297\nIntrusion Prevention Systems (IPS) and Intrusion Detection Systems (IDS)\n300\nCisco NetFlow in the Data Center\n301\nCisco Guard\n302\nData Center Infrastructure Protection\n302\nData Center Segmentation and Tiered Access Control\n303\nSegmenting the Data Center with the Cisco FWSM\n306\nCisco FWSM Modes of Operation and Design Considerations\n306\nConfiguring the Cisco Catalyst Switch\n309\nCreating Security Contexts in the Cisco FWSM\n310\nConfiguring the Interfaces on Each Security Context\n312\nConfiguring Network Address Translation\n313\nControlling Access with ACLs\n317\nVirtual Fragment Reassembly\n322\nDeploying Network Intrusion Detection and Prevention Systems\n322\nSending Selective Traffic to the IDS/IPS Devices\n322\nMonitoring and Tuning\n325\nDeploying the Cisco Security Agent (CSA) in the Data Center\n325\nCSA Architecture\n325\nConfiguring Agent Kits\n326\nPhased Deployment\n326\nSummary\n327\nChapter 11\nIPv6 Security 329\nReconnaissance\n330\nFiltering in IPv6\n331\nFiltering Access Control Lists (ACL)\n331\nICMP Filtering\n332\nExtension Headers in IPv6\n332\n"
        },
        {
            "page_number": 17,
            "text": "xvi\nSpoofing\n333\nHeader Manipulation and Fragmentation\n333\nBroadcast Amplification or Smurf Attacks\n334\nIPv6 Routing Security\n334\nIPsec and IPv6\n335\nSummary\n337\nPart IV\nCase Studies\n339\nChapter 12\nCase Studies 341\nCase Study of a Small Business\n341\nRaleigh Office Cisco ASA Configuration\n343\nConfiguring IP Addressing and Routing\n343\nConfiguring PAT on the Cisco ASA\n347\nConfiguring Static NAT for the DMZ Servers\n349\nConfiguring Identity NAT for Inside Users\n351\nControlling Access\n352\nCisco ASA Antispoofing Configuration\n353\nBlocking Instant Messaging\n354\nAtlanta Office Cisco IOS Configuration\n360\nLocking Down the Cisco IOS Router\n360\nConfiguring Basic Network Address Translation (NAT)\n376\nConfiguring Site-to-Site VPN\n377\nCase Study of a Medium-Sized Enterprise\n389\nProtecting the Internet Edge Routers\n391\nConfiguring the AIP-SSM on the Cisco ASA\n391\nConfiguring Active-Standby Failover on the Cisco ASA\n394\nConfiguring AAA on the Infrastructure Devices\n400\nCase Study of a Large Enterprise\n401\nCreating a New Computer Security Incident Response Team (CSIRT)\n403\nCreating New Security Policies\n404\nPhysical Security Policy\n404\nPerimeter Security Policy\n404\nDevice Security Policy\n405\nRemote Access VPN Policy\n405\nPatch Management Policy\n406\nChange Management Policy\n406\nInternet Usage Policy\n406\n"
        },
        {
            "page_number": 18,
            "text": "xvii\nDeploying IPsec Remote Access VPN\n406\nConfiguring IPsec Remote Access VPN\n408\nConfiguring Load-Balancing\n415\nReacting to a Security Incident\n418\nIdentifying, Classifying, and Tracking the Security Incident or Attack\n419\nReacting to the Incident\n419\nPostmortem\n419\nSummary\n420\nIndex\n422\n"
        },
        {
            "page_number": 19,
            "text": "xviii\nCommand Syntax Conventions\nThe conventions used to present command syntax in this book are the same conventions used in the \nIOS Command Reference. The Command Reference describes these conventions as follows:\n•\nBoldface indicates commands and keywords that are entered literally as shown. In actual \nconfiguration examples and output (not general command syntax), boldface indicates \ncommands that are manually input by the user (such as a show command).\n•\nItalics indicate arguments for which you supply actual values.\n•\nVertical bars (|) separate alternative, mutually exclusive elements.\n•\nSquare brackets [ ] indicate optional elements.\n•\nBraces { } indicate a required choice.\n•\nBraces within brackets [{ }] indicate a required choice within an optional element.\n"
        },
        {
            "page_number": 20,
            "text": "xix\nForeword\nDefense-in-Depth is a phrase that is often used and equally misunderstood. This book gives an excellent \noverview of what this really means and, more importantly, how to apply certain principles to develop \nappropriate risk mitigation strategies.\nAfter you have assimilated the content of this book, you will have a solid understanding of several \naspects of security. The author begins with an overview of the basics then provides comprehensive \nmethodologies for preparing for and reacting to security incidents and, finally, illustrates a unique \nframework for managing through the lifecycle of security known as SAVE. Also provided are various \nDefense-in-Depth strategies covering the most current advanced technologies utilized for protecting \ninformation assets today. Equally as important are the case studies which provide the reader with \nreal-world examples of how to put these tools, processes, methodologies, and frameworks to use.\nMany reference documents and lengthy periodicals delve into the world of information security. \nHowever, few can capture the essence of this discipline and also provide a high-level, demystified \nunderstanding of information security and the technical underpinning required to achieve success.\nWithin these pages, you will find many practical tools both process related and technology related \nthat you can draw on to improve your risk mitigation strategies. The most effective security programs \ncombine attention to both deeply technical issues and business process issues. The author clearly \ndemonstrates that he grasps the inherent challenges posed by combining these disparate approaches, \nand he conveys them in an approachable style. You will find yourself not only gaining valuable insight \nfrom End-to-End Network Security, but also returning to its pages to ensure you are on target in your \nendeavors.\nWe have seen dramatic increases in the type and nature of threats to our information assets. The \nchallenge we face is to fully understand the compensating controls and techniques that can be deployed \nto offset these threats and do so in a way that is consistent with the business processes and growth \nstrategies of the businesses and government we are trying to protect. This book strikes that delicate \nbalance, and you will find it an invaluable element of your protection initiatives far into the future.\nBruce Murphy\nVice President\nWorld Wide Security Practice\nCisco\n"
        },
        {
            "page_number": 21,
            "text": "xx\nIntroduction\nThe network security lifecycle requires specialized support and a commitment to best practice \nstandards. In this book, you will learn best practices that draw upon disciplined processes, frameworks, \nexpert advice, and proven technologies that will help you protect your infrastructure and organization. \nYou will learn end-to-end security best practices, from strategy development to operations and \noptimization.\nThis book covers the six-step methodology of incident readiness and response. You must take a \nproactive approach to security; an approach that starts with assessment to identify and categorize \nyour risks. In addition, you need to understand the network security technical details in relation to \nsecurity policy and incident response procedures. This book covers numerous best practices that will \nhelp you orchestrate a long-term strategy for your organization.\nWho Should Read This Book?\nThe answer to this question is simple—everyone. The principles and best practices covered in this \nbook apply to every organization. Anyone interested in network security should become familiar with \nthe information included in this book—from network and security engineers to management and \nexecutives. This book covers not only numerous technical topics and scenarios, but also covers a wide \nrange of operational best practices in addition to risk analysis and threat modeling.\n"
        },
        {
            "page_number": 22,
            "text": "xxi\nHow This Book Is Organized\nPart I of this book includes Chapter 1 which covers an introduction to security technologies and \nproducts. In Part II, which encompasses Chapters 2 through 7, you will learn the six-step methodology \nof incident readiness and response. Part III includes Chapters 8 through 11 which cover strategies used \nto protect wireless networks, IP telephony implementations, data centers, and IPv6 networks. Real-life \ncase studies are covered in Part IV which contains Chapter 12.\nThe following is a chapter-by-chapter summary of the contents of the book.\nPart I, “Introduction to Network Security Solutions,” includes:\n•\nChapter 1, “Overview of Network Security Technologies.” This chapter covers an introduc-\ntion to security technologies and products. It starts with an overview of how to place firewalls \nto provide perimeter security and network segmentation while enforcing configured policies. \nIt then dives into virtual private network (VPN) technologies and protocols—including \nIP Security (IPsec) and Secure Socket Layer (SSL). In addition, this chapter covers \ndifferent technologies such as intrusion detection systems (IDS), intrusion protection systems \n(IPS), anomaly detection systems, and network telemetry features that can help you identify \nand classify security threats. Authentication, authorization, and accounting (AAA) offers \ndifferent solutions that provide access control to network resources. This chapter introduces AAA \nand identity management concepts. Furthermore, it includes an overview of the Cisco Network \nAdmission Control solutions that are used to enforce security policy compliance on all devices \nthat are designed to access network computing resources, thereby limiting damage from \nemerging security threats. Routing techniques can be used as security tools. This chapter \nprovides examples of different routing techniques, such as Remotely Triggered Black Hole (RTBH) \nrouting and sinkholes that are used to increase the security of the network and to react to \nnew threats.\nPart II, “Security Lifecycle: Frameworks and Methodologies,” includes:\n•\nChapter 2, “Preparation Phase.” This chapter covers numerous best practices on how to \nbetter prepare your network infrastructure, security policies, procedures, and organization as \na whole against security threats and vulnerabilities. This is one of the most important chapters \nof this book. It starts by teaching you risk analysis and threat modeling techniques. You will \nalso learn guidelines on how to create strong security policies and how to create Computer \nSecurity Incident Response Teams (CSIRT). Topics such as security intelligence and social \nengineering are also covered in this chapter. You will learn numerous tips on how to increase \nthe security of your network infrastructure devices using several best practices to protect the \ncontrol, management, and data plane. Guidelines on how to better secure end-user systems \nand servers are also covered in this chapter.\n"
        },
        {
            "page_number": 23,
            "text": "xxii\n•\nChapter 3, “Identifying and Classifying Security Threats.” This chapter covers the next \ntwo phases of the six-step methodology for incident response—identification and classification \nof security threats. You will learn how important it is to have complete network visibility and \ncontrol to successfully identify and classify security threats in a timely fashion. This chapter \ncovers different technologies and tools such as Cisco NetFlow, SYSLOG, SNMP, and others \nwhich can be used to obtain information from your network and detect anomalies that might be \nmalicious activity. You will also learn how to use event correlation tools such as CS-MARS \nand open source monitoring systems in conjunction with NetFlow to allow you to gain better \nvisibility into your network. In addition, this chapter covers details about anomaly detection, \nIDS, and IPS solutions by providing tips on IPS/IDS tuning and the new anomaly detection \nfeatures supported by Cisco IPS.\n•\nChapter 4, “Traceback.” Tracing back the source of attacks, infected hosts in worm \noutbreaks, or any other security incident can be overwhelming for many network \nadministrators and security professionals. Attackers can use hundreds or thousands of botnets \nor zombies that can greatly complicate traceback and hinder mitigation once traceback \nsucceeds. This chapter covers several techniques that can help you successfully trace back \nthe sources of such threats. It covers techniques used by service providers and enterprises.\n•\nChapter 5, “Reacting to Security Incidents.” This chapter covers several techniques that \nyou can use when reacting to security incidents. It is extremely important for organizations to \nhave adequate incident handling policies and procedures in place. This chapter shows you \nseveral tips on how to make sure that your policies and procedures are adequate to successfully \nrespond to security incidents. You will also learn general information about different laws and \npractices to use when investigating security incidents and computer crimes. In addition, this \nchapter includes details about different tools you can use to mitigate attacks and other security \nincidents with your network infrastructure components including several basic computer \nforensics topics.\n•\nChapter 6, “Postmortem and Improvement.” It is highly recommended that you complete a \npostmortem after responding to security incidents. This postmortem should identify the \nstrengths and weaknesses of the incident response effort. With this analysis, you can identify \nweaknesses in systems, infrastructure defenses, or policies that allowed the incident to take \nplace. In addition, a postmortem helps you identify problems with communication channels, \ninterfaces, and procedures that hampered the efficient resolution of the reported problem. This \nchapter covers several tips on creating postmortems and executing post-incident tasks. It \nincludes guidelines for collecting post-incident data, documenting lessons learned during the \nincident, and building action plans to close gaps that are identified. \n•\nChapter 7, “Proactive Security Framework.” This chapter covers the Security \nAssessment, Validation, and Execution (SAVE) framework. SAVE, formerly known as \nthe Cisco Operational Process Model (COPM), is a framework initially developed for service \nproviders, but its practices are applied to enterprises and organizations. This chapter provides \nexamples of techniques and practices that can allow you to gain and maintain visibility and \ncontrol over the network during normal operations or during the course of a security incident \nor an anomaly in the network.\n"
        },
        {
            "page_number": 24,
            "text": "xxiii\nPart III, “Defense-In-Depth Applied,” includes:\n•\nChapter 8, “Wireless Security.” When designing and deploying wireless networks, it is \nimportant to consider the unique security challenges that can be inherited. This chapter \nincludes best practices to use when deploying wireless networks. You will learn different \ntypes of authentication mechanisms, including 802.1x, which is used to enhance the security of \nwireless networks. In addition, this chapter includes an overview of the Lightweight Access \nPoint Protocol (LWAPP), Cisco Location Services, Management Frame Protection (MFP), and \nother wireless features to consider when designing security within your wireless infrastructure. \nThe chapter concludes with step-by-step configuration examples of the integration of IPS \nand the Cisco NAC Appliance on the Cisco Unified Wireless Network solution.\n•\nChapter 9, “IP Telephony Security.” IP Telephony solutions are being deployed at a fast \nrate in many organizations. The cost savings introduced with Voice over IP (VoIP) solutions are \nsignificant. On the other hand, these benefits can be heavily impacted if you do not have the \nappropriate security mechanisms in place. In this chapter, you will learn several techniques \nused to increase the security of IP Telephony networks. This chapter covers how to secure \ndifferent IP telephony components such as the Cisco Unified CallManager, Cisco Unified \nCME, Cisco Unity, Cisco Unity Express, and Cisco Unified Personal Assistant. In addition, \nit covers several ways to protect against voice eavesdropping attacks.\n•\nChapter 10, “Data Center Security.” In this chapter, you will learn the security strategies, \ntechnologies, and products designed to protect against attacks on your data center from both \ninside and outside the enterprise. Integrated security technologies, including secure connectivity, \nthreat defense, and trust and identity management systems, create a Defense-in-Depth strategy \nto protect each application and server environment across the consolidated IP, storage, and \ninterconnect data center networking infrastructure. Configuration examples of different \nsolutions such as the Firewall Services Module (FWSM), the Intrusion Detection/Prevention \nSystem Module (IDSM), and the Application Control Engine (ACE) module for the Catalyst \n6500 series switches are covered in detail. This chapter also covers the use of Layer 2 to \nLayer 7 security features in infrastructure components to successfully identify, classify, and \nmitigate security threats within the data center.\n•\nChapter 11, “IPv6 Security.” This chapter covers an introduction to security topics in \nInternet Protocol Version 6 (IPv6) implementations. Although it is assumed that you already \nhave a rudimentary understanding of IPv6, this chapter covers basic IPv6 topics. This chapter \ndetails the most common IPv6 security threats and the best practices that many organizations \nadopt to protect their IPv6 infrastructure. IPsec in IPv6 is also covered, with guidelines on \nhow to configure Cisco IOS routers to terminate IPsec in IPv6 networks.\nPart IV, “Case Studies,” includes: \n•\nChapter 12, “Case Studies.” This chapter covers several case studies representing \nsmall, medium-sized, and large-scale enterprises. Detailed example configurations and \nimplementation strategies of best practices learned in earlier chapters are covered to \nenhance learning.\n"
        },
        {
            "page_number": 25,
            "text": ""
        },
        {
            "page_number": 26,
            "text": "P A R T I\nIntroduction to Network Security \nSolutions\nChapter 1 \nOverview of Network Security Technologies  \n"
        },
        {
            "page_number": 27,
            "text": "This chapter covers the following topics:\n•\nFirewalls\n•\nVirtual Private Networks (VPN)\n•\nIntrusion Detection Systems (IDS) and Intrusion Prevention Systems (IPS)\n•\nAnomaly Detection Systems\n•\nAuthentication, Authorization, and Accounting (AAA) and Identity Management\n•\nNetwork Admission Control\n•\nRouting Mechanisms as Security Tools\n"
        },
        {
            "page_number": 28,
            "text": "C H A P T E R 1\nOverview of Network Security \nTechnologies\nTechnology can be considered your best friend. Nowadays, you can do almost everything \nover networked systems or the Internet—from simple tasks, such as booking a flight \nreservation, to a multibillion dollar wire transfer between two large financial organizations. \nYou cannot take security for granted! An attacker can steal credit card information from \nyour online travel reservation or launch a denial of service (DoS) attack to disrupt a wire \ntransfer. It is extremely important to learn new techniques and methodologies to combat \nelectronic penetrations, data thefts, and cyberattacks on critical information systems.\nOrganizations and individuals must educate themselves to be able to select the \nappropriate security technologies, tools, and methodologies to prevent and mitigate any \nsecurity threats before they impact the business. This chapter describes the most common \nand widely used security products and technologies. These products and technologies \ninclude the following:\n•\nFirewalls\n•\nVirtual private networks (VPN)\n•\nIntrusion detection systems (IDS) and intrusion prevention systems (IPS)\n•\nAnomaly detection systems\n•\nAuthentication, authorization, and accounting (AAA) and identity management\n•\nNetwork admission control\nNOTE\nThis chapter introduces a range of security technologies and products. Becoming familiar \nwith these topics will help you understand the methodologies and solutions presented in the \nrest of this book.\nFirewalls\nIf you are a network administrator, security engineer, manager, or simply an end user, \nyou have probably heard of, used, or configured a firewall. Historically, firewalls have been \nused as barriers to keep intruders and destructive forces away from your network. Today, \n"
        },
        {
            "page_number": 29,
            "text": "6\nChapter 1:  Overview of Network Security Technologies\nfirewalls and security appliances have many robust and sophisticated features beyond the \ntraditional access control rules and policies. As you read through this section, you will learn \nmore about the different types of firewalls and how they work, the threats they can protect \nyou from, and their limitations.\nTIP\nA detailed understanding of how firewalls and their related technologies work is extremely \nimportant for all network security professionals. This knowledge will help them to \nconfigure and manage the security of their networks accurately and effectively. \nSeveral network firewall solutions offer user and application policy enforcement that \nprovides multivector attack protection for different types of security threats. They often \nprovide logging capabilities that allow the security administrators to identify, investigate, \nvalidate, and mitigate such threats. In addition, several software applications can run on a \nsystem to protect only that host. These types of applications are known as personal \nfirewalls. This section includes an overview of both network and personal firewalls and \ntheir related technologies.\nNetwork Firewalls\nNetwork firewalls come in many flavors and colors. They range from simple packet filters \nto sophisticated solutions that include stateful and deep-packet inspection features. For \nexample, you can configure simple access control lists (ACL) on a router to prevent an \nattacker from accessing corporate resources. Figure 1-1 illustrates how to configure a router \nto block access from unauthorized hosts and users on the Internet.\nFigure 1-1\nBasic Packet Filter—Router with Basic ACLs\nIn Figure 1-1, the router is configured to deny all incoming traffic from Internet hosts to its \nprotected network (the corporate network). In this example, an attacker tries to scan the \nprotected network from the Internet, and the router drops all traffic.\nInternet\nIOS Router\nCorporate\nNetwork\nAttacker\n"
        },
        {
            "page_number": 30,
            "text": "Firewalls     7\nNOTE\nThe use and configuration of different types of ACLs is covered in Chapter 2, “Preparation \nPhase.” \nThe purpose of packet filters is to control access to specific network segments by defining \nwhich traffic can pass through to them. Packet filters usually inspect incoming traffic at the \ntransport layer of the Open Systems Interconnection (OSI) model. For example, packet \nfilters can analyze TCP or UDP packets and judge them against a set of predetermined rules \ncalled ACLs. They inspect the following elements within a packet:\n•\nSource address\n•\nDestination address\n•\nSource port\n•\nDestination port\n•\nProtocol\nBasic packet filters commonly do not inspect additional Layer 3 and Layer 4 fields such as \nsequence numbers, TCP control flags, and TCP acknowledgement (ACK) fields.\nNOTE\nThe previous example illustrates a router configured with only a basic ACL. The Cisco IOS \nfirewall solution provides enterprises and small/medium businesses sophisticated features \nbeyond the traditional packet filters.\nNetwork Address Translation (NAT)\nFirewalls can also provide Network Address Translation (NAT) services. They can translate \nthe IP addresses of protected hosts to a publicly routable address. \nNOTE\nFirewalls often use NAT; however, other devices such as routers and wireless access points \nprovide support for NAT.\nFigure 1-2 shows how a firewall translates the IP address of an internal host \n(192.168.1.100) to a public IP address (209.165.200.225) when the host attempts\nto access Cisco.com. \n"
        },
        {
            "page_number": 31,
            "text": "8\nChapter 1:  Overview of Network Security Technologies\nFigure 1-2\nBasic NAT\nNAT enables organizations to use any IP address space as the internal network. A best \npractice is to use the address spaces that are reserved for private use (see RFC 1918, \n“Address Allocation for Private Internets”). Table 1-1 lists the private address ranges \nspecified in RFC 1918.\nTable 1-1\nPrivate Address Ranges Specified in RFC 1918\nNAT techniques come in various types. The most common are Port Address Translation \n(PAT) and Static NAT. PAT allows many devices on a network segment to be translated to \none IP address by inspecting the Layer 4 information on the packet. Figure 1-3 illustrates \nhow three different machines on the corporate network are translated to a single public \naddress.\nIn Figure 1-3, the host with IP address 192.168.1.100 attempts to access the web server with \nIP address 209.165.200.230. The firewall translates the internal address to 209.165.200.226 \nusing the source TCP port 1024 and mapping it to TCP port 1234. Notice that the \ndestination port remains the same (port 80) .\nIP Address Range\nNetwork Mask\n10.0.0.0 to 10.255.255.255\n10.0.0.0/8\n172.16.0.0 to 172.31.255.255\n172.16.0.0/12\n192.168.0.0 to 192.168.255.255\n192.168.0.0/16\nInternet\nFirewall\ncisco.com\n192.168.1.100\n209.165.200.225\nPrivate Address\nTranslated Address\n"
        },
        {
            "page_number": 32,
            "text": "Firewalls     9\nFigure 1-3\nPAT\nStateful Firewalls\nStateful inspection firewalls track every connection passing through their interfaces by \nexamining not only the packet header contents but also the application layer information \nwithin the payload. This is done to find out more about the transaction than just the source \nand destination addresses and ports. Typically, a stateful firewall monitors the state of the \nconnection and maintains a table with the Layer 3 and Layer 4 information. More \nsophisticated firewalls perform upper-layer protocol analysis, also known as deep-packet \ninspection, which is discussed later in this chapter. The state of the connection details \nwhether such connection has been established, closed, reset, or is being negotiated. These \nmechanisms offer protection for different types of network attacks.\nCisco IOS firewall, Cisco Adaptive Security Appliances (ASA), Cisco PIX firewalls, and \nthe Cisco Firewall Services Module (FWSM) for the Cisco Catalyst 6500 series switches \nare examples of stateful firewalls. They also have other rich features such as deep packet \ninspection.\nInternet\n209.165.200.230\n192.168.1.0/24\nFirewall\nSource Address: 192.168.1.100\nDestination Address: 209.165.200.230\nSource Port: 1024\nDestination Port: 80\nSource Address: 209.165.200.226\nDestination Address: 209.165.200.230\nSource Port: 1234\nDestination Port: 80\n(PAT)\n"
        },
        {
            "page_number": 33,
            "text": "10\nChapter 1:  Overview of Network Security Technologies\nNOTE\nFor detailed deployment, configuration, and troubleshooting information, see the \nCisco Press book titled Cisco ASA: All-in-One Firewall, IPS, and VPN Adaptive Security \nAppliance.\nDeep Packet Inspection\nSeveral applications require special handling of data packets when they pass through \nfirewalls. These include applications and protocols that embed IP addressing information \nin the data payload of the packet or open secondary channels on dynamically assigned \nports. Sophisticated firewalls and security appliances such as the Cisco ASA, Cisco PIX \nfirewall, and Cisco IOS firewall offer application inspection mechanisms to handle the \nembedded addressing information to allow the previously mentioned applications and \nprotocols to work. Using application inspection, these security appliances can identify the \ndynamic port assignments and allow data exchange on these ports during a specific \nconnection.\nWith deep packet inspection, firewalls can look at specific Layer 7 payloads to protect \nagainst security threats. For example, you can configure a Cisco ASA or a Cisco PIX \nfirewall running version 7.0 or later to not allow peer-to-peer (P2P) applications to be \ntransferred over HTTP tunnels. You can also configure these devices to deny specific FTP \ncommands, HTTP content types, and other application protocols.\nNOTE\nThe Cisco ASA and Cisco PIX firewall running version 7.0 or later provide a Modular \nPolicy Framework (MPF) that allows a consistent and flexible way to configure application \ninspection and other features in a manner similar to the Cisco IOS Software Modular \nquality of service (QoS) command-line interface (CLI).\nDemilitarized Zones\nNumerous firewalls can configure network segments (or zones), usually called \ndemilitarized zones (DMZ). These zones provide security to the systems that reside \nwithin them with different security levels and policies between them. DMZs have a \ncouple of purposes: as segments on which a web server farm resides or as extranet \nconnections to a business partner. Figure 1-4 shows a firewall (a Cisco ASA in this case) \nwith two DMZs.\n"
        },
        {
            "page_number": 34,
            "text": "Firewalls     11\nFigure 1-4\nDMZ Example\nIn Figure 1-4, DMZ 1 hosts web servers that are accessible by internal and Internet hosts. \nThe Cisco ASA controls access from an extranet business partner connection on DMZ 2. \nNOTE\nIn large organizations, you can deploy multiple firewalls in different segments and DMZs.\nPersonal Firewalls\nPersonal firewalls are popular software applications that you can install on end-user \nmachines or servers to protect them from external security threats and intrusions. The term \npersonal firewall typically applies to basic software that can control Layer 3 and Layer 4 \naccess to client machines. Today, sophisticated software is available that not only provides \nbasic personal firewall features but also protects the system based on the behavior of \nthe applications installed on such systems. An example of this type of software is the \nCisco Security Agent (CSA). CSA provides several features that offer more robust security \nthan a traditional personal firewall. The following are CSA-rich security features:\n•\nHost intrusion prevention \n•\nProtection against spyware\n•\nProtection against buffer overflow attacks \nInternet\nInternal\nNetwork\nPartner Network\nExtranet Connection\nto a Business Partner\nWeb Server Farm\nCisco ASA\nDMZ 1\nDMZ 2\n"
        },
        {
            "page_number": 35,
            "text": "12\nChapter 1:  Overview of Network Security Technologies\n•\nDistributed host firewall features \n•\nMalicious mobile code protection \n•\nOperating system integrity assurance \n•\nApplication inventory \n•\nExtensive audit and logging capabilities \nNOTE\nHost intrusion prevention systems (HIPS) are detailed and described later in this chapter.\nVirtual Private Networks (VPN)\nOrganizations of all sizes deploy VPNs to provide data integrity, authentication, and \ndata encryption to assure confidentiality of the packets sent over an unprotected network \nor the Internet. VPNs are designed to avoid the cost of unnecessary leased lines. \nMany different protocols are used for VPN implementations, including these:\n•\nPoint-to-Point Tunneling Protocol (PPTP)\n•\nLayer 2 Forwarding (L2F) Protocol\n•\nLayer 2 Tunneling Protocol (L2TP)\n•\nGeneric Routing Encapsulation (GRE) Protocol\n•\nMultiprotocol Label Switching (MPLS) VPN\n•\nInternet Protocol Security (IPsec) \n•\nSecure Socket Layer (SSL)\nNOTE\nPPTP, L2F, L2TP, GRE, and MPLS VPNs do not provide data integrity, authentication, and \ndata encryption. On the other hand, you can combine L2TP, GRE, and MPLS with IPsec \nto provide these benefits. Many organizations use IPsec as their preferred protocol because \nit supports all three features described earlier (data integrity, authentication, and data \nencryption).\nVPN implementations can be categorized into two distinct groups:\n•\nSite-to-site VPNs: Allow organizations to establish VPN tunnels between two or \nmore sites so that they can communicate over a shared medium such as the Internet. \nMany organizations use IPsec, GRE, and MPLS VPN as site-to-site VPN protocols.\n"
        },
        {
            "page_number": 36,
            "text": "Virtual Private Networks (VPN)     13\n•\nRemote-access VPNs: Allow users to work from remote locations such as their \nhomes, hotels, and other premises as if they were directly connected to their corporate \nnetwork.\nFigure 1-5 illustrates a site-to-site IPsec tunnel between two sites (corporate headquarters \nand a branch office), as well as a remote access VPN from a telecommuter working from \nhome.\nFigure 1-5\nSite-to-Site and Remote Access VPN Example\nCisco ASAs are used in the example shown in Figure 1-5. The Cisco ASA integrates many \nIPsec and SSL VPN features with firewall capabilities. Other Cisco products that support \nVPN features are as follows:\n•\nCisco VPN 3000 series concentrators\n•\nCisco IOS routers\n•\nCisco PIX firewalls\n•\nCisco Catalyst 6500 switches and Cisco 7600 series routers WebVPN services module\n•\nCisco 7600 series/Catalyst 6500 series IPsec VPN shared port adapter \nNOTE\nThe use and deployment of these devices are described in Chapter 2. You can also find \ninformation about these devices at the Cisco website at cisco.com/go/security.\nIPsec Tunnel\nIPsec Tunnel\nBranch\nOffice\nCorporate\nHeadquarters\nInternet\n"
        },
        {
            "page_number": 37,
            "text": "14\nChapter 1:  Overview of Network Security Technologies\nTechnical Overview of IPsec\nIPsec uses the Internet Key Exchange (IKE) Protocol to negotiate and establish secured \nsite-to-site or remote access VPN tunnels. IKE is a framework provided by the Internet \nSecurity Association and Key Management Protocol (ISAKMP) and parts of two other \nkey management protocols, namely Oakley and Secure Key Exchange Mechanism \n(SKEME).\nNOTE\nIKE is defined in RFC 2409, “The Internet Key Exchange.”\nISAKMP has two phases. Phase 1 is used to create a secure bidirectional communication \nchannel between the IPsec peers. This channel is known as the ISAKMP Security \nAssociation (SA).\nPhase 1\nWithin Phase 1 negotiation, several attributes are exchanged, including the following:\n•\nEncryption algorithms\n•\nHashing algorithms\n•\nDiffie-Hellman groups\n•\nAuthentication method\n•\nVendor-specific attributes\nThe following are the typical encryption algorithms:\n•\nData Encryption Standard (DES): 64 bits long\n•\nTriple DES (3DES): 168 bits long\n•\nAdvanced Encryption Standard (AES): 128 bits long \n•\nAES 192: 192 bits long\n•\nAES 256: 256 bits long\nHashing algorithms include these:\n•\nSecure Hash Algorithm (SHA)\n•\nMessage digest algorithm 5 (MD5)\nThe common authentication methods are preshared keys (where the peers agree on a shared \nsecret) and digital certificates with the use of Public Key Infrastructure (PKI).\n"
        },
        {
            "page_number": 38,
            "text": "Virtual Private Networks (VPN)     15\nNOTE\nTypically, small and medium-sized organizations use preshared keys as their authentication \nmechanism. Several large organizations use digital certificates for scalability, for \ncentralized management, and for the use of additional security mechanisms.\nYou can establish a Phase 1 SA in two ways:\n•\nMain mode\n•\nAggressive mode\nIn main mode, the IPsec peers complete a six-packet exchange in three round-trips to \nnegotiate the ISAKMP SA, whereas aggressive mode completes the SA negotiation in three \npacket exchanges. Main mode provides identity protection if preshared keys are used. \nAggressive mode only provides identity protection if digital certificates are used.\nNOTE\nCisco products that support IPsec typically use main mode for site-to-site tunnels and \naggressive mode for remote-access VPN tunnels. This is the default behavior when \npreshared keys are used as the authentication method.\nFigure 1-6 illustrates the six-packet exchange in main mode negotiation.\nFigure 1-6\nMain Mode Negotiation\nDES\nMD5\nDH1\nPreshared\n3DES\nSHA\nDH2\nPreshared\n3DES\nSHA\nDH2\nPreshared\nDiffie-Hellman Key\nExchange – SKEYID\nderived\nIDs are exchanged and\nHASH is verified.\n*These two packets are\nencrypted.\n1\n2\nHDR, SA proposal\nHDR, SA choice\n3\n4\nHDR, KE i, Nonce i\nHDR, KE R, Nonce R\n5\n6\nHDR*, ID i, HASH i\nHDR*, ID R, HASH R\nPhase 1 SA parameter negotiation complete\nR1\nR2\nInitiator\nResponder\nIKE\n"
        },
        {
            "page_number": 39,
            "text": "16\nChapter 1:  Overview of Network Security Technologies\nIn Figure 1-6, two Cisco IOS Software routers are configured to terminate a site-to-site \nVPN tunnel between them. The router labeled as R1 is the initiator, and R2 is the responder. \nThe following are the steps illustrated in Figure 1-6.\nStep 1\nR1 (the initiator) has two ISAKMP proposals configured. In the first \npacket, R1 sends its configured proposals to R2. \nStep 2\nR2 evaluates the received proposal. Because it has a proposal that \nmatches the offer of the initiator, R2 sends the accepted proposal back to \nR1 in the second packet.\nStep 3\nDiffie-Hellman exchange and calculation is started. R1 sends the Key \nExchange (KE) payload and a randomly generated value called a nonce.\nStep 4\nR2 receives the information and reverses the equation using the proposed \nDiffie-Hellman group/exchange to generate the SKEYID.\nStep 5\nR1 sends its identity information. The fifth packet is encrypted with the \nkeying material derived from the SKEYID. The asterisk in Figure 1-6 is \nused to illustrate that this packet is encrypted. \nStep 6\nR2 validates the identity of R1, and R2 sends the identity information of \nR1. This packet is also encrypted.\nPhase 2\nPhase 2 is used to negotiate the IPsec SAs. This phase is also known as quick mode. The \nISAKMP SA protects the IPsec SAs, because all payloads are encrypted except the \nISAKMP header. Figure 1-7 illustrates the Phase 2 negotiation between the two routers that \njust completed Phase 1.\nFigure 1-7\nPhase 2 Negotiation\nESP\n3DES\nSHA\nESP\n3DES\nSHA\n1\n2\n3\nHDR*, HASH2\nR1\nR2\nInitiator\nResponder\nPhase 2 – Quick Mode\nHDR*, HASH2, SA proposal, Nonce r [KEr], [ID ci, ID cr]\nHDR*, HASH1, SA proposal, Nonce i [KEi], [ID ci, ID cr]\n"
        },
        {
            "page_number": 40,
            "text": "Virtual Private Networks (VPN)     17\nThe following are the steps illustrated in Figure 1-7.\nStep 1\nR1 sends the identity information, IPsec SA proposal, nonce payload, \nand (optional) KE payload if Perfect Forward Secrecy (PFS) is used. PFS \nis used to provide additional Diffie-Hellman calculations. \nStep 2\nR2 evaluates the received proposal against its configured proposal and \nsends the accepted proposal back to R1 along with its identity \ninformation, nonce payload, and the optional KE payload. \nStep 3\nR1 evaluates the R2 proposal and sends a confirmation that the IPsec SAs \nhave been successfully negotiated. This starts the data encryption \nprocess.\nIPsec uses two different protocols to encapsulate the data over a VPN tunnel:\n•\nEncapsulation Security Payload (ESP): IP Protocol 50\n•\nAuthentication Header (AH): IP Protocol 51\nNOTE\nESP is defined in RFC 2406, “IP Encapsulating Security Payload (ESP),” and AH is defined \nin RFC 2402, “IP Authentication Header.”\nIPsec can use two modes with either AH or ESP:\n•\nTransport mode: Protects upper-layer protocols, such as User Datagram Protocol \n(UDP) and TCP\n•\nTunnel mode: Protects the entire IP packet\nTransport mode is used to encrypt and authenticate the data packets between the peers. A \ntypical example of this is the use of GRE over an IPsec tunnel. Tunnel mode is used to \nencrypt and authenticate the IP packets when they are originated by the hosts connected \nbehind the VPN device. Tunnel mode adds an additional IP header to the packet, as \nillustrated in Figure 1-8.\nFigure 1-8 demonstrates the major difference between transport and tunnel mode. It \nincludes an example of an IP packet encapsulated in GRE and the difference when it is \nencrypted in transport mode and tunnel mode.\nNOTE\nTunnel mode is the default mode in Cisco IPsec devices.\n"
        },
        {
            "page_number": 41,
            "text": "18\nChapter 1:  Overview of Network Security Technologies\nFigure 1-8\nTunnel and Transport Mode Example\nSSL VPNs\nSSL-based VPNs are in high demand today. SSL is a matured protocol that has been in \nexistence since the early 1990s. SSL is also referred to as Transport Layer Security (TLS). \nThe Internet Engineering Task Force (IETF) created TLS to consolidate the different SSL \nvendor versions into a common and open standard.\nOne of the most popular features of SSL VPN is the ability to launch a browser like \nMicrosoft Internet Explorer and Firefox and simply connect to the address of the VPN \ndevice. In most implementations, a clientless solution is possible. Users can access \ncorporate intranet sites, portals, and e-mail from almost anywhere (even from an airport \nkiosk). Because most people allow SSL (TCP port 443) over their firewalls, it is unnecessary \nto open additional ports.\nFor more elaborate access to corporate resources, a lite-SSL client can be installed on a \nuser machine. Cisco supports both clientless SSL VPN (WebVPN) and a lite-client. The \nSSL VPN Client (SVC) gives remote users the benefits of an IPsec VPN client without \nthe need for network administrators to install and configure IPsec VPN clients on remote \ncomputers. The SVC uses the SSL encryption that is already present on the remote \ncomputer to authenticate to the VPN device. Cisco supports SSL VPN on the following \nproducts:\n•\nCisco ASA\n•\nCisco VPN 3000 series concentrators\n•\nCisco IOS routers\n•\nCisco WebVPN Services Module\nESP hdr\nIP hdr 3\nData\nTCP hdr\nIP Hdr 1\nData\nTCP hdr\nIP Hdr 1\nGRE hdr\nIP hdr 2\nData\nTCP hdr\nIP Hdr 1\nGRE hdr\nESP hdr\nIP hdr 2\nData\nTCP hdr\nIP Hdr 1\nGRE hdr\nIP hdr 2\nGRE Over IPsec\nTunnel Mode\nGRE Over IPsec\nTransport Mode\nGRE\nEncapsulation\nOriginal Packet\n"
        },
        {
            "page_number": 42,
            "text": "Intrusion Detection Systems (IDS) and Intrusion Prevention Systems (IPS)     19\nIntrusion Detection Systems (IDS) and Intrusion \nPrevention Systems (IPS)\nThis section includes an overview of intrusion detection systems (IDS) and intrusion \nprevention systems (IPS). IDSs are devices that detect (in promiscuous mode) attempts \nfrom an attacker to gain unauthorized access to a network or a host to create performance \ndegradation or to steal information. They also detect distributed denial of service (DDoS) \nattacks, worms, and virus outbreaks. IPS devices are capable of detecting all these security \nthreats; however, they are also able to drop noncompliant packets inline. Packets that do not \ncomply with security policies will not pass to the protected network. This is the major \ndifference between IDS and IPS systems. Figure 1-9 shows how an IDS device is \nconfigured to promiscuously detect security threats. \nFigure 1-9\nIDS Example\nIn Figure 1-9, an attacker sends a malicious packet to a web server. The IDS device analyzes \nthe packet and sends an alert to a monitoring system (CS-MARS in this example). The \nmalicious packet makes it to the web server. In contrast, Figure 1-10 shows how an IPS \ndevice is placed inline and drops the noncompliant packet, while sending an alert to the \nmonitoring system.\nFigure 1-10 IPS Example\nAlert!\nMARS\nWeb\nServer\nAttacker\nIDS\nAlert!\nCS-MARS\nWeb\nServer\nAttacker\nIPS\n"
        },
        {
            "page_number": 43,
            "text": "20\nChapter 1:  Overview of Network Security Technologies\nTwo different types of IPS exist:\n•\nNetwork-based (NIPS)\n•\nHost-based (HIPS)\nNOTE\nExamples of NIPSs are the Cisco IPS 4200 sensors, the Catalyst 6500 IPS Module, and the \nCisco ASA with the Advanced Inspection and Prevention Security Services Module \n(AIP-SSM).An example of a host-based IPS is CSA. More details and recommendation on \nhow to protect your network with IPS devices are covered in Chapter 2. \nNetwork-based IDS and IPS use several detection methodologies, such as the following:\n•\nPattern matching and stateful pattern-matching recognition\n•\nProtocol analysis\n•\nHeuristic-based analysis\n•\nAnomaly-based analysis\nPattern Matching\nPattern matching is a methodology in which the intrusion detection device searches for a \nfixed sequence of bytes within the packets traversing the network. Generally, the pattern is \naligned with a packet that is related to a respective service or, in particular, associated with \na source and destination port. This approach reduces the amount of inspection made on \nevery packet. However, it is limited to services and protocols that are associated with well-\ndefined ports. Protocols that do not use Layer 4 port information are not categorized. This \ntactic uses the concept of signatures. A signature is a set of conditions that point out some \ntype of intrusion occurrence. For example, if a specific TCP packet has a destination port \nof 1234, and its payload contains the string “ff11ff22,” an alert is triggered to detect such a \nstring. Alternatively, the signature might include an explicit starting point and endpoint for \ninspection within the specific packet.\nTIP\nOne of the main disadvantages of pattern matching is that it can lead to a considerably high \nrate of false positives. False positives are alerts that do not represent a genuine malicious \nactivity. In contrast, any alterations to the attack can lead to overlooked events of real \nattacks, which are normally referred to as false negatives.\nA more refined method was created to address some of these limitations. This methodology \nis called stateful pattern-matching recognition, which dictates that systems performing this \ntype of signature analysis must consider the chronological order of packets in a TCP stream. \nIn particular, they should judge and maintain a stateful inspection of such packets and flows.\n"
        },
        {
            "page_number": 44,
            "text": "Intrusion Detection Systems (IDS) and Intrusion Prevention Systems (IPS)     21\nProtocol Analysis\nProtocol analysis (or protocol decode-base signatures) is referred to as the extension to \nstateful pattern recognition. A network-based IDS accomplishes protocol analysis by \ndecoding all protocol or client-server conversations. The NIDS identifies the elements of \nthe protocol and analyzes them while looking for an infringement. Some intrusion detection \nsystems look at explicit protocol fields within the inspected packets. Others require more \nsophisticated techniques, such as examination of the length of a field within the protocol or \nthe number of arguments. For example, in Simple Mail Transfer Protocol (SMTP), the \ndevice may look at specific commands and fields such as HELO, MAIL, RCPT, DATA,\nRSET, NOOP, and QUIT. This technique diminishes the possibility of encountering false \npositives if the protocol being analyzed is properly defined and enforced. On the other hand, \nthe system can alert numerous false positives if the protocol definition is ambiguous or \ntolerates flexibility in its implementation.\nHeuristic-Based Analysis\nA different approach to network intrusion detection is to perform heuristic-based analysis.\nHeuristic scanning uses algorithmic logic from statistical analysis of the traffic passing \nthrough the network. Its tasks are CPU and resource intensive. This is an important \nconsideration while planning your deployment. Heuristic-based algorithms may require \nfine tuning to adapt to network traffic and minimize the possibility of false positives. For \nexample, a system signature can generate an alarm if a range of ports is scanned on a \nparticular host or network. The signature can also be orchestrated to restrict itself from \nspecific types of packets (for example, TCP SYN packets). \nAnomaly-Based Analysis\nA different practice keeps track of network traffic that diverges from “normal” behavioral \npatterns. This practice is called anomaly-based analysis. You must define what is \nconsidered to be normal behavior. Systems and applications whose behavior can be easily \nconsidered normal could be classified as heuristic-based systems. However, sometimes it \nis challenging to classify a specific behavior as normal or abnormal based on different \nfactors. These factors include negotiated protocols and ports, specific application changes, \nand changes in the architecture of the network.\nA variation of this type of analysis is profile-based detection. This allows systems to \norchestrate their alarms on alterations in the way that other systems or end users interrelate \non the network.\nAnother kind of anomaly-based detection is protocol-based detection. This scheme is \nrelated to, but not to be confused with, the protocol-decode method. The protocol-based \ndetection technique depends on well-defined protocols because it detects as an anomaly any \nunpredicted value or configuration within a field in the respective protocol.\nMore sophisticated anomaly detection techniques exist. These are described in the next \nsection.\n"
        },
        {
            "page_number": 45,
            "text": "22\nChapter 1:  Overview of Network Security Technologies\nAnomaly Detection Systems\nIDS and IPS provide excellent application layer attack-detection capabilities. However, \nthey do have a weakness—they cannot detect DDoS attacks using valid packets. IDS and \nIPS devices are optimized for signature-based application layer attack detection. Most of \nthem do not provide day-zero protection.\nNOTE\nAlthough some IPS devices do offer anomaly-based capabilities, which are required \nto detect such attacks, they require extensive manual tuning by experts and do not \nidentify the specific attack flows. Cisco IPS Software Version 6.x and later support \nmore sophisticated anomaly detection techniques. More information can be obtained at \nhttp://www.cisco.com/go/ips. \nYou can use anomaly-based detection systems to mitigate DDoS attacks and day-zero \noutbreaks. Typically, an anomaly detection system monitors network traffic and alerts or \nreacts to any sudden increase in traffic and any other anomalies. Cisco delivers a complete \nDDoS protection solution based on the principles of detection, diversion, verification, and \nforwarding to help ensure total protection. Examples of sophisticated anomaly detection \nsystems are the Cisco Traffic Anomaly Detectors and the Cisco Guard DDoS Mitigation \nAppliances.\nYou can also use NetFlow as an anomaly detection tool. NetFlow is a Cisco technology that \nsupports monitoring of network traffic. The beauty of NetFlow is that it is free with any \nlicensed Cisco IOS image. \nNOTE\nRefer to the Cisco feature navigator to find out in what Cisco IOS image NetFlow is \nsupported. You can access this tool at http://tools.cisco.com/ITDIT/CFN/jsp/index.jsp.\nNetFlow uses a UDP-based protocol to periodically report on flows seen by the Cisco IOS \ndevice. A flow is a Layer 7 concept that consists of session setup, data transfer, and session \nteardown. You can also integrate NetFlow with Cisco Secure Monitoring and Response \nSystem (CS-MARS). When NetFlow is integrated with CS-MARS, you can take advantage \nof anomaly detection using statistical profiling, which can pinpoint day-zero attacks such \nas worm outbreaks.\nNOTE\nChapter 3, “Identifying and Classifying Security Threats,” provides more information on \nhow to identify security threats using anomaly detection systems.\n"
        },
        {
            "page_number": 46,
            "text": "Authentication, Authorization, and Accounting (AAA) and Identity Management     23\nAuthentication, Authorization, and Accounting (AAA) \nand Identity Management\nAAA offers different solutions that provide access control to network resources. This \nsection introduces AAA and identity management concepts.\nAuthentication is the process of validating users based on their identity and predetermined \ncredentials, such as passwords and other mechanisms like digital certificates. \nAuthentication is widely used in many different applications, from a user attempting to log \nin to the network, web server, and wireless access point to an administrator logging in to a \nfirewall, router, or any other network device to successfully configure the former.\nThe authentication concept is simple. Before you can withdraw money from your favorite \nbank, the teller asks for your credentials (driver's license, account number, and so on). \nSimilarly, networking devices, servers, and other systems can ask you for credentials such \nas passwords and digital certificates for you to obtain access to the network or any other \nresources.\nAuthorization is the method by which a network device assembles a set of attributes that \nregulates what tasks the user is authorized to perform. These attributes are measured against \na user database. The results are returned to the network device to determine the user \nqualifications and restrictions. \nAccounting is the process of gathering and sending user information to an AAA server used \nto track login times (when the user logged in and logged off) and the services that users \naccess. This information can be used for billing, auditing, and reporting purposes. \nTwo common AAA protocols are used in networking today:\n•\nRemote Authentication Dial-in User Service (RADIUS) \n•\nTerminal Access Controller Access Control System Plus (TACACS+)\nRADIUS\nRADIUS is a widely implemented authentication standard protocol that is defined in RFC \n2865. RADIUS operates in a client/server model. A RADIUS client is usually referred to \nas a network access server (NAS). A NAS is responsible for passing user information to the \nRADIUS server. Network devices such as routers, firewalls, and switches can act as a NAS \nand authenticate users based on the RADIUS server response.\nCisco develops and sells a RADIUS and TACACS+ server called Cisco Secure Access \nControl Server (ACS). Cisco Secure ACS supports a rich set of AAA features and \napplications. These advanced features include the following:\n•\nLightweight Directory Access Protocol (LDAP) and Open Database Connectivity \n(ODBC) user authentication support \n"
        },
        {
            "page_number": 47,
            "text": "24\nChapter 1:  Overview of Network Security Technologies\n•\nFlexible 802.1X authentication type support, including Extensible Authentication \nProtocol Transport Layer Security (EAP-TLS), Protected EAP (PEAP), EAP-Flexible \nAuthentication via Secure Tunneling (EAP-FAST), and EAP-Message Digest \nAlgorithm 5 (EAP-MD5) and other protocols\n•\nTimed-based access \n•\nDownloadable for any Layer 3 device, including Cisco routers, Cisco PIX firewalls, \nCisco ASA, and Cisco VPNs \n•\nDevice command authorization \n•\nAdvanced database synchronization and replication features\n•\nNetwork access restrictions \n•\nDetailed reporting and accounting capabilities\n•\nUser and device group profiles\nNOTE\nFor more information about Cisco Secure ACS, go to http://www.cisco.com/go/acs.\nFigure 1-11 illustrates the basic RADIUS authentication process.\nFigure 1-11 RADIUS Authentication Process\nThe following are the steps illustrated in Figure 1-11.\nStep 1\nAn access-request is sent from the AAA client (a router in this example) \nto the RADIUS server.\nAAA Client\nRADIUS Server\n1\nAccess–Request\n3\nAccounting Request (Start)\n5\nAccounting Request (Stop)\n2\nAccess–Accept (With Authorization Attributes)\n4\nAccounting Response to Client\n6\nAccounting Response to Client\n"
        },
        {
            "page_number": 48,
            "text": "Authentication, Authorization, and Accounting (AAA) and Identity Management     25\nStep 2\nIf the user is successfully authenticated, an access-accept is sent from the \nRADIUS server to the AAA client. This access-accept packet can contain \nauthorization attributes if authorization is enabled. If the user is not \nsuccessfully authenticated, an access-reject is sent instead.\nStep 3\nAn accounting request (start) message is sent from the AAA client (if \nconfigured to do accounting) to the RADIUS server.\nStep 4\nIf the RADIUS server is configured for accounting, it replies with an \nacknowledgement.\nStep 5\nAt the end of the user session, an accounting request (stop) message is sent \nfrom the AAA client (if configured to do accounting) to the RADIUS server.\nStep 6\nIf the RADIUS server is configured for accounting, it replies with an \nacknowledgement.\nThis exchange is done over UDP. Older implementations of RADIUS use UDP port 1645 \nfor authentication and UDP port 1646 for accounting. The newer implementations use UDP \nport 1812 for authentication and UDP port 1813 for accounting.\nNOTE\nA RADIUS server can also send IETF or vendor-specific attributes to the AAA client \ndepending on the implementation and services used. These attributes can contain \ninformation such as an IP address to assign the client and authorization information. \nRADIUS servers combine authentication and authorization phases into a single request and \nresponse communication cycle.\nTACACS+\nTACACS+ is an AAA security protocol developed by Cisco that provides centralized \nvalidation of users who are attempting to gain access to network access devices. The \nTACACS+ protocol offers support for separate and modular AAA facilities. The primary \ngoal of the TACACS+ protocol is to supply complete AAA support for managing multiple \nnetwork devices. Unlike RADIUS, TACACS+ uses TCP port 49 by default instead of UDP \nfor its communications. However, it can allow vendors to use UDP. Cisco products use the \nTCP version for their TACACS+ implementation. The TACACS+ authentication concept is \nsimilar to RADIUS. The NAS sends an authentication request to the TACACS+ server, \nwhich in turn sends any of the following messages back to the NAS:\n•\nACCEPT: The user has been successfully authenticated and the requested service will \nbe allowed. If authorization is required, the authorization process will begin at this point.\n•\nREJECT: User authentication was denied. The user may be prompted to retry \nauthentication depending on the TACACS+ server and NAS.\n"
        },
        {
            "page_number": 49,
            "text": "26\nChapter 1:  Overview of Network Security Technologies\n•\nERROR: An error took place during authentication. This can be happen because of \nnetwork connectivity problems or a configuration error.\n•\nCONTINUE: The user is prompted to provide further authentication information.\nAfter the authentication process is complete, if authorization is required, the TACACS+ \nserver proceeds with the authorization phase. The user must first successfully be \nauthenticated before proceeding to TACACS+ authorization.\nAs an industry standard, RADIUS is a more widely deployed protocol than TACACS+.\nIdentity Management Concepts\nMany identity management solutions and systems automatically manage user access privileges \nwithin an organization. Today, enterprises are under great pressure to increase security and\nmeet regulatory and governance requirements, resulting in greater urgency to deploy \nidentity management solutions. Role-based authentication is a key concept of identity \nmanagement. It helps to answer the critical compliance questions of “Who has access to what, \nwhen, how, and why?” For example, with role-based authentication, a contractor logging in to \nthe network can access only the resources he should have access to. Based on his role and \nauthorization parameters, he can be restricted from accessing critical financial information.\nIEEE 802.1X is a standard that defines the encapsulation methodologies for the transport \nof EAP over any PPP or Ethernet media. 802.1X allows you to enforce port-based network \naccess control when devices attempt to access the network. The 802.1x standard has three \ncomponents:\n•\nSupplicant\n•\nAuthenticator\n•\nAuthentication server\nThe supplicant is the software that resides on the end-user machine. The authenticator\n(typically a switch or wireless access point) relays the EAP information from the supplicant \nto an authentication server via the RADIUS protocol.\nCisco has a comprehensive identity management solution based on 802.1x called Identity-\nBased Networking Services (IBNS). IBNS is an integrated solution that uses Cisco \nproducts which offer authentication, access control, and user policies to secure network \nconnectivity and resources. These products include the following:\n•\nCisco Catalyst family of switches\n•\nWireless LAN access points and controllers\n•\nCisco Secure ACS\n•\nCisco Secure Services Client\nAdditional and optional components include X.509 public key infrastructure (PKI) \ncertificate architecture. \n"
        },
        {
            "page_number": 50,
            "text": "Network Admission Control     27\nNOTE\nYou can find detailed IBNS information including configuration and deployment guidelines \nat http://www.cisco.com/go/ibns.\nInformation on how the IBNS and 802.1x solution is integrated into Cisco NAC is covered \nin the following section.\nNetwork Admission Control\nNetwork Admission Control is a multipart solution that validates the security posture of an \nendpoint system before entering the network. With NAC, you can also define what \nresources the endpoint has access to, based on the results of its security posture. NAC is a \nkey part of the Cisco Self-Defending Network Initiative (SDNI). The SDNI mission is to \ndramatically improve the ability of the network to identify, prevent, and adapt to threats. \nNAC comes in two flavors:\n•\nNAC Appliance: Based on the Cisco Clean Access (CCA)\n•\nNAC Framework: A Cisco-sponsored industry wide initiative\nNAC Appliance\nNAC Appliance or Cisco Clean Access (CCA) enables an organization to enforce security \npolicies by blocking, quarantining, and performing remediation of noncompliant systems. \nRemediation occurs at the discretion of the administrator. The policies and requirements \nenforced by NAC Appliance include checks for latest antivirus software, operating system \n(OS) patches and security patches. NAC Appliance can also perform vulnerability scanning \non the end-user machine in addition to role-based authentication on users attempting to \nconnect to the network. The NAC Appliance solution can restrict what resources these users \ncan access, based on their role. All these policies and configurations are done in the Clean \nAccess Manager (CAM).\nThe Cisco NAC Appliance has three major components:\n•\nClean Access Server (CAS): Acts as a network control device\n•\nClean Access Manager (CAM): Manages one or more servers\n•\nClean Access Agent (optional): Serves as an end-point lightweight client for device-\nbased registry scans in unmanaged environments\nThe CAM can manage up to 40 CASs depending on the license and is licensed based on \nthe number of CASs it supports. The CAS supports up to 1500 users depending on the \nlicense that is installed. The CAS license is based on the concurrent number of clients/users \nit supports.\n"
        },
        {
            "page_number": 51,
            "text": "28\nChapter 1:  Overview of Network Security Technologies\nNOTE\nFor more information about the NAC Appliance licensing, visit http://www.cisco.com/en/\nUS/products/ps6128/prod_pre_installation_guide09186a008073136b.html.\nCAS can be deployed in in-band (IB) or out-of-band (OOB) modes. CASs can pass traffic \nin one of two ways:\n•\nBridged mode: Typically called Virtual Gateway mode\n•\nRouted mode: In Real IP Gateway or NAT Gateway configurations\nNOTE\nYou can configure the CASs in either mode, but only in one mode at a time. For example, \nif you configure a CAS in Virtual Gateway configuration, you cannot also configure \nit as a Real IP Gateway. This is because the mode selection affects the logical traffic \npath.\nFigure 1-12 illustrates a CAS configured in Virtual Gateway mode. In this example, the \nunprotected (untrusted) segment is VLAN 110 and the protected (trusted) network is \nVLAN 10.\nFigure 1-12 CAS in Virtual Gateway Mode\nRouter\n10.10.10.1/24\nCAS in Virtual Gateway\nInline Mode\nSwitch\nDHCP Client\n10.10.10.55/24\nVLAN 110\nVLAN 10\nVLAN 110\n"
        },
        {
            "page_number": 52,
            "text": "Network Admission Control     29\nThe client workstation has an IP address on the same subnet/range of the trusted network \n(10.10.10.0/24). In Virtual Gateway mode, the CAS acts as a bridge. DHCP client routes \npoint directly to network devices on the protected network.\nFigure 1-13 shows a CAS configured in Real IP mode.\nFigure 1-13 CAS in Real IP Mode\nIn Real IP mode, the CAS acts as a Layer 3 router. In this example, the CAS trusted and \nuntrusted interfaces are in different subnets. The trusted subnet is 10.10.10.0/24, and the \nuntrusted subnet is 192.168.10.0/24. In Real IP mode, DHCP clients usually point to the \nCAS to obtain their IP addresses and other DHCP information. It is a best practice to assign \na 30-bit address to the DHCP clients. This enables you to isolate machines that can be \ninfected with a virus and block them from infecting other machines in the network.\nNOTE\nThe CAS can optionally be configured to translate the trusted network.\nIn summary, the NAC Appliance can operate in in-band (IB) or out-of-band (OOB) modes: \n•\nIB Virtual Gateway (L2 transparent bridge mode): Acts as a bridge between the \nuntrusted and trusted networks.\n•\nIB Real-IP Gateway: Operates as the default gateway for the untrusted network.\n•\nIB NAT Gateway (used for testing only): Acts as an IP router/default gateway and \ntranslates (NAT) the untrusted network.\nRouter\n10.10.10.1/24\nTrusted side IP address\n10.10.10.100/24\nCAS in Real IP Mode\nUntrusted side IP address\n192.168.10.100/24\nSwitch\nDHCP Client\n192.168.10.123/24\nVLAN 110\nVLAN 10\nVLAN 110\n"
        },
        {
            "page_number": 53,
            "text": "30\nChapter 1:  Overview of Network Security Technologies\n•\nOOB Virtual Gateway (L2 transparent bridge mode): Initially acts as a virtual \ngateway during authentication and certification, before the user is switched out-of-band.\n•\nOOB Real-IP Gateway: Initially acts as a Real-IP gateway during authentication and \ncertification, before the user is switched out-of-band. (That is, the user is connected \ndirectly to the access network.)\n•\nOOB NAT Gateway (used for testing only): Acts as a NAT gateway during \nauthentication and certification, before the user is switched out-of-band.\nYou can deploy CASs in three physical deployment modes:\n•\nEdge deployment\n•\nCentralized deployment\n•\nCentralized edge deployment\nNOTE\nThe physical deployment method does not affect whether a CAS is in Layer 2 (bridged), \nLayer 3 (routed), IB, or OOB mode.\nFigure 1-14 illustrates a NAC Appliance edge deployment. In this example, the untrusted \ninterface is connected to VLAN 110, and the trusted interface is connected to VLAN 10. \nThe CAM resides on the management segment (VLAN 123). In this example, the CAS is \nconfigured in Virtual Gateway mode and is mapping VLAN 10 with VLAN 110.\nFigure 1-14 NAC Appliance Edge Deployment\nRouter\nSW1\nCAM\nCAS\nEdge Deployment\nClient\nVLAN 123\nVLAN 10\nVLAN 110\nVLAN 110\n"
        },
        {
            "page_number": 54,
            "text": "Network Admission Control     31\nFigure 1-15 illustrates a NAC Appliance centralized deployment. In this example, both the \nCAS trusted and untrusted interfaces are physically connected to the central switch (SW1). \nThe switch is configured with several VLANs. The untrusted VLAN is VLAN 110, the \ntrusted VLAN is VLAN 10, and the management VLAN is VLAN 123.\nFigure 1-15 NAC Appliance Centralized Deployment\nThe NAC Appliance centralized deployments are the most common deployment option, \nbecause they are better suited for scalability in medium-to-large environments. In this \nexample, the CAS is logically, not physically, in-line. \nThe NAC Appliance solution supports failover for high-availability. You can deploy the \nCAM and CAS in failover pairs, as illustrated in Figure 1-16.\nThe example shown in Figure 1-16 includes two CAMs (CAM-1 and CAM-2). CAM-1 is \nthe primary (active) manager, and CAM-2 is configured in standby mode. If CAM-1 fails, \nCAM-2 takes over. In Figure 1-16, a total of four CASs are deployed: two active and two \nin standby. For scalability reasons, CAS-1 is performing posture validation for clients on \nthe first three untrusted VLANs (VLAN 110, 111, and 112). The CAS-2 is enforcing \nposture validation on the last three untrusted VLANs (VLAN 113, 114, and 115). If CAS-1 \nfails, CAS-3 will take over, and if CAS-2 fails, CAS-4 will take over.\nRouter\nSW1\nCAM\nCAS\nCentralized\nDeployment\nClient\nVLAN 123\nVLAN 10\nVLAN 110\nVLAN 110\nVLAN 110\n"
        },
        {
            "page_number": 55,
            "text": "32\nChapter 1:  Overview of Network Security Technologies\nFigure 1-16 NAC Appliance High Availability\nNOTE\nActive-active failover configuration is not currently supported.\nIn most scenarios, a combination of different CAS deployment strategies are used. These \nare examples of the most common deployment types:\n•\nLayer 2 IB for wireless environments\n•\nLayer 3 or Layer 2 IB for remote access VPN\n•\nLayer 2 OOB for campus LAN deployments\nCAS-3\n(Standby)\nCAM-2\n(Standby)\nCAS-4\n(Standby)\nCAS-1\n(Active)\nCAM-1\n(Active)\nCAS-2\n(Active)\nSi\nSi\nVLAN 900\nVLAN 110\nVLAN 111\nVLAN 112\nVLAN 113\nVLAN 114\nVLAN 115\nVLANs 10, 11, 12\nVLANs 110, 111, 112\nVLANs 13, 14, 15\nVLANs 113, 114, 115\nVLANs 10, 11, 12\nVLANs 110, 111, 112\nVLANs 13, 14, 15\nVLANs 113, 114, 115\n"
        },
        {
            "page_number": 56,
            "text": "Network Admission Control     33\nNOTE\nThis chapter introduces the basics of the NAC Appliance solution. For information \nabout the configuration and troubleshooting of NAC Appliance, go to \nhttp://www.cisco.com/go/cca. Chapter 2 demonstrates how to deploy NAC Appliance \nto provide posture validations while preparing your network and infrastructure to \nself-protect against security threats.\nNAC Framework\nNAC Framework is a Cisco-led industry initiative to provide posture validation using \nembedded software in Cisco network access devices (NAD) such as routers, switches, \nVPN concentrators, Cisco ASA, wireless access points, and others. Many vendors are \npart of the Cisco NAC program. These Cisco partners include antivirus software vendors, \nremediation and patch management companies, identity software manufacturers, and \nothers.\nNOTE\nTo obtain the latest list of NAC program vendors/partners, go to http://www.cisco.com/go/\nnac and click on NAC program.\nSimilar to NAC Appliance, NAC Framework has three basic components:\n•\nNAC Agent\n•\nNAD\n•\nPolicy Server (Cisco Secure ACS or NAC Manager)\nOptionally, you can use other vendor products such as external policy servers, remediation \nservers, and audit servers to provide more comprehensive admission control features. The \nNADs enforce policies configured in a centralized manager, while relaying the security \ncredentials/information presented by the end-host NAC Agent. NAC Framework supports \nfour different mechanisms when performing security posture validation on end-host \nmachines:\n•\nNAC Layer 3 IP: Uses EAP over UDP (EoU) and is typically deployed in Cisco IOS \nrouters, Cisco ASA, and VPN 3000 concentrators.\n•\nNAC Layer 2 IP: Uses EoU and is typically deployed in Cisco Catalyst switches. \nAddress Resolution Protocol (ARP) and DHCP are the trigger mechanisms.\n•\nNAC Layer 2 802.1x: Combines the traditional IBNS identity features and services \nwith in-depth security posture validation.\n"
        },
        {
            "page_number": 57,
            "text": "34\nChapter 1:  Overview of Network Security Technologies\nThe basic diagram shown in Figure 1-17 illustrates the NAC Framework from a high-\nlevel view.\nFigure 1-17 NAC Framework High-Level Overview\nThe following steps are illustrated in Figure 1-17:\nStep 1\nThe NAD (a switch in this example) challenges the end-host to present \nits credentials. This is done via EoU or EAP over 802.1x.\nStep 2\nThe NAD forwards the end-host credentials to the NAC Manager (Cisco \nSecure ACS server in this example) using the EAP protocol over \nRADIUS.\nStep 3\nOptionally, the Cisco Secure ACS forwards user or machine credentials \nto an external vendor server. This server can be an antivirus vendor \nserver, authentication server, or any other external policy server. The \nvendor server replies to the Cisco Secure ACS with a token, based on the \nposture results for the end-host that is attempting to connect to the \nnetwork.\nStep 4\nThe Cisco Secure ACS receives the token or checks its internal policies.\nStep 5\nThe Cisco Secure ACS sends the posture information to the NAD. \nSubsequently, the NAD enforces policies based on the posture of the end-\nhost device.\nVendor Server\nCisco Secure ACS\nCatalyst Switch\nHost with\nNAC Agent\n5\nEAP Over RADIUS\n1\nEAP Over UDP or\nEAP Over 802.1x\n2\n4\nEAP Over RADIUS\n3\nHCAP\n"
        },
        {
            "page_number": 58,
            "text": "Network Admission Control     35\nNOTE\nThe NAD periodically polls the end-hosts to determine if a change has been made in their \nposture. The NAC Agent alerts the NAD of any changes on the client machine. The NAD \nuses this information to issue full revalidation and posture assessment. This mechanism \nprevents hosts from being validated but not checked if their security posture has changed \nafter they have been granted access to the network. \nNAC Agentless Hosts (NAH) are devices on which the Cisco NAC Agent has not been \ninstalled. These devices can be printers, IP Phones, scanners, and other systems such as \ncontractor and guest workstations. If a device does not have the NAC Agent, it cannot \nrespond to the EoU or 802.1x request from the NAD. Separate policies can be configured \non the NAD to exclude the NAH MAC or IP address, or a range of addresses. In addition, \na global policy can be configured on Cisco Secure ACS.\nCisco developed a protocol called Generic Authorization Message Exchange (GAME). \nThird-party audit servers use this protocol to communicate with Cisco Secure ACS when \nperforming elaborate scans and audits on NAC nonresponsive hosts. An example of an audit \nserver vendor is Qualys. Cisco Secure ACS is responsible for triggering the audit process \nfor nonresponsive hosts with the audit server. Audit servers can scan the nonresponsive \ndevice for known threats and vulnerabilities to further determine their security posture.\nNOTE\nFor more information about the Cisco-Qualys NAC solution, go to http://www.cisco.com/\nweb/partners/downloads/partner/WWChannels/programs/nac_qualys_sol_guide.pdf or to \nthe Qualys website at http://www.qualys.com/products/qgent/integrations/nac/.\nIt is recommended that you use an event correlation and reporting system, such as \nCS-MARS, in conjunction with NAC. The process of collecting, correlating, \ntroubleshooting, and trending NAC event information enables you to make necessary \nreal-time corrections and ongoing improvements to the security posture of your end-host \ndevices. This subsequently decreases the risk of known and unknown security threats in \nyour organization.\n"
        },
        {
            "page_number": 59,
            "text": "36\nChapter 1:  Overview of Network Security Technologies\nNOTE\nThis chapter introduces the basics of the NAC Framework solution. For information about \nthe detailed deployment, configuration, and troubleshooting, refer to the Cisco Press books \ntitled Cisco Network Admission Control, Volume I: NAC Framework Architecture and \nDesign and Cisco Network Admission Control, Volume II: NAC Deployment and \nTroubleshooting.\nChapter 2 demonstrates how to deploy NAC Framework to provide posture validations \nwhile preparing your network and infrastructure to self-protect against security threats.\nRouting Mechanisms as Security Tools\nMany people do not realize that routing is one of the most powerful security tools available. \nSeveral routing techniques help identify, classify, and mitigate security threats. Examples \ninclude remotely triggered black holes (RTBH) and sinkholes.\nRTBH is a filtering technique that provides the ability to drop malicious traffic before it \npenetrates your network. Historically, RTBH has been a tool that many service providers \nhave used to mitigate DDoS attacks. Many other organizations are now adopting RTBH. \nIn technical terms, a typical RTBH deployment requires running internal Border Gateway \nProtocol (iBGP) at the access and choke points and configuring a separate router \nstrategically placed in the network to act as a trigger. This triggering router injects iBGP \nupdates to the edge, causing the specified traffic to be sent to a null0 interface and \nsubsequently be dropped. RTBH is highly scalable; therefore, it is primarily designed to \nmitigate against DDoS and worm outbreaks. \nNOTE\nChapter 2 describes RTBH benefits, operational gains, deployment considerations, and \nsample router configurations.\nA sinkhole, in some cases, is just a router used to redirect malicious traffic to a single IP \naddress where it can be scrutinized in greater detail. In other cases, it is just a segment \n(place or interface) within the network where this traffic is sent. Service providers initially \nimplemented this technique to identify hosts where an attack or worm traffic was being \ngenerated. As with RTBH, enterprises now apply sinkholes. Initially, configuring a sinkhole \n"
        },
        {
            "page_number": 60,
            "text": "Routing Mechanisms as Security Tools     37\nrouter assisted in detecting infected devices or attackers when network intrusion detection \nor prevention systems were not available or when there were other architectural constraints. \nToday, IDSs are being integrated with sinkholes to better identify and classify these threats, \nconsequently increasing infrastructure protection. \nHow do sinkhole routers work? A sinkhole router advertises IP addresses/networks not yet \nallocated by the Internet Assigned Numbers Authority (IANA). These addresses are \nreferred to as bogon and dark IP addresses.\nNOTE\nYou can find detailed information about bogon addresses at http://www.iana.org.\nSome worms and attackers accidentally attempt to exploit these bogon addresses, which are \nadvertised only locally. When the sinkhole router receives this traffic, it can log and discard \nit. These logs provide a list of infected hosts or attackers. \nTIP\nIn enterprise environments, it is important to monitor dark IP address space instead of only \nbogon address space. In the future, you may see worms coded to ignore bogon addresses to \navoid detection.\nFigure 1-18 shows how to deploy a sinkhole router within an enterprise network. \nIn Figure 1-18, the host on the left is infected with a worm and is attacking and attempting \nto compromise the user machines. The traffic destined for both bogon addresses and the \ndark IP address space are inspected by the sinkhole alerting the administrator of this \nanomaly. You can integrate elaborate tools with sinkholes to easily detect these types of \nthreats.\nNOTE\nChapter 2 details the use of sinkholes as part of the preparation phase of the six-step \nmethodology of incident readiness and response.\n"
        },
        {
            "page_number": 61,
            "text": "38\nChapter 1:  Overview of Network Security Technologies\nFigure 1-18 Sinkhole Deployment Example\nSi\nSi\nInternet\nInfected\nHost\nSink Hole\nRouter\nUsers\n"
        },
        {
            "page_number": 62,
            "text": "Summary     39\nSummary\nThis chapter introduced a range of security technologies and products to help you \nunderstand the best practices and methodologies you will learn in later chapters. It \npresented an overview of how to place firewalls to provide perimeter security and network \nsegmentation while enforcing configured policies. This chapter also gave an overview of \nVPN technologies and protocols. It covered IPsec and its related protocols in detail to \nenhance the learning. It also presented an overview of SSL VPNs and their uses. \nIDS and IPS systems can aid in identifying and classifying security threats within your \nnetwork. This chapter covered an overview and the differences between IDS and IPS \ntechnologies. Beyond IDS and IPS, anomaly detection systems help you react to day-zero \noutbreaks. This chapter also helps you understand the concept and technologies of anomaly \ndetection systems.\nAAA offers different solutions that provide access control to network resources. This \nchapter introduced AAA and identity management concepts. It included an overview of the \nCisco Network Admission Control solutions used to enforce security policy compliance on \nall devices seeking to access network computing resources, thereby limiting damage from \nemerging security threats.\nYou can use routing techniques as security tools. This chapter gave you an example of \ndifferent routing techniques such as RTBH and sinkholes that you can use to increase the \nsecurity of the network and to react to new threats.\n"
        },
        {
            "page_number": 63,
            "text": ""
        },
        {
            "page_number": 64,
            "text": "P A R T II\nSecurity Lifestyle: Frameworks \nand Methodologies \nChapter 2\nPreparation Phase\nChapter 3\nIdentifying and Classifying Security Threats\nChapter 4\nTraceback\nChapter 5\nReacting to Security Incidents \nChapter 6\nPost-Mortem and Improvements\nChapter 7\nProactive Security Framework\n"
        },
        {
            "page_number": 65,
            "text": "This chapter covers the following topics:\n•\nRisk Analysis\n•\nSocial Engineering\n•\nSecurity Intelligence\n•\nCreating a Computer Security Incident Response Team (CSIRT)\n•\nBuilding Strong Security Policies\n•\nInfrastructure Protection\n•\nEndpoint Security\n•\nNetwork Admission Control \n"
        },
        {
            "page_number": 66,
            "text": "C H A P T E R 2\nPreparation Phase\nWhile computer networks and sophisticated applications have allowed individuals to be \nmore productive, the need to prepare for security threats has increased dramatically. \nGuarding against security threats includes preparing the infrastructure to protect not only \nagainst worms, viruses, and external denial of service (DoS) attacks, but also from internal \nthreats such as theft of information and corporate espionage.\nA six-step methodology on security incident handling has been adopted by many \norganizations, including service providers, enterprises, and government organizations. This \nmethodology is composed of the following steps:\n•\nPreparation\n•\nIdentification\n•\nClassification\n•\nTraceback\n•\nReaction\n•\nPostmortem\nThis chapter covers the first and most crucial step in this methodology—the preparation \nphase.\n Risk Analysis\nRisk analysis is crucial. You need to know what you are protecting and how you are \nprotecting it. What are your critical systems and assets? What constitutes your organization \ntoday? These are some initial questions you should ask yourself when starting any risk \nanalysis process. You must know the difference between threats and vulnerabilities. Threats\nare occurrences that can affect a system or an organization as a whole. Examples of threats \ninclude fraud, theft of information, and physical theft. Vulnerabilities are flaws that make a \nsystem, an individual, or an organization exposed and susceptible to a threat or an attack.\nOn several occasions, when you ask security engineers, managers, architects, and executives \nto list or describe the critical systems of their organization their answers are contradictory. \nOne of the main goals that members of an organization should have is to understand their \nenvironment and what they are trying to protect and what risks are most imminent. \n"
        },
        {
            "page_number": 67,
            "text": "44\nChapter 2:  Preparation Phase\nSeveral methods of risk analysis have been published in books, websites, magazines, and \nblogs. Some take the quantitative approach; some take the qualitative approach; and others \nmeasure impact versus probability. This chapter does not favor one method over another but \ninstead presents several best practices when analyzing security risks.\nThreat Modeling\nThe primary goal of any threat modeling technique is to develop a formal process while \nidentifying, documenting, and mitigating security threats. This process has a huge impact \non any organization because it is basically a methodology used to understand how attacks \ncan take place and how they will impact the network, systems, and users.\nOrganizations have adopted several threat modeling techniques. For example, Microsoft \nuses the DREAD model. The DREAD acronym defines five key areas: \n•\nDamage potential\n•\nReproducibility\n•\nExploitability\n•\nAffected users\n•\nDiscoverability\nIn the DREAD model, the first step is to quantify or estimate the damage potential of a \nspecific threat. This estimate can include monetary and productivity costs followed by a \nprobability study on the reproducibility and exploitability of the vulnerability at hand. In \naddition, the first step should identify which users and systems will be affected and how \neasily the threat can be discovered and identified. \nNOTE\nYou can find more information about Microsoft threat modeling at \nhttp://msdn2.microsoft.com/en-us/security/aa570411.aspx.\nMicrosoft also has a threat modeling tool at \nhttp://msdn.microsoft.com/msdnmag/issues/03/11/resourcefile/default.aspx.\nAnother threat modeling technique is to create attack trees. Bruce Schneier, the chief \ntechnology officer of Counterpane Internet Security and the inventor of the Blowfish and \nTwo-fish encryption algorithms, initially introduced this method. Attack trees represent \nattacks against a system or network in a hierarchical tree structure. The root node describes \na goal, and the leaf nodes are various ways of reaching such a goal.\n"
        },
        {
            "page_number": 68,
            "text": "Risk Analysis\n45\nFor example, the main goal of a specific attack may be to interrupt the services of an \ne-commerce web server farm. This goal will be the root of the tree. Each subsequent “tree \nbranch or leaf” describes the methods used to take down that web server farm (that is, \nsending millions of spoofed TCP packets, compromising zombies on the Internet to launch \nDDoS attacks, and so on). \nNOTE\nA detailed white paper on attack tress by Bruce Schneier is posted at \nhttp://www.schneier.com/paper-attacktrees-ddj-ft.html.\nSeveral other threat modeling techniques suggest the use and understanding of system and \ndevice roles. Identify what the network devices do and how they are used and placed within \nthe infrastructure. Document and identify their functionality in the context of the \norganization as a whole; furthermore, configure them according to their role. For example, \nthe same configuration of Internet-edge routers is not suitable for data center devices. \nCreate easy-to-understand architecture diagrams that describe the composition and \nstructure of your infrastructure and its devices. Elaborate the diagram by adding details \nabout the trust boundaries, authentication, and authorization mechanisms.\nCisco has developed a methodology that goes beyond typical threat modeling techniques. \nThis methodology or framework is called the Cisco Operational Process Model (COPM). \nCOPM is a process model that was initially designed for service providers but has recently \nbeen adopted by many other organizations. This threat-mitigation practice goes beyond a \nsingle product or technology. The COPM framework helps you to prepare and anticipate \nthe lack of operational security expertise by minimizing threats that cannot be completely \ncontrolled while controlling those that can be. \nNOTE\nChapter 7, “Proactive Security Framework,” describes COPM in detail.\nCOPM focuses on both business and technology groups throughout an organization, while \nalso focusing on the availability and reliability of the infrastructure and its systems. \nTotal network visibility and complete control of elements is crucial to maintain services and \nbusiness continuity. COPM is designed to introduce flexibility while improving security \nwithout relying on a single technology or product. Multiple technologies and features are \nused throughout the network to obtain visibility into network behavior and to maintain \ncontrol during abnormal behavior.\nHow good is your network if you cannot manage it when an outbreak or attack is underway? \nVisibility is twofold. Network administrators should always have complete visibility of \nnetworking devices and the traffic within their infrastructure. At the same time, intruders \n"
        },
        {
            "page_number": 69,
            "text": "46\nChapter 2:  Preparation Phase\nmust not have visibility to unnecessary services or vulnerable systems that can be exploited \nwithin an organization. The following section describes how you can perform periodic \nsecurity penetration tests and audits to assess and evaluate the visibility of vulnerable \nsystems within the organization. The “Infrastructure Protection” section later in this chapter \ndescribes several techniques that you can use to maintain the visibility of devices and \nsystems within your infrastructure.\nPenetration Testing\nPenetration testing is often referred to as ethical hacking. Using this procedure, a trusted \nthird party or a security engineer of an organization attempts to compromise or break into \nthe network and its devices by scanning, simulating live attacks, and exploiting vulnerable \nmachines to measure the overall security posture. Penetration testing techniques are of \nthree common types:\n•\nBlack-box\n•\nWhite-box\n•\nGray or Crystal-box\nIn the black-box technique, the tester has no prior knowledge of the network of the \norganization. Typically, the organization only gives the tester information about a specific \nsystem or domain for the “externally attempted” hack. In the white-box technique, the \ntester has been given more information (that is, network diagrams, list of devices, and so \non) prior to starting the tests. The crystal-box test occurs when the tester is provided with \nan account on the internal network and standard access to the network. \nNOTE\nThis section describes and lists several tools that you can use to assess the security posture \nof an organization. However, it is strongly recommended that you do not use any of these \nif you are unsure of the complications and side effects they may have in your organization. \nOn many occasions, it is better to hire a third-party company to perform such tests. \nNumerous security tools are designed to automate and ease the penetration testing process. \nThese tools can be a combination of commercial vulnerability assessment tools and \nfree open-source tools. Professional ethical hackers also develop their own tools to \nautomate the test or to specifically test for new vulnerabilities. Commercial tools work \nby using sets of thousands of preset configurations or vulnerability tags (vuln-tags). Some \nof these commercial tools are focused on different areas (for example, web security, \nwireless security, and so on). Examples of commercial tools are Qualys Guard \n(http://www.qualys.com), and e-Eye Retina (http://www.eeye.com/html/index.html).\n"
        },
        {
            "page_number": 70,
            "text": "Risk Analysis\n47\nHundreds of open-source tools exist, ranging from meticulously developed and supported \ntools to small scripts developed to perform a specific task. Table 2-1 lists some of the most \ncommonly used open-source tools.\nYou can combine penetration testing with infrastructure device configuration audits to \nprovide a comprehensive study of the security posture of an organization. For instance, on \ncompletion of the penetration test, you have an understanding of the current vulnerable \nsystems within your organization. Even more, you have determined how visible these \nsystems are to a potential attacker. You can combine this information with an analysis of the \nconfiguration of your infrastructure components, such as routers and firewalls. \nTable 2-1\nCommon Open-Source Security Tools\nTool\nDescription\nWebsite\nMetasploit\nComprehensive set of penetration \ntesting and vulnerability \nassessment tools\nhttp://metasploit.org\nNmap\nScanner\nhttp://insecure.org/nmap\nCain and Abel\nPassword cracking\nhttp://www.oxid.it/cain.html\nJohn the Ripper\nPassword cracking\nhttp://www.openwall.com/john/\nAirCrack\nWEP/WPA cracking tool\nhttp://www.aircrack-ng.org/\ndoku.php\nAirSnort\n802.11 WEP encryption cracking \ntool\nhttp://airsnort.shmoo.com/\nNessus\n(Now commercial) network \nscanner\nhttp://www.nessus.org\nRainbow Crack\nPassword cracker\nhttp://www.antsight.com/zsl/\nrainbowcrack/\nSara\nVulnerability assessment tool\nhttp://www-arc.com/sara\nHPing2\nPacket crafter\nhttp://www.hping.org\nKismet\nWireless sniffer\nhttp://www.kismetwireless.net\nNetStumbler\nWindows-based wireless sniffer\nhttp://www.stumbler.net\nKisMAC\nMAC-based wireless sniffer\nhttp://kismac.de\nNikto\nWeb scanner\nhttp://www.cirt.net/code/\nnikto.shtml\nParos Proxy\nWeb vulnerability assessment \nproxy\nhttp://www.parosproxy.org\n"
        },
        {
            "page_number": 71,
            "text": "48\nChapter 2:  Preparation Phase\nNOTE\nSome commercial tools are designed to perform device configuration and firewall rule \nanalysis. Examples of these tools are the Cisco Configuration Assurance Solution (CCAS) \n(http://www.cisco.com/en/US/products/ps6364/prod_bulletin0900aecd802c8487.html), \nthe AlgoSec Firewall Analyzer (http://www.algosec.com), and Security Risk Auditor from \nRedseal Systems (http://www.redseal.net).\nCCAS automatically completes systematic audits of the production network configuration \nto detect device misconfigurations, policy violations, inefficiencies, and security gaps.\nCisco Advanced Services for Network Security group also provides comprehensive \nsecurity posture assessment services, including detailed network security architectural \nreviews. For more information, go to http://www.cisco.com/en/US/products/svcs/ps2961/\nps2952/serv_group_home.html.\nThe manual analysis of complex firewall policies is almost impossible because it is very \ntime-consuming. As a result, it is difficult to detect many risks. The use of automated tools \nor professional services is a must.\nTIP\nConduct penetration tests and network security architectural reviews periodically, because \nnew threats and vulnerabilities are introduced on a daily basis. Doing so allows you to \nmeasure the effectiveness of the methods used to improve the overall security after the \ninitial tests and architectural review. \nYou need to understand the confidentiality requirements and risks of these types of tests. To \nensure unbiased results, executives often hire third-party security professionals to perform \nhigh-level audits within the network and infrastructure readiness tests without telling their \nown security engineers and managers. The results of such tests are often kept a secret until \na contingency plan has been built. You also need to understand the ethics and laws \ngoverning these types of activities. If you are a security professional hired by an \norganization to perform these types of tests and reviews, going outside your contractual \nboundaries is not only unethical, but also illegal.\nNOTE\nThe Cisco Press book titled Penetration Testing and Network Defense by Andrew Whitaker \nand Daniel P. Newman covers all the best practices of penetration testing in detail.\n"
        },
        {
            "page_number": 72,
            "text": "Social Engineering     49\nSocial Engineering\nSocial engineering is one of the most dangerous risks that exist today. It goes beyond the \nmost rigid and sophisticated security products and infrastructure components. How good is \nit to have the most expensive and elaborate authentication system in the world if your \nemployee is going to give an outsider the password to access your network? The social \nengineering problem can only be solved with one of the most fundamental tools—\neducation.\nSome people say that social engineering comes in two types: technology based and human \nbased. An example of technology-based social engineering is the use of technical tools to \nfool users into providing sensitive information. Human-based social engineering is the \nmost dangerous of the two types. It can be accomplished through a simple phone call or by \nlistening to a conversation in a break room within your organization. The attacker can use \nhuman psychology to obtain sensitive information. For example, someone can call one of \nyour employees and try to obtain chunks of information that can be put together for further \nintrusion. An attacker can call one of your employees identifying himself as a security \nengineer who is performing a routine maintenance check on your system and ask for such \nsensitive information as IP addresses, gateways, and even passwords. Phishing is one of the \nmost common types of social engineering today. The most common targets are financial \ninstitutions and online service companies. Phishing itself is not new, but its frequency has \nincreased over the past few years. The typical phishing e-mail is the one claiming that your \nfinancial account information with a specific financial institution needs updating. The \ne-mail includes a link that sends you to a fake website where you are instructed to enter your \npassword to update your information.\nYou need to be aware of another not-so-sophisticated social engineering technique. This \none may include just a smile. Yes, a smile. Your organization may include the most colorful \nand elaborate badges for all employees, locked doors, and even security guards. However, \nemployees tend to hold doors open for those who follow them into the building, especially \nif they are smiling and look confident. When they let others in, employees seldom check the \nphotos of their IDs or whether they have an ID.\nEducation is one of the most fundamental safeguards and the most crucial in these types \nof scenarios and threats. Developing a good security awareness program is necessary \nfor an organization of any size. You can use several techniques to educate your users \n(from flyers and periodic e-mails to web-based training and video-on-demand that \nyour employees can view from anywhere anytime). This type of training should be \nmandatory.\nNOTE\nMore information on end-user security awareness is covered in the section titled “Building \nStrong Security Policies” later in this chapter.\n"
        },
        {
            "page_number": 73,
            "text": "50\nChapter 2:  Preparation Phase\nSecurity Intelligence\nAlways keep up-to-date by analyzing intelligence reports about current vulnerabilities \nand threats. In addition, try to educate yourself on advanced security topics to help you \nbetter protect your network and reduce organizational risks. You can obtain security \nintelligence reports and information about new threats from numerous sites, such as \nhttp://hackerwatch.org, http://www.cert.org, and http://first.org.\nCisco has a free website where you can obtain the latest information on security \nvulnerabilities, worms, viruses, and other threats. This website is called the Cisco Security \nCenter, and you can access it at http://tools.cisco.com/security/center/home.x. The \nCisco Security Center includes not only a comprehensive list of threats, but also information \non how you can use your existing infrastructure to reduce exposure to such threats. In \naddition, it includes information about the latest intrusion detection system/intrusion \nprevention system (IDS/IPS) signatures to detect and protect your network from the threats. \nSeveral educational institutions also collaborate with large corporations like Cisco on many \nresearch activities. An example is the Internet Motion Sensor (IMS) created by the \nUniversity of Michigan. IMS is a large cluster of systems configured to monitor blocks of \nroutable unused IP addresses. Its website is http://ims.eecs.umich.edu, and it contains \ndetailed information on the measurement and identification of the latest security threats and \nanomalies. Examples of other research initiatives and organizations are as follows:\n•\nCAIDA Network Telescope: http://www.caida.org/analysis/security\n•\nThe iSink: http://wail.cs.wisc.edu\n•\nCommon Vulnerability and Exposures: http://cve.mitre.org\n•\nTeam CYMRU Darknet Project: http://www.cymru.com/darknet\n•\nThe Honeynet Project: http://honeynet.org\nWhen obtaining security intelligence information, you must determine the level of risk of \nthese vulnerabilities and the impact they may have in your organization. A good way to \ncalculate this risk is by using the emerging standard in vulnerability scoring called the \nCommon Vulnerability Scoring System (CVSS).\nCommon Vulnerability Scoring System\nThe National Infrastructure Advisory Council (NIAC) commissioned the development of \nCVSS as a combined effort by many industry leaders including Cisco. The CVSS standard \nis now maintained by the Forum for Incident Response and Security Teams (FIRST).\nNOTE\nFor more information about FIRST, go to http://www.first.org.\n"
        },
        {
            "page_number": 74,
            "text": "Security Intelligence     51\nCVSS metrics are divided into three major components:\n•\nBase metrics\n•\nTemporal metrics\n•\nEnvironmental metrics\nCisco has an online tool where you can calculate your CVSS score at \nhttp://tools.cisco.com/security/center/cvssCalculator.x.\nBase Metrics\nSeven categories are used to calculate a “base score.” These categories are the most \nelementary qualities of a specific vulnerability. \n1 Access vector: Measures whether a vulnerability is exploitable locally, remotely, or \nboth.\n2 Access complexity: Appraises the complexity and level of effort required to exploit a \nspecific vulnerability.\n3 Authentication: Determines whether an attacker must be authenticated to exploit the \nvulnerability.\n4 Confidentiality impact: Gauges the impact on confidentiality of a successful \nexploitation.\n5 Integrity impact: Gauges the impact on confidentiality of a successful exploitation.\n6 Availability impact: Describes the impact on availability of a successful exploitation \nof the vulnerability on the target system.\n7 Impact bias: Allows you to prioritize one of the three impact metrics over the \nother two.\nTemporal Metrics\nCVSS has three different temporal metrics:\n1 Exploitability: Describes the complexity required to exploit the vulnerability \n(unproven, proof-of-concept, functional, or highly exploitable).\n2 Remediation level: Includes the level of an available workaround or solution. \nDescribes whether there is an official fix, a temporary fix, a workaround, or no \navailable solution.\n3 Report confidence: Measures the credibility and confidence of the reported \nvulnerability (unconfirmed, uncorroborated, or confirmed).\n"
        },
        {
            "page_number": 75,
            "text": "52\nChapter 2:  Preparation Phase\nEnvironmental Metrics\nThe environmental metrics are not scored in the Cisco Security Center website however, \nyou can use them to represent the impact of a vulnerability based on your specific \nenvironment. Two metrics are used to calculate this impact:\n1 Collateral damage potential: The likelihood for a loss of data, physical equipment, \nor property damage.\n2 Target distribution: The relative size of the systems susceptible to such vulnerability.\n— None: When no target systems exist\n— Low: Typically when the vulnerability affects 1 to 15 percent of the systems \nwithin the organization\n— Medium: Typically when the vulnerability affects 16 to 49 percent of the \nsystems within the organization\n— High: Typically when the vulnerability affects 50 percent or more of the \nsystems within the organization\nNOTE\nDetailed information about the CVSS formulas is documented in a white paper published \nby NIAC at http://www.first.org/cvss/cvss-dhs-12-02-04.pdf.\nCreating a Computer Security Incident Response \nTeam (CSIRT)\nIt is unfortunate when large Fortune 500 companies do not have a Computer Security \nIncident Response Team (CSIRT). In some occasions, their CSIRT consists of one part-\ntime employee. This is why it is extremely important to have management support when \ncreating CSIRTs. It is difficult and problematic to create a CSIRT without management \napproval and support. Also, the support needed goes beyond budget and money. It includes \nexecutives, managers, and their staffs committing time to participate in the planning and \nimprovement processes. Furthermore, it is equally crucial to get management commitment \nto award empowerment to the CSIRT. How good is a CSIRT if it does not have the \nauthority to make an emergency change within the infrastructure if the organization is \nunder attack or a victim of an outbreak?\nNOTE\nCSIRTs operate differently depending on the organization, its staff, their expertise, and \nbudget resources. On the other hand, the best practices described in this chapter apply, \ngenerally, to any organization. \n"
        },
        {
            "page_number": 76,
            "text": "Creating a Computer Security Incident Response Team (CSIRT)     53\nWho Should Be Part of the CSIRT? \nFinding and retaining qualified security professionals is challenging. It can be also a \nstruggle for organizations to justify additional headcount, especially for network security. \nTraditionally, information technology (IT) expenses are justified based on return on \ninvestment (ROI) and productivity metrics. On the other hand, security has been \nhistorically viewed as an additional cost. The opinion of many executives is changing, as \norganizations discover that better network security makes business transactions safer and \nreduces a big ticket item—liability.\nIn some cases, additional headcount is needed to create a formal CSIRT within an \norganization. However, on many occasions, the CSIRT can comprise staff from different \ndepartments within an organization. For example, an organization can have representatives \nfrom IT, Information Security (InfoSec), and engineering to be part of the CSIRT. The \ndecision of whether to hire new staff or develop an in-house team depends on your \norganizational needs and budget. Clearly identify who needs to be involved at each level of \nthe CSIRT planning, implementation, and operation. For instance, one of the most \nchallenging tasks is the process of identifying the staff that will be performing security \nincident response functions.\nIn addition, identify which internal and external organizations will interface with the \nCSIRT. Evangelize and communicate the CSIRT responsibilities accordingly.\nA question that many engineers, managers, and executives commonly ask is this: what \nskills should the CSIRT staff possess? The answer certainly goes beyond the in-depth \ntechnical expertise that the CSIRT contributor must have. Communication skills—both \nwritten and oral—are a plus. The CSIRT personnel must be able to communicate effectively \nto ensure that they obtain and supply the necessary and appropriate information. This leads \nto other critical qualities: the ability to respect confidentiality and integrity. This is obvious: \nintegrity and confidentiality are crucial. Other key skills include:\n•\nHandling stressful situations competently\n•\nManaging time \n•\nProblem solving/troubleshooting skills\n•\nWorking with teams effectively\n•\nHandling situations diplomatically\nNOTE\nCERT has a section within its website dedicated to information about CSIRTs \n(http://www.cert.org/csirts). \n"
        },
        {
            "page_number": 77,
            "text": "54\nChapter 2:  Preparation Phase\nIncident Response Collaborative Teams\nSeveral virtual teams and collaborative efforts exist between large corporations and \ngovernment organizations to exchange incident information and intelligence. The \nCisco Critical Infrastructure Assurance Group (CIAG) has formed two groups that provide \nguidance and exchange ideas and information with many other large organizations. These \ngroups are the Information Sharing and Analysis Centers (ISAC) and the Cisco Incident \nResponse Communication Arena (CIRCA). CIRCA, specifically, exchanges information \nwith several excellent sources, such as:\n•\nWorldwide ISAC \n•\nTelecom ISAC \n•\nInformation Technology ISAC \n•\nProduct Security Incident Response Team (PSIRT)\nNOTE\nYou can obtain more information about these organizations at http://www.cisco.com/web/\nabout/security/security_services/ciag/incident_response_support/index.html.\nTasks and Responsibilities of the CSIRT\nYou must develop and document roles and responsibilities for all CSIRT members and \nidentify areas where authority may be ambiguous or overlapping. In addition, you \nmay want to create a diagram or flowchart defining the CSIRT processes. You must develop \npolicies and corresponding procedures. The following section details the importance of \nbuilding strong security policies and procedures.\n Building Strong Security Policies\nWhat good does a firewall, IPS sensor, encryption device, and your favorite security \nproduct and tool do if you do not have guidelines, policies, and best practices on how to \neffectively configure and use them? Building strong security policies is crucial for any \norganization. These policies should be strong, yet realistically flexible to accommodate \never-changing requirements. \nPolicies communicate not only a standard but also an agreement on what should be the best \npractice for a specific situation (in this case, related to security). Policies must be detailed \nyet easy to understand and must also balance enforcement and productivity. A security \npolicy is useless if it impedes productivity.\nDuring the security policy design stages, you should define the reasons why such policy is \nneeded. Also define the stakeholders, contacts, and their responsibilities. In addition, you \nshould discuss how to handle violations to such a policy.\n"
        },
        {
            "page_number": 78,
            "text": "Building Strong Security Policies     55\nDepending on the size and goals of your organization, you may document the security \npolicies in one large document or several small ones.\nTIP\nIn most cases, smaller documents are easier to maintain and update. Occasionally, certain \npolicies are appropriate for every site within your organization; others may be specific to \nspecific environments.\nAn organization can have many different policies depending on its applications and \nsystems. Some policies are implemented because of regulatory compliance to standards \nlike Sarbanes-Oxley and the Health Insurance Portability and Accountability Act \n(HIPAA) of 1996. The following are some of the most common policies in every \norganization: \n•\nPhysical security policies\n•\nInformation protection\n•\nPerimeter security\n•\nDevice security\n•\nAcceptable use of specific applications and systems\n•\nRemote access\n•\nWireless security policies\n•\nData center security policies\n•\nExtranets and demilitarized zones (DMZ)\n•\nPatch management\nThe following are examples of other elaborate policies:\n•\nLab security\n•\nAcceptable encryption protocols\n•\nNetwork admission control policies\n•\nIdentity management policies\nTrust is the main subject in many policies. Many say that policies will not be written if you \ntrust everyone to do the right thing. Ideally, you want to trust all resources, but that is \nunrealistic. Even defects in software and hardware are risks that you do not want to take by \ntrusting everything that is not human. Different types of people (like your staff, guests, and \ncontractors) should be trusted at different levels. Ensure that the level of access is \ncommensurate with the level of trust.\n"
        },
        {
            "page_number": 79,
            "text": "56\nChapter 2:  Preparation Phase\nTIP\nSANS has several security policy templates that you can download at \nhttp://www.sans.org/resources/policies/#template.\nCisco has a Security Policy Builder tool at http://www.ciscowebtools.com/spb/.\nSome people think of security policies as long documents that merely define what level \nof access systems and people have. However, policies include all of the previously \nmentioned items and topics, such as:\n•\nBaseline router configuration parameters\n•\nGuidelines for forwarding e-mails to external addresses\n•\nConfiguration management procedures and change control\nConfiguration management procedures and change control is a hot topic when planning \nincident response procedures. Security changes are defined as changes to network \nequipment that might impact the overall security of the network. Remember that these \npolicies have to be flexible enough to accommodate the changes that staff members make \nto respond to security incidents and outbreaks. All security teams (such as InfoSec, \nCSIRTs, and so on) should review the list of business and technical requirements to identify \nspecific network configuration or design issues to meet security needs.\nPatch management is also a hot topic today. Always ensure that the current software \nrevision levels of network equipment, desktop machines, and servers are up-to-date with \nsecurity patches and hotfixes.\nUpdate security policies regularly, or as needed. At a minimum, schedule an annual review \nto ensure that security policies do not become obsolete because of technology changes and \ndemands. Also, include a provision for ad-hoc updates when higher-priority changes are \nneeded.\nIt is recommended that you engage subject matter experts (SME) when reviewing existing \npolicies because you should consider several factors in addition to those included during \nthe initial development. SMEs can provide valuable input into changes in technology and \nbest practices that may need to be incorporated in the specific policy. Security violations, \ndeviations, and relevant audit information should also be reviewed when considering an \nexisting policy.\nYou can use various techniques when planning, developing, and updating security \npolicies. Always take the following basic idea into consideration: the policy must \nprimarily reflect what is good for the security of the organization as a whole without \nlimiting productivity. \n"
        },
        {
            "page_number": 80,
            "text": "Infrastructure Protection     57\nInfrastructure Protection\nA typical network infrastructure is built with routers, switches, and other equipment that \nprovide indispensable services designed to increase the productivity of your organization. \nEach day results in new security threats, including DoS attacks and worm and virus \noutbreaks deliberately created to directly or indirectly disrupt the services that your \nnetwork infrastructure attempts to provide. That is why it is critical to understand how to \nprotect your organizational infrastructure by using security tools and best practices to \nprotect each system in your network. You need to know not only how to protect the \ninfrastructure, but also how infrastructure components can help you identify, classify, and \nprotect against these security threats.\nYou need to understand the different router planes and their architecture to better protect \nyour infrastructure devices. \nRFC 3654 defines two planes: \n•\nControl plane\n•\nForwarding plane\nITU X805 defines three planes:\n•\nControl plane\n•\nManagement plane\n•\nEnd-user plane\nFinally, Cisco defines three planes:\n•\nControl plane\n•\nManagement plane\n•\nData plane\nNOTE\nThe techniques you will learn in this chapter apply to all the techniques and processes \npreviously described. The Cisco definitions are used. \nThe control plane traffic includes routing protocol traffic—that is, Border Gateway Protocol \n(BGP), Open Shortest Path First (OSPF), and Enhanced Interior Gateway Routing Protocol \n(EIGRP) updates. The management plane traffic is basically all management \ncommunications, such as Secure Shell (SSH), Telnet, Simple Network Management \nProtocol (SNMP), RADIUS, and TACACS+. The data plane traffic (as derived from its \nname) includes all transit traffic not destined to the router. Figure 2-1 illustrates the \ndifference between the three planes.\n"
        },
        {
            "page_number": 81,
            "text": "58\nChapter 2:  Preparation Phase\nFigure 2-1\nRouter Planes\nIn the first (1) part of Figure 2-1, two workstations are sending traffic to each other, and the \ntraffic is routed via an intermediary router. The data plane handles all this traffic. In the \nsecond (2) part of Figure 2-1, two routers are exchanging OSPF updates. The control plane \nhandles this traffic. The third (3) and last part of Figure 2-1 illustrates a network \nadministrator managing the router using the SSH protocol. The management plane handles \nthis traffic.\nThe control and management plane traffic is always destined to the router. The processor in \nsoftware platforms handles this traffic (traffic is Cisco Express Forwarding (CEF) \nswitched in interrupt level.) In contrast, in high-end platforms such as the Catalyst 6500 or \nthe Cisco 12000 series routers, control and management plane traffic is sent to hardware \nmodules like the MFSC/SUP720 and then sent to the process level for processing. In some \ncases, data plane traffic may also reach the control plane. For instance, packets with IP \noptions are process-switched (handled by the processor). Another example is when a \nrouter receives a packet that cannot be routed, the packet is sent to the control plane; \nsubsequently, the router generates an Internet Control Message Protocol (ICMP) \nunreachable message.\nFrom the many techniques you can use to better prepare and protect your infrastructure, \nthese are the most crucial and frequently implemented:\n•\nStrong device access control\n•\nSecuring of routing protocols\n•\nDisabling of unnecessary services on network components\nTransit traffic handled by the data plane.\nOSPF Update\nRouting protocol packets handled by the control plane.\nSSH Management Traffic\nManagement packets handled by the management plane.\n1\n2\n3\n"
        },
        {
            "page_number": 82,
            "text": "Infrastructure Protection     59\n•\nLocking down of unused ports on network access devices\n•\nControl of resource exhaustion \n•\nPolicy enforcement\n•\nTelemetry and logging\nStrong Device Access Control\nStrong device access control implies establishing the appropriate mechanisms to prevent \nunauthorized access to networking devices such as routers and switches. You can spend \nmillions of dollars on the most sophisticated network devices, but these devices can be the \nworst investment you have ever made if they can be easily “owned” by the enemy \n(attackers). This is why it is critical to become familiar with what access mechanisms are \navailable on each infrastructure device. You need to know how they work, which ones \nare “on by default,” and how others can be “turned on.” It is also useful to know how to \nsecure/restrict these mechanisms as necessary so you can better protect the infrastructure \nas a whole.\nMany access mechanisms are supported by different network access devices. Following are \nsome examples:\n•\nConsole access\n•\nAsynchronous connections\n•\nTelnet\n•\nrlogin\n•\nSSH\n•\nHTTP and HTTPs access via web-based GUIs\nNOTE\nSeveral of these access mechanisms are enabled by default in infrastructure devices. For \nexample, console and modem access are enabled by default in Cisco routers, while other \nmechanisms need to be enabled manually.\nCisco and other organizations recommend several best practices to help secure access to \nnetwork devices. The following sections include those most commonly recommended.\nSSH Versus Telnet\nSSH is a protocol that provides strong authentication and encryption. This is why it is \nrecommended over insecure protocols like rlogin and Telnet. SSH comes in Version 1 \nand Version 2. The second version of SSH is recommended and should be used whenever \n"
        },
        {
            "page_number": 83,
            "text": "60\nChapter 2:  Preparation Phase\nit is supported, because it fixes a series of security issues found in the previous version. SSH \nsupports the most common encryption ciphers: \n•\nAdvanced Encryption Standard (AES)\n•\nData Encryption Standard (DES)\n•\nTriple DES (3DES)\n•\nInternational Data Encryption Algorithm (IDEA)\n•\nRC4-128\nSSH can also tunnel TCP connections that allow file transfers with secure copy (SCP).\nFour basic steps are required to enable SSH on a Cisco IOS Software device:\nStep 1\nConfigure a hostname and domain name. The hostname “myrouter” and \nthe domain name “cisco.com” are used in this example.\nRouter(config)# hostname myrouter\nmyrouter(config)# ip domain-name cisco.com\nStep 2\nGenerate a Rivest, Shamir, and Adleman (RSA) protocol key pair. This \nautomatically enables SSH.\nmyrouter(config)#crypto key generate rsa\nThe name for the keys will be: myrouter.cisco.com\nChoose the size of the key modulus in the range of 360 to 2048 for your\n  General Purpose Keys. Choosing a key modulus greater than 512 may take\n  a few minutes.\nHow many bits in the modulus [512]: 2048\n% Generating 1024 bit RSA keys, keys will be non-exportable...[OK]\nmyrouter(config)#\n*Dec 14 02:40:23.093: %SSH-5-ENABLED: SSH 2.0 has been enabled\nStep 3\n(Optional) Configure time-out and number of authentication retries. \nThese values depend on your environment; however, the 60-second \ntimeout is appropriate in most cases.\nmyrouter(config)# ip ssh time-out 60\nmyrouter(config)# ip ssh authentication-retries 2\nStep 4\nOptionally, but highly recommended, configure VTYs to only accept \nSSH.\nmyrouter(config)# line vty 0 4\nmyrouter(config-line)# transport input ssh\nThe following steps demonstrate how to enable SSH on a PIX security appliance or a \nCisco Adaptive Security Appliance (ASA):\nStep 1\nConfigure the hostname and domain name in the security appliance.\nciscoasa(config)#hostname ciscoasa1\nciscoasa1(config)#domain-name cisco.com\n"
        },
        {
            "page_number": 84,
            "text": "Infrastructure Protection     61\nStep 2\nConfigure a username and password, and use authentication, \nauthorization, and accounting (AAA) authentication. In this example, \nlocal authentication is used. The username is user1, and the password is \ncisco123.\nciscoasa1(config)#username user1 password cisco123\nciscoasa1(config)#aaa authentication ssh console LOCAL\nStep 3\nGenerate the RSA key pair for the security appliance (similarly to IOS). \nIn this example, the modulus size is 2048.\nciscoasa1(config)#crypto key generate rsa modulus 2048\nStep 4\nDefine the hosts/networks allowed to connect to the specific interfaces of \nthe security appliance. In this example, only machines in the 10.10.10.0/24 \nnetwork can connect via SSH on the inside interface.\nciscoasa1 (config)#ssh 10.10.10.0 255.255.255.0 inside\nStep 5\nOptionally, you can specify the version of SSH allowed on the PIX/ASA. \nBy default, both SSH Version 1 and Version 2 are allowed. In this \nexample, only clients that support SSH Version 2 are allowed to connect \nto the appliance.\nciscoasa1(config)# ssh version 2\nLocal Password Management\nTACACS+ and RADIUS servers provide the best options for authentication of \nmanagement access to networking devices. They provide numerous functions that ease the \nmanagement of user accounts while providing higher security mechanisms. Local \nauthentication is more susceptible to being broken than authentication using remote \nTACACS+ or RADIUS servers. That is why it is recommended to do the following:\n•\nEncrypt any passwords shown in the configuration files. In IOS devices, \nyou can encrypt the passwords in their configuration file by using the \nservice password-encryption global command.\n•\nChange default passwords.\n•\nLimit the authentication failure rate. It is recommended, as a best practice, to \nconfigure a maximum threshold of three consecutive unsuccessful login attempts and \nto enable the generation of log messages when this limit is reached by using the \nsecurity authentication failure rate 3 log command in IOS devices. This locks \naccess to the router for a period of 15 seconds after three unsuccessful login attempts \nto protect against dictionary attacks. Dictionary attacks are an old trick. An attacker \nuses a script that tries thousands of words stored in a file using them as the password. \nA dictionary attack can be successful if a weak password is used or if you do not \nprotect against it by limiting the authentication failure rate.\n"
        },
        {
            "page_number": 85,
            "text": "62\nChapter 2:  Preparation Phase\nConfiguring Authentication Banners\nSometimes people overestimate the benefits of configuring authentication banners. Banners \nwith detailed warnings often make it easier to prosecute attackers who break into your \nsystems. In some cases, you may be forbidden to monitor the activities of unauthorized \nusers unless you have taken steps to notify them of your intent to do so. \nTypically, authentication banners include the following information:\n•\nA warning that the system you are trying to access should be used only by authorized \npersonnel\n•\nA detailed explanation that the unauthorized use of such a device is illegal, and \nindividuals who attempt to break in are subject to prosecution\n•\nA notice that the use of such a device may be monitored\n•\nSpecific notices required by certain local authorities\nInteractive Access Control\nYou have already learned that you can access network devices via several interactive \nmethods such as Telnet, rlogin, SSH, and local asynchronous, even modem connections \nfor out-of-band access. On Cisco IOS devices, these interactive access methods have two \nbasic types of lines (or sessions). The first type is the use of standard lines used by console \nand dialup modem connections. The first type of these connections are known as TTYs. \nTTY stands for “Text Telephone.” The “Y” has a historical value referenced to the first text \ntelephones. Now the term TTY refers to a serial connection to a computerized device. The \nsecond type of standard lines is the virtual TTYs (VTYs). VTYs are used by remote \nconnections such as Telnet and SSH. This section shows the best way to protect interactive \naccess.\nOne of the most common practices in Cisco IOS devices is to disable interactive logins on \nlines that will not need them. You can use the login and no password commands at the line \nconfiguration level. Another good practice is to restrict access to allow only the specific \nprotocols (that is, SSH). In Cisco IOS devices, you can do this with the transport input\ncommand (for example, transport input ssh).\nAlways restrict the IP addresses or networks from which access will be granted to network \naccess devices. In Cisco IOS, you can achieve this by using the access-class command in \nconjunction with an ACL. In the following example, an access list is configured to allow \ndevices only on the 10.10.10.0/24 network to access the router via SSH.\nMyrouter#configure terminal\nmyrouter(config)#access-list 10 permit 10.10.10.0 0.0.0.255\nmyrouter(config)#line vty 0 4\nmyrouter(config-line)#access-class 10 in\nmyrouter(config-line)#transport input ssh\n"
        },
        {
            "page_number": 86,
            "text": "Infrastructure Protection     63\nOn the Cisco ASA and PIX, you can restrict administrative access in a similar fashion by \nusing the ssh, telnet, http, and asdm location commands. The ssh command restricts SSH \nconnections to the security appliance. The telnet command restricts Telnet connections. \nThe http and asdm location commands restrict HTTPS access via the Adaptive Security \nDevice Manager (ASDM). In the following example, the only host allowed to access and \nmanage the Cisco ASA via SSH and ASDM is 172.18.85.123.\nciscoasa# configure terminal\nciscoasa(config)# ssh 172.18.85.123 255.255.255.255 inside\nciscoasa(config)# http 172.18.85.123 255.255.255.255 inside\nciscoasa(config)# asdm location 172.18.85.123 255.255.255.255 inside\nAs with the Cisco ASA/PIX, in Cisco IOS, you can enable HTTP authentication with the \nip http authentication command. The following example shows a configuration listing for \nHTTP authentication using RADIUS.\nmyrouter(config)#aaa new-model\nmyrouter(config)#aaa authentication login default group radius\nmyrouter(config)#aaa authorization exec default group radius\nmyrouter(config)#ip http server\nmyrouter(config)#ip http authentication aaa\nmyrouter(config)#tacacs-server host 172.18.85.181\nmyrouter(config)#tacacs-server key cisco123\nYou can also restrict who can administer the IOS device via HTTP by using the \nip http access-class command. The following example shows how 10.10.10.123 is the \nonly host allowed to connect via HTTP to the router.\nmrouter(config)# access-list 9 permit host 10.10.10.123\nmrouter(config)# ip http access-class 9\nmyrouter(config)# ip http max-connections 3\nIn this example, the router is configured to limit the maximum number of concurrent \nconnections to three with the ip http max-connections command.\nYou can also configure timeouts to avoid idle sessions from consuming an administrative \nsession indefinitely. In Cisco IOS, you can modify the idle timeout with the exec-timeout\ncommand, as shown in the following example. In this example, the exec-timeout is \nconfigured for 5 minutes.\nmyrouter(config)#line vty 0 4\nmyrouter(config-line)#exec-timeout 5\nOn the Cisco ASA, you can do the same by configuring the ssh timeout or telnet timeout\ncommands as follows.\nciscoasa(config)# ssh timeout 5\nciscoasa(config)# telnet timeout 5\nAnother trick on Cisco IOS devices is to enable TCP keepalives on incoming sessions with \nthe service tcp-keepalives-in command. The use of this command protects against \nmalicious orphan connections.\nSeveral IOS login enhancements have occurred since Cisco IOS Software Release 12.3(4)T. \nThe login delay command was introduced to allow a delay between login attempts, making \ndictionary attacks harder to exploit.\n"
        },
        {
            "page_number": 87,
            "text": "64\nChapter 2:  Preparation Phase\nNOTE\nDictionary attacks were defined earlier in this chapter.\nThe login block-for command allows you to limit the frequency of failed login attempts in \nCisco IOS routers. The frequency is limited by defining a maximum number of failed \nattempts within a specified period. When this number is reached, the Cisco IOS router does \nnot accept additional connections for a “quiet period.” You can also create an ACL to \ninclude trusted systems and networks from which legitimate connections are expected. \nThis is called an exception ACL, and it is configured in conjunction with the \nlogin quiet-mode access-class global command.\nIn the example that follows, the Cisco IOS router will enter a 60-second quiet period if 15 \nfailed login attempts are exceeded within 60 seconds. The access list included next will \nmake an exception for the authorized system with IP address 10.10.10.123. In addition, \nlogging messages will be generated for every 10th failed login and every 15th successful \nlogin.\nmyrouter(config)# access-list 99 permit host 10.10.10.123\nmyrouter(config)# login block-for 60 attempts 15 within 60\nmyrouter(config)# login quiet-mode access-class 99\nmyrouter(config)# login on-failure log every 10\nmyrouter(config)# login on-success log every 15\nRole-Based Command-Line Interface (CLI) Access in Cisco IOS\nRole-based command-line interface (CLI) access is often referred to as CLI views. This is \na feature introduced in Cisco IOS Software Release 12.3(7)T. The purpose of this feature \nis to explicitly control the commands that are accepted and the configuration information \nthat is visible to different groups of users depending on their role. For instance, certain users \nfrom your network operations group could have limited access to EXEC and configuration \ncommands and no access to security configuration commands. In contrast, you may want \nto allow the users in your security group to invoke security configuration commands such \nas crypto commands and others. \nThe three basic views or levels of access are as follows:\n•\nRoot view: The highest administrative view, this is equivalent to a user with level 15 \nprivileges. To create new CLI views, you need to be in “root view” access.\n•\nSuperview: Do not include commands; in fact, you can only configure commands in \nCLI views. However, users logged into a superview account can access all the \ncommands that are configured for any of the CLI views that are part of the superview.\n•\nLawful intercept view: This view is only available in Cisco IOS devices that support \nthe lawful intercept subsystem. The purpose of this view is to restrict access to lawful \nintercept commands and configuration information. \n"
        },
        {
            "page_number": 88,
            "text": "Infrastructure Protection     65\nNOTE\nThere is one root view, by default. You can define a total of 15 CLI views and superviews \nand only 1 lawful intercept view. For you to create a view, an “enable” password must exist. \nIn addition, AAA must be enabled with the aaa new-model command, and the \nadministrator must have level 15 privileges to access the root view. You must enable \nauthorization with the aaa authorization command.\nFollow these steps to create CLI views in Cisco IOS routers.\nStep 1\nUse the enable view command to access the root view, as shown in the \nfollowing example:\nmyrouter# enable view\nPassword: (enter enable or enable secret password)\n*Dec 25 00:03:28.123: %PARSER-6-VIEW_SWITCH: successfully set to view \n‘root’ \nStep 2\nAfter entering in root view mode, you can create a new view with the \nparser view command. In the following example, a view called \nmyADMIN is created with the password 1qaz@WSX.\nmyouter# configure terminal\nmyrouter(config)# parser view myADMIN\n*Dec 25 01:08:51.123: %PARSER-6-VIEW_CREATED: view ‘Admin123’ \n  successfully created.\nmyrouter(config-view)# password 5 1qaz@WSX\nStep 3\nYou can permit or exclude commands within the view with the \ncommands sub-command, as follows:\nmyrouter(config-view)# commands exec include show interfaces\nmyrouter(config-view)# commands exec include all\nmyrouter(config-view)# commands configure include-exclusive crypto\nStep 4\nYou can assign a user or a group to a CLI view in two ways. The first \nmethod is with the use of a AAA local user database. The second (and \npreferred method) is to use an external AAA server. You can associate \nlocal users to a CLI view with the username command, as shown here:\nmyrouter(config)# username operator1 view Operators password 1qaz@WSX\nmyrouter(config)# username sec_op1 view SecOps password xsw2ZAQ!\nIn this example, two users are created. The user operator1 is associated \nwith a view called Operators. The second user, sec_op1, is associated \nwith a view called SecOps.\nTIP\nWhen you use an external AAA server, you must use the attribute “cli-view-name” to assign \na user to a specific CLI view.\n"
        },
        {
            "page_number": 89,
            "text": "66\nChapter 2:  Preparation Phase\nControlling SNMP Access\nSNMP is a network management protocol that many organizations use. Administrators use \nSNMP not only to manage infrastructure devices but also to manage servers and other \nsystems within their organization. SNMP is a powerful tool, because administrators can \nreach numerous devices within a large network, push and download configurations, and \nobtain system statistics. SNMP is considered a “double-edged sword” by many people, \nbecause an attacker can do the same thing when SNMP is not secured properly. \nSNMP has three versions:\n•\nVersion 1\n•\nVersion 2 (commonly referred to as 2c)\n•\nVersion 3\nVersion 1 and Version 2c are weak in security functions and existing vulnerabilities. \nHowever, they are the most commonly deployed. In Version 1 and 2c, access to MIB \nobjects is controlled by the use of community strings. However, these versions do not \nprovide authentication or encryption mechanisms. Not having basic security capabilities \nsuch as authentication or encryption on a management protocol is like leaving your car \nunlocked and with the windows down in the worst neighborhood. SNMP Version 3 \nincorporates security features such as authentication, identity, and access control. \nVersion 3 has multiple authentication options, including username, message digest \nalgorithm 5 (MD5), and Secure Hash Algorithm (SHA) authentication. This version also \nprovides privacy with DES encryption, and authorization and access controls based on \nviews. Of course, the recommendation is for you to use SNMP Version 3 over the other two \nversions. On the other hand, this may not be possible because you may have devices (or \nSNMP applications) that do not support SNMP Version 3. In this case, you can improve \nsecurity by doing the following:\n•\nChanging any default or standard community strings such as “private” or “public” \n•\nDefining nontrivial community strings\n•\nSetting SNMP to send a trap on community-name authentication failures\n•\nDefining access control rules on networking devices to only allow SNMP \ncommunication from trusted management hosts; of course, the management host \nshould also be secured. You will learn how to secure management hosts and other \nsystems in the “Endpoint Security” section.\nSecuring Routing Protocols \nRouting protocols play a crucial role in the infrastructure of any organization. They use \nalgorithms to select the best paths for datagrams within a network or set of networks. \nUnderstanding how to configure and use routing protocols is a must for any network \nadministrator. On the same note, understanding how to secure these protocols is vital. \n"
        },
        {
            "page_number": 90,
            "text": "Infrastructure Protection     67\nThis book assumes that you are already familiar with routing protocols. However, here is a \nquick refresh. Routing protocols are divided into two major categories:\n•\nInterior Gateway Protocols (IGP)\n•\nExterior Gateway Protocols (EGP)\nIGPs handle routing within an autonomous system. In other words, typically IGPs route \ntraffic between the routers within an enterprise. These protocols keep track of how to get \nfrom one destination to the other inside a network or set of networks that you administer. \nIn most cases, all the networks you manage combined are just one autonomous system. \nSome large organizations use more complex techniques, including several autonomous \nsystems. IGPs are also divided into two categories:\n•\nDistance vector protocols: Use a distance calculation plus an outgoing network \ninterface (a vector) to choose the best path to a destination network. Routing \nInformation Protocol (RIP) and Interior Gateway Routing Protocol (IGRP) are \nexamples of distance vector protocols.\n•\nLink state protocols: These track the status and connection type of each link and \nproduce a calculated metric based on these and other factors, including some set by \nthe network administrator. Link state protocols know whether a link is up or down and \nhow fast it is. Using this information, link state protocols calculate the “cost” of \nrouting the datagrams within a network. For example, link state protocols may take a \npath that has more hops but uses a faster medium in preference to a path using a slower \nmedium with fewer hops. Open Shortest Path First (OSPF) is the most widely used \nlink state protocol.\nEGPs control routing outside an autonomous system. Internet service providers (ISP) \ntypically use EGPs to route traffic between separate organizations. The most common \nexterior gateway routing protocol is BGP.\nYou can use many different techniques to attack routing protocols. The most common are \nthe injection of illegitimate routing updates and DoS attacks specifically against routing. \nSeveral tools you can use are already built into BGP, Intermediate System-to-Intermediate \nSystem (IS-IS), OSPF, EIGRP, and RIPv2 that help secure your infrastructure routing. \nThe most common tools/techniques are as followed:\n•\nConfiguring static routing peers\n•\nAuthentication\n•\nRoute filtering\n•\nTime-to-live (TTL) security checks\n"
        },
        {
            "page_number": 91,
            "text": "68\nChapter 2:  Preparation Phase\nConfiguring Static Routing Peers\nSeveral routing protocols include different mechanisms that dynamically discover routing \npeers. Unfortunately, the same mechanisms can be easily used to insert bogus routers into \nthe routing infrastructure. You can statically configure a list of trusted neighbors to avoid \nthis problem. However, this technique causes controversy among administrators because, \nin large organizations, it can mean hundreds of configuration lines. For this reason, many \nprefer to use authentication mechanisms.\nAuthentication\nAuthentication is now available on most routing protocols. You can configure routing \ndevices with a predefined shared secret key that is used to validate each routing update. \nMost routing protocols support two types of neighbor authentication: plaintext and MD5. \nWith plaintext authentication, a secret key is included inside each routing update message. \nThis does not provide much security because an attacker can easily read keys. MD5 \nauthentication works by processing each routing update with an MD5 hash function and by \nincluding the resulting signature (digest) as part of the routing update message. When you \nare using MD5, the shared secret key is never sent over the network only the hashing \ninformation or digest.\nFigure 2-2 illustrates a topology in which four Cisco IOS routers and a Cisco ASA are \nconfigured with OSPF and with MD5 authentication.\nFigure 2-2\nOSPF Authentication\nAll routers and the Cisco ASA belong to the OSPF area 0. The following example shows \nthe configuration of OSPF MD5 neighbor authentication on the router labeled Router 1.\nrouter ospf 10\n  network 172.18.124.0 0.0.0.255 area 0\n  network 10.10.10.0 0.0.0.255 area 0\n  area 0 authentication message-digest\nInternet\nRouter 2\nRouter 3\nRouter 4\nRouter 1\nCisco\nASA\nOSPF (Area 0)\n172.18.124.0/24\n10.10.10.2\n10.10.10.1\n"
        },
        {
            "page_number": 92,
            "text": "Infrastructure Protection     69\n!\ninterface Ethernet1\n  ip address 10.10.10.2 255.255.255.0\n  ip ospf authentication message-digest\n  ip ospf message-digest-key 10 md5 1qaz@WSX\nThe first highlighted line shows how MD5 authentication is enabled for area 0. The second \nand third highlighted lines show how OSPF MD5 authentication is enabled on Ethernet 1. \nThe shared key on this example is 1qaz@WSX.\nThe following example shows the configuration of the Cisco ASA. The commands are \nalmost identical to the Cisco IOS router. \nrouter ospf 5\n  network 10.10.10.0 0.0.0.255 area 0\n  area 0 authentication message-digest\n!\ninterface GigabitEthernet0/1\n  ip address 10.10.10.1 255.255.255.0\n  ospf authentication message-digest\n  ospf message-digest-key 10 md5 1qaz@WSX\nNotice that the Cisco ASA OSPF authentication configuration is similar to the Cisco IOS \nrouter. The actual code was ported from IOS. One of the differences is that OSPF interface \nsubcommands are not preceded by the word “ip.” \nNOTE\nFor more information about neighbor authentication in Cisco IOS, refer to \nhttp://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124cg/hsec_c/part25/\nschroutr.htm.\nFor more about routing authentication in Cisco ASA, refer to http://www.cisco.com/\nunivercd/cc/td/doc/product/multisec/asa_sw/v_7_2/conf_gd/general/ip.htm.\nRoute Filtering\nYou can use route filtering to prevent specific routes from being propagated throughout the \nnetwork. You can use route filtering as a security mechanism, because filters can help \nensure that only legitimate networks are advertised and that networks that are not supposed \nto be propagated are never advertised. For example, you can filter RFC-1918 private \naddresses.\nNOTE\nFor more information about routing security, see \nhttp://www.cisco.com/en/US/netsol/ns744/networking_solutions_program_home.html.\n"
        },
        {
            "page_number": 93,
            "text": "70\nChapter 2:  Preparation Phase\nTime-to-Live (TTL) Security Check\nTTL Security Check is a security feature implemented in BGP. It helps protect BGP peers \nfrom multihop attacks. This feature is based on the Generalized TTL Security Mechanism \n(GTSM) defined in RFC 3682 and applies only to external BGP (eBGP).\nNOTE\nSeveral organizations are working to implement this feature for other routing protocols, \nsuch as OSPF and EIGRP.\nYou can configure a minimum acceptable TTL value for the packets exchanged between \ntwo eBGP peers when you use the TTL Security Check feature in Cisco IOS. After you \nenable TTL Security Check, both BGP peers send all their updates with a TTL of 255. In \naddition, routers establish a peering session only if the other eBGP peer sends packets with \na TTL equal to or greater than the TTL value configured for the peering session. By default, \neBGP uses a TTL value of 1; the only exception is when eBGP multihop is used.\nNOTE\nIf a router receives a packet with TTL values less than the calculated value, it silently \ndiscards it.\nYou can enable the TTL security check by using the neighbor <ip address> ttl-security\ncommand as shown in the following example:\nRouter(config)# router bgp 123\nRouter(config-router)# neighbor 209.165.200.226 ttl-security hops 3\nIn this example, TTL security check is enabled for the 209.165.200.226 eBGP neighbor \nwhich is three hops away. This router then accepts only BGP packets with a TTL value of \n252 or greater.\nNOTE\nFor more information about TTL security check, go to http://www.cisco.com/en/US/\nproducts/ps6350/products_configuration_guide_chapter09186a0080455621.html.\nDisabling Unnecessary Services on Network Components\nInfrastructure devices in some cases come with a list of services turned on by default that \nare considered appropriate for most network environments. However, it is always a good \nidea to disable unnecessary services because some services present a vulnerability that \ncould be used maliciously to gain unauthorized access or disrupt service. \n"
        },
        {
            "page_number": 94,
            "text": "Infrastructure Protection     71\nNOTE\nNot all environments have the same requirements but, on many occasions, disabling \nthese unnecessary services not only enhances security but also helps preserve system \nresources.\nThe following is the list of Cisco IOS services that Cisco recommends you disable because \nthey have the possibility of being used for malicious purposes:\n•\nCisco Discovery Protocol (CDP)\n•\nFinger\n•\nDirected Broadcast\n•\nMaintenance Operations Protocol (MOP)\n•\nBOOTP Server\n•\nICMP redirects\n•\nIP source routing\n•\nPAD\n•\nProxy ARP\n•\nIDENT\n•\nTCP and User Datagram Protocol (UDP) small servers\n•\nIPv6\nCisco Discovery Protocol (CDP)\nCDP is a protocol that allows you to obtain information about other devices within the \nnetwork. This information can include the platform, model, software version, and IP \naddresses of network devices adjacent to the Cisco IOS routers. \nNOTE\nCDP is a Cisco proprietary Layer 2 protocol that is enabled by default.\nCDP is a useful tool in the hands of an administrator, but it is a tool to be feared in the hands \nof an attacker. You can disable CDP globally when the service is not used or per interface \nwhen CDP is still required. As a rule of thumb, you should disable CDP on interfaces facing \nnontrusted networks such as the Internet. To disable CDP globally, use the no cdp run\ncommand. If you want to disable CDP on a specific interface, you can use the \nno cdp enable interface subcommand. For example:\nmyrouter(config)# interface Ethernet1 \nmyrouter(config-if)# no cdp enable\n"
        },
        {
            "page_number": 95,
            "text": "72\nChapter 2:  Preparation Phase\nTIP\nYou should always check for features that depend on CDP before disabling it. Features that \ndepend on CDP are On-Demand Routing (ODR) and Cisco IP Telephony solutions.\nFinger\nThe Finger protocol is used to obtain information about users logged into systems within \nthe network. If you are running Cisco IOS Software versions prior to 12.1(5) and 12.1(5)T, \nFinger is on by default. Attackers can use Finger in reconnaissance attacks because it does \nnot reveal much sensitive information. However, attackers can use chunks of information \nto obtain a better understanding of your environment. Always disable Finger whenever \npossible. You can do this with the no service finger command. In Versions 12.1(5) or \n12.1(5)T and later, the Finger service is disabled by default; however, if for some reason it \nwas turned on, you can disable it with the no ip finger command.\nDirected Broadcast\nCisco IOS software versions prior to 11.2 have IP Directed Broadcast enabled by default. \nYou are probably not running a version of IOS this old. However, because directed \nbroadcasts have been used for DoS attacks (that is, SMURF), it is always recommended \nthat you keep IP Directed Broadcast disabled. If for some reason the IP Directed Broadcast \nfeature was enabled, you can disable it with the no ip directed-broadcast interface \nsubcommand, as shown in the following example:\nmyrouter(config)# interface Ethernet1\nmyrouter(config-if)# no ip directed-broadcast\nMaintenance Operations Protocol (MOP)\nMOP was designed for remote communications between hosts and servers. Cisco IOS \nrouters can use MOP to gather configuration information when communicating with \nDECnet networks. \nNOTE\nBy default, MOP is enabled on all Ethernet interfaces and disabled on all other type of \ninterfaces.\nIt is recommended that you disable the MOP service whenever possible, because this \nservice has several vulnerabilities. To disable MOP, use the no mop enabled interface \nsubcommand, as shown in the following:\nmyrouter(config)# interface Ethernet1\nmyrouter(config-if)# no mop enabled\n"
        },
        {
            "page_number": 96,
            "text": "Infrastructure Protection     73\nBOOTP Server\nThe Bootstrap protocol allows a system to configure itself at boot time by dynamically \nobtaining the following information:\n•\nAn IP address\n•\nThe IP address of the BOOTP server\n•\nA configuration file\nBOOTP is defined in RFC 951. Cisco IOS routers can act as BOOTP servers. This service \nis turned on by default and is used by features such as AutoInstall. If not needed, this \nservice should be disabled with the no ip bootp server global configuration command.\nICMP Redirects\nCisco IOS routers send ICMP redirect messages when ICMP redirects a packet through the \nsame interface on which it was received. Attackers can sniff these packets and use them to \ndiscover network topology information. Disable ICMP redirects whenever possible with \nthe no ip redirects interface subcommand, as shown here:\nmyrouter(config)# interface Ethernet1\nmyrouter(config-if)# no ip redirects\nIP Source Routing\nIP source routing enables a device to control the route that the datagram will take toward \nits destination. This feature is rarely used because it is not practical in environments today. \nAttackers can take advantage of older IP implementations that do not process source-routed \npackets properly and may be able to crash machines running these implementations by \nsending altered packets with source routing options. It is recommended that you disable IP \nsource routing whenever possible with the no ip source-route command.\nPacket Assembler/Disassembler (PAD)\nPacket Assembler/Disassembler (PAD) allows some devices such as character-mode \nterminals to connect to legacy X.25 networks. PAD is enabled on Cisco IOS routers. In \nsome cases, PAD can be used to gain unauthorized access, because its security is weak. \nDisable PAD whenever possible with the no service pad global command.\nProxy Address Resolution Protocol (ARP)\nProxy Address Resolution Protocol (ARP) is used to reach devices on a remote subnet \nwithout configuring specific routes to a network device. When you are performing proxy \nARP, a network device answers all ARP requests on the local subnet on behalf of systems \n"
        },
        {
            "page_number": 97,
            "text": "74\nChapter 2:  Preparation Phase\nsome hops away. Attackers can also use proxy ARP to obtain information about hosts \nbehind routers in attempting to figure out the topology of your network.\nNOTE\nProxy ARP is defined in RFC 1027.\nIt is recommended that you disable Proxy ARP on interfaces that connect to untrusted \nnetworks. On Cisco IOS, you can disable Proxy ARP with the no ip proxy-arp interface \nsubcommand, as shown in the following example:\nmyrouter(config)# interface Ethernet1\nmyrouter(config-if)# no ip proxy-arp\nIDENT\nThe TCP Client Identity Protocol (IDENT) allows a system to query the identity of a user \ninitiating a TCP connection or a host responding to a TCP connection. The IDENT protocol \nenables you to obtain identity information by connecting to a TCP port on a system and \nissuing a simple text string requesting information. \nNOTE\nIDENT is defined in RFC 1413.\nAttackers can use IDENT as another reconnaissance tool. Always disable IDENT whenever \npossible with the no ip identd global configuration command.\nTCP and User Datagram Protocol (UDP) Small Servers\nTCP and UDP small servers are daemons that typically run on UNIX systems and that were \ndesigned for diagnostic purposes. Cisco IOS Software also provides an implementation of \nUDP and TCP small servers that enables echo, chargen, daytime, and discard services. \nUnless strictly necessary, these services should be disabled because a potential attacker can \nuse them to gather information or even to redirect traffic. \nTCP and UDP small services are disabled by default on Cisco IOS Software Versions 11.3 \nand later. However, if for some reason they have been enabled, you can disable them by \nusing the no service tcp-small-servers and no service udp-small-servers global \nconfiguration commands.\n"
        },
        {
            "page_number": 98,
            "text": "Infrastructure Protection     75\nIP Version 6 (IPv6)\nHistorically, Cisco IOS–affected systems running IPv6 have had a couple of vulnerabilities. \nThe execution of these vulnerabilities could lead to a system crash or the execution of \narbitrary code. Only devices that were explicitly configured to process IPv6 traffic have \nbeen affected. That is why it is recommended that you disable IPv6 when not required, \nsubsequently eliminating the potential exposure to vulnerabilities like those previously \nmentioned.\nYou can disable IPv6 on a per-interface basis using the no ipv6 enable and no ipv6 address\ninterface subcommands, as shown here:\nmyrouter(config)# interface Ethernet1\nmyrouter(config-if)# no ipv6 enable\nmyrouter(config-if)# no ipv6 address\nNOTE\nChapter 11, “IPv6 Security,” details how to secure IPv6 implementations.\nLocking Down Unused Ports on Network Access Devices\nThis is a best practice that may be common sense for you but many network administrators \noverlook it. Several network devices have their ports and interfaces enabled by default. For \ninstance, all Ethernet ports on Cisco Catalyst Switches running CatOS are enabled by \ndefault. Leaving unused ports enabled opens the chance for unauthorized access. It is \nalways recommended that you keep all unused ports disabled. You can disable a port/\ninterface on a Cisco Catalyst switch running CatOS with the set port disable command, as \nshown in the following example:\nConsole> (enable) set port disable 2/4\nPort 2/4 disabled.\nConsole> (enable) \nIn this example, Ethernet port 2/4 is disabled on a Cisco Catalyst switch. \nOn devices running Cisco IOS, all interfaces are disabled by default; however, if an \ninterface has been enabled and it is not in use, you should disable it with the shutdown \ninterface subcommand as shown next:\nmyrouter(config)# interface Ethernet1\nmyrouter(config-if)# shutdown\nControl Resource Exhaustion\nToday, a growing number of DDoS attacks are being designed to specifically target key \ninfrastructure devices. These types of attacks typically try to consume CPU resources, input \nqueues, and memory. Worms and viruses that are generally designed to target end hosts \ngenerate large volumes of traffic that quite often exhaust most of the resources available in \n"
        },
        {
            "page_number": 99,
            "text": "76\nChapter 2:  Preparation Phase\ninfrastructure equipment. You can implement several best practices by controlling the \nutilization of the limited resources in a device:\n•\nResource thresholding notification\n•\nCPU protection\n•\nReceive access control lists (rACLs)\n•\nControl Plane Policing (CoPP)\n•\nScheduler Allocate/Interval \n Resource Thresholding Notification\nAlways monitor the resource usage of infrastructure devices for unusual sustained high \nlevels of CPU utilization, low free memory, and large volumes of dropped packets. These \npractices ease the detection and classification of attacks and outbreaks. \nNOTE\nChapter 3, “Identifying and Classifying Security Threats,” details numerous techniques to \nsuccessfully identify and classify network attacks and outbreaks.\nSeveral Cisco platforms provide automatic notification mechanisms that are generally \nbased on SNMP or syslog. These mechanisms generate alarms when unusual levels of CPU \nor memory are detected. It is recommended that you use the Cisco IOS CPU thresholding \nnotification and memory thresholding notification. \nNOTE\nThe CPU thresholding notification was introduced in Cisco IOS Software Version 12.0(26)S.\nYou can configure two types of thresholds:\n•\nRising CPU threshold: Specifies the percentage of CPU utilization that will trigger \na notification.\n•\nFalling CPU threshold: Specifies the percentage of CPU resources that triggers a \nCPU threshold notification when CPU usage falls below this level for a configured \nperiod.\nThe following are the steps required to configure CPU threshold notification.\nStep 1\nEnable CPU threshold violation notification as traps and inform requests \nwith the snmp-server enable traps cpu threshold command as follows:\nmyrouter(config)# snmp-server enable traps cpu threshold\n"
        },
        {
            "page_number": 100,
            "text": "Infrastructure Protection     77\nStep 2\nConfigure the router to send CPU traps to a trusted SNMP server \n(10.10.10.123 in this example). \nmyrouter(config)# snmp-server host 10.10.10.123 traps \nmycommunitystring cpu\nStep 3\nConfigure the threshold notification parameters. In the following \nexample, the CPU utilization threshold is set to 80 percent for a rising \nthreshold notification and 20 percent for a falling threshold notification \nwith a 5-second polling interval.\nmyrouter(config)# process cpu threshold type total rising 80 interval 5 \nfalling 20 interval 5\nYou can also configure memory threshold notifications. You can configure the router to send \nnotifications to a trusted SNMP server to indicate that free memory has fallen below a \nconfigured threshold. In addition, you can reserve memory to ensure that sufficient memory \nis available to issue critical notifications.\nNOTE\nMemory threshold notifications were introduced in Cisco IOS Software Version 12.2(18)S.\nYou can configure processor memory or input/output memory thresholds. To configure a \nprocessor memory threshold, use the memory free low-watermark processor threshold\nglobal command. You can specify input/output memory thresholds with the memory free \nlow-watermark io threshold command.\nIn addition, you can mitigate low-memory conditions by reserving a region of memory for \nthe router to use for the issuing of critical notifications. Reserving a block of memory for \nthese functions is useful because when a router is overloaded by processes the amount of \navailable memory might fall to levels insufficient for it to issue critical notifications. Use \nthe memory reserve critical kilobytes command to accomplish this.\nNOTE\nYou can obtain more information about Cisco IOS memory thresholding notification at \nhttp://www.cisco.com/en/US/products/sw/iosswrel/ps1838/\nproducts_feature_guide09186a00801b1bee.html.\nCPU Protection \nAttackers already know that targeting CPUs and network processors can affect more than \njust one server within an organization. Worms and DDoS can bring network infrastructure \ndevices onto their knees costing thousands of dollars. Attackers typically follow two \nstrategies when targeting a CPU. The first tactic that attackers employ is generating large \n"
        },
        {
            "page_number": 101,
            "text": "78\nChapter 2:  Preparation Phase\nvolumes of traffic to the CPU or network processor because CPUs always have a finite \ncapacity for processing packets. All processors have a limit regardless of the size or \ntechnology used. For this reason, some security experts say, It does not matter how much \ntraffic a device can pass; what’s important is how much traffic a device can drop. \nThe second tactic that attackers employ is making the network device generate large \nvolumes of packets. They do this by sending traffic to the network device, to the location \non the device where the CPU is expected to process and generate certain responses to \nspecific requests. An example is sending malformed packets and making the network \ndevice send ICMP unreachable messages. \nTo counteract these two strategies be sure to take advantage of the following best practices:\n•\nFiltering of traffic sent to the CPU: This is a key best practice. You should always \nmake sure that only the expected protocols are used with the network device. When \nbuilding these filters consider that, under normal circumstances, most traffic handled \nby infrastructure equipment is in transit over the forwarding path. Only a small \nportion of the traffic needs to be sent to the CPU for further analysis over the receive \npath. The traffic destined to the infrastructure equipment typically includes routing \nprotocols, remote access protocols such as SSH and Telnet, or SNMP.\nNOTE\nRemember the rules you learned earlier in this chapter for protecting SNMP \ncommunications. Receive ACLs (or rACLs) are an example of a filtering technique.\n•\nRate limit traffic sent to the CPU: The filters discussed in the previous bullet should \nbe combined with rate limiting techniques whenever possible. Another best practice \nis to implement a feature available on Cisco IOS routers called Control Plane Policing \n(CoPP). CoPP combines filtering with rate limiting to ensure that permitted traffic \nnever reaches levels that could overwhelm the CPU. This feature is covered later on \nin this chapter (in the “Control Plane Policing (CoPP)” section).\n•\nTraffic requiring CPU packet generation: Always control traffic that requires the \nCPU to generate packets. An example is using the ip icmp rate-limit command on \nCisco IOS routers to prevent ICMP unreachable attacks.\n•\nProcessor versus interrupt time: Each time a Cisco router or switch (depending on \nthe platform and feature implemented) receives a packet, it needs to interrupt other \ntasks to find out what to do with the packet. You can implement the scheduler allocate\ncommand or feature to tell the router to stop processing interrupts and to handle other \ntasks at regular intervals. This helps reduce the effects of fast packet floods.\nReceive Access Control Lists (rACLs)\nReceive access control lists (rACLs) are used to protect the Route Processor (RP) on high-\nend routers from malicious or unwanted traffic that could degrade performance.\n"
        },
        {
            "page_number": 102,
            "text": "Infrastructure Protection     79\nNOTE\nFrom the time this rACLs feature was originally introduced in 12.0 (22S for the \nCisco 12000 series routers), numerous service providers have taken advantage of it. \nHowever, it is now available on other high-end routing platforms including the \nCisco 7500 Series Routers and the Cisco 10000 Series Routers.\nAn rACL is just a standard or an extended ACL that controls the traffic sent by the various \nline cards to the RP. Because these high-end routers are designed in a distributed \narchitecture, this type of ACL only affects the traffic destined to the RP and does not affect \nthe transit traffic (traffic passing through the router).\nrACLs comprise mainly permit statements that allow the protocols and specific sources that \nare expected to send traffic to the RP. These ACLs may also include deny statements to \nblock specific unwanted traffic.\nNOTE\nAll ACLs have an implicit deny statement at the end.\nThe following is an example of an rACL. The rACL number is 123. It can be any number, \nhowever, all the access control entries (ACE) must use the same number. In the following \nexample, the router IP address is 209.165.200.225. Only BGP and OSPF are permitted from \nthe 192.168.10.0/24 network; all other traffic is denied.\n!The following ACEs allow BGP traffic to the RP (209.165.200.225)\naccess-list 123 permit tcp 192.168.10.0 0.0.0.255 host 209.165.200.225 eq bgp \naccess-list 123 permit tcp 192.168.10.0 0.0.0.255 eq bgp host 209.165.200.225\n!\n!The following ACEs allow OSPF traffic to the RP (notice that the OSPF multicast \n  address is\n!used instead of 209.165.200.225)\naccess-list 123 permit ospf 192.168.10.0 0.0.0.255 host 224.0.0.5\nOptionally, you can deny specific traffic to protocols like UDP, TCP, and ICMP for tracking \npurposes. To do so, you can add the following lines to the ACL.\naccess-list 123 deny udp any any \naccess-list 123 deny tcp any any\naccess-list 123 deny icmp any any\naccess-list 123 deny ip any any\nip receive access-list 123\nNOTE\nDo not forget to always apply the rACL with the ip receive access-list <num> command,\nas shown in the last line in the previous example. rACLs are created on the RP and then \npushed to the line card processors. All received packets are first sent to the line card CPU; \nhowever, any packets requiring processing by the RP are then compared against the rACL \nbefore they are sent to the RP.\n"
        },
        {
            "page_number": 103,
            "text": "80\nChapter 2:  Preparation Phase\nrACLs increase security by protecting the RP from direct attacks. However, because they \nare just filters, they do not provide rate limiting benefits that could control large volumes of \ntraffic that may match the permitted sources and protocols. CoPP offers rate limiting \ntechniques that replace the need for rACLs.\nTIP\nWhen deploying the rACLs, always remember to start slowly. In other words, gradually \nimprove security over time because, if you start too aggressively, your chance of dropping \nlegitimate traffic increases.\nControl Plane Policing (CoPP)\nYou can configure Quality of Service (QoS) policies to rate limit the traffic sent to the RP \nthat is protecting the control plane from reconnaissance and DDoS attacks. With the \nModular QoS Command-line (MQC) policies, you can permit, block, or rate limit traffic to \nthe RP. You can use MQC to define traffic into separate classes and to apply distinct QoS \npolicies based on different criteria.\nNOTE\nCoPP was introduced initially in 12.2(18)S for Cisco 7200, Cisco 7300, and Cisco 7500 \nseries routers, and it is now available on most IOS-based platforms.\nThe following example includes the definition of two classes: one for OSPF traffic, and one \nfor SSH used for remote management.\n!ACL classifying OSPF traffic sourced from 192.168.10.0/24\nip access-list extended ospf-traffic-acl\n remark OSPF traffic class\npermit ospf 192.168.10.0 0.0.0.255 host 244.0.0.4\n!\n!ACL classifying SSH traffic sourced from a management network (192.168.20.0/24)\nip access-list extended mgmt-traffic-acl\n remark CoPP remote management traffic\npermit tcp 192.168.20.0 0.0.0.255 host 209.165.200.225 eq 22\n!\n!Once the ACLs are configured, they are applied to each access class\nclass-map match-all ospf-class\n  match access-group name ospf-traffic-acl\n!\nclass-map match-all ssh-class\n  match access-group name mgmt-traffic-acl\n!\n!Apply the specific class to the actual policy (policy-map)\npolicy-map copp-policy\n class ospf-class\n!SSH traffic is limited to a rate of 15,000 bps; if traffic\n!exceeds that rate, it is dropped\n  class ssh-class\n"
        },
        {
            "page_number": 104,
            "text": "Infrastructure Protection     81\n     police 15000 1500 1500 conform-action transmit exceed-action drop\n!\n!Finally, apply the policy to the control plane\ncontrol-plane\n  service-policy input copp-policy\nNOTE\nYou can obtain an informative white paper on how to deploy CoPP from \nhttp://www.cisco.com/en/US/products/sw/iosswrel/ps1838/\nproducts_white_paper0900aecd802b8f21.shtml.\nScheduler Allocate/Interval\nYou can use the scheduler interval command to control the CPU time spent on processes \nversus interrupts. This is helpful when you are under attack or during a worm outbreak. \nWhen the router is handling thousands of packets per second, the console or Telnet/SSH \naccess may be slow and it may be almost impossible do anything.\nIn the following example, process-level tasks will be handled no less frequently than every \n500 milliseconds.\nmyrouter(config)# scheduler interval 500\nIn newer platforms, the scheduler allocate command is used instead of scheduler interval.\nThe scheduler allocate command is used to configure two intervals: \n•\nInterval with interrupts enabled\n•\nInterval with interrupts masked\nThe following example includes the scheduler allocate command with the values included \nin AutoSecure (a Cisco IOS feature explained later in this chapter in the “Cisco IOS \nAutoSecure” section). \nmyrouter(config)# scheduler allocate 4000 1000\nCisco recommends these values for most environments.\nNOTE\nThe scheduler interval and scheduler allocate commands should not cause negative \neffects. It is recommended that these two commands be part of your standard router \nconfiguration, unless you have a specific reason to avoid using them. \nPolicy Enforcement\nAn entire book could be devoted to a discussion of policy enforcement. Also, you must \ndesign the enforcement of security policies according to your organization goals. \nTherefore, this section cannot fully cover policy enforcement or provide recommendations \n"
        },
        {
            "page_number": 105,
            "text": "82\nChapter 2:  Preparation Phase\nspecific to your own business organization. It can, however, outline some common \nstrategies that you can use when configuring network infrastructure devices to make sure \nthat access to the areas of your network and its devices is granted only when needed by \nauthorized sources.\nThe most common security policy enforcement mechanism is the use of packet filters at the \nvarious edges of the network. For example, you can configure firewalls or ACLs on routers \nto act as the first line of protection against external threats. Again, you should configure \nsecurity policies based on the area in which your infrastructure components reside. For \nexample, you will not configure the same policies for your Internet edge devices as the \npolicies configured for your datacenter, core, and so on. Many engineers call this \n“configuration per device role.” The roles of your device should develop your configuration \ntemplates. You can take several best practices into consideration when developing such \nconfiguration templates: \n•\nAlways make sure that external authorized sources can only communicate with \ninternal devices via the expected protocols and ports. \n•\nRFC 3330 describes the special use of IP addresses that may require filtering from \nsources of external devices. You should always filter packets with RFC 1918 private \nIP addresses that are not expected to be routed on the Internet. \n•\nFollow the basic antispoofing services defined in RFC 2827. \nThe common technique used to accomplish these tasks is called Infrastructure Protection \nACLs (iACLs). You can also configure Unicast Reverse Path Forwarding (Unicast RPF) for \nantispoofing.\nInfrastructure Protection Access Control Lists (iACLs)\nUsing iACLs is a technique that was developed by ISPs, however, it is now a common \npractice by enterprises and other organizations. Employing iACLs involves the use of ACLs \nthat prevent direct attacks to infrastructure devices. You configure these ACLs to \nspecifically allow only authorized traffic to the infrastructure equipment while allowing \ntransit traffic. Cisco recommends that you configure iACLs into four different sections or \nmodules:\n1 On the Internet edge, deny packets from illegal sources (RFC 1918 and RFC 3330 \naddresses). In addition, deny traffic with source addresses belonging within your \naddress space entering from an external source. For example, if your address space is \n209.165.201.0/24, you should configure an iACL to deny traffic from any external \nsource by using an address from this space. The following example includes iACL \nentries (part of ACL number 123) used to deny RFC 3330 special-use addresses.\n   access-list 123 deny ip host 0.0.0.0 any\n   access-list 123 deny ip 127.0.0.0 0.255.255.255 any\n   access-list 123 deny ip 192.0.2.0 0.0.0.255 any\n   access-list 123 deny ip 224.0.0.0 31.255.255.255 any\nThe following entries deny RFC 1918 traffic.\n"
        },
        {
            "page_number": 106,
            "text": "Infrastructure Protection     83\n   access-list 123 deny ip 10.0.0.0 0.255.255.255 any\n   access-list 123 deny ip 172.16.0.0 0.15.255.255 any\n   access-list 123 deny ip 192.168.0.0 0.0.255.255 any\n2 Configure iACL entries providing explicit permission for traffic from trusted external \nsources destined to your infrastructure address space.\n3 Deny all other traffic from external sources destined to infrastructure components \naddresses as shown in the following example.\n   access-list 123 deny ip any 209.165.201.0 0.0.0.255\n4 Unlike ISPs, enterprises are the destination for traffic. The last section of the iACL \npermits all other normal backbone traffic destined to noninfrastructure destinations \nfor only specific protocols and ports. For example, you can allow HTTP for a web \nserver bank with IP address space 209.165.200.0/24, as follows:\n   access-list 123 permit tcp any 209.165.200.0 0.0.0.255 eq http\nISPs allow all transit traffic at the end of the iACL using a permit ip any any ACL\nentry.\nUnicast Reverse Path Forwarding (Unicast RPF)\nUnicast Reverse Path Forwarding (Unicast RPF) is a feature that can replace the use of RFC \n2827 ingress traffic filtering techniques. Unicast RPF is configured and enabled on a per-\ninterface basis. The main purpose of Unicast RPF is to verify that all packets received from \na specific interface have a source address that is reachable via that same interface. The \nrouter drops all packets that do not comply.\nNOTE\nYou must turn on Cisco Express Forwarding (CEF) for Unicast RPF to work.\nTwo Unicast RPF modes are available: \n•\nStrict mode: Requires that the source IP address of an incoming packet has a reverse \npath to the same interface from which it has arrived.\n•\nLoose mode: Requires that the source IP address of an incoming packet has a reverse \npath to any interface on the device (except null0). In many cases, an enterprise may \nhave dual connections to the Internet; therefore, Unicast RPF strict mode is not \nfeasible. Only use Unicast RPF strict mode in deployments where the reverse path \nentries match the traffic paths, otherwise you risk discarding legitimate traffic.\nThe following example demonstrates how to enable Unicast RPF strict mode on an \ninterface (FastEthernet 1/0 in this case).\nRouter(config)# interface FastEthernet 1/0\nRouter(config-if)# ip verify unicast source reachable-via rx\n"
        },
        {
            "page_number": 107,
            "text": "84\nChapter 2:  Preparation Phase\nThe following example demonstrates how to enable Unicast RPF loose mode on an \ninterface (Serial2 in this case).\nRouter(config)# interface Serial2\nRouter(config-if)# ip verify unicast source reachable-via any\nAutomated Security Tools Within Cisco IOS\nThe feature within Cisco IOS called AutoSecure enables you to lock down your routers by \nenhancing the security of the management and the forwarding planes. Similarly, you can \nperform automatic audit and self-configuration options with Cisco Security Device \nManager (SDM).\nCisco IOS AutoSecure\nCisco AutoSecure disables the unnecessary global services previously discussed in this \nchapter. It also enables certain services that help further secure global services that are often \nnecessary. In addition, Cisco AutoSecure hardens administrative access by enabling \nappropriate security-related logging features. It is recommended in most environments \nbecause it implements a range of best practices that help secure any organization. It also \nreduces the time required to configure each item by hand.\nNOTE\nCisco AutoSecure was introduced in Cisco IOS Software Version 12.3 and in subsequent \n12.3T releases for the Cisco 800, 1700, 2600, 3600, 3700, 7200, and 7500 Series Routers.\nCisco AutoSecure has two modes of operation:\n•\nInteractive: Users select their own options for services and other security-related \nfeatures.\n•\nNoninteractive: This mode automatically enables a set of Cisco recommended \nsecurity features and disables unnecessary services.\nTIP\nThe Interactive mode enables you to have more control over the router security features that \nyou want to enable. However, if you need to quickly secure a router without much human \nintervention, the noninteractive mode is appropriate.\nYou can also specify what part of the AutoSecure suite of commands and features \nyou would like to configure. The following example shows the options of the auto secure\ncommand.\n"
        },
        {
            "page_number": 108,
            "text": "Infrastructure Protection     85\nmyrouter#auto secure ?\n  firewall       AutoSecure Firewall\n  forwarding     Secure Forwarding Plane\n  full           Interactive full session of AutoSecure\n  login          AutoSecure Login\n  management     Secure Management Plane\n  no-interact    Non-interactive session of AutoSecure\n  ntp            AutoSecure NTP\n  ssh            AutoSecure SSH\n  tcp-intercept  AutoSecure TCP Intercept\n  <cr>\nIn the next example, the auto secure command is invoked with no options; therefore, the \ncomplete suite of configuration options is presented to the user.\nmyrouter#auto secure\n                --- AutoSecure Configuration ---\n*** AutoSecure configuration enhances the security of\nthe router, but it will not make it absolutely resistant\nto all security attacks ***\nAutoSecure will modify the configuration of your device.\nAll configuration changes will be shown. For a detailed\nexplanation of how the configuration changes enhance security\nand any possible side effects, please refer to Cisco.com for\nAutoSecure documentation.\nAt any prompt you may enter ‘?’ for help.\nUse ctrl-c to abort this session at any prompt.\nGathering information about the router for AutoSecure\nIs this router connected to internet? [no]: yes\nEnter the number of interfaces facing the internet [1]: 1\nInterface                  IP-Address      OK? Method Status                Protocol\nFastEthernet0/0            unassigned      YES NVRAM  administratively down down\nFastEthernet0/1            unassigned      YES NVRAM  administratively down down\nEnter the interface name that is facing the internet: FastEthernet0/0\nSecuring Management plane services...\nDisabling service finger\nDisabling service pad\nDisabling udp & tcp small servers\nEnabling service password encryption\nEnabling service tcp-keepalives-in\nEnabling service tcp-keepalives-out\nDisabling the cdp protocol\nDisabling the bootp server\nDisabling the http server\nDisabling the finger service\nDisabling source routing\nDisabling gratuitous arp\nHere is a sample Security Banner to be shown\nat every access to device. Modify it to suit your\nenterprise requirements. \nAuthorized Access only\n  This system is the property of So-&-So-Enterprise.\n  UNAUTHORIZED ACCESS TO THIS DEVICE IS PROHIBITED.\n  You must have explicit permission to access this\n  device. All activities performed on this device\n  are logged. Any violations of access policy will result\n  in disciplinary action.\nEnter the security banner {Put the banner between\nk and k, where k is any character}:\n~  UNAUTHORIZED ACCESS TO THIS DEVICE IS PROHIBITED.\n  You must have explicit permission to access this\n  device. All activities performed on this device\n  are logged. Any violations of access policy will result\n  in disciplinary action.\n"
        },
        {
            "page_number": 109,
            "text": "86\nChapter 2:  Preparation Phase\n~\nEnable secret is either not configured or\n is the same as enable password\nEnter the new enable secret:1qaz@WSX\nConfirm the enable secret :1qaz@WSX\nEnter the new enable password:2wsx!QAZ\nConfirm the enable password:2wsx!QAZ\nConfiguration of local user database\nEnter the username: admin\nEnter the password:1qaz@WSX\nConfirm the password:1qaz@WSX\nConfiguring AAA local authentication\nConfiguring Console, Aux and VTY lines for\nlocal authentication, exec-timeout, and transport\nSecuring device against Login Attacks\nConfigure the following parameters\nBlocking Period when Login Attack detected: 15\nMaximum Login failures with the device: 3\nMaximum time period for crossing the failed login attempts: 60\nConfigure SSH server? [yes]: yes\nEnter the domain-name: cisco.com\nConfiguring interface specific AutoSecure services\nDisabling the following ip services on all interfaces:\n no ip redirects\n no ip proxy-arp\n no ip unreachables\n no ip directed-broadcast\n no ip mask-reply\nDisabling mop on Ethernet interfaces\nSecuring Forwarding plane services...\nEnabling CEF (This might impact the memory requirements for your platform)\nEnabling unicast rpf on all interfaces connected\nto internet\nConfigure CBAC Firewall feature? [yes/no]: yes\nThis is the configuration generated:\nno service finger\nno service pad\nno service udp-small-servers\nno service tcp-small-servers\nservice password-encryption\nservice tcp-keepalives-in\nservice tcp-keepalives-out\nno cdp run\nno ip bootp server\nno ip http server\nno ip finger\nno ip source-route\nno ip gratuitous-arps\nno ip identd\nbanner motd ^C  UNAUTHORIZED ACCESS TO THIS DEVICE IS PROHIBITED.\n  You must have explicit permission to access this\n  device. All activities performed on this device\n  are logged. Any violations of access policy will result\n  in disciplinary action.\n^C\nsecurity passwords min-length 6\nsecurity authentication failure rate 10 log\nenable secret 5 $1$gGZi$aoXeicM9JVVMfi0K6lFl50\nenable password 7 14141B180F0B7B79777C66\nusername admin password 7 030752180500701E1D\naaa new-model\naaa authentication login local_auth local\nline con 0\n"
        },
        {
            "page_number": 110,
            "text": "Infrastructure Protection     87\n login authentication local_auth\n exec-timeout 5 0\n transport output telnet\nline aux 0\n login authentication local_auth\n exec-timeout 10 0\n transport output telnet\nline vty 0 4\n login authentication local_auth\n transport input telnet\nline tty 1\n login authentication local_auth\n exec-timeout 15 0\nline tty 192\n login authentication local_auth\n exec-timeout 15 0\nlogin block-for 15 attempts 3 within 60\nip domain-name cisco.com\ncrypto key generate rsa general-keys modulus 1024\nip ssh time-out 60\nip ssh authentication-retries 2\nline vty 0 4\n transport input ssh telnet\nservice timestamps debug datetime msec localtime show-timezone\nservice timestamps log datetime msec localtime show-timezone\nlogging facility local2\nlogging trap debugging\nservice sequence-numbers\nlogging console critical\nlogging buffered\ninterface FastEthernet0/0\n no ip redirects\n no ip proxy-arp\n no ip unreachables\n no ip directed-broadcast\n no ip mask-reply\n no mop enabled\ninterface FastEthernet0/1\n no ip redirects\n no ip proxy-arp\n no ip unreachables\n no ip directed-broadcast\n no ip mask-reply\n no mop enabled\nip cef\naccess-list 100 permit udp any any eq bootpc\ninterface FastEthernet0/0\n ip verify unicast source reachable-via rx allow-default 100\nip inspect audit-trail\nip inspect dns-timeout 7\nip inspect tcp idle-time 14400\nip inspect udp idle-time 1800\nip inspect name autosec_inspect cuseeme timeout 3600\nip inspect name autosec_inspect ftp timeout 3600\nip inspect name autosec_inspect http timeout 3600\nip inspect name autosec_inspect rcmd timeout 3600\nip inspect name autosec_inspect realaudio timeout 3600\nip inspect name autosec_inspect smtp timeout 3600\nip inspect name autosec_inspect tftp timeout 30\nip inspect name autosec_inspect udp timeout 15\nip inspect name autosec_inspect tcp timeout 3600\nip access-list extended autosec_firewall_acl\n permit udp any any eq bootpc\n deny ip any any\n"
        },
        {
            "page_number": 111,
            "text": "88\nChapter 2:  Preparation Phase\ninterface FastEthernet0/0\n ip inspect autosec_inspect out\n ip access-group autosec_firewall_acl in\n!\nend\nApply this configuration to running-config? [yes]:yes\nIn the previous example, the router has the interface (FastEthernet0/0) that is connected to \nthe Internet. The AutoSecure utility applies predefined commands based on best practices \nfor Internet-edge routers. The router then guides the user on enabling other features, such \nas defining a banner, configuring passwords and administrative accounts, and enabling \nCisco IOS Firewall set or Context-Based Access Control (CBAC).\nCisco Secure Device Manager (SDM)\nSDM is an intuitive web-based tool designed for configuring LAN, WAN, and security \nfeatures on a router. SDM includes a feature called Security Audit that is used to verify your \nexisting router configuration and make sure that it includes the recommended security \nmechanisms suited for most environments. The SDM Security Audit is based on the Cisco \nIOS AutoSecure feature.\nNOTE\nSDM does not support all AutoSecure features. For a complete list of the functions that \nSecurity Audit checks for, and for a list of the few AutoSecure features unsupported by \nSecurity Audit, go to http://www.cisco.com/en/US/products/sw/secursw/ps5318/\nproducts_user_guide_chapter09186a0080656061.html#wp1061799.\nComplete the following steps to have SDM perform a security audit, and then fix the \nconfiguration deficiencies it finds. \nStep 1\nLog in to SDM via HTTPS. For example, if your router IP address is \n192.168.10.1, you can access SDM by typing https://192.168.10.1.\nStep 2\nAfter you have logged in, select Security Audit from the left frame or \nnavigation panel.\nStep 3\nClick Perform Security Audit. The Welcome page of the Security Audit \nWizard appears. \nStep 4\nClick Next. The Security Audit Interface Configuration screen is shown. \nStep 5\nYou have to tell SDM which of your router interfaces connect to the \nInternet (or outside networks) and which connect to your protected (or \ninside) networks. Select either the Inside or Outside check box to \nindicate where each interface connects and click Next.\n"
        },
        {
            "page_number": 112,
            "text": "Infrastructure Protection     89\nStep 6\nSDM verifies your router configuration and identifies any security \ndeficiencies. A window pops-up displays listing the configuration \noptions being audited and whether the current router configuration passes \nsuch tests. Optionally, you can save the audit report to a file by clicking \nSave Report.\nStep 7\nClick Close.\nStep 8\nThe list of possible security problems is displayed. Check the Fix it\nboxes next to any problems that you want SDM to fix. You can view a \ndescription of each problem and a list of the Cisco IOS commands that \nwill be added to your configuration by clicking Problem Description.\nStep 9\nClick Next. SDM may display one or more screens requiring you to enter \ninformation to fix certain problems. Enter the information as required \nand click Next for each of those screens. \nStep 10 A summary page listing all the configuration changes that SDM will \nmake is displayed. To send those changes to the router, click Finish.\nNOTE\nYou can also use the One-Step Lockdown feature in SDM to test your router configuration \nfor any potential security problems and fix them automatically.\nTelemetry\nThe automated measurement and transmission of data for analysis is what many people call \ntelemetry. Cisco routers and switches have different mechanisms that offer a form of \ntelemetry. An example is NetFlow. You can use NetFlow to obtain statistical information \nthat can help you identify and classify attacks. This information can be collected from the \nCLI or can be exported to monitoring tools such as Cisco Secure Monitoring, Analysis, and \nResponse System (CS-MARS) and Arbor Peakflow. The use of monitoring and event \ncorrelation tools is recommended because it can save you numerous hours of your busy \nschedule trying to digest information from logs, NetFlow, and other sources. \nNOTE\nDetailed information about how to identify and classify attacks is covered in Chapter 3. \nHowever, this section includes several telemetry best practices that help you better prepare \nand protect your infrastructure.\nYou must accurately synchronize the time and date with network telemetry. This is why it \nis crucial to enable Network Time Protocol (NTP) in network devices. Imagine trying to \nanalyze and correlate network events if all your routers, switches, firewalls, and other \n"
        },
        {
            "page_number": 113,
            "text": "90\nChapter 2:  Preparation Phase\nnetwork devices have different times and dates. For instance, if you were analyzing firewall \nlogs and correlating them to NetFlow data, and the time was not synchronized, this task \ncould be impossible. \nNOTE\nYou can obtain information about NTP at http://www.ntp.org or at http://www.cisco.com/\nen/US/tech/tk648/tk362/tk461/tsd_technology_support_sub-protocol_home.html.\nAnother best practice is to send network telemetry information over out-of-band (OOB) \nmechanisms because this minimizes the chance for disruption of the information that \nprovides network visibility, which is critical to successfully operating and defending the \nnetwork. This is why it is always recommended that you have a management VLAN or \nsection of the network where an interface of each network device can communicate with \nmanagement stations and systems. \nNetFlow data helps you identify DDoS attacks, network worms, and other forms of \nundesirable traffic. In addition, it is a key auditing and forensics tool. For instance, you can \ncollect NetFlow data and map Network Address Translations (NAT) and ensure that your \npolicy enforcement measures are working as expected.\nNOTE\nChapter 3 includes several NetFlow configuration examples. It also shows how you can \nidentify and classify security events using event correlation tools, such as CS-MARS. \nEndpoint Security\nThis section includes several best practices and tips that you can use when implementing \ntechniques and tools to increase the security of your endpoints (workstations, servers, and \nso on). You need to perform two major tasks when you are preparing your organization to \nenhance endpoint security. The first is patch management and keeping the endpoint systems \n(servers and workstations specifically) up-to-date. The second is using security software \nlike the Cisco Security Agent (CSA) on servers and user desktop machines to protect them \nagainst known and unknown security threats.\nPatch Management\nA solid patch management strategy is crucial with the rise of widespread worms and \nmalicious code that targets known vulnerabilities on unpatched systems. This is why the \nincreasing governance and regulatory compliance enforcement by organizations like \n"
        },
        {
            "page_number": 114,
            "text": "Endpoint Security     91\nHIPAA and Sarbanes-Oxley has pressed organizations hard to gain better control and \noversight of their information assets. \nThe main objective of a patch management program is to create a consistently configured \nenvironment that is secure against known vulnerabilities in operating system and \napplication software. Patch management solutions vary in design and implementation. \nRegardless, several technology-neutral best practices are listed in this section and can be \nfollowed no matter what patch management software or solution you use. \nA good practice is to designate a point person or a team that is responsible for keeping up-\nto-date on newly released patches and security threats that affect the systems and \napplications deployed within your organization. Have a complete and accurate asset \ninventory to determine whether all existing systems are accounted for when preparing and \ndeploying patches and updates. \nAlso, prioritize and schedule the necessary application patches/updates. A patch update \ncycle must exist to facilitate the application of standard patch releases and updates. You can \nperform the cycle in a scheduled time fashion or based on events. You can implement the \ntime-based scheduled cycle weekly, biweekly, or monthly, depending on the organization \npolicies. In contrast, you can coordinate the scheduling cycle with critical security patches \nand updates. This plan should help you deal with the prioritization and scheduling of \nupdates that must be deployed in a more immediate fashion. \nPreferably, you should test patches and updates before deploying them to your systems. In \ncritical situations when a security patch is needed because of a worm or a security outbreak, \ndetailed testing may not be possible or feasible. The initial phases of production rollout can \nbe considered an additional component of the testing process. Rollouts are often \nimplemented in tiers with the initial tiers often involving less critical systems. Based on the \nperformance of these stages of the patch deployment process, the entire environment will \nbe updated, and the testing process can be considered finished with the completion of final \nacceptance testing. \nRegular audits and assessment help gauge the success and extent of patch management \nefforts. You should always determine what systems you need to patch for any given \nvulnerability or a bug. In addition, you should always verify that the systems that are \nsupposed to be updated have been patched.\nPatch management software packages are available from many vendors. The following are \nsome of the most popular ones:\n•\nIBM Tivoli\n•\nUnicenter\n•\nMicrosoft SMS\n•\nPatchLink\n•\nAltiris\n"
        },
        {
            "page_number": 115,
            "text": "92\nChapter 2:  Preparation Phase\nThe major requirement for any patch management system is the ability to accurately track \ndeployed hardware and software throughout the enterprise, including remote users and \noffice locations. \nCisco Security Agent (CSA)\nCSA provides several more robust security features than a traditional antivirus or a personal \nfirewall solution. The rich security features of CSA include:\n•\nHost intrusion prevention \n•\nProtection against spyware\n•\nProtection against buffer overflow attacks \n•\nDistributed host firewall features \n•\nMalicious mobile code protection \n•\nOperating system integrity assurance \n•\nApplication inventory \n•\nExtensive audit and logging capabilities \n•\nProtection against file modification or deletion\nThe CSA solution has two major components:\n•\nCisco Security Agent Management Center (CSA-MC): The management console \nwhere all groups, policies, and agent kits are configured\n•\nCisco Security Agent: The agent installed on end-user machines\nThe CSA-MC is the central management system that allows you to define and distribute \npolicies, provide software updates, and maintain communications to the CSAs installed in \nend-user machines and servers. CSA-MC comes with a list of predefined groups you can \nuse to meet initial needs. A group is the only element required to build an agent kit. The use \nof groups eases the management of large numbers of agents. When using groups, you can \nconsistently apply the same policy to numerous hosts. \nAgent kits are the configuration and installation packages of the agent software to be \ndeployed to end-user machines. You must associate agent kits with configured groups. \nAgents installed on end-user hosts are automatically placed into their assigned group or \ngroups when they register with CSA-MC. The agents enforce the associated policies of \neach group.\nNOTE\nChapter 12, “Case Studies,” includes a case study showing the deployment of CSA. You can \nget more information and documentation at http://www.cisco.com/en/US/products/sw/\nsecursw/ps5057/index.html.\n"
        },
        {
            "page_number": 116,
            "text": "Endpoint Security     93\nIt is recommended that you place the CSAMC server on your management network \n(management VLAN). When doing this, you need to understand how the agents \ncommunicate with CSAMC and vice versa. The agents communicate with CSAMC over \nTCP port 5401, with a fallback to TCP port 443 (if TCP port 5401 communication is not \npossible). By default, CSA Profiler uses TCP port 5402 to communicate with CSAMC; \nhowever, this is configurable. Make sure that any firewalls or filtering devices allow this \ncommunication. CSAMC should be reached by all systems that are running the agent.\nAnother important factor is that the hardware running CSAMC must be sized appropriately. \nThe current version of CSAMC is capable of managing up to 100,000 agents. However, it \nis recommended that you install and strategically deploy additional CSAMC servers \ndepending on your network topology and geographical needs.\nNOTE\nFor a list of hardware requirements, refer to the release notes on the Cisco website at \nhttp://www.cisco.com/en/US/products/sw/secursw/ps5057/index.html.\nDuring the lab test and pilot phases, it is recommended that you start by using the default \nCSA policies (depending on the type of system where the agent is installed). The default \nCSA policies provide a good level of protection to the end hosts. Tuning of these is \nrecommended; however, these default policies are known for stopping new and unknown \nthreats.\nAlways select at least one host per each distinct application environment during the initial \ntesting phase. During the pilot, the test hosts should be a mirror sample of the production \nsystems. In addition, you may want to use a test machine per each server type to ensure no \nnegative impact from CSA agent software installation. It is also recommended that you \ncreate a group for each type of application environment that needs to be protected. \nBuilding and tuning of CSA policies is a continuous task; therefore, you must have the \nproper staff and procedures to minimize the administrative burden. The security staff is not \nonly responsible for maintaining the CSAMC policies, but also for creating and organizing \nexception rules appropriately, and for monitoring user activity. You can organize the \nexception rules as follows:\n•\nCreate a global exception policy to allow legitimate traffic and application behavior \nthat is required on all the systems within the organization. Subsequently, add these \nglobal exception rules to this exception policy.\n•\nCreate one exception policy for each group. \n•\nApply these policies to their respective groups, and collect all necessary data to \ncomplete any additional tuning.\n"
        },
        {
            "page_number": 117,
            "text": "94\nChapter 2:  Preparation Phase\nWhen you start the deployment of the agent kits throughout the organization, always start \nby deploying the agents in test mode throughout your organization. It is a best practice to \ncollect and analyze results and start policy tuning (as needed). After the initial tuning is \ndone, enable protection mode. \nNOTE\nMake sure that your security, operations, and engineering staff members are trained to \nsupport your deployment.\nNetwork Admission Control\nIn Chapter 1, “Overview of Network Security Technologies,” you learned the concepts of \nNetwork Admission Control (NAC) and the differences between the appliance-based \napproach and the architecture-based framework solution. The architecture-based \nframework solution is intended to use a collection of both Cisco networking and security \ntechnologies, as well as existing deployments of security and management solutions from \nother vendors. This section includes several best practices when implementing NAC within \nyour environment. These best practices can be followed when preparing, designing, or \nimplementing any of the NAC solutions (Framework or Appliance).\nNOTE\nChapter 12 includes a case study where NAC is deployed. The configuration of NAC \nappliance and NAC Framework components is also in that chapter.\nPhased Approach\nTo achieve a successful enterprise-wide deployment of the Cisco NAC solutions, it is first \nnecessary to have a solid background in the operational, management, and support \nfunctions required by such a deployment. Create a clear and detailed test and \nimplementation plan to overcome challenges and follow a phased approached. For \ninstance, it is always strongly recommended that you test any new technology or product \nin a lab environment first. Subsequently, you should complete and carefully evaluate a pilot \nwithin a limited production environment. If at all possible, this environment should include \na sample of the systems available within the rest of the production network. This allows \nyour network and security staff to quantify the effects of the new NAC solution on the \norganization without actually affecting the production network. This may not be easy to do \nin many smaller environments; however, it is still recommended. Your security and network \nstaff members will gain valuable training and experience with the new technologies being \ndeployed and understand their interaction with the existing infrastructure.\n"
        },
        {
            "page_number": 118,
            "text": "Network Admission Control     95\nThe following are the key points and phases when planning, designing, testing, and \ndeploying NAC throughout your organization:\n•\nReadiness assessment: Complete a readiness assessment of your current \ninfrastructure. Assuming that the organization has a corporate security policy, \ncomplete a gap analysis determining what NAC policies to develop.\n•\nStakeholders: Identify who will be the stakeholders during the initial tests and the \nrest of the deployment. \n•\nInitial lab testing: Build an initial lab environment.\n•\nTest plans: Create a detailed test plan for lab and limited-production pilot.\n•\nInitial tuning: Complete any initial tuning of policies, configurations, and procedures \non the test network.\n•\nFinal deployment strategy: Start the deployment in the production environment in \naccordance with the deployment model devised from the pilot environment. Monitor \nthe deployment stages and tune accordingly.\nTesting and validation are critical best practices. Proper lab testing can significantly reduce \nproduction downtime, help your network and security support staff to become familiar with \nthe NAC solution, and assist in streamlining the implementation processes. To be effective, \nhowever, the organization must allocate the necessary resources to build and maintain the \nappropriate lab environment, apply necessary resources to perform the correct tests, and use \na recommended testing methodology that includes measurement collection. Without giving \neach of these areas detailed attention, the testing and validation process may not meet the \nexpectations of an organization. \nMany organizations do not take the time to build the recommended test lab environment. \nConsequently, they have deployed solutions incorrectly and have experienced network \nfailures that could have been isolated in a lab environment. In some environments, this is \nacceptable because the cost of downtime does not offset the cost of a sophisticated lab \nenvironment. Many organizations, however, cannot tolerate downtime. These organizations \nare strongly urged to develop the recommended test labs, test types, and test methodologies \nto improve production network quality.\nIdentify a section of the network where you can successfully test the new NAC features and \ndevices you may be implementing. This helps to minimize potential exposure and to more \nsafely identify any production issues. For example, in the previous chapter, you learned \nhow to successfully deploy Layer 2, Layer 3, wireless, and remote access VPN NAC \nfeatures on different sites within an organization. During the pilot selection phase, you may \nidentify an area or branch office where you can test the specific features to be deployed. \nPilot selection identifies where and how the pilot will be completed. The limited-production \npilot may start with one device in a low-impact area and extend to multiple devices in a \nhigher-impact area. You should perform a risk analysis to identify what areas and users can \ndeal with some possible production impacts. You can also use the “monitor-mode” \napproach. In other words, you can configure the Cisco Secure ACS policies for Healthy, \n"
        },
        {
            "page_number": 119,
            "text": "96\nChapter 2:  Preparation Phase\nQuarantine, and Transition. You should, however, still allow users to access the network. \nThis way you can quantify the impact of enforcing the configured policies and determine \nwhat and why machines are being quarantined or placed into any other state.\nBase the duration of this pilot on the time it takes to sufficiently test and evaluate all the \nsoftware, hardware, and third-party features and their dependencies. During the pilot phase, \nmonitor and document results in a manner similar to that used in the initial lab testing. This \ncan include user surveys, pilot data collection, and problem identification. \nAdministrative Tasks\nYou need to recognize the administrative tasks that are involved in maintaining all the NAC \npolicies. Some of the most common administrative tasks include:\n•\nKeeping the operating system (OS) policies up-to-date: Update your NAC policies \nin ACS every time a new OS critical patch comes out. If you fail to update, the host \nwill be allowed to the network without having this update installed. This can be an \nadministrative headache. That is why it is important that you have clear procedures \nand the correct staff in place to be able to support these tasks.\n•\nKeeping your antivirus policies up-to-date: In the NAC Appliance solution, you can \nconfigure the Clean Access Manager (CAM) to automatically download information \nfrom Cisco about the latest antivirus patches. In contrast, in NAC framework solution, \nyou have to configure Cisco Secure ACS to work in concert with antivirus vendor \nsoftware (such as Trend Micro OfficeScan policy server) to validate endpoint antivirus \ncredentials. In this case, you also have to keep up with the latest signatures in the \nantivirus server. Commonly, this is done by automatic mechanisms helping the \nadministrative overhead of such tasks.\n•\nMaintaining remediation servers and third-party software: Remediation servers \nneed to be up-to-date so that you can successfully remediate machines that are put into \nquarantine for not having the latest version of the required software dictated in the \nconfigured NAC policies. What good is an expensive car if you do not have the fuel \nto run it? The same principle applies here. You can have the most elaborate \nremediation servers and mechanisms; however, if you do not keep them up-to-date, \nthey might not be useful when you try to fix machines that have been put into \nquarantine because of the discovery of security deficiencies. You can obtain the most \ncurrent list of third-party remediation partners from http://www.cisco.com/en/US/\nnetsol/ns466/networking_solutions_package.html.\n Staff and Support\nPrepare your networking and security staff members to support the common administrative \ntasks discussed in the previous section. In addition, establish a clear technical support \nstructure and a well-structured call routing process to provide end users the correct \n"
        },
        {
            "page_number": 120,
            "text": "Summary     97\nresources as quickly as possible. Most NAC-related support calls to your help desk will \ninvolve users who are not able to access the network (or are granted limited access) because \ntheir machines do not meet the standards that the security policy is enforcing. \nConsequently, these calls will most likely be high severity/priority calls. This is a worthy \nconsideration when you are planning the deployment of the NAC solution and evaluating \nthe impact on your support staff. \nEducating users on setting the severity of the service request accurately, based on the \nimpact to the organization, allows you to allocate the appropriate resources to resolve \nproblems more efficiently. Using online resources and education material will also help \nalleviate the support process. The “life expectancy” of these calls will depend on why the \nuser cannot access the network. For instance, a user may open a service request because his \nmachine has been placed into quarantine and has failed to install an OS patch or antivirus \nsignature update. In another instance, a user workstation may be infected and require more \ndetailed work. \nHave clearly defined escalation procedures. Having solid escalation procedures prevents \nservice requests from being escalated prematurely. During the troubleshooting process, the \nengineer assigned to assist the user may determine that an onsite engineer is required to \nresolve the issue. Have a clear process in place for the engineer to contact a resource onsite.\nSummary\nThis chapter is one of the most vital chapters of this book. It covered the fundamentals of \nhow to better prepare yourself, your network, and your organization as a whole against \nsecurity threats and vulnerabilities. It presented risk analysis and threat modeling \ntechniques and discussed the process of creating strong security policies. This chapter also \ndescribed how necessary CSIRTs are for your organization and provided the most common \ntechniques when forming and managing a CSIRT.\nTopics such as security intelligence and social engineering were covered in this chapter. \nSecuring your infrastructure is one of the most challenging tasks. This chapter gave you \ndetailed information on how to protect your infrastructure against many different \nvulnerabilities and threats. \nYou learned how to better secure end-user systems and servers (endpoint security) in this \nchapter. In addition, you read a summary of how identity management and Network \nAdmission Control (NAC) can help you protect against viruses, worm outbreaks, and other \nvulnerabilities. The best practices outlined in this chapter are crucial for any organization.\n"
        },
        {
            "page_number": 121,
            "text": "This chapter covers the following topics:\n•\nNetwork Visibility\n•\nTelemetry and Anomaly Detection\n•\nIntrusion Detection and Intrusion Prevention Systems (IDS/IPS)\n"
        },
        {
            "page_number": 122,
            "text": "C H A P T E R 3\nIdentifying and Classifying \nSecurity Threats\nWorms and denial of service (DoS) attacks are used maliciously to consume the resources \nof your hosts and network that would otherwise be used to serve legitimate users. In some \ncases, misconfigured hosts and servers can send traffic that consumes network resources \nunnecessarily. Having the necessary tools and mechanisms to identify and classify security \nthreats and anomalies in the network is crucial. This chapter presents several best practices \nand methodologies you can use to successfully and quickly identify and classify such \nthreats.\nMost people classify security attacks into two separate categories: logic attacks and \nresource attacks. Logic attacks exploit existing software deficiencies and vulnerabilities to \ncause systems to crash, to substantially degrade their performance, or to enable attackers to \ngain access to a system. An example of this type of attack is the exploit of the Microsoft \nPnP MS05-039 Overflow Vulnerability, in which the attacker exploits a stack overflow in \nthe Windows “plug and play” (PnP) service. You can exploit this vulnerability on Windows \n2000 without a valid user account. Another example is the famous and old ping-of-death,\nwhereby an attacker sends the system Internet Control Message Protocol (ICMP) packets \nthat exceed the maximum legal length (65535 octets). You can prevent most of these attacks \nby either upgrading the vulnerable software or by filtering particular packet sequences.\nThe second category of attacks is referred to as resource attacks. The goal with these types \nof attacks is to overwhelm the victim system/network resources, such as CPU and memory. \nIn most cases, this is done by sending numerous IP packets or forged requests. An attacker \ncan build up a more powerful attack with a more sophisticated and effective method of \ncompromising multiple hosts and installing small attack daemon(s). This is what many call \nzombies or bot hosts/nets. Subsequently, an attacker can launch a coordinated attack from \nthousands of zombies onto a single victim. This daemon typically contains both the code \nfor sourcing a variety of attacks and some basic communications infrastructure to allow for \nremote control. A zombie attack is illustrated in Figure 3-1.\n"
        },
        {
            "page_number": 123,
            "text": "100\nChapter 3:  Identifying and Classifying Security Threats\nFigure 3-1\nZombies and Bots\nZombies\nZombies\nZombies\nSi\nSi\nSi\nSi\nCoffee Shop\nCompany A\nCompany B\nVictim\nInternet\nZombies\nZombies\nZombies\n"
        },
        {
            "page_number": 124,
            "text": "Network Visibility     101\nIn Figure 3-1, an attacker controls compromised hosts in Company A and Company B to \nattack a web server farm in another organization.\nYou can use different mechanisms and methodologies to successfully identify and classify \nthese threats/attacks depending on their type. In other words, depending on the threat, you \ncan use specific techniques to identify and classify them accordingly. Following are the \nmost common methodologies:\n•\nThe use of anomaly detection tools \n•\nNetwork telemetry using flow-based analysis\n•\nThe use of intrusion detection and intrusion prevention systems (IDS/IPS)\n•\nAnalyzing network component logs (that is, SYSLOG from different network \ndevices, accounting records, application logs, Simple Network Management Protocol \n(SNMP), and so on)\nComplete visibility is one of the key requirements when identifying and classifying security \nthreats. The following sections explain best practices for achieving complete network \nvisibility and the use of the previously mentioned tools and mechanisms.\nNetwork Visibility \nThe first step in the process of preparing your network and staff to successfully identify \nsecurity threats is achieving complete network visibility. You cannot protect against or \nmitigate what you cannot view/detect. You can achieve this level of network visibility \nthrough existing features on network devices you already have and on devices whose \npotential you do not even realize. In addition, you should create strategic network diagrams \nto clearly illustrate your packet flows and where, within the network, you may enable \nsecurity mechanisms to identify, classify, and mitigate the threat. Remember that network \nsecurity is a constant war. When defending against the enemy, you must know your own \nterritory and implement defense mechanisms in place. Figure 3-2 illustrates a fairly simple \nhigh-level enterprise diagram. \n"
        },
        {
            "page_number": 125,
            "text": "102\nChapter 3:  Identifying and Classifying Security Threats\nFigure 3-2\nHigh-Level Enterprise Diagram\nSi\nInternet\nBranch\nOffice\nBranch\nOffice\nIPsec Tunnel\nIPsec Tunnel\nSi\nSi\nSi\n1st Floor\n2nd Floor\n3rd Floor\n4th Floor\nCall Center\nDistribution\nLayer\nAccess\nLayer\nCore\n1\n2\n3\n4\n5\nData Center\n"
        },
        {
            "page_number": 126,
            "text": "Network Visibility     103\nIn Figure 3-2, the following sections are numbered:\n1 The Internet edge: In this example, the enterprise headquarters is connected to the \nInternet via redundant links. Two Cisco Adaptive Security Appliances (ASA) are \nconfigured to protect the infrastructure.\n2 Site-to-Site VPN: The headquarters office is connected to two branches via IPsec \nsite-to-site VPN tunnels terminated on two Cisco IOS routers.\n3 End users: The headquarters building has its sales, finance, engineering, and \nmarketing departments on four separate floors.\n4 Call center: There is a call center with more than 100 agents on the 5th floor. \n5 Data center: The data center includes e-commerce, e-mail, database, and other \napplication servers.\nYou can create this type of diagram not only to understand the architecture of your \norganization but also to strategically identify places within the infrastructure where you can \nimplement telemetry mechanisms like NetFlow and identify choke points where you can \nmitigate an incident. Notice that the access, distribution, and core layers/boundaries are \nclearly defined.\nLook at the example illustrated in Figure 3-3. A workstation at the call center usually \ncommunicates over TCP port 80 (HTTP) to a server in the data center. This traffic is allowed \nwithin the access control lists because it is legitimate traffic to the server. However, the \ntraffic from this specific workstation increased more than 400 percent over normal. \nSubsequently, performance on the server is degraded, and the infrastructure is congested \nwith unnecessary packets.\nIn this case, NetFlow was configured at the distribution layer switch, and the administrator \nwas able to detect the anomaly. The administrator then configures a host-specific ACL to \ndeny the traffic from the call center workstation, as shown in Figure 3-4. In more \nsophisticated environments, you can even implement remotely triggered black hole \n(RTBH) routing to mitigate this incident.\nIn the example illustrated in Figure 3-4, the problem was a defect within the call center \nworkstation application. The administrator was able to perform detailed analysis and patch \nthe machine while preventing disruption of service.\n"
        },
        {
            "page_number": 127,
            "text": "104\nChapter 3:  Identifying and Classifying Security Threats\nFigure 3-3\nNetFlow at the Distribution Switch\nSi\nInternet\nBranch\nOffice\nBranch\nOffice\nIPsec Tunnel\nIPsec Tunnel\nSi\nSi\nSi\n1st Floor\n2nd Floor\n3rd Floor\n4th Floor\nCall Center\nDistribution\nLayer\nAccess\nLayer\nCore\n1\n2\n3\n4\n5\nSi\nNet Flow\nData Center\n"
        },
        {
            "page_number": 128,
            "text": "Network Visibility     105\nFigure 3-4\nAbnormal Traffic Stopped\nSi\nInternet\nBranch\nOffice\nBranch\nOffice\nIPsec Tunnel\nIPsec Tunnel\nSi\n1st Floor\n2nd Floor\n3rd Floor\n4th Floor\nCall Center\nDistribution\nLayer\nAccess\nLayer\nCore\n1\n2\n3\n4\n5\nSi\nSi\nData Center\n"
        },
        {
            "page_number": 129,
            "text": "106\nChapter 3:  Identifying and Classifying Security Threats\nTIP\nTo detect abnormal and possibly malicious activity, you must first establish a baseline of \nnormal network activity, traffic patterns, and other factors. NetFlow, as well as other \nmechanisms, can be enabled within your infrastructure to successfully identify and classify \nthreats and anomalies. Prior to implementing an anomaly-detection system, you should \nperform traffic analysis to gain an understanding of general traffic rates and patterns. In \nanomaly detection systems, learning is generally performed over a significant interval, \nincluding both the peaks and valleys of network activity. Anomaly detection and telemetry \nare covered in detail later in this chapter.\nYou can also develop a different type of diagram to visualize operational risks within your \norganization. These diagrams are based on device roles and can be developed for critical \nsystems you want to protect. For example, identify a critical system within your \norganization and create a layered diagram similar to the one in Figure 3-5. In this example, \na database called ABC is the most critical application/data source for this company. The \ndiagram presents ABC Database Server in the center.\nFigure 3-5\nLayered Diagram for Visualizing Risk\nABC Database Server\nin the Data Center\nData Center Access\nand Distribution Layers\n(Data Center Firewalls\nreside here)\nCore\nDistribution Layer\nAccess Layer\nData\nVoice\nVPN Routers\nCisco 3750s\nCAT 6K 2&3\nCisco ASAs\nCisco 4948s\nCAT 6K 1&2\nSales\nDepartment\nInternet\nBranch\nOffices\nCall Center Users\n"
        },
        {
            "page_number": 130,
            "text": "Network Visibility     107\nYou can use this type of diagram to audit device roles and the type of services they should \nbe running. For example, you can decide in what devices you can run services like Cisco \nNetFlow or where to enforce security policies. In addition, you can see the life of a packet \nwithin your infrastructure depending on the source and destination. An example is \nillustrated in Figure 3-6. \nFigure 3-6\nIllustrating a Packet Flow\nFigure 3-6 shows the packet flow that occurs when a user from the sales department \naccesses an Internet site. You know exactly where the packet is going based on your \narchitecture and your security and routing policies. This is a simple example; however, \nyou can use this concept to visualize risks and to prepare your isolation policies.\nNOTE\nAdditional examples and techniques are covered in Chapter 7, “Proactive Security \nFramework.”\nABC Database Server\nin the Data Center\nData Center Access\nand Distribution Layers\n(Data Center Firewalls\nreside here)\nCore\nDistribution Layer\nAccess Layer\nData\nVoice\nVPN Routers\nCisco 3750s\nCAT 6K 2&3\nCisco ASAs\nCisco 4948s\nCAT 6K 1&2\nSales\nDepartment\nCAT 6K 4&5\nCisco 3750s\nCall Center Users\nBranch\nOffices\nInternet\n"
        },
        {
            "page_number": 131,
            "text": "108\nChapter 3:  Identifying and Classifying Security Threats\nTelemetry and Anomaly Detection\nAnomaly detection systems passively monitor network traffic, looking for any deviation \nfrom “normal” or “baseline” behavior that may indicate a security threat or a \nmisconfiguration. You can use several commercial tools and even open source tools to \nsuccessfully identify security threats within your network. These tools include the \nfollowing:\n•\nCisco NetFlow\n•\nCisco Security Monitoring, Analysis and Response System (CS-MARS)\n•\nCisco Traffic Anomaly Detectors and Cisco Guard DDoS Mitigation Appliances\n•\nCisco IPS sensors (Version 6.x and later)\n•\nCisco Network Analysis Module (NAM)\n•\nOpen Source Monitoring tools\nThe following are other technologies and tools you can use to achieve complete visibility \nof what is happening within your network:\n•\nSyslog\n•\nSNMP\nNetFlow\nCisco NetFlow was initially introduced as a packet accounting system for network \nadministration and, in some cases, for billing. However, today you can use NetFlow to \nlisten to the network itself, thereby gaining valuable insight into the overall security state \nof the network. This is why it is classified as a form of telemetry that provides information \nabout traffic passing through or directly to each router or switch. \nNetFlow is supported in the following Cisco platforms:\n•\nCisco 1700\n•\nCisco 1800\n•\nCisco 2800\n•\nCisco 3800\n•\nCisco 4500\n•\nCisco 7200\n•\nCisco 7300\n•\nCisco 7500\n"
        },
        {
            "page_number": 132,
            "text": "Telemetry and Anomaly Detection     109\n•\nCisco 7600/6500 (hybrid and native configurations)\n•\nCisco 10000\n•\nCisco 12000\nNOTE\nIndicated models have platform-specific considerations. Please refer to \nhttp://www.cisco.com/go/netflow for more compatibility information.\nThe word netflow is a combination of net (or network) and flow. What is a flow? An \nindividual flow comprises, at a minimum, the following elements:\n•\nSource IP address.\n•\nDestination IP address.\n•\nProtocol.\n•\nSource port number. (With certain protocols, this can be a type/code or any other \nconstruct—for example, ICMP.)\n•\nDestination port number. (With certain protocols, this can be a type/code or any other \nconstruct—for example, ICMP.)\nNetFlow also can give you information about network traffic. This information varies \nsomewhat depending on what version of NetFlow Data Export (NDE) you run. The most \ncommonly deployed versions are Versions 5 and 9. Following is some of the additional \ninformation you can obtain from a flow in NetFlow Version 5:\n•\nStart time of the flow.\n•\nEnd time of the flow.\n•\nNumber of packets in the flow.\n•\nAmount of data transferred in the flow.\n•\nType of Service (ToS) bits present in the flow or Differentiated Services Code Point \n(DSCP) type.\n•\nLogical OR of all TCP flags present in TCP-based flows (platform-specific caveats \napply).\n•\nInput interface ifIndex.\n•\nOutput interface ifIndex.\n•\nOrigin-AS or destination-AS information, if Border Gateway Protocol (BGP) is \nenabled on the routers/Layer 3 switches in question. (The selection of origin- or \ndestination-AS reporting is made during the configuration of NetFlow on each \ndevice.)\n"
        },
        {
            "page_number": 133,
            "text": "110\nChapter 3:  Identifying and Classifying Security Threats\n•\nBGP next-hop information, if BGP is enabled on the routers/Layer 3 switches in \nquestion.\n•\nFragmentation information (known as fragmentation bit).\nAll this information can be exported to monitoring systems for further analysis. NetFlow \nVersion 9 supports the same reporting capabilities as NetFlow Version 5 with some \nadditional information. One of the biggest advantages of NetFlow Version 9 is its ability to \nbe configured by the use of templates to use various features to export additional or \ndifferent information to external systems. In NetFlow Version 5 and earlier, you can export \nthe flow data over UDP. NetFlow Version 9 supports NDE via TCP and SCTP, as well as \nthe classic UDP mode.\nNOTE\nAll new NetFlow development is based on NetFlow Version 9.\nIn NetFlow Version 9, you can use a template describing the NDE fields within the flow \ninformation. This template information is contained in the first NetFlow Version 9 NDE \npackets sent to the NDE destination (monitoring system) after NDE is enabled on the router \nor switch. This information is also periodically retransmitted. When the configuration of \nNDE fields is changed on the router or switch, the updated template is immediately \ntransmitted.\nThe IETF Internet Protocol Flow Information eXport (IPFIX) working group (WG) has \nbeen tasked with developing a common standard for IP-based flow export. This working \ngroup has selected Cisco NetFlow Version 9 as the technology of choice.\nNOTE\nThe IPFIX requirements are defined in RFC 3917. RFC 3954 explains the evaluation of \nNetFlow Version 9 in IPFIX. The actual outcome and the criteria for the selection of \nNetFlow Version 9 as the basis for the IPFIX standard are defined in RFC 3955.\nIt is recommended that you use an isolated out-of-band (OOB) management network to \nallow you to access and control NetFlow-enabled devices over the network, even when you \nare under attack or during any security incident or network malfunction. When you transmit \nnetwork telemetry over the OOB network, you reduce the chance for disruption of the \ninformation that provides insightful network visibility.\n"
        },
        {
            "page_number": 134,
            "text": "Telemetry and Anomaly Detection     111\nEnabling NetFlow\nTypically, enabling NetFlow on software-based platforms consists of one or two steps: \n•\nEnabling NetFlow on the relevant physical and logical interfaces \n•\n(Optional) Enabling the device (NDE) to export the flow information from the device \nto an external monitoring system\nWhen you configure NetFlow, you must decide between ingress or egress NetFlow for each \ndevice. This decision depends on the use and the topology. You can also enable NetFlow for \nboth ingress and egress. \nNOTE\nEgress NetFlow is dependent on the version of Cisco IOS you are running. For more \ninformation, go to http://www.cisco.com/go/fn.\nThe following example shows how you can enable ingress NetFlow on a particular interface \n(GigabitEthernet0/0 in this case):\nmyrouter#configure terminal\nmyrouter(config)#interface GigabitEthernet0/0\nmyrouter(config-if)#ip flow ingress\nTo enable egress NetFlow, use the ip flow egress interface subcommand as follows:\nmyrouter(config)#interface GigabitEthernet0/0\nmyrouter(config-if)#ip flow egress\nNOTE\nIngress NetFlow is the most commonly used method. Egress NetFlow is more commonly \nused with MPLS VPN. The MPLS Egress NetFlow Accounting feature allows you to \ncapture IP flow information for packets undergoing MPLS label disposition. In other \nwords, it captures packets that arrive on a router as MPLS packets and are transmitted as IP \npackets. Egress NetFlow accounting might adversely affect network performance because \nof the additional accounting-related computations that occur in the traffic-forwarding path \nof the router.\nThe following example shows how to configure the NetFlow-enabled device to export the \nflow data to a monitoring system:\nmyrouter(config)#ip flow-export version 5\nmyrouter(config)#ip flow-export source loopback 0\nmyrouter(config)#ip flow-export destination 172.18.85.190 2055\n"
        },
        {
            "page_number": 135,
            "text": "112\nChapter 3:  Identifying and Classifying Security Threats\nIn this example, NDE Version 5 is used. All NetFlow export packets are sourced from \na loopback interface configured in the router (loopback 0). The destination is a Cisco \nSecure Monitoring and Response System (CS-MARS) box with the IP address \n172.18.85.190 and the destination UDP port 2055.\nIt is recommended that you alter the setting of the active flow timeout parameter from its \ndefault of 30 minutes to the minimum value of one minute. This helps you achieve an \nenvironment that is closer to real time. You can do this with the ip flow-cache timeout \nactive command, as shown here:\nmyrouter(config)#ip flow-cache timeout active 1\nNOTE\nThe default value for the number of minutes that an active flow remains in the cache before \nit times out is 30. \nThe default value for the number of seconds that an inactive flow remains in the cache \nbefore it times out is 15. \nCollecting NetFlow Statistics from the CLI\nTo view the basic NetFlow information from the CLI, you can use the show ip cache flow\ncommand, as shown in Example 3-1:\nExample 3-1\nOutput of the show ip cache flow Command \nmyrouter#show ip cache flow \nIP packet size distribution (9257M total packets):\n   1-32   64   96  128  160  192  224  256  288  320  352  384  416  448  480\n   .088 .314 .011 .011 .027 .001 .007 .001 .013 .016 .002 .002 .000 .001 .000\n    512  544  576 1024 1536 2048 2560 3072 3584 4096 4608\n   .000 .001 .002 .043 .452 .000 .000 .000 .000 .000 .000\nIP Flow Switching Cache, 4456704 bytes\n  43 active, 65493 inactive, 884110623 added\n  3341579080 ager polls, 0 flow alloc failures\n  Active flows timeout in 30 minutes\n  Inactive flows timeout in 15 seconds\n  last clearing of statistics never\nProtocol         Total    Flows   Packets Bytes  Packets Active(Sec) Idle(Sec)\n--------         Flows     /Sec     /Flow  /Pkt     /Sec     /Flow     /Flow\nTCP-Telnet     1072696      0.2        17   578      4.4       9.8      15.3\nTCP-FTP          33386      0.0      2392    57     18.6     697.2       7.6\n"
        },
        {
            "page_number": 136,
            "text": "Telemetry and Anomaly Detection     113\nIn the highlighted line, you can see that a host (172.18.124.223 is sending 19,992,167 \npackets to 14.36.1.203. This may be abnormal behavior or an infected machine. The \nprotocol is 06 (TCP), the source port is 33029 (Hex 8105), and the destination port is 8995 \n(Hex 2323). \nTCP-FTPD          2967      0.0      2869  1049      1.9       4.3      15.2\nTCP-WWW        9091735      2.1       222   904    470.3       6.0       5.6\nTCP-SMTP        538619      0.1         1    59      0.2       6.9      15.9\nTCP-X             3246      0.0        44   909      0.0       0.1      13.4\nTCP-BGP         280550      0.0         2    44      0.1       7.2      15.8\nTCP-NNTP          2306      0.0         1    46      0.0       0.0      18.1\nTCP-Frag             7      0.0        19   152      0.0       8.8      15.4\nTCP-other     48037166     11.1       115   887   1289.2       4.5       6.2\nUDP-DNS        1043579      0.2         2    74      0.4       3.9      15.9\nUDP-NTP         891663      0.2         1    79      0.2       0.0      15.5\nUDP-TFTP        138376      0.0         7    55      0.2      21.2      15.5\nUDP-Frag          9736      0.0       182  1366      0.4      22.1      15.4\nUDP-other    816395802    190.0         1   109    316.9       0.1      18.8\nICMP           6533952      1.5        13    95     20.5       8.3      15.5\nGRE                239      0.0        41    97      0.0      66.9      15.2\nIP-other         34558      0.0      3907   156     31.4      66.1      15.0\nTotal:       884110583    205.8        10   750   2155.4       0.5      17.9\nSrcIf         SrcIPaddress    DstIf         DstIPaddress    Pr SrcP DstP  Pkts\nFa1/1         14.38.1.9       Null          255.255.255.255 11 0044 0043     1\nFa1/1         0.0.0.0         Null          255.255.255.255 11 0044 0043   209\nFa0/0         172.18.173.68   Fa1/0         14.36.1.208     06 05BC 01BB   452\nFa0/0         172.18.173.68   Fa1/0         14.36.1.186     06 0631 01BB   388\nFa1/0         14.36.1.120     Null          14.36.255.255   11 008A 008A     3\nFa0/0         14.36.1.120     Null          14.36.255.255   11 008A 008A     3\nFa0/0         172.18.124.223  Fa1/0         14.36.197.213   06 8107 2323  1547\nFa0/0         172.18.124.66   Null          14.36.1.184     06 EC83 01BB     1\nFa1/0         14.36.8.48      Fa0/0         172.18.124.154  06 15FE 0FA5     1\nFa1/0         14.36.8.48      Fa0/0         172.18.124.154  06 15FF 0FA5     1\nFa1/0         14.36.8.48      Fa0/0         172.18.124.154  06 15FD 0FA5     1\nFa1/0         14.36.1.3       Fa0/0         172.18.123.69   01 0000 0303     3\nFa1/0         14.36.8.36      Fa0/0         172.18.124.66   11 0202 0202     4\nFa1/0         14.36.99.77     Fa0/0         172.18.124.225  06 01BB 137C    85\nFa1/0         14.36.197.213   Fa0/0         172.18.124.223  06 2323 8107   780\nFa0/0         172.18.124.223  Fa1/0         14.36.1.203     06 8105 2323  19992167\nFa0/0         172.18.85.169   Local         14.36.1.1       06 8E5E 0017    97\nFa0/0         172.18.124.225  Fa1/0         14.36.99.77     06 137C 01BB    85\nFa0/0         172.18.124.128  Fa1/0         14.36.1.128     06 916E 2323   138\nFa0/0         172.18.124.128  Fa1/0         14.36.1.128     06 916D 2323    54\nFa1/0         14.36.1.208     Fa0/0         172.18.173.68   06 01BB 05BC   678\nExample 3-1\nOutput of the show ip cache flow Command (Continued)\n"
        },
        {
            "page_number": 137,
            "text": "114\nChapter 3:  Identifying and Classifying Security Threats\nYou can also obtain export flow information using the show ip flow export command, as \nshown in Example 3-2:\nIn Example 3-2, you can see that the router is exporting the NetFlow information to the \n172.18.85.190 device (a CS-MARS in this case) over UDP port 2055. The source IP \naddress is 172.18.124.47. A total of 884,111,088 flows have been exported in 31,352,026 \nUDP datagrams. Please note that all protocol numbers, source ports, and TCP/UDP \ndestination ports are shown in hexadecimal. ICMP packets are represented with the source \nport field set to 0000, the first two bytes of the destination field set to the ICMP type, and \nthe second two bytes to the ICMP code. If you are using features such as policy-based \nrouting (PBR), Web Cache Communications Protocol (WCCP), Network Address \nTranslation (NAT), or Unicast Reverse Path Forwarding (uRPF) ACLs, you will see a \n(DstIf) value of Null. To see packet drops caused by ACLs, uRPF, PBR, or null routes, use \nthe show ip cache flow with the include Null option, as shown in Example 3-3:\nTo see flows that contain thousands or millions of packets, you can use show ip cache flow \n| include K or show ip cache flow | include M commands, respectively. \nThe Cisco Catalyst 6500 switches and Cisco 7600 router obtain NetFlow information via \nthe Multilayer Switching (MLS) cache. In addition, the amount and type of data recorded \nin the table must be selected. The mls flow ip interface-full command provides the most \nuseful information and can be configured as follows:\nCAT6k(config)# mls flow ip interface-full\nCAT6k(config)# mls nde interface\nExample 3-2\nOutput of the show ip flow export Command \nmyrouter#show ip flow export\nFlow export v5 is enabled for main cache\n  Exporting flows to 172.18.85.190 (2055)\n  Exporting using source IP address 172.18.124.47\n  Version 5 flow records\n  884111088 flows exported in 31352026 udp datagrams\n  0 flows failed due to lack of export packet\n  4 export packets were sent up to process level\n  0 export packets were dropped due to no fib\n  0 export packets were dropped due to adjacency issues\n  0 export packets were dropped due to fragmentation failures\n  0 export packets were dropped due to encapsulation fixup failures\nExample 3-3\nOutput of the show ip cache flow | include Null Command\nmyrouter#show ip cache flow | include Null\nFa1/0         14.36.1.8       Null          255.255.255.255 11 0044 0043     1\nFa1/1         0.0.0.0         Null          255.255.255.255 11 0044 0043   891\nFa0/0         172.18.124.66   Null          14.36.1.184     06 80AC 01BB     3\nFa0/0         14.1.17.111     Null          14.38.201.1     06 51CD 00B3     2\nFa1/0         172.18.124.11   Null          172.18.124.255  11 0089 0089    18\nFa1/0         172.18.124.153  Null          172.18.124.255  11 008A 008A     3\n"
        },
        {
            "page_number": 138,
            "text": "Telemetry and Anomaly Detection     115\nTIP\nIf your NetFlow table has too many entries, you can try to reduce the MLS aging time. \nFor PFC2, set the aging time high enough to keep the number of entries within the 32,000 \nflow range of the PFC2. For PFC3, set the aging time high enough to keep the number \nof entries within the 64,000 flow range of the PFC3.\nMake sure you set the aging time to 1 second when using bridged-flow statistics with a \nSupervisor Engine 2 (SUP2). If some protocols have fewer packets per flow running, reduce \nthe MLS fast aging time.\nThe following site includes detailed configuration and design information for NetFlow on \nCatalyst 6500 switches:\nhttp://www.cisco.com/en/US/partner/products/hw/switches/ps708/\nproducts_configuration_guide_chapter09186a0080207758.html\nSYSLOG\nSystem logs or SYSLOG provide you with information for monitoring and \ntroubleshooting devices within your infrastructure. In addition, they give you excellent \nvisibility into what is happening within your network. You can enable SYSLOG on \nnetwork devices such as routers, switches, firewalls, VPN devices, and others. This \nsection covers how to enable SYSLOG on routers, switches, the Cisco ASA, and Cisco \nPIX security appliances.\nEnabling Logging (SYSLOG) on Cisco IOS Routers and Switches\nThe logging facility on Cisco IOS routers and switches allows you to save SYSLOG \nmessages locally or to a remote host. By default, routers send logging messages to a logging \nprocess. The logging process controls the delivery of logging messages to various \ndestinations, such as the logging buffer, terminal lines, a SYSLOG server, or a monitoring \nevent correlation system such as CS-MARS. You can set the severity level of the messages \nto control the type of messages displayed, in addition to a time stamp to successfully track \nthe reported information.\nTIP\nIt is extremely important that your SYSLOG and other messages are time-stamped with the \ncorrect date and time. This is why the use of NTP is strongly recommended (see the NTP \nexample in Chapter 2, “Preparation Phase”).\n"
        },
        {
            "page_number": 139,
            "text": "116\nChapter 3:  Identifying and Classifying Security Threats\nThe following example shows the commands necessary to configure SYSLOG on Cisco \nIOS devices:\nmyrouter#configure terminal\nmyrouter(config)#logging on\nmyrouter(config)#logging host 172.18.85.190\nIn this example, the router is configured to send the SYSLOG messages to a host with IP \naddress 172.18.85.190. (This is the CS-MARS used in the examples of the previous \nsections.)\nOn Cisco IOS routers, the log messages are not time-stamped by default. To enable time \nstamping of log messages, use the service timestamps log datetime command. The \nfollowing example shows the different options of this command:\nmyrouter(config)#service timestamps log datetime ?\n  localtime      Use local time zone for timestamps\n  msec           Include milliseconds in timestamp\n  show-timezone  Add time zone information to timestamp\n  year           Include year in timestamp\nYou can specify the severity level of the SYSLOG messages. The following are the different \nlevels you can configure:\n•\nLevel 0: Emergencies\n•\nLevel 1: Alerts\n•\nLevel 2: Critical\n•\nLevel 3: Errors\n•\nLevel 4: Warnings\n•\nLevel 5: Notifications\n•\nLevel 6: Informational\n•\nLevel 7: Debugging\nTo set the severity level of log messages sent to a SYSLOG server, use the logging trap\ncommand. The following example shows the options of this command:\nmyrouter(config)#logging trap ?\n  <0-7>          Logging severity level\n  alerts         Immediate action needed           (severity=1)\n  critical       Critical conditions               (severity=2)\n  debugging      Debugging messages                (severity=7)\n  emergencies    System is unusable                (severity=0)\n  errors         Error conditions                  (severity=3)\n  informational  Informational messages            (severity=6)\n  notifications  Normal but significant conditions (severity=5)\n  warnings       Warning conditions                (severity=4)\nIt is recommended that you send SYSLOG messages over a separate management segment, \njust as you learned to do earlier in this chapter in the “NetFlow” section. \n"
        },
        {
            "page_number": 140,
            "text": "Telemetry and Anomaly Detection     117\nEnabling Logging Cisco Catalyst Switches Running CATOS\nTo enable the logging of system messages to a SYSLOG server on Cisco Catalyst switches \nrunning Catalyst Operating System (CATOS), use the following commands:\nset logging server enable \nset logging server syslog server 172.18.85.190 \nset logging timestamp enable \nset logging server severity 4\nIn this example, the switch is configured to send the SYSLOG messages to the host with IP \naddress 172.18.85.190. Time stamp is enabled, and the severity level of the messages sent \nto the external server is set to 4 or warnings. Setting logging to the debugging level can \ncause performance problems. A good rule of thumb is to set the logging severity to 4 or \nwarnings.\nNOTE\nA good whitepaper describing best practices when managing Cisco Catalyst switches \nrunning CATOS is located at http://www.cisco.com/en/US/products/hw/switches/ps663/\nproducts_tech_note09186a0080094713.shtml.\nEnabling Logging on Cisco ASA and Cisco PIX Security Appliances\nThe commands used to enable logging and to send SYSLOG messages to a SYSLOG \nserver are the same on the Cisco ASA and the Cisco PIX security appliances. To enable \nlogging, use the logging on command. To configure the ASA or PIX to send logs to a \nSYSLOG server, use the logging host command, and to change the log severity level, use \nthe logging trap command. The following example demonstrates the use of these \ncommands.\nciscoasa(config)# logging on\nciscoasa(config)# logging host inside 172.18.85.190\nciscoasa(config)# logging trap informational\nIn this example, the Cisco ASA is configured to send its logs to the host with IP address \n172.18.85.190, and the severity level is set to informational.\nOn the Cisco ASA and Cisco PIX security appliances, all SYSLOG messages begin with a \npercent sign (%) and are designed as follows:\n%PIX|ASA  Level Message_number: Message_text\nThe following is an example of a SYSLOG message.\nApr 09 2007 07:35:56: %ASA-6-302021: Teardown ICMP connection for faddr \n192.168.202.22/0 gaddr 192.168.202.40/0 laddr 192.168.202.40/0\n"
        },
        {
            "page_number": 141,
            "text": "118\nChapter 3:  Identifying and Classifying Security Threats\n•\nPIX|ASA:A static value indicating that the log message is generated by a Cisco ASA \nor Cisco PIX.\n•\nLevel: The severity level (1–7). For most environments, it is recommended that you \nset the severity level to 4 to avoid performance issues. You may want to temporally \nincrease it to a higher value when troubleshooting a specific problem.\n•\nMessage number: A unique 6-digit number that identifies the SYSLOG message.\n•\nMessage text: The description of the log message. It sometimes includes IP \naddresses, port numbers, or usernames.\nYou can filter SYSLOG messages on the Cisco ASA, Cisco PIX, and Cisco FWSM to send \nonly specific events to a particular output destination. In other words, you can configure \nthe device to send all SYSLOG messages to one output destination and also to send a subset \nof those SYSLOG messages to a different output destination. You can also configure the \nCisco ASA, Cisco PIX, and Cisco FWSM to send SYSLOG messages based on specific \ncriteria, such as the following: \n•\nMessage ID number (range of 104024 to 105999)\n•\nSeverity level \n•\nMessage class\nFor example, you can use the logging class <message_class> command to specify the \nspecific class.\nTIP\nAll Cisco ASA and Cisco PIX messages are defined in detail at http://www.cisco.com/\nunivercd/cc/td/doc/product/multisec/asa_sw/v_7_2/syslog/logmsgs.htm.\nThis site also includes the different SYSLOG message classes and associated message ID \nnumbers.\nSNMP\nSNMP is one of the most basic forms of getting information from your network. It is a \nLayer 7 protocol designed to obtain information from network devices. This information \nincludes but is not limited to the following:\n•\nDevice health statistics (CPU, memory, and so on)\n•\nDevice errors\n•\nNetwork traffic statistics\n•\nPacket rates\n•\nPacket errors\n"
        },
        {
            "page_number": 142,
            "text": "Telemetry and Anomaly Detection     119\nThe SNMP solution has three components: \n•\nAn SNMP manager: The system used to control and monitor the activities of \nnetwork hosts using SNMP.\n•\nAn SNMP agent: The software component within the managed device that maintains \nthe data for the device and reports this data, as needed, to managing systems.\n•\nA Management Information Base (MIB): An information storage medium that \ncontains a collection of managed objects (MIB modules) within each device. MIB \nmodules are written in the SNMP MIB module language, as defined in STD 58, RFC \n2578, RFC 2579, and RFC 2580.\nIn Chapter 2, you learned about the three versions of SNMP and the security implications \nof each version. That chapter also showed you how to protect SNMP environments. This \nsection covers the basic commands on how to enable SNMP on Cisco IOS and the Cisco \nASA and Cisco PIX security appliances.\nEnabling SNMP on Cisco IOS Devices\nAs a best practice, you should set the system contact, location, and serial number of the \nSNMP agent so that your management servers can obtain these descriptions. This \ninformation is useful when responding to incidents. The following example shows how to \nenter the contact information on the Cisco IOS device:\nmyrouter#configure terminal\nmyrouter(config)#snmp-server contact John Route\nmyrouter(config)#snmp-server location 1st Floor NY Office\nmyrouter(config)#snmp-server chassis-id ABC12345\nIn the previous example, the name of the administrator is John Route, the device is located \non the 1st floor of an office in New York, and the chassis identification number is \nABC12345.\nThe following example shows how you can configure SNMP Version 3 on a Cisco IOS \ndevice:\nmyrouter(config)#snmp-server group mygroup v3 auth\nSNMP Version 3 supports authentication. In the previous example, an SNMP group named \nmygroup is configured for SNMP Version 3. Authentication is also enabled with the auth\nkeyword. When you configure the snmp-server group command, there are no default \nvalues for authentication. To specify authentication user parameters, use the snmp-server \nuser command, as shown in the following example:\nmyrouter(config)#snmp-server user admin1 mygroup v3 auth md5 zxasqw12\n*Feb  8 15:45:04.902: Configuring snmpv3 USM user, persisting snmpEngineBoots. \nPlease Wait...\n"
        },
        {
            "page_number": 143,
            "text": "120\nChapter 3:  Identifying and Classifying Security Threats\nIn the previous example, a user (admin1) is configured and mapped to the SNMP group \nmygroup. Authentication is done with MD5, and the password is zxasqw12. After you \ninvoke this command, the preceding warning message is displayed. You should match all \nthis information in your SNMP management server.\nTo verify the configuration, you can invoke the show snmp user command as follows:\nmyrouter#show snmp user\nUser name: admin1\nEngine ID: 8000000903000013C4EC5528\nstorage-type: nonvolatile        active\nAuthentication Protocol: MD5\nPrivacy Protocol: DES\nGroup-name: mygroup\nTo view SNMP group information, invoke the show snmp group command, as shown in \nExample 3-4.\nThe configured group (mygroup) is shown in the highlighted line.\nNOTE\nThe following site includes detailed information on how to configure SNMP Version 1 \nand 2: \nhttp://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124tcg/tnm_c/snmp/\nconfsnmp.htm#wp1032846\nThis document also includes the following information:\n• Configuring the router as an SNMP manager\n• Enabling the SNMP Agent Shutdown mechanism\n• Defining the maximum SNMP Agent packet size \n• Disabling the SNMP Agent \n• Limiting the number of Trivial File Transfer Protocol (TFTP) servers used via SNMP\nExample 3-4\nOutput of the show snmp group Command\nmyrouter#show snmp group \ngroupname: ILMI                             security model:v1\nreadview : *ilmi                            writeview: *ilmi                    \nnotifyview: <no notifyview specified>\nrow status: active\ngroupname: ILMI                             security model:v2c\nreadview : *ilmi                            writeview: *ilmi                    \nnotifyview: <no notifyview specified>\nrow status: active\ngroupname: mygroup                          security model:v3 auth\nreadview : v1default                        writeview: <no writeview specified> \nnotifyview: <no notifyview specified>\nrow status: active\n"
        },
        {
            "page_number": 144,
            "text": "Telemetry and Anomaly Detection     121\n• Configuring SNMP notifications\n• Configuring interface index display and interface indexes and configuring long name \nsupport\n• Configuring SNMP support for VPNs\n• Configuring MIB persistence\nEnabling SNMP on Cisco ASA and Cisco PIX Security Appliances\nThe Cisco ASA and the Cisco PIX security appliances support only SNMP Versions 1 and \n2c. They both support traps and SNMP read access; however, SNMP write access is not \nsupported. The following example shows how to configure an ASA to receive SNMP \nVersion 2c requests from host 172.18.85.190 on the inside interface: \nciscoasa(config)# snmp-server host inside 172.18.85.190 Version 2c\nciscoasa(config)# snmp-server location Raleigh NC Branch\nciscoasa(config)# snmp-server contact Jeff Firewall\nciscoasa(config)# snmp-server community th1s1sacommstrng\nThe ASA in this example is located in a branch office in Raleigh, North Carolina. The point \nof contact is Jeff Firewall, and the community string is <th1s1sacommstrng>. You can use \nthe snmp deny version command to deny SNMP packets from other SNMP versions. The \nfollowing example shows the available options:\nciscoasa(config)# snmp deny version ?\nconfigure mode commands/options:\n  1   SNMP version 1\n  2   SNMP version 2 (party based)\n  2c  SNMP version 2c (community based)\n  3   SNMP version 3\nNOTE\nYou can obtain the MIBs for any Cisco device at http://www.cisco.com/public/sw-center/\nnetmgmt/cmtk/mibs.shtml.\nCisco Security Monitoring, Analysis and Response System \n(CS-MARS)\nCS-MARS enables you to identify, classify, validate, and mitigate security threats. In the \nprevious sections in this chapter, you learned different mechanisms that give you \nvisibility of the network and its devices, such as NetFlow, SYSLOGs, and SNMP. The \nanalysis and manipulation of the data provided by these features can be a time-consuming \nprocess and, in some environments, may even be impossible because of the staff \nrequirements.\n"
        },
        {
            "page_number": 145,
            "text": "122\nChapter 3:  Identifying and Classifying Security Threats\nCS-MARS supports the correlation of events from numerous networking devices from \ndifferent vendors. The supported devices include:\n•\nCisco IOS routers and switches\n•\nCisco ASA\n•\nCisco PIX\n•\nNetFlow\n•\nCisco Security Agent\n•\nCisco Secure ACS\n•\nCisco IDS/IPS\n•\nThird-party firewalls such as Checkpoint and Netscreen\n•\nThird-party antivirus software\n•\nThird-party IDS/IPS systems such as snort\n•\nOperating system (Windows and UNIX/Linux) events\n•\nApplication-specific events \nNOTE\nA complete of list of supported devices can be found at http://www.cisco.com/en/US/\nproducts/ps6241/products_device_support_tables_list.html.\nFor a complete list of available CS-MARS models, go to http://www.cisco.com/go/mars.\nCS-MARS provides a powerful and interactive dashboard with several key items. It \nincludes a topology map that comprises real-time hotspots, incidents, attack paths, and \ndetailed investigation with full incident disclosure, allowing immediate verification of valid \nthreats. Figure 3-7 shows the CS-MARS main dashboard. \nNote that the system has processed more than 22,000,000 NetFlow events (or flows) over a \nperiod of 24 hours, and more than 44,000,000 security and network events. This automated \nprocess is accomplished by analyzing device logs such as firewalls and by using intrusion \nprevention applications, third-party vulnerability assessment data, and Cisco Security \nMARS endpoint scans to eliminate false positives. Users can quickly fine-tune the system \nto further reduce false positives. This will be impossible to successfully analyze without the \nuse of a system such as CS-MARS. \nFigure 3-8 shows the bottom part of the CS-MARS main dashboard. There you can see a \ntopology map of devices within the network, an attack diagram, and event statistics and \ngraphs.\n"
        },
        {
            "page_number": 146,
            "text": "Telemetry and Anomaly Detection     123\nFigure 3-7\nCS-MARS Main Dashboard\nFigure 3-8\nCS-MARS Topology Map, Attack Diagram, and Event Statistics\n"
        },
        {
            "page_number": 147,
            "text": "124\nChapter 3:  Identifying and Classifying Security Threats\nYou can view the topology map and attack diagram in full view, as shown in Figure 3-9. \nObtaining information about the security incident is simple. If you click on any of the \narrows representing the traffic flow, a new window displays with information about the \nspecific incident or session. \nFigure 3-9\nCS-MARS Attack Diagram Full View\nThe hosts are color-coded:\n•\nBrown means that the host is the attacker.\n•\nRed means that the host is being attacked.\n•\nPurple means that the host is being attacked and is attacking other hosts in the \nnetwork.\nCS-MARS can do a reverse DNS lookup to give you exact information on the specific hosts \nand devices. You can run numerous reports in CS-MARS. Figure 3-10 shows an example \nof reports and graphics you can obtain in CS-MARS.\n"
        },
        {
            "page_number": 148,
            "text": "Telemetry and Anomaly Detection     125\nFigure 3-10 CS-MARS Detailed Graphics and Reports\nIn Figure 3-10, you can see a summary of the most used ports and protocols within a given \nperiod. These graphics are based on NetFlow information. The graphic on the right shows \nthe traffic trend. Notice that the traffic starts increasing during normal business hours of \n8:00 a.m. to around 5:00 p.m. (0800 to 1700). These types of graphics can help you to create \na baseline of what is normal within your network. Then you can identify anomalies and \npossible security incidents. \nNOTE\nChapter 12, “Case Studies,” includes a case study in which CS-MARS is used to \nsuccessfully identify, classify, and mitigate an attack. It also includes examples of how to \nadd monitored devices into CS-MARS.\nCisco Network Analysis Module (NAM)\nThe Cisco Network Analysis Module (NAM) is designed to analyze and monitor traffic in \nthe Catalyst 6500 series switches and Cisco 7600 series Internet routers. It uses remote \nmonitoring (RMON), RMON extensions for switched networks (SMON), and SNMP \nMIBs to obtain information from the device. The NAM can also collect and analyze \nNetFlow information on remote devices.\n"
        },
        {
            "page_number": 149,
            "text": "126\nChapter 3:  Identifying and Classifying Security Threats\nTo use the NAM to collect NetFlow data from a remote device, you must configure the \nremote device to export NDE packets to UDP port 3000 on the NAM. By default, the local \nsupervisor engine of the switch is always available as an NDE device. Optionally, SNMP \ncommunity strings are used to upload convenient textual strings for interfaces on the remote \ndevices that are monitored in NetFlow records.\nNOTE\nA complete NAM installation and configuration guide is located at http://www.cisco.com/\nen/US/products/sw/cscowork/ps5401/products_installation_and_configuration_guides_\nlist.html.\nOpen Source Monitoring Tools\nYou can use several open source monitoring tools in conjunction with NetFlow. If your \norganization is small, or if you do not have the budget for more sophisticated monitoring \ntools, you can take advantage of any of these open source tools that are freely available. \nTable 3-1 includes the most commonly used open source monitoring tools.\nMost of these tools are designed to run in common *NIX-type operating systems, including \nLinux, FreeBSD, Mac OS/X, and Solaris. Some of these tools support the storage of data \nTable 3-1\nOpen Source Monitoring Tools\nTool Name\nWebsite\nCaida’s Cflowd Analysis Software\nhttp://www.caida.org/tools/measurement/cflowd\nMy Netflow Reporting System by \nDynamic Networks \nhttp://www.dynamicnetworks.us/netflow/index.html\nOSU Flow-tools\nhttp://www.splintered.net/sw/flow-tools\nFlow Viewer\nhttp://ensight.eos.nasa.gov/FlowViewer\nFlowd\nhttp://www.mindrot.org/projects/flowd\nNetFlow Monitor (NF)\nhttp://netflow.cesnet.cz\nNtop\nhttp://ntop.ethereal.com/ntop.html\nPanoptis\nhttp://panoptis.sourceforge.net\nPlixer’s Scrutinizer\nhttp://www.plixer.com/products/free-netflow.php\nStager\nhttp://software.uninett.no/stager\n"
        },
        {
            "page_number": 150,
            "text": "Telemetry and Anomaly Detection     127\nin databases such as MySQL and Oracle. Despite the fact that these open source tools are \nfree, they are extremely useful for collecting NetFlow from routers and storing the raw \nflows for auditing and forensic purposes. The most commonly used tool is the OSU flow-\ntool, which is typically used in conjunction with other packages that provide detailed \ngraphs, charts, and on-demand queries. Visit each of the websites listed in Table 3-1 to learn \nmore about which tool is most suitable for your environment.\nCisco Traffic Anomaly Detectors and Cisco Guard DDoS Mitigation \nAppliances\nThe Cisco traffic anomaly detectors and DDoS mitigation appliances provide a new \napproach that not only detects increasingly complex and unrepresentative denial of service \nattacks but also mitigates their effect to ensure business continuity and resource availability. \nThe Cisco DDos solution has two distinct appliances:\n•\nCisco Traffic Anomaly Detector (TAD) XT\n•\nCisco Guard XT\nThis solution is also available in the form of two individual modules for the Catalyst 6500 \nseries switches and the Cisco 7600 Internet routers:\n•\nCatalyst 6500/Cisco 7600 Router Anomaly Guard Module \n•\nCatalyst 6500/Cisco 7600 Router Traffic Anomaly Detector Module\nThe detectors (whether the appliances or the modules) are designed to promiscuously \nmonitor network traffic while looking for any variation from what is “normal,” which may \nindicate a DDoS attack or a worm outbreak. The Cisco TAD XT alerts the Cisco Guard XT \nwhen it detects an anomaly by providing detailed reports and specific alerts.\nThis solution uses a Multiverification Process (MVP) architecture integrating different \nverification, analysis, and enforcement techniques. The MVP has five components:\n•\nStatic and dynamic DDoS filters\n•\nActive verification (anti-spoofing) implementing source-authentication mechanisms \nthat help ensure proper identification of legitimate traffic\n•\nAnomaly recognition\n•\nProtocol analysis designed to identify Layer 7 attacks, such as HTTP error attacks \n•\nRate limiting that prevents flows from overwhelming the target while more detailed \nmonitoring is taking place\nFigure 3-11 illustrates how the Cisco TAD XT and the Cisco Guard XT work.\n"
        },
        {
            "page_number": 151,
            "text": "128\nChapter 3:  Identifying and Classifying Security Threats\nFigure 3-11 Cisco TAD XT Detects an Anomaly and Updates the Guard XT\nIn Figure 3-11, two zones are protected by the Cisco TAD XT: a web server farm and an e-\nmail server farm. The Cisco Guard is placed at the Internet edge, and the Cisco TAD XT \nresides a couple of hops in the inside of the corporate network. The following are the steps \nillustrated in Figure 3-11.\nStep 1\nAn attacker starts a DDoS from the Internet, and the Cisco TAD XT \ndetects the anomaly (spike of traffic).\nStep 2\nThe Cisco TAD XT updates the Cisco Guard XT. The Cisco Guard XT \ncan be triggered in several ways:\n— Through direct use of the web-based device manager\n— Via the CLI\n— Through automatic use of the “protect by packet” feature \n(illustrated in this example)\nProtected Zone 1:\nWeb Servers\nProtected Zone 2:\nEmail Servers\nCisco Guard\nCisco Traffic\nAnomaly\nDetector\n1. Detected!\n2. Detected!\n3. Route Update\nInternet\nAttacker\n"
        },
        {
            "page_number": 152,
            "text": "Telemetry and Anomaly Detection     129\nStep 3\nAfter the Cisco Guard XT is activated, the Cisco Guard XT performs \nadditional screening, and then the traffic destined to the zone under attack \nis diverted to the Cisco Guard XT in any of the following ways:\n— The Cisco Guard XT can issue a BGP route update telling the \nrouter to divert the traffic to the Cisco Guard TX.\n— If you are using the Catalyst 6500/7600 modules, the Route Health \nInjection (RHI) feature can trigger the packet diversion.\n— A route is injected externally into the network.\nStep 4\nThe attack traffic is redirected to the Cisco Guard XT, and legitimate \ntraffic is allowed to the protected zone, as illustrated in Figure 3-12.\nFigure 3-12 Attack Traffic Redirected\nProtected Zone 1:\nWeb Servers\nProtected Zone 2:\nEmail Servers\nCisco Guard\nCisco Traffic\nAnomaly\nDetector\nInternet\nAttacker\nLegitimate\nTraffic\n"
        },
        {
            "page_number": 153,
            "text": "130\nChapter 3:  Identifying and Classifying Security Threats\nThe Cisco Guard can also be deployed with other anomaly detection systems. Examples of \nthis include Arbor’s Peakflow SP and Peakflow X. Arbor’s Peakflow SP is designed for \nservice providers, and Peakflow X is designed for enterprises. Typically, enterprises deploy \nthe Cisco Guard XT at their Internet edge, or they co-locate it at their Internet service \nprovider network to avoid the unnecessary traffic consuming their bandwidth. Because of \nthis, numerous service providers offer managed network DDoS protection, hosting DDoS \nprotection, peering point DDoS protection, and infrastructure protection services. This is \nbased on a solution that Cisco makes available to service providers called “clean pipes.” \nNOTE\nFor more information about clean pipes, go to http://www.cisco.com/go/cleanpipes.\nFigure 3-13 illustrates the protection cycle that the Cisco Guard XT follows to analyze, \nfilter, and rate-limit the traffic. \nFigure 3-13 Cisco Guard XT Protection Cycle \nWhen the traffic is redirected to the Cisco Guard XT, it first filters the traffic using several \nfiltering techniques. If the Cisco Guard XT determines that the packets are malicious, it \ndrops them at this stage. If the packets are not malicious, the packets are sent to different \nprotection levels using several types of authentication methods. Subsequently, the Cisco \nGuard XT analyzes the traffic flow, drops the traffic that exceeds the defined rate that the \nzone can handle, and then injects the legitimate traffic back to the zone. A closed-loop \nfeedback cycle dynamically adjusts its protection policies. \nAnalysis\nProtection\nLevel\nBasic\nProtection\nLevel\nFiltering\nStatistical\nAnalysis\nRate\nLimiting\nStrong\nProtection\nLevel\nDrop\nDrop\nDiverted\nTraffic\nTraffic to\nProtected\nZone\nControl Feedback\n"
        },
        {
            "page_number": 154,
            "text": "Intrusion Detection and Intrusion Prevention Systems (IDS/IPS)     131\nNOTE\nFor more detailed information on how to configure the Cisco Guard XT and the Cisco TAD \nXT, go to http://www.cisco.com/en/US/products/ps5888/\nproducts_installation_and_configuration_guides_list.html.\nIntrusion Detection and Intrusion Prevention Systems \n(IDS/IPS)\nIn Chapter 1, “Overview of Network Security Technologies,” you learned the basics about \nIDS and IPS systems. IDSs are devices that in promiscuous mode detect malicious activity \nwithin the network. IPS devices are capable of detecting all these security threats; however, \nthey are also able to drop noncompliant packets inline. Traditionally, IDS systems have \nprovided excellent application layer attack-detection capabilities; however, they were not \nable to protect against day-zero attacks using valid packets. The problem is that most \nattacks today use valid packets. On the other hand, now IPS systems such as the Cisco IPS \nsoftware Version 6.x and later offer anomaly-based capabilities that help you detect such \nattacks. This is a big advantage, since it makes the IPS devices less dependent on signature \nupdates for protection against DDoS, worms, and any day-zero threats. Just like any other \nanomaly detection systems, the sensors need to learn what is “normal.” In other words, they \nneed to create a baseline of legitimate behavior. \n The Importance of Signatures Updates\nTraditionally, IPS and IDS systems depend on signatures to operate. Because of this, it is \nextremely important to tune the IPS/IDS device accordingly and to develop policies and \nprocedures to continuously update the signatures. The Cisco IPS software allows you to \nautomatically download signatures from a management station. Signature updates are \nposted to Cisco.com almost on a weekly basis. In Chapter 2, you learned about the Cisco \nSecurity Center (historically named mySDN or my Self Defending Network). This is an \nexcellent resource to obtain information about the latest IPS signatures and other security \nintelligence information.\nNOTE\nThe Cisco Security Center site is http://www.cisco.com/security.\nThe Cisco Security Center provides up-to-date security intelligence data, in addition to \ndetailed IDS/IPS signature information.\nAlthough the IPS sensors can work without a license key, you must have a license key to \nobtain signature updates from Cisco.com. To obtain a license key, you must have a Cisco \nService for IPS service contract. For more information, go to http://www.cisco.com/go/\nlicense.\n"
        },
        {
            "page_number": 155,
            "text": "132\nChapter 3:  Identifying and Classifying Security Threats\nThe Cisco IPS Device Manager (IDM) is a web-based configuration utility used to manage \nindividual IPS sensors, Catalyst 6500 IPS modules, and the Advanced Inspection and \nPrevention Security Services Module (AIP-SSM) for the Cisco ASA. You can configure the \nIPS device via IDM to automatically obtain and install signatures from an FTP or SCP server.\nNOTE\nYou cannot automatically download service pack and signature updates from Cisco.com. \nYou need to download service packs and signatures updates from Cisco.com to an FTP or \nSCP server. Then you can configure your IPS device to access the files on your server. You \ncan also use the Cisco Security Manager IPS Manager Console (IPSMC) to manage your \nIPS devices. You can configure IPSMC to automatically download the signature updates \nand service packs from Cisco.com and then install them in your IPS devices. For more \ninformation about IPSMC, go to http://www.cisco.com/go/security. \nComplete the following steps to configure IDM to automatically download signatures from \nyour FTP or SCP server.\nStep 1\nLog in to IDM with an administrator account and navigate to \nConfiguration > Auto Update.\nStep 2\nSelect the Enable Auto Update check box.\nStep 3\nEnter the IP address of the remote server where the signature update or \nservice packs are saved. \nStep 4\nSelect either FTP or SCP for your transport mechanism/server type.\nStep 5\nEnter the path to the directory on the remote server where the updates are \nlocated in the Directory Path.\nStep 6\nEnter the username and password of the account in your FTP or SCP \nserver.\nStep 7\nYou can configure the IPS device to check for updates hourly or on a \nweekly basis. If you want your IPS device to check for updates hourly, \ncheck the Hourly check box. Then enter the time you want the updates \nto start and the hour interval at which you want the IPS device to contact \nyour remote server for updates. The IPS sensor checks the directory you \nspecified for new files in your server. Only one update is installed per \ncycle even if there are multiple available files. \nStep 8\nCheck the Daily check box if you want the IPS device to automatically \ncheck for updates on a daily basis. Then enter the time you want the \nupdates to start and check the days you want the IPS device to check for \nupdates in your SCP or FTP server. \nStep 9\nTo save and apply your configuration, click Apply.\n"
        },
        {
            "page_number": 156,
            "text": "Intrusion Detection and Intrusion Prevention Systems (IDS/IPS)     133\nThe Importance of Tuning\nChapter 1 showed you the important factors to consider when tuning your IPS/IDS devices. \nEach IPS/IDS device comes with a preset number of signatures enabled. These signatures \nare suitable in most cases; however, it is important that you tune your IPS/IDS devices when \nyou first deploy them and then tune them again periodically. You could receive numerous \nfalse positive events (false alarms), which could cause you to overlook real security \nincidents. The initial tuning will probably take more time than any subsequent tuning. The \ninitial tuning process is hard to perform manually, especially in large environments where \nseveral IPS/IDS devices are deployed and hundreds of events are generated in short periods. \nThis is why it is important to use event correlation systems to alleviate this process and save \nnumerous hours. CS-MARS is used in the following example to perform initial tuning and \nevent analysis.\nIn this example, several IPS devices are sending their events to a CS-MARS. The \nadministrator completes the following steps to perform initial tuning:\nStep 1\nLog in to the CS-MARS via the web interface.\nStep 2\nClick Query/Reports tab.\nStep 3\nSelect the Activity: All–Top Event Types (Peak View) option from the \nsecond pull-down menu under the Load Report as On-Demand Query \nwith Filter section, as shown in Figure 3-14.\nFigure 3-14 CS-MARS Query/Reports\n"
        },
        {
            "page_number": 157,
            "text": "134\nChapter 3:  Identifying and Classifying Security Threats\nStep 4\nClick the Edit button to select the time interval for the query and enter 1\nday under the Filter by time section to trigger the CS-MARS to display \nthe top event types in the past 24 hours, as shown in Figure 3-15.\nFigure 3-15 Selecting the Query Time Interval\nStep 5\nClick Apply and Submit Inline in the next screen to obtain the report. \nThe report in Figure 3-16 is shown. In this report, the administrator \nnotices that there have been more than 480 ARP Reply-to-Broadcast \nevents detected in the past 24 hours.\nStep 6\nClick the event to obtain more information and read the following from \nthe CS-MARS details screen: “This signature detects an ARP Reply \npacket where the destination MAC address in the ARP payload is a layer \n2 broadcast address. This is not normal traffic and can indicate an ARP \npoisoning attack.” \nStep 7\nClick q by the event and select Source IP Address Ranking under the \nResult format section to investigate the source, as shown in Figure 3-17.\n"
        },
        {
            "page_number": 158,
            "text": "Intrusion Detection and Intrusion Prevention Systems (IDS/IPS)     135\nFigure 3-16 Top Event Types\nFigure 3-17 Verifying Sources\n"
        },
        {
            "page_number": 159,
            "text": "136\nChapter 3:  Identifying and Classifying Security Threats\nStep 8\nClick Apply and Submit Inline in the following screen to obtain the \nnew report, including the source IP addresses for the ARP Reply-to-\nBroadcast events. The report is shown as illustrated in Figure 3-18.\nFigure 3-18 IP Sources Report\nThe administrator notices that only one device (10.10.1.254) is \ntriggering these events. After further investigation, he discovers that \nthis is the normal behavior of an application that is running on that \nmachine and marks this incident as a False Positive in CS-MARS. \nThe administrator notices that these events are not shown anymore in CS-\nMARS; however, they are still shown using the show events command \nin the CLI of the IPS sensors. This is because when you mark an incident/\nevent/session in CS-MARS as a False Positive, it does not disable or tune \nthis signature in the actual IPS device. The events are still sent to the CS-\nMARS from the IPS devices; however, CS-MARS does not process these \nevents. If you do not want the IPS sensor to send or process the events, \nyou must tune or disable the signature on the IPS device. You can \ntune signatures based on source and destination. For example, in this \ncase, you can tune the IPS signature not to alert you if the host with the \n"
        },
        {
            "page_number": 160,
            "text": "Intrusion Detection and Intrusion Prevention Systems (IDS/IPS)     137\nIP address 10.10.1.254 sends this type of packet. However, you can \nconfigure the IPS signature to alert you if any other device generates this \ntype of traffic.\nAnomaly Detection Within Cisco IPS Devices\nWhen you configure a Cisco IPS device running Versions 6.x and later with anomaly \ndetection services, the IPS device initially goes through a learning process. This is done to \nconfigure a set of policy thresholds based on the normal behavior of your network. Three \ndifferent modes of operation take place when an IPS device is configured with anomaly \ndetection:\n•\nLearning mode\n•\nDetect mode\n•\nInactive mode\nThe initial learning mode is performed over a period of 24 hours, by default. The initial \nbaseline is referred to as the knowledge base (KB) of your traffic. \nTIP\nThe IPS sensor does not detect attacks during the initial learning phase. If you experience \nan attack during this period, your results will not reflect a baseline of normal network \nbehavior. This is an important point to take into consideration. Depending on your \nenvironment, you may want to have the IPS device in learning mode longer than the default \n24 hours because this is a configurable value. Do not initially enable your IPS device with \nanomaly detection over a weekend if your organization operates mostly during normal \nbusiness hours and days. This is a huge mistake that many people make.\nTo configure the IPS sensor using IDM to start the learning mode, go to Configuration > \nPolicies > Anomaly Detections > ad0 > Learning Accept Mode and select the \nAutomatically accept learning knowledge base check box. In that section, you can also \nspecify the learning period length.\nAfter the learning process, a KB is created that replaces the initial KB. The IPS device then \nautomatically goes into detect mode. Any traffic flows that violate thresholds in the KB \ntrigger the IPS device to generate alerts. The IPS device also keeps track of gradual changes \nto the KB that do not violate the thresholds and adjusts its configuration. \nYou can turn off the anomaly detection functionality on your IPS device. This is called \nbeing in inactive mode. In certain circumstances, this is needed. An example is when you \nhave an asymmetric environment and the IPS device gets traffic from different directions, \ncausing it to operate incorrectly.\n"
        },
        {
            "page_number": 161,
            "text": "138\nChapter 3:  Identifying and Classifying Security Threats\nNOTE\nThe traffic anomaly engine in Cisco IPS devices uses nine anomaly detection signatures \ncovering TCP, UDP, and other protocols. Each signature has two subsignatures: one for the \nscanner and the other for the worm-infected host. All of these signatures are enabled by \ndefault, and they are in the 13000 range.\nSimilarly to the Cisco TAD XT, the anomaly detection feature in Cisco IPS devices uses \nzones. The purpose of configuring zones is to make sure that you do not have false \npositives and false negatives. A zone is a set of destination IP addresses. Three different \nzones exist:\n•\nInternal: You configure this zone with the IP address range of your internal \nnetwork.\n•\nIllegal: You configure this zone with IP address ranges that should never be seen in \nnormal traffic. Here you should use unallocated IP addresses or bogon IP addresses.\n•\nExternal: This is the default zone. By default, it has the Internet range of 0.0.0.0-\n255.255.255.255.\nTo configure the Internal zone in your IPS device using IDM, complete the following steps:\nStep 1\nNavigate to Configuration > Policies > Anomaly Detections > ad0 > \nInternal Zone. The Internal Zone tab appears. \nStep 2\nClick the General tab. \nStep 3\nSelect the Enable the Internal Zone check box.\nStep 4\nEnter your internal subnets/IP address range in the Service Subnets\nfield. IDM also allows you to configure protocol and other specific \nthresholds.\nNOTE\nFor more information on how to configure other thresholds and anomaly detection \nfunctionality, refer to the Cisco IPS configuration guides located at http://www.cisco.com/\nunivercd/cc/td/doc/product/iaabu/csids/csids13/idmguide/index.htm.\n"
        },
        {
            "page_number": 162,
            "text": "Summary     139\nSummary\nIdentification and classification of security threats mainly concerns visibility. In this \nchapter, you learned how important it is to have complete network visibility and control to \nsuccessfully identify and classify security threats in a timely fashion. This chapter also \ncovered different technologies and tools that can be used to obtain information from your \nnetwork and detect anomalies that can be malicious activity. This chapter provided \noverviews of Cisco NetFlow, SYSLOG, and SNMP. You also learned about robust event \ncorrelation systems, such as CS-MARS and open source monitoring systems that can be \nused in conjunction with NetFlow to allow you to gain better visibility in your network. \nThis chapter also provided an overview of anomaly detection solutions, in addition to tips \non IPS/IDS tuning and the new anomaly detection features that Cisco IPS software \nsupports.\n"
        },
        {
            "page_number": 163,
            "text": "This chapter covers the following topics:\n•\nTraceback in the Service Provider Environment\n•\nTraceback in the Enterprise\n"
        },
        {
            "page_number": 164,
            "text": "C H A P T E R 4\nTraceback\nFor many years, enterprises, service providers, the government, and many other \norganizations have tried to develop tools and techniques to aid in the traceback of attacks. \nThis chapter covers several lessons learned and techniques developed over the past to \nsuccessfully trace back attacks or prepare the infrastructure to make this process easier. The \ntechniques to track individual packets in a network must be done in an efficient, scalable \nfashion. The main goal of the traceback process is to find the source of attack or malignant \ntraffic. By analyzing the packet contents of the attack traffic, you can determine information \nthat may lead you to the source. \nThe traceback level of effort and methodologies may not be the same in all organizations. \nFor instance, Internet service providers may use different techniques than those used in \nenterprises.\nIn the past, it was sometimes difficult to trace back attacks because of the use of spoofed \npackets. In addition, the packet stream may have been transmitted though many network \ndevices that performed NAT, making it difficult for some enterprises and service providers \nto trace the original source IP address of the packet. Service providers and enterprises are \nnow implementing antispoofing techniques that make it more difficult for spoofed attacks \nto succeed. For this reason, most attacks today are not sourced from spoofed IP addresses. \nAntispoofing techniques include the following:\n•\nSource address validation described in RFC 2827/BCP38 and RFC 3704/BCP84\n•\nDenial of your address space from external sources\n•\nDenial of RFC 1918 private address space in your Internet edge routers\n•\nDenial of multicast source addresses\n•\nFiltering for RFC 3330 special use IPv4 addresses\n•\nUse of Unicast Reverse Path Forwarding (uRPF)\n•\nCable source verification—Enhancements within Cisco cable modem termination \nsystem (CMTS) products that protect against spoofed attacks in Data-over-Cable \nService Interface Specifications (DOCSIS) cable systems\n"
        },
        {
            "page_number": 165,
            "text": "142\nChapter 4:  Traceback\nNOTE\nIn Chapter 2, “Preparation Phase,” you learned these techniques and how to protect your \ninfrastructure against spoofed packets. See Chapter 2 to learn how to implement these \ntypes of infrastructure protection mechanisms.\nTraceback in the Service Provider Environment\nFor the implementation of traceback techniques to be successful, they must meet the \nfollowing requirements: \n•\nDo not violate current protocol semantics and can be successful without changes in \nthe core routing structure\n•\nAre difficult for the attacker to detect and can function in a passive mode, without \nrequiring much intervention\n•\nAre useful in asymmetric environments \n•\nWork through multiple hops, across jurisdictions\n•\nAllow you to generate a good postmortem after an attack has mitigated \nIn some cases, it is difficult for the implementation of traceback techniques to meet all the \nrequirements previously listed, and it is especially difficult for service providers. This is \nwhy it is extremely important for service providers to cooperate with each other to \nsuccessfully trace back attacks. This is especially true because attackers are aware of many \ntraceback schemes.\nTIP\nMajor cooperative efforts exist between service providers and several organizations \nthat promote these efforts. An example is the North American Network Operators \nGroup (NANOG), which has excellent resources and information at http://www.nanog.org.\nAnother example is the Forum for Incident Response and Security Teams \n(FIRST), which has excellent resources and best practice guides at \nhttp://www.first.org/resources/guides.\nWhen there are large numbers of sources or when sources are well distributed, traceback \nsolutions often become extremely complex and expensive. Speed is a significant limitation \nof hop-by-hop traceback; therefore, hop-by-hop traceback can be difficult. It also requires \n"
        },
        {
            "page_number": 166,
            "text": "Traceback in the Service Provider Environment     143\nsubstantial collaboration. For example, Figure 4-1 illustrates an old method being used by \nan individual who is attacking a victim who is numerous hops away from different \nservice providers.\nFigure 4-1\nHop-by-Hop Traceback\nIn this case, collaboration between service providers may be needed, and hop-by-hop \ntraceback may take longer than expected. However, this is not what we typically see today. \nFigure 4-2 illustrates a more interesting scenario.\nAttacker\nVictim\nService Provider C\nService Provider B\nService Provider A\n"
        },
        {
            "page_number": 167,
            "text": "144\nChapter 4:  Traceback\nFigure 4-2\nHop-by-Hop Traceback with Botnets or Zombies\nAttacker\nVictim\nBotNet 3\nBotNet 2\nService\nProvider B\nService Provider A\nService\nProvider C\nBotNet 1\n"
        },
        {
            "page_number": 168,
            "text": "Traceback in the Service Provider Environment     145\nIn Figure 4-2, the attacker controls three different botnets or groups of zombies. In this case, \nhop-by-hop traceback can be time consuming and ineffective. Botnets can consist of several \nhundred compromised machines. Even a relatively small botnet with only a couple of \nhundred bots can cause significant damage. The IP distribution of these bots makes the \nimplementation of ingress filters (or filtering) difficult, especially because separate \norganizations are involved. In most cases, botnets are used to infect or spread malware to \nother machines. In numerous cases, botnets are controlled by the attacker who is using \nencrypted tunnels to protect his own communication channel.\nBotnets come in hundreds of different types, some of which include:\n•\nAgobot/Phatbot/Forbot/XtremBot\n•\nSDBot/RBot/UrBot/UrXBot\n•\nmIRC-based bots\n•\nDSNX bots\n•\nQ8 bots\n•\nkaiten.cPerl-based bots\nTIP\nShadowserver.com is an excellent website that reports botnet activity on the Internet on a \ndaily basis. Many organizations use this information to become familiar with current \ntrends. This site provides detailed graphics and metrics.\nYou can also obtain technical information about different types of bots at \nhttp://www.cert.org or at http://packetstormsecurity.nl.\nAttackers who launch DDoS attacks can gain a major advantage by using reflectors to \ncomplicate the traceback process; this is known as attack obfuscation. Instead of the victim \nbeing able to trace back the attack traffic from himself directly to the slave, he must induce \nthe operator of one of the reflector sites to do so on his behalf which can be administratively \ncumbersome or difficult. \nTracking botnets is a dilemma for many service providers and other organizations. To \nsuccessfully perform traceback, you need to gather a significant amount of data about \nexisting botnets, in many cases by analyzing captured malware. Many organizations are \nengaged in research to learn more about botnets and new techniques to combat them. An \nexample of this is the Honeynet Project (http://honeynet.org). Honeynets are a collection \nof purposefully insecure machines (or honeypots) that are placed on the Internet for \nattackers to compromise. Researchers can then investigate and learn more about current \n"
        },
        {
            "page_number": 169,
            "text": "146\nChapter 4:  Traceback\nthreats. At the minimum, honeynets collect the following information to learn more about \nbotnets:\n•\nDNS name or IP address of the Internet relay chat (IRC) server and port number \n•\nIn some cases, passwords to connect to the IRC server (when applicable) \n•\nNickname of bot and ident (identification) structure \n•\nIRC channel to join and channel password\nMany researchers have observed that updates on the botnet malware are performed \nfrequently. To understand this process more fully, consider an old worm whose propagation \nstarted in several botnets, Zotob.x. Zotob was created by Farid Essebar (known by his \nhandle as Diabl0). He was a small-time adware/spyware installer, using Mytob (a mass \nmailing worm) to infect machines and install adware for money. On August 25, 2005, \nEssebar was arrested in Morocco. The FBI stated that it holds evidence that Essebar was \npaid by Atilla Ekici (known as coder), who used stolen credit card numbers to build Mytob \nvariants, as well as Zotob. Many service providers and other organizations spent numerous \nhours investigating this incident. One of the methods used was the backscatter technique.\nBackscatter is a system that Chris Morrow and Brian Gemberling created while they were \nworking at a major service provider in the United States. This method addresses the need \nof finding the entry point of a spoofed attack. It combines sinkhole routers and remotely \ntriggered black hole (RTBH) filtering to create a traceback system that provides a result \nwithin minutes.\nYou can use Border Gateway Protocol (BGP)-enabled routers to set specific prefixes to a \nknown and individually handled “next-hop” and see interesting effects when you set the \n“next-hop” in BGP for a host that is under attack to a single address that will be routed \nlocally. Typically, you set a static route to Null0 so that the attack traffic is advertised with \nthe new “next-hop.” An Internet Control Message Protocol (ICMP) unreachable message is \ntransmitted by a network device when it receives packets whose destination is unreachable \n(Null0). This “unreachable noise” is called a backscatter.\nNOTE\nBackscatter has been advocated by many people, but many also question its benefits. You \ncan find more details about the backscatter technique at http://www.secsup.org/Tracking. \nAnother good presentation on backscatter, which is by Barry Greene, a senior Cisco SP \nexpert, is located at http://www.nanog.org/mtg-0110/ppt/greene.ppt.\nFurthermore, if that traceback is then performed using a scheme that relies on observing a \nhigh volume of spoofed traffic, such as ITRACE or probabilistic packet marking, the \nattacker can undermine the traceback by spreading the trigger traffic of each slave across \n"
        },
        {
            "page_number": 170,
            "text": "Traceback in the Enterprise     147\nmany reflectors. Doing this greatly increases the amount of time required by the traceback \nscheme to gather sufficient traffic to analyze. These methodologies have been suggested \ndue to research initiatives by several organizations (mainly educational institutions). \nHowever, the initiatives, in most cases, are considered “science projects.”\nMany others have attempted IP traceback techniques such as probabilistic packet marking \nand deterministic packet markings; these attempts, however, have also been considered \nscience projects.\nNOTE\nWikipedia has a good, high-level description of probabilistic packet marking and \ndeterministic packet markings at http://en.wikipedia.org/wiki/IP_Traceback.\nTraceback in the Enterprise\nThe ability to track where attacks are coming from and the techniques that are used within \nan enterprise depend on the type of attack. If the attacks are coming from external sources, \nsuch as the Internet, the enterprises often depend on their providers to be able to track down \nsources of attack. Additionally, the network telemetry techniques and features discussed in \nChapter 3, “Identifying and Classifying Security Threats,” are extremely helpful for \ntracking where attack traffic is being generated.\nOne of the most powerful tools is NetFlow because it can give macroanalytical information \non the traffic traversing your network. Traceback goes hand in hand with the identification \nand classification phases of incident response. NetFlow, SYSLOGs, DNS, and other \ntelemetry mechanisms in conjunction with event correlation tools such as Cisco Secure \nMonitoring and Response System (CS-MARS) and Arbor Peakflow X are particularly \nhelpful to trace back security incidents.\nJust from a router command line (CLI), you can use NetFlow to collect valuable \ninformation. For example, if you notice a sudden increase in traffic over TCP port 445, you \ncan use the show ip cache flow command with the include option to see the hosts that are \nsending this type of traffic, as shown in the following example:\nmyrouter>show ip cache flow | include 01BD\nFa1/0         10.36.1.66      Fa0/0         172.18.85.178   06 C5BC 01BD    93123135\nBecause NetFlow uses hexadecimal numbers for the protocol, source, and destination ports, \n01BD is used in the include statement (01BD hexadecimal = 445 decimal). As you can see \nfrom the output, the router has received 93123135 TCP port 445 packets on its FastEthernet \n1/0 interface from a host with the IP address 10.36.1.66, which is destined to a host with \nthe IP address 172.18.85.178 residing on the FastEthernet0/0 interface.\n"
        },
        {
            "page_number": 171,
            "text": "148\nChapter 4:  Traceback\nIn the following example, CS-MARS is used in combination with NetFlow and a Cisco IPS \nsensor. In Figure 4-3, the CS-MARS alerts the administrator about a host spreading the \nNachi worm and doing a DoS via ICMP ping. The incident ID is I:155164925.\nFigure 4-3\nWorm Incident in CS-MARS\nWhen the administrator clicks the Attack Path icon on the right, a new screen with the \nattack topology is displayed, as shown in Figure 4-4.\nIn Figure 4-4, you can see that the infected host is 172.19.124.35, and it is attacking a host \nwith the IP address 172.18.124.67. This is a simple topology; however, CS-MARS is able \nto show you each hop based on the information imported and its configuration. Graphical \nrepresentation like this one can save you many hours of investigation.\nAn additional example is shown in Figure 4-5.\n"
        },
        {
            "page_number": 172,
            "text": "Traceback in the Enterprise     149\nFigure 4-4\nAttack Path\nFigure 4-5\nDot-Dot Attack\n"
        },
        {
            "page_number": 173,
            "text": "150\nChapter 4:  Traceback\nIn Figure 4-5, a host with the IP address 10.10.1.10 (HQ-host1) is attempting to crash an \nIIS server (192.168.1.10 or HQ-web-1) by performing a dot-dot crash and running an \nattack. Notice that each hop in between is clearly represented, making the traceback process \nsimple. CS-MARS correlated this information analyzing events from a Cisco IPS sensor \nand from firewall logs from a Cisco PIX security appliance.\nTracing botnet controllers and determining if you are a victim can be difficult. The \nfollowing tips might help you or your organization if it has zombies:\n•\nIf you see a good deal of IRC traffic within your organization, it may be worth \ninvestigating further. IRC traffic is not common in most enterprises, and most of the \nbotnets are organized and controlled over IRC.\n•\nYou can look for the most commonly used default IRC port (6667). In addition, you \nwill want to expand to the full port range (from 6660 to 6669 or 7000). On the other \nhand, many botnet controllers can use nonstandard IRC ports. If you have a firewall \nwithin your organization, take a look at outbound connection attempts on any \nsuspicious ports. \n•\nIRC traffic usually manifests itself in cleartext, so sensors can be built to sniff \nparticular IRC commands or other protocol keywords on a network gateway.\n•\nIf you notice that a large quantity of systems within your organization are trying to \nresolve the same DNS names or accessing the same server at once, you should \nimmediately investigate further because those systems may be zombies. Also, \nperiodically check your DNS caches. Many command and control tools will use a \nDNS domain that the herder (botnet administrator) can easily change as needed to \nrelocate the botnet infrastructure. \n•\nYou can look for other obvious symptoms of being a victim. For example, if you see \nmuch port-scan traffic, it is a definite sign that machines are infected. You can use \nproper IDS/IPS signatures to find these and then investigate the source. In addition, if \nyou see a lot of unexpected outbound SMTP traffic, you are likely to be hosting spam \nbots. You can use NetFlow to get statistics about these type of attacks.\nNOTE\nChapter 12, “Case Studies,” includes case studies with examples of how different types of \norganizations identify, classify, trace, and react to security incidents. Common traceback \nmechanisms are used in those examples.\n"
        },
        {
            "page_number": 174,
            "text": "Summary     151\nSummary\nTracing back the source of attacks, infected hosts in worm outbreaks, or any other security \nincident can be overwhelming for many network administrators and security professionals. \nAttackers can use hundreds or thousands of botnets or zombies that can greatly complicate \ntraceback and hinder mitigation after traceback succeeds. This chapter covered several \ntechniques that can help you successfully trace back the sources of such threats; covering \nboth service provider and enterprise techniques. Remember, traceback mainly involves the \npacket source. Using network telemetry tools like NetFlow, syslog, DNS, and others in \nconjunction with event correlation systems can save you hundreds of work hours and, \nconsequently, save you money.\n"
        },
        {
            "page_number": 175,
            "text": "This chapter covers the following topics:\n•\nAdequate Incident-Handling Policies and Procedures \n•\nLaws and Computer Crimes\n•\nSecurity Incident Mitigation Tools\n•\nForensics\n"
        },
        {
            "page_number": 176,
            "text": "C H A P T E R 5\nReacting to Security Incidents\nReacting to security incidents can be an overwhelming and difficult task if you are not \nprepared. This chapter covers several best practices, techniques, and tips for use when \nreacting to security incidents. In the previous chapters, you learned how to identify, classify, \nand trace security incidents. Without successful identification, classification, and traceback, \nyou will never be able to effectively react to any security event. Therefore, it is important \nthat you understand the topics covered in previous chapters before reading this one.\nAdequate Incident-Handling Policies and Procedures\nThe steps you take when reacting to security incidents depend on the type of threat you are \nmitigating. For example, if you are mitigating a distributed denial-of-service (DDoS) \nattack, you will probably not take the same steps as when reacting to a theft of information \nwhere the attacker does not make that much noise on the network. However, when reacting \nto any security incident, time is one of the most critical factors. \nIt is extremely important to have well-defined incident handling policies in place. In \nChapter 2, “Preparation Phase,” you learned that without defined policies and procedures \nfor mitigation, you can put yourself in a difficult position when a security outbreak or event \noccurs. Following these policies or procedures is important. \nThese policies may be in the form of standalone documentation, or they may be \nincorporated into other documentation such as company security policies or disaster \nrecovery plans. You may consider developing different procedures and response \nmechanisms when responding to a direct DDoS attack versus a worm outbreak, or when \ninformation has been stolen. Not all security incidents are the same, and you should make \nsure that the appropriate response procedures are in place. \nYou should try to create a security policy and be serious about covering all facets of \nsecurity. Ideally, you should develop security policies in the preparation phase.\nCollaboration between support teams within your organization may be necessary when \nresponding to security incidents. After you have successfully identified a security incident, \nclassified it, and tracked it, you must notify the appropriate personnel. For example, if you \nare a member of the Information Security (InfoSec) or Security Operations (OpSec) team, \nyou may need to involve administrators from separate parts of your organization. You may \n"
        },
        {
            "page_number": 177,
            "text": "154\nChapter 5:  Reacting to Security Incidents\nnot have access to the affected device or may not be an expert on a specific application. This \nis why collaboration is so important. \nThe reason for setting up collaboration between support teams is to establish lines of \ncommunication and ensure that personnel understand the areas of responsibility and \ncapability for each partner. In addition, you should provide a detailed description of \nthe incidents technical aspects to your collaborative teams. This will aid in prompt \nacknowledgment and understanding of the problem. However, great care should be taken, \nbecause you do not want to distribute sensitive information unnecessarily. \nYou should also have adequate emergency procedures in place. In some cases, you may \nneed to discuss issues and tasks within external teams. For example, suppose that you are \na member of the OpSec group and you are trying to get information about a specific system \nthat an external team controls. After several attempts, you have received no response. With \nthe correct escalation procedures in place, the task of getting the right people involved \nbecomes easier. Similarly, you should have emergency procedures when other teams try to \nengage your staff. The main goal of incident response is to restore control of the network \nand its systems and to limit the impact and damage. Many people say that, in some cases, \nshutting down affected systems or disconnecting the system from the network may the only \npractical solution. However, if you have the necessary tools in place, you may be able to \nquarantine and remediate such systems without unplugging them from the network. For \nexample, you can use routing as a security mechanism and isolate systems within your \nnetwork. You can use mechanisms such as remotely triggered blackholes (discussed later \nin this chapter) and in other cases put systems in quarantine segments so that you can patch \nthem accordingly when security outbreaks occur.\nHaving a systematic approach for patch management is crucial. For instance, if you have a \ngood system in place to provide security operating system and application patches as soon \nas they become available, your systems are far less likely to fall prey to major attacks. An \nupdated security management system is not a top priority for many companies; however, \nattackers, worms, and malware do not wait for you to patch every system manually. More \nimportantly, in the case of worm outbreaks, having a distributed patch management system \ncan save you and your staff considerable time thereby saving your organization money.\nIt is important to create checklists of procedures to be followed during an incident. \nDocumenting events as they happen is important. On most occasions, you may feel as if \nyou do not have time to completely document events in detail during the incident. However, \nduring the identification, classification, and traceback phases, you should gather as much \ninformation about the incident as possible. Attempt to answer the following questions:\n•\nWhat type of incident are you experiencing?\n•\nWhen did the attack occur (date and time)?\n•\nWhere did the attack occur?\n•\nWhat systems were affected and compromised?\n"
        },
        {
            "page_number": 178,
            "text": "Laws and Computer Crimes     155\nNOTE\nChapter 6, “Postmortem and Improvement,” includes examples of these checklists and \nincident response reports.\nThese are some of the most fundamental questions that need to be answered. You may \ndevelop more specific questions on a case-by-case basis.\nAnother procedure that you must document is when to involve law enforcement. Incident \nresponse is probably one of the disciplines most affected by legal considerations because \nmany incidents involve some sort of crime. Consequently, your organization might want to \nprosecute the attacker, and in this case, it must consider the legal implications of the \nincident. If legal implications are present, you must assist law enforcement in all aspects of \ntheir investigation. Different laws and regulations are covered in the next section. \nLaws and Computer Crimes\nIn most cases, United States and international laws might affect or impact the incident \nresponse process. If you want to prosecute an attacker, you might merely have to contact \nlocal authorities. In some cases, however, you will need to contact the Federal Bureau of \nInvestigation or equivalent organizations in other countries, especially when dealing with \nattacks that involve international boundaries. International and inter-jurisdictional \ncooperation is difficult. What is illegal in one country may not be in another. \nTypically, you have three different options. The first option is to mitigate the problem and \nmove on. The second is to prosecute the attacker in his own country (assuming that the \nsecurity event you experienced is illegal in that country). The third option is to apply \nfor extradition and prosecute the offender in the country where the incident happened. If \nyou opt for the second or third option, you should seek assistance from your local \nauthorities.\nNOTE\nThe procedures and circumstances for engaging law enforcement depend on your local \nlaws. International laws may also apply.\nThe U.S. laws distinguish between crimes against computers and crimes involving\ncomputers. For example, a DDoS or a person gaining unauthorized access to a computer or \nnetwork is classified as a crime “against a computer.” On the other hand, if a person \ncommits an assault against someone else or any other felony in which a computer was only \nthe tool used to commit the crime, this is classified as a crime “involving a computer.”\n"
        },
        {
            "page_number": 179,
            "text": "156\nChapter 5:  Reacting to Security Incidents\nThe “Computer Fraud and Abuse Act” is the standard statute covering computer crimes in \nthe United States. This was initially introduced in 1986 and updated ten years later in 1996. \nTitle 18, Section 1030, covers crimes against computers.\nNOTE\nYou can access Title 18, Section 1030 at the Cornell University Law School website at \nhttp://www4.law.cornell.edu/uscode/html/uscode18/usc_sec_18_00001030----000-.html.\nThe U.S. Department of Justice has a website where you can obtain specific information on \nwho to contact when reporting a security incident. You can access the website at \nhttp://www.cybercrime.gov/reporting.htm.\nAn excellent document titled “Searching and Seizing Computers and Obtaining \nElectronic Evidence in Criminal Investigations” can be accessed at \nhttp://www.cybercrime.gov/s&smanual2002.htm.\nAnother initiative by the U.S. government is the Internet Crime Complaint Center (IC3). \nIC3 is a partnership between the Federal Bureau of Investigation (FBI) and the National \nWhite Collar Crime Center (NW3C). The website is http://www.ic3.gov.\nTIP\nInfragard is an organization that is the product of a collaborative effort between the FBI, \nlocal enforcement agencies, and private organizations. It has created Special Interest \nGroups (SIGs), which are resources dedicated to the safeguarding of specific critical \ninfrastructures of both private industry and government through information-sharing \nnetworks and a private secure portal of communication. You can obtain more information \nabout Infragard and local chapters at http://www.infragard.net\nIf you work in the health care industry, you should be aware of several new regulations, \nsuch as the Health Industry Portability and Accountability Act (HIPAA). The act requires \nall persons with access to this information to take reasonable care to protect the integrity \nand confidentiality of patient data. Not only hospitals and health care facilities, but also \ninsurers are now implementing security safeguards and completing risk assessments to \nensure the privacy of patients.\nSecurity Incident Mitigation Tools\nThis section includes several tools and techniques that you can use when mitigating security \nincidents, such as DDoS and worm outbreaks.\n"
        },
        {
            "page_number": 180,
            "text": "Security Incident Mitigation Tools     157\nTIP\nThe mitigation technique and enforcement depends on your network architecture and \ndesign. This section covers the most common techniques. As a rule of thumb, you want to \nbase your mitigation operations as close as possible to the source of the attack.\nAccess Control Lists (ACL)\nWhen you react to a DDoS or to a worm outbreak, one of the most important matters is how \nfast you can quarantine and isolate the problem. Quarantining is the process of identifying \nall infected machines and blocking them from the network to prevent them from infecting \nother systems (in case of a worm outbreak). The easiest way to quarantine or block systems \nis by using router and firewall access control lists (ACL) and VLAN ACLs (or VACL) on \nCisco switches. VACLs allow port-level filtering on a VLAN basis. In most cases, VACLs \nare more feasible when blocking an infected machine. VACLs are applied directly on the \nswitch port, thereby enabling you to do per-host filtering.\nIt is extremely important that you be familiar with your network topology and understand \nhow all the VLANs are configured. It is a best practice to document the devices (or at least \nthe device types) that reside within each VLAN. This will be extremely helpful to you when \nyou are in the mitigating phase of your reaction to attacks and worm outbreaks. \nAnother best practice is to prioritize your network resources and critical systems. During \nthe reaction phase, you should protect the most critical systems first.\nFor more information on tools that can be used for asset management and asset \nclassification, see Chapter 7, “Proactive Security Framework.” \nTIP\nThe Cisco Catalyst 6000 series of switches has a switching engine known as a Policy \nFeature Card (PFC) that contains specialized application-specific integrated circuits \n(ASIC) that enable the blocking of traffic to occur at close to wire speed on the switch.\nOne of the major problems with ACLs and VACLs is that you must apply them throughout \nthe network quickly. You can use tools such as the Cisco Security Manager (CSM) to deploy \nACLs quickly in your network. You can also use commercial tools such as OpsWare, and \nSolSoft.\nMany security administrators allocate a range of extended ACL numbers that can be \ndynamically used when mitigating security incidents. For instance, you can assign 190 to \n199 for security reaction ACLs, if this range is not in use anywhere else in your network. \nSome people recommend configuring, on each network, a dummy list device which is well \ndocumented with a detailed description so that staff will know that this ACL is reserved \n"
        },
        {
            "page_number": 181,
            "text": "158\nChapter 5:  Reacting to Security Incidents\nand will know its purpose. If you have NetConfig, you can create templates to ease the \ndeployment. \nPrivate VLANs\nPrivate VLANs can be used to achieve Layer 2 isolation of hosts within a VLAN. Some people \nuse private VLANs in their data center to isolate servers in case they are compromised or \ninfected. However, private VLANs do not provide perfect isolation. For example, you can \ninsert a Layer 3 device to a promiscuous port and hop from one system to another using the \ndestination IP address with the Layer 3 device MAC address. This type of attack and others are \nexplained extensively in the whitepaper at http://www.cisco.com/en/US/netsol/ns340/ns394/\nns171/ns128/networking_solutions_white_paper09186a008014870f.shtml#wp1002364.\nRemotely Triggered Black Hole Routing\nRemotely triggered black hole (RTHB) routing is a technique that can be used to drop \nall attack traffic based on either destination or attack source addresses. Source and \ndestination-based RTBH filter undesirable traffic by forwarding it to the Null0 interface (a \npseudointerface that is always up and can never forward or receive traffic). Performance \nis not a significant challenge with RTBH because it occurs directly in the forwarding path \nor Cisco Express Forwarding (CEF).\nNOTE\nThis section assumes that you have a basic understanding of Border Gateway Protocol \n(BGP). If you need to review BGP, refer to http://www.cisco.com/en/US/tech/tk365/tk80/\ntsd_technology_support_sub-protocol_home.html which includes a comprehensive list of \nBGP-related FAQs, configuration guidelines, and troubleshooting tips.\nDestination-based RTBH works by filtering traffic destined to the hosts being attacked \nor by filtering an infected host (in worm outbreaks) at the boundary closest to the source. \nThe trigger is typically a router that sends a routing update (iBGP in most cases) to other \nedge routers configured for black hole filtering. The trigger sends an update with the \nnext-hop IP address defined in a static route pointing to Null0. This is illustrated in \nFigure 5-1.\n"
        },
        {
            "page_number": 182,
            "text": "Security Incident Mitigation Tools     159\nFigure 5-1\nDestination-Based RTBH\nIn Figure 5-1, two zombies are attacking a web server (10.10.10.123). The network \nadministrator in the Network Operations Center (NOC) notices the attack and configures a \nstatic route on the trigger router with the destination host address (10.10.10.123), pointing \nit to Null0. This trigger router then sends an iBGP update to the two other routers causing \nit to drop the attack traffic. Example 5-1 is the trigger router configuration:\nExample 5-1\nTrigger Router Configuration \ninterface loopback0\n ip address 10.20.30.18 255.255.255.255\n!\ninterface Null0\n no ip unreachables\n!\nrouter bgp 64555\n no synchronization\n no bgp client-to-client reflection\n bgp log-neighbor-changes\n redistribute static route-map rtbh-trigger\n neighbor rtbh-group peer-group\n neighbor rtbh-group remote-as 64555\n neighbor rtbh-group update-source loopback0\n neighbor rtbh-group route-reflector-client\n neighbor 10.20.30.1 peer-group rtbh-group\n!\nroute-map rtbh-trigger permit 10\n match tag 666\n set ip next-hop 192.168.20.1\ncontinues\nNetwork\nOperations\nCenter\n(NOC)\nAttacker/Zombie\nAttacker/Zombie\nAttack Traffic\nEdge Router 1\n(10.20.30.1)\nEdge Router 2\n(10.20.30.2)\niBGP Update\nOriginal\nAttack Path\nTrigger\nRouter\nVictim\n(10.10.10.123)\n"
        },
        {
            "page_number": 183,
            "text": "160\nChapter 5:  Reacting to Security Incidents\nIn the previous configuration example, a static route for the IP address (10.10.10.123) of \nthe victim is configured pointing to Null0 and with a tag of 666. A route map called rtbh-\ntrigger is applied prior to redistributing the static route into BGP. This route map is \nconfigured to match on a tag value of 666. It also sets the next-hop to 192.168.20.1 which \nis an unused address space that you must configure to selectively drop the traffic. The \ntrigger router sets the next-hop route for the destination IP address whose traffic will be \ndropped. Route updates are used to propagate this route to all iBGP peer routers. These \nrouters then set their next-hop to the destination. You must configure a static route for the \nnext-hop address (in this example, 192.168.20.1) pointing to Null0 in all the routers where \nyou want the traffic to be dropped. This enables the edge routers to set their next-hops \naccordingly and forward all traffic for the black-holed destination IP address to Null0. In \nthis example, the local preference is set to 200, and the origin is set to the remote Interior \nGateway Protocol (IGP) system. The community is set to no-export, so these routes will not \nbe advertised to external BGP (eBGP) peers.\nNOTE\nFor RTBH to operate successfully, the trigger router must have an iBGP peering \nrelationship with the other two routers. If you use BGP route reflectors, the trigger router \nmust have an iBGP relationship with the route reflectors in every cluster.\nIf the attacker uses nonspoofed addresses for the attack, you can also do source-based \nRTBH just by adding a static route to the source or source network, as shown in the \nfollowing example.\nip route 192.168.20.2 255.255.255.255 Null0 tag 666\nIn this example, the attacker is using the IP address 192.168.20.2. However, an attacker \ncould target a legitimate IP address by spoofing it as the source of an attack and counting \non you to black-hole the source using sourced-based RTBH filtering. This is why having \nantispoofing mechanisms in place is crucial for every network in any organization.\nForensics\nMany people say that computer forensics is similar to a crime scene investigation, in most \ncases, the security event you are investigating may be an actual crime. You should \ndetermine which computer forensic methodology is most appropriate for your organization. \n set local-preference 200\n set origin igp\n set community no-export\nroute-map rtbh-trigger deny 20\n! The following is the static route that drops the traffic from the infected machine\nip route 10.10.10.123 255.255.255.255 Null0 tag 666\nExample 5-1\nTrigger Router Configuration (Continued)\n"
        },
        {
            "page_number": 184,
            "text": "Forensics\n161\nThis investigation can be done by you or your own staff, by law enforcement, or by private \nsector computer forensic specialists. One of the most critical items to remember is the \nconsequences of mishandling evidence. Forensics is a broad topic, and the laws and \nhandling of evidence vary based on your locality. This chapter is intended to give you only \nsome of the common tools and mechanisms that you can use to perform basic forensics \nafter a security event. \nNOTE\nReferences to several whitepapers and tools are listed in the sections that follow.\nLog Files\nAfter a security incident, you can use log files to obtain clues on what happened. However, \nlogs are useful only if they are actually read. Even in small networks, logs from servers, \nnetworking devices, end-host machines, and other systems can be large, and their analysis \nmay be tedious and time consuming. That is why it is important to use event correlation \nsystems and other tools to better analyze and study log entries. You can use robust systems \nsuch as CS-MARS or even simple tools and programs such as Swatch. Swatch stands for \nSimple Watcher. It is an open source tool written in Perl that is capable of searching a file \nfor a list of strings and then performing specific actions when such a string is found. Swatch \nwas designed to do real-time monitoring of server log files; however, you can also use it to \nhandle a standalone file. It was also designed to analyze syslog archives, but you can use it \non any file.\nNOTE\nThe Swatch open source project is maintained on Source Forge at \nhttp://swatch. sourceforge.net.\nAnother excellent tool is Splunk. You can use this tool to conduct real-time searches of \ndifferent types of event logs from different systems. \nNOTE\nFor more information about Splunk, go to http://www.splunk.com. In addition, \nhttp://www.loganalysis.org includes information about numerous log parsers that can be \nused for forensic purposes.\nDifferent systems have different log formats. If it is necessary to compare files, it can be \nchallenging to match up fields. For example, logs from routers are not the same as logs from \n"
        },
        {
            "page_number": 185,
            "text": "162\nChapter 5:  Reacting to Security Incidents\nfirewalls or other networking devices. Similarly, logs from Linux or UNIX servers are not \nthe same as logs from Windows systems. CS-MARS can help you analyze all these \ndifferent types of logs. Also, some open source tools can help you analyze system logs from \nUNIX/Linux and Windows machines. The following sections include the most commonly \nused tools.\nLinux Forensics Tools\nTwo of the most commonly used Linux forensics tools are Autopsy and the Sleuth Kit. \nThese programs are intuitive and are a compilation of the following:\n•\nFile system layer tools\n•\nFile system journal tools\n•\nMeta data layer tools\n•\nDisk image file tools\nDespite the fact that Autopsy and the Sleuth Kit run on Linux, they support the NTFS, FAT, \nExt2/3, and UFS1/2 file systems. You can download Autopsy and the Sleuth Kit free from \nhttp://www.sleuthkit.org.\nFigure 5-2 is a screen shot of Autopsy.\nFigure 5-2\nAutopsy Linux Forensics Tool\n"
        },
        {
            "page_number": 186,
            "text": "Forensics\n163\nFigure 5-2 shows how you can use Autopsy to analyze the files and directories within a \nsystem. You can use this tool to see the names of deleted files. Autopsy can create timelines \nthat contain entries for the “Modified, Access, and Change” times of both allocated and \nunallocated files. It also allows you to create a “case” to track each security incident.\nWhen collecting information from a Linux or UNIX-based system, you can also use simple \ntools and commands such as netstat and pstree. You can use the netstat -tap command as \nshown in Figure 5-3 to obtain information about the active connections in a system.\nFigure 5-3\nnetstat Command Output\nIn Figure 5-3, you can see the output showing the different established connections on the \nsystem.\nNOTE\nOn UNIX- and Linux-based systems (including Mac OS X), use the man netstat command\nto obtain detailed documentation on the available options of the netstat command.\nYou can also use the pstree utility on a Linux system to display the processes on the system \nin the form of a tree diagram. This allows you to have a better view of the processes \nrunning on the system that may be part of malicious software. Figure 5-4 includes a screen \nshot of the output of the pstree -hp command. The -h option is used to show the current \nprocess and its ancestors, and the -p option is used to display the process IDs (PID).\n"
        },
        {
            "page_number": 187,
            "text": "164\nChapter 5:  Reacting to Security Incidents\nFigure 5-4\npstree Command Output\nThe detailed whitepaper titled “Checking UNIX/LINUX Systems for Signs of Compromise” \nsupplies insightful information on the forensics of Linux and UNIX systems. You can \ndownload the whitepaper from http://www.ucl.ac.uk/cert/nix_intrusion.pdf.\nWindows Forensics\nThe most commonly used toolkit for forensics in Windows-based systems is Systernals. \nSysternals is a compilation of several tools used for analysis, troubleshooting, and forensics \nof Windows machines. This toolkit was initially created by Mark Russinovich and Bryce \nCogswell, and Microsoft acquired it in July 2006. Systernals toolkit includes the following:\n•\nFile and disk utilities\n•\nNetwork statistical and analysis utilities\n•\nProcess illustration and analysis utilities\n•\nSecurity configuration utilities\n•\nSystem resource usage and configuration tools\n"
        },
        {
            "page_number": 188,
            "text": "Summary     165\nNOTE\nMicrosoft has an excellent whitepaper about Windows forensics best practices and \nmethodologies at http://www.microsoft.com/technet/security/guidance/disasterrecovery/\ncomputer_investigation/default.mspx.\nGuidance Software also develops sophisticated forensics tools. Its EnCase product suite \nincludes different integrated tools that facilitate seamless sharing of evidentiary data and \nsolve the resource drain of encrypted data. \nNOTE\nFor more information about the EnCase suite of tools, go to \nhttp://www.guidancesoftware.com.\nIt is important to remember that no matter the vendor, the forensics tool you select must \ngive you flexibility when conducting investigations and should help mask complexity when \nforensics data is shared with untrained individuals.\nSummary\nIn this chapter, you learned how important it is for any organization to have adequate \nincident handling policies and procedures. You also learned general information about the \ndifferent laws and practices involved when you are investigating security incidents and \ncomputer crimes. This chapter also included detailed information about different tools you \ncan use to mitigate attacks and other security incidents with your network infrastructure \ncomponents. This chapter concluded with a discussion of basic computer forensics topics.\n"
        },
        {
            "page_number": 189,
            "text": "This chapter covers the following topics:\n•\nCollected Incident Data\n•\nRoot-Cause Analysis and Lessons Learned \n•\nBuilding an Action Plan \n"
        },
        {
            "page_number": 190,
            "text": "C H A P T E R 6\nPostmortem and Improvement\nAfter any security incident, you should hold a postmortem. At this postmortem, you should \nlook at the full chronology of events that took place during the incident. This chapter \nincludes common best practices when documenting a security incident postmortem.\nThe postmortem is one of the most critical steps in incident management. The development \nof the postmortem should be based on analysis of the gaps that enabled a security incident \nto occur and resulting recommendations for improvements. These recommendations will \nimpact your policies, processes, standards, and guidelines. They will also indirectly impact \npeople—your staff and other personnel. Based on gap analysis, you should design and \nimplement solutions as necessary. \nPostmortems can also help you justify increases to your budget for technology solutions \nthat can help you avoid damage that you experienced during the incident. This is why it is \nimportant that you identify all weaknesses and holes in systems, infrastructure defenses, or \npolicies that allowed the incident to take place.\nCollected Incident Data\nThe postmortem is one of the most important parts of incident response and is also the part \nthat is most often omitted. As mentioned in the previous chapter, documenting events that \noccurred during the previous phases (identification, classification, traceback, and reaction) \nis important to effectively create a good postmortem following a security incident. The \ncollection of this data is important because it can be used for future improvement in the \nprocess, policies, and device configuration. This data can also be used to calculate the cost \nand the total hours of involvement and may help you justify additional funding of the \nincident response team. \nThis also can help you to understand changes in new security threats and trends. You can \nuse the data and lessons learned from the postmortem as input to improve security policies, \nprocesses, and system configurations. This is illustrated in Figure 6-1. \n"
        },
        {
            "page_number": 191,
            "text": "168\nChapter 6:  Postmortem and Improvement\nFigure 6-1\nPostmortem Looped Feedback\nTry to address the “who, what, how, when, why” questions in your postmortem. Table 6-1 \ndemonstrates this approach.\nTable 6-1\nTypical Questions Answered in a Postmortem \nType\nQuestion\nWho\nWho was affected by this incident?\nWho reported the incident? \nWere the right people engaged?\nWere customers impacted?\nWere partners impacted?\nWas communication between staff and other teams appropriate?\nWhat\nWhat systems were affected by this incident?\nWhat processes were affected by this incident?\nWhat tools were used to identify, classify, trace back, and mitigate the \nincident?\nWhat worked well?\nWhat did not work well?\nWhat were the key lessons learned from the incident? \nWhat other contingency plans in the organization could be applied?\nPreparation\nIdentification\nClassification\nTraceback\nReaction\nPostmortem\n"
        },
        {
            "page_number": 192,
            "text": "Collected Incident Data\n169\nThe answers to questions like those included in Table 6-1 should be collected in a \ncollaborative effort between the team members who help on the identification, \nclassification, traceback, and reaction phases. Keep in mind that if you ask questions that \nare too broad, you may have different perspectives within your staff. This is not necessarily \na problem; however, you want to collect clear and concrete facts. If you ask questions that \nare too narrow, you may end up limiting the input and information that you can collect and \nanalyze from your team experience during the incident. On the other hand, you should \ncollect data that is clear and concrete, rather than collecting data simply because it is \navailable and may be incorrect.\nThe analysis of the data collected in the postmortem will also help you to measure the \nsuccess of the incident response team. However, the postmortem process will fail miserably \nif the problem review board is used as a forum to point fingers at specific staff members or \norganizational divisions. The most important thing is to understand that the data collected \nin the initial stage of the postmortem helps you organize a list of lessons learned during the \nincident.\nFigure 6-2 shows the first part of a basic incident response report and postmortem. In \nthis example, Joe Doe from a fictitious company called SecureMe is the author of the \nreport.\nHow\nHow was the incident first identified?\nHow could the recovery process have been shortened after a fix was \nidentified?\nHow effective was the incident diagnosis and response? \nHow effective was the communication process?\nWhen\nWhen was the incident first identified?\nWhen was the incident first reported?\nWhen was the incident mitigated? \nWhy\nWhy did a procedure fail? \nWhy was a procedure difficult to implement?\nWhy was your methodology successful? \nTable 6-1\nTypical Questions Answered in a Postmortem (Continued)\nType\nQuestion\n"
        },
        {
            "page_number": 193,
            "text": "170\nChapter 6:  Postmortem and Improvement\nFigure 6-2\nIncident Response Report and Postmortem Example\nSecureMe, Inc. Incident Response Report and Postmortem\nReported by: Joe Doe\nPhone: (555) 123-1234\nDate of Incident: 07/04/2009\nIncident ID (if applicable): CSIRT-987654321\nDate: 07/05/2009\nEmail: jdoe@somedomain.com\nTime of Incident: 9:30 a.m. EST\nExternal Service Request (If applicable): 601234569\nIncident Summary:\nNumerous ICMP packets were sent by an unauthorized system to a sales e-commerce web-server farm.\nHow was it discovered?\nAbnormal behavior was noticed from CS-MARS incident\nusing Netflow data. An automatic e-mail notification from\nthe system was received at 9:30 a.m.\nWhat actions and technical mitigation have been\ntaken?\nThe source of attack was confirmed by using Netflow data\nand CS-MARS reports. An access control list was\ndeployed at the Internet edge router to mitigate the attack.\nSelect the type of incident:\nDenial of Service Attack\nList all the systems that were affected:\nSales e-Commerce web servers\nWhere any of the affected systems mission critical?\n[X] Yes    [  ] No\nWhat was the source?\nX\nExternal unauthorized user\nWas law enforcement contacted? [  ] Yes    [x] No\nIf yes, what department (i.e., local enforcement, FBI, etc):\nUnauthorized Application Access\nWebsite Defacement\nIdentity Theft\nList all departments or business units that were affected:\nSales Department\nWas the source of the attack/incident spoofed?\n[  ] Yes    [x] No\nFormer employee\nInternal guest\nUnknown\nOther\nOther\n(please specify):\n(please specify):\nX\nWorm or Virus\nTheft of information data\nInternal employee (full time)\nContractor\n"
        },
        {
            "page_number": 194,
            "text": "Root-Cause Analysis and Lessons Learned     171\nIn Figure 6-2, a member of the SecureMe incident response team reports that numerous \nICMP packets were sent to a web server farm that is part of an e-commerce solution that \nbelongs to its sales department. The fields on the form include most of the questions listed \nin Table 6-1. Figure 6-2 is merely a basic example. You can expand this form by \nincorporating more detailed information that is appropriate for your environment and \norganization, such as the following:\n•\nTotal person-hours spent working on the incident\n•\nElapsed time from the beginning of the incident to its resolution\n•\nElapsed time for each stage of the incident handling process \n•\nTotal hours spent by the incident response team in responding to the initial report of \nthe incident\n•\nEstimated monetary damage from the incident\nRoot-Cause Analysis and Lessons Learned\nAlways remember that “lessons learned” is knowledge or understanding gained \nby experience (in this case, by the experience during the security incident). The \nLessons Learned section in your postmortem should focus on identifying incremental and \ninnovative improvements that will measurably improve the following areas of the \norganization:\n•\nProcesses and policies\n•\nTechnology and configurations\nThe postmortem should include both negative and positive experiences. You should \nhighlight the recurrence of successful outcomes while helping to prevent the recurrence of \nunsuccessful outcomes.\nThe Lessons Learned section in the postmortem will also help you to improve your risk \nmanagement processes. You can incorporate these lessons learned into several areas of risk \nmanagement. One of the key inputs to risk identification is historical information. An input \nto both qualitative and quantitative risk analysis is identified risks, which can be obtained \nin your postmortem. Each incident response team should evolve to reflect new threats, \nimproved technology, and lessons learned.\nYou should establish criteria for a lessons learned process. More importantly, you should \nturn “lessons learned” into “applied lessons.” The following section gives you tips on how \nto build an action plan from the lessons learned during each phase of the incident response.\nFigure 6-3 shows the Lessons Learned section of the SecureMe Incident Response Report \nand Postmortem.\n"
        },
        {
            "page_number": 195,
            "text": "172\nChapter 6:  Postmortem and Improvement\nFigure 6-3\nLessons Learned Section of Report\nThe questions and information in the form outlined in Figure 6-3 are just examples of the \nitems you can incorporate within your Lessons Learned section in your postmortem. In \naddition, you can build a rating system of different areas within your incident response \necosystem. For instance, you can list several areas under several major sections, such as the \nfollowing:\n•\nTools and resources\n•\nIncident response policies and processes\n•\nIncident response team\n•\nTimeliness of resolution\n•\nCollaboration with other teams\nSecureMe, Inc. Incident Response Report and Postmortem\nLessons Learned\nSuccess stories (describe what good, repeatable practices and procedures took place):\nHow well did the incident response staff and management perform in dealing with the incident?\nWere the documented procedures followed? Explain if they were adequate.\nWhat information was needed sooner?\nWhat should be done differently the next time a similar incident takes place?\nWhat corrective actions can prevent similar incidents in the future?\nWhat additionally tools or resources are needed?\n"
        },
        {
            "page_number": 196,
            "text": "Building an Action Plan\n173\nUnder each of these categories, you can list more detailed items or subcategories and then \nrate them. You can use a simple scale from 1 to 5, such as the following:\n1 Poor\n2 Needs improvement\n3 Average\n4 Good\n5 Excellent\nNOTE\nThe rating system outlined here is just an example. The numbering scheme should be based \non the needs of your organization.\nAt the end of this phase, you can calculate an overall average and use metrics to rate the \neffectiveness of your incident response process and resources.\nBuilding an Action Plan \nAfter you have collected all necessary information and documented the different lessons \nlearned, you should build a comprehensive action plan to address any deficiencies in \nprocesses, policies, or technology. Some underlying causes may remain unknown at the \ntime of the initial post-incident meetings; however, you can capture these causes as open \naction items to be closed when you have completed your final research. \nPrioritize the gaps identified to make sure that you address the most critical first. In \naddition, understand the root cause of gaps and problems identified. One aspect that \nsometimes gets lost in the incident postmortems is exploring the reasons for the problems \nidentified. If you do not pay attention to underlying causes, you may fix specific problems \nand improve particular procedures; however, you will likely encounter different \nconsequences of the same fundamental errors that caused those particular problems.\nWhen you build an improvement plan based on the information collected in the lessons \nlearned, each action item should have the following (at the very minimum):\n•\nClear description\n•\nPerson assigned\n•\nDue date for follow-up\n•\nPriority\n"
        },
        {
            "page_number": 197,
            "text": "174\nChapter 6:  Postmortem and Improvement\nThis reduces risks that could develop if you fail to follow up on items that can present future \nthreats. This concept is illustrated in Figure 6-4.\nFigure 6-4\nAction Items\nSummary\nIt is highly recommended that your Computer Security Incident Response Team (CSIRT) \nperform a postmortem after any security incident. This postmortem should identify the \nstrengths and weaknesses of the incident response effort. With this analysis, you can \nidentify weaknesses in systems, infrastructure defenses, or policies that allowed the \nincident to take place. In addition, the postmortem can help you identify problems with \ncommunication channels, interfaces, and procedures that hampered the efficient resolution \nof the reported problem.\nThis chapter offered you several tips on how to create effective postmortems and how to \nexecute post-incident tasks. It included guidelines for collecting post-incident data, \ndocumenting lessons learned during the incident, and building action plans to close any \ngaps that are identified. \nClear, Detailed\nDescription of the\nGap Identified\nPerson Assigned\nAction Item\nDue Date\nPriority\n"
        },
        {
            "page_number": 198,
            "text": "Summary     175\nIt is worth mentioning that many individuals claim to always conduct post-incident \nanalysis; however, they rarely execute and close the gaps identified. Always make sure that \nyou follow up an incident by addressing all the gaps and communicating the lessons learned \nto other members of the organization. Follow up by educating employees, especially the \nincident coordinators. Having a group of people who know all the processes and who can \nguide the various departments of the company to cooperate in response to an issue is \nimportant. Work with incident coordinators to fix processes or create new ones. Incident \ncoordinators may also be able to help educate the rest of the company on these processes. \nYou definitely want everyone in the organization to understand at least where to report a \nsuspected problem or concern.\n"
        },
        {
            "page_number": 199,
            "text": "This chapter covers the following topics:\n•\nSAVE Versus ITU-T X.805\n•\nIdentity and Trust\n•\nVisibility\n•\nCorrelation\n•\nInstrumentation and Management\n•\nIsolation and Virtualization\n•\nPolicy Enforcement\n•\nVisualization Techniques\n"
        },
        {
            "page_number": 200,
            "text": "C H A P T E R 7\nProactive Security Framework\nMany network security frameworks are in the marketplace and most of them have the \ncommon goal of providing a methodical and efficient approach to network security. No \nframework is perfect, you should choose an approach that can help reduce the time, cost, \nand resources needed to plan and deploy your security strategy. This chapter highlights best \npractices and benefits of different security frameworks. \nA framework can help you establish a view of your entire security landscape, identify \npotential capability gaps, and prioritize initiatives for improvement.\nThe Security Assessment, Validation, and Execution (SAVE) framework, formerly known \nas the Cisco Operational Process Model (COPM), is a security framework that enables \nvisibility and control for end-to-end security. Cisco initially designed SAVE for the Internet \nservice provider (ISP) part of the Next-Generation Network (NGN) initiative. However, \nyou can also apply its practices to enterprises. \nToday, malicious traffic within ISPs is spreading faster than before because attack tools are \nbecoming more sophisticated and easier to find. ISPs have witnessed a transformation in \nthe community that engages in cybercrime activities for financial reward, otherwise known \nas the miscreant economy. The principles introduced by SAVE allow ISPs and other \norganizations to defend against these threats while maintaining control and visibility of \ntheir networks.\nSAVE defines network security in six major categories or “pillars.” Figure 7-1 illustrates \nthe different categories within the SAVE framework.\nThe six pillars in SAVE are as follows:\n•\nIdentity and trust\n•\nVisibility\n•\nCorrelation\n•\nInstrumentation and management\n•\nIsolation and virtualization\n•\nPolicy enforcement\n"
        },
        {
            "page_number": 201,
            "text": "178\nChapter 7:  Proactive Security Framework\nFigure 7-1\nSAVE Categories Illustrated\nSAVE Versus ITU-T X.805 \nThere is a security methodology created by the Lucent consulting practice called ITU-T \nX.805, “Security Architecture for Systems Providing End-to-End Communications.” \nITU-T X.805 defines a threat model that includes five categories:\n•\nDestruction\n•\nCorruption\n•\nRemoval\n•\nDisclosure\n•\nInterruption\nITU-T X.805 defines three security layers:\n•\nInfrastructure layer\n•\nServices layer\n•\nApplications layer\nIdentity\nand\nTrust\nVisibility\nCorrelation\nInstrumentation\nand\nManagement\nIsolation\nand\nVirtualization\nPolicy\nEnforcement\nIdentity\nState of\nTrust\nObserve IP\nPackets\nLayer 2\n through\nLayer 7\nStateful and\nStateless\nRelational\nAnalysis of\nSystem-\nWide\nEvents\nDevice\nHardening\nand\nOperational\nViews\nSegmentation\nand\nPartition\nEnforce\nSubscribed\nBehavior\nTotal Visibility\nClassify, Categorize and Associate\nEvents to a Given Control Policy\nComplete Control\nService Policies that allow for Containment,\nMitigation and Service Constraint Enforcement\nResiliency\n"
        },
        {
            "page_number": 202,
            "text": "SAVE Versus ITU-T X.805     179\nFigure 7-2\nITU-T X.805 Security Layers\nThe ITU-T X.805 infrastructure layer includes all infrastructure devices, including:\n•\nRouters\n•\nSwitches\n•\nFirewalls\n•\nServers\n•\nEnd-user workstations\nThe services layer includes services such as the following:\n•\nVoice over IP (VoIP)\n•\nQuality of service (QoS)\n•\nLocation services\n•\nOther IP services\nThe applications layer includes all Layer 7 applications that run on the network \ninfrastructure. Each layer has unique threats, vulnerabilities, and ways to mitigate them. \nX.805 also has three security planes:\n•\nEnd-user plane\n•\nControl/Signaling plane\n•\nManagement plane\nThese security planes are illustrated in Figure 7-3.\nDestruction\nCorruption\nRemoval\nDisclosure\nITU-T X.805\nInfrastructure Layer\n• Routers\n• Switches\n• Firewalls\n• Servers and Workstations\nServices Layer\n• Voice over IP (VoIP)\n• Quality of Service (QoS)\n• Location Services\n• Other IP Services\nApplications Layer\n• Web Browsing\n• E-mail\n• E-Commerce\n• Mobile Web\nInterruption\n"
        },
        {
            "page_number": 203,
            "text": "180\nChapter 7:  Proactive Security Framework\nFigure 7-3\nITU-T X.805 Planes\nX.805 also includes eight security dimensions that apply to each security layer and plane. \nThe following are these dimensions:\n•\nAccess control: Firewall policies and access control lists (ACL).\n•\nAuthentication: Public key infrastructure (PKI), shared secrets, and one-time-\npasswords.\n•\nNonrepudiation: Syslogs and digital signatures.\n•\nData confidentiality: This confidentiality occurs through the use of encryption.\n•\nCommunication security: Transport mechanisms such as IP Security (IPsec) and \nSecure Socket Layer (SSL) virtual private networks (VPN), in addition to Layer 2 \nTunneling Protocol (L2TP) tunnels.\n•\nData integrity: Hashing with message digest algorithm 5 (MD5) and Secure Hash \nAlgorithm (SHA).\n•\nAvailability: Examples include redundancy with Hot Standby Router Protocol \n(HSRP) or Virtual Router Redundancy Protocol (VRRP).\n•\nPrivacy: Encryption and Network Address Translation (NAT).\nThe eight security dimensions are illustrated in Figure 7-4.\nConfused yet? X.805 is an overcomplicated approach. Cisco has tried to evolve it to make \nit more practical to use; however, X.805 is not a true end-to-end security framework and is \neven potentially harmful in the market and in standards.\nDestruction\nCorruption\nRemoval\nDisclosure\nInfrastructure Layer\n• Routers\n• Switches\n• Firewalls\n• Servers and Workstations\nServices Layer\n• Voice over IP (VoIP)\n• Quality of Service (QoS)\n• Location Services\n• Other IP Services\nApplications Layer\n• Web Browsing\n• E-mail\n• E-Commerce\n• Mobile Web\nInterruption\nEnd-User Security\nControl/Signaling Security\nManagement Security\n"
        },
        {
            "page_number": 204,
            "text": "SAVE Versus ITU-T X.805     181\nFigure 7-4\nITU-T X.805 Security Dimensions\nSAVE introduces a roles-based approach for security assessment in a simple manner. \nEach device on the network serves a purpose and has a role; subsequently, you should \nconfigure each device accordingly. SAVE defines five different planes:\n•\nManagement plane: Distributed and modular network management environment.\n•\nControl plane: Includes routing control. This is often a target because the control \nplane depends on direct CPU cycles.\n•\nUser/Data plane: Receives, processes, and transmits network data among all network \nelements.\n•\nServices plane: Layer 7 application flow built on the foundation of the other layers. \n•\nPolicies: The business requirements. Cisco calls policies the business glue for the \nnetwork. Policies and procedures are part of this section, and they apply to all the \nplanes in this list. \n• Access Control\n• Authentication\n• Non-Repudiation\n• Data Confidentiality\n• Communication Security\n• Data Integrity\n• Availability\n• Privacy\nDestruction\nCorruption\nRemoval\nDisclosure\nInfrastructure Layer\n• Routers\n• Switches\n• Firewalls\n• Servers and Workstations\nServices Layer\n• Voice over IP (VoIP)\n• Quality of Service (QoS)\n• Location Services\n• Other IP Services\nApplications Layer\n• Web Browsing\n• E-mail\n• E-Commerce\n• Mobile Web\nInterruption\nEnd-User Security\nControl/Signaling Security\nManagement Security\n"
        },
        {
            "page_number": 205,
            "text": "182\nChapter 7:  Proactive Security Framework\nThese planes are illustrated in Figure 7-5.\nFigure 7-5\nPlanes in SAVE\nSAVE also presents security in two different perspectives:\n•\nOperational (reactive) security\n•\nProactive security\nThis is illustrated in Figure 7-6.\nFigure 7-6\nOperational and Proactive Security\nData\nControl\nManagement\nServices\nPolicies\nOperational\nSecurity\nProactive\nSecurity\nImprove your capabilities to react to security\nincidents.\nProactively prepare your infrastructure, staff, and\norganization as a whole. Learn about new attack\nvectors and mitigate them with the appropriate\nhardware, software, and architecture solutions.\n"
        },
        {
            "page_number": 206,
            "text": "Identity and Trust     183\nYou should have a balance between proactive and reactive security approaches. Prepare \nyour network, staff, and organization as a whole to better identify, classify, trace back, and \nreact to security incidents. In addition, proactively protect your organization while learning \nabout new attack vectors, and mitigate those vectors with the appropriate hardware, \nsoftware, and architecture solutions. You can achieve this balance using what you learned \nin Chapter 2, “Preparation Phase.” The best practices described there help you to \nproactively prepare and protect your network and organization as a whole.\nIdentity and Trust\nIdentity and trust is one of the SAVE pillars. You should consider deploying a complete trust \nand identity management solution for secure network access and admission at every point \nin the network. The following are the most common technologies that are part of the \nidentity and trust pillar:\n•\nAuthentication, authorization, and accounting (AAA)\n•\nCisco Guard active verification\n•\nDHCP snooping\n•\nDigital certificates and PKI\n•\nInternet Key Exchange (IKE) protocol\n•\nIP Source Guard\n•\nNetwork Admission Control and 802.1x\n•\nRouting protocol authentication\n•\nStrict Unicast Reverse Path Fowarding (Unicast RPF)\nThese technologies are illustrated in Figure 7-7.\nAAA\nIn Chapter 1, “Overview of Network Security Technologies,” you learned the basic concepts \nof AAA. In Chapter 2, “Preparation Phase,” you learned best practices for enabling \nauthentication on networking devices for infrastructure protection. In this chapter, AAA \nconcepts are aligned to the identity and trust pillar. A lack of appropriate user management \ntechniques creates numerous direct business risks, including lower productivity, duplicate \nand conflicting user information, lack of information security, and difficulty in evaluating \nregulatory compliance. AAA goes beyond the normal authentication and authorization when \naccessing network devices for management purposes. You should implement a combination \nof authentication, access control, and user policies to secure network connectivity and \nresources to which only specific users should be provided access. This access includes the \nauthentication of databases, web servers, e-mail, and other applications, in addition to \nauthentication of users when they attempt to access network segments and their resources. \n"
        },
        {
            "page_number": 207,
            "text": "184\nChapter 7:  Proactive Security Framework\nFigure 7-7\nIdentity and Trust\nOther examples include authentication for remote access VPN and authentication of \nwireless users. The identity lifecycle consists of account setup, maintenance, and teardown. \nAccount setup includes giving users the appropriate level of access to resources necessary \nto do their jobs. Account maintenance consists of keeping user identity information \nup-to-date and appropriately adjusting levels of access to resources needed to conduct \nbusiness. Account teardown consists of deactivating the user account when the user is no \nlonger affiliated with the company.\nStronger forms of authentication, such as PKI and one-time passwords (OTP), are \nincreasingly used to control user access to corporate resources. Several solutions provide \nthese kinds of services. You should always look for solutions that provide flexible \nauthorization policies that are tied to the user identity, the network access type, and the \nIdentity and Trust\nAAA\nCisco Guard Active Verification\nDHCP Snooping\nDigital Certificates and PKI\nIKE\nIP Source Guard\nNetwork Admission Control\nStrict uRPF\nRouting Protocol Authentication\nSpoofed\nCerts\nRadius\nTACACS+\nActive\nDirectory,\nLDAP, etc.\n"
        },
        {
            "page_number": 208,
            "text": "Identity and Trust     185\nsecurity of the machine used to access the network. In addition, the ability to centrally track \nand monitor the connectivity of network users is of primary importance in isolating \nunwanted and excessive use of valuable network resources.\nNOTE\nManagement, monitoring (correlation), and isolation are discussed later in this chapter, \nbecause they are separate SAVE categories or pillars.\nAs you learned in Chapter 1, TACACS+ and RADIUS are the most commonly used AAA \nprotocols. Cisco Secure ACS supports both of these protocols and provides support for \nadvanced authentication mechanisms, including the interoperability to external directory \nservices, OTP servers, PKI, and other authentication solutions.\nCisco Secure ACS is an important component of the Cisco Identity-Based Networking \nServices (IBNS) architecture based on port-security standards such as 802.1x (an IEEE \nstandard for port-based network access control). It is also the “brains” behind the \nCisco Network Admission Control (NAC) Framework solution.\nNOTE\nExamples of the use of Cisco Secure ACS are discussed in the case studies included in \nChapter 12, “Case Studies.” The Cisco Secure ACS documentation is located at \nhttp://www.cisco.com/en/US/products/sw/secursw/ps2086/\ntsd_products_support_maintain_and_operate.html.\nA good white paper on how to place the Cisco ACS servers within your network is located \nat http://www.cisco.com/en/US/products/sw/secursw/ps2086/\nproducts_white_paper09186a0080092567.shtml.\nCisco Guard Active Verification\nThe Cisco Guard provides multiple layers of defense to identify and block all types of \nattacks with extreme accuracy. It has integrated dynamic filtering capabilities and active \nverification technologies. These capabilities and technologies are implemented through the \nuse of a patented Multiverification Process (MVP) architecture, which can process \nsuspicious flows by applying numerous levels of analysis. The MVP enables malicious \npackets to be identified and removed, while allowing legitimate packets to flow freely.\nNOTE\nIn Chapter 3, “Identifying and Classifying Security Threats,” you learned how to use the \nCisco Guard in conjunction with the Cisco Detector and other third-party solutions to \nidentify and classify attacks.\n"
        },
        {
            "page_number": 209,
            "text": "186\nChapter 7:  Proactive Security Framework\nDHCP Snooping\nDHCP snooping is another technology or feature that can be considered part of identity and \ntrust. It is a DHCP security feature that filters DHCP messages by building and maintaining \na binding table. This table contains information that corresponds to the local untrusted \ninterfaces of a switch, such as:\n•\nMAC address of the device connected to the switch\n•\nIP address of the device connected to the switch\n•\nDHCP lease time\n•\nDHCP binding type\n•\nVLAN number\n•\nInterface information\nNOTE\nThe DHCP snooping table does not contain information regarding hosts interconnected \nwith a trusted interface. An untrusted interface is an interface that is configured to receive \npackets from an untrusted network or device. A trusted interface is an interface that is \nconfigured to receive only messages from within the trusted network or device. \nYou can configure DHCP snooping for a single VLAN or a range of VLANs. The following \nexample shows how to enable DHCP snooping on VLANs 10 through 50: \nExample 7-1\nIP DHCP Snooping \n!enable DHCP snooping globally\n!\nip dhcp snooping vlan 10 50 \n!apply DHCP snooping on VLANs 10 to 50\n!\nip dhcp snooping information option \n!\ninterface GigabitEthernet1/1\nip dhcp snooping limit rate 100 \n!this interface is classified as an untrusted interface, and the rate limit is \n  configured. \n!You may not want to configure untrusted rate limiting to more than 100 pps. \n!Normally, the rate limit applies to untrusted interfaces. \n!If you want to set up rate limiting for trusted interfaces, keep in mind that \n  trusted \n!interfaces aggregate all DHCP traffic in the switch, and you will need to adjust \n  the rate \n!limit to a higher value.\n"
        },
        {
            "page_number": 210,
            "text": "Identity and Trust     187\nYou can use the show ip dhcp snooping command to verify your configuration, as shown \nin the following example:\nIn the previous example, you can see that DHCP snooping is enabled on VLANs 10, 20, 30, \n40, and 50 (which are VLANs enabled on this switch). The interface GigabitEthernet1/1 is \nan untrusted interface, and rate limit is applied to 100 packets per second (pps). To \nconfigure an interface as a trusted interface, you must use the ip dhcp snooping trust \ninterface subcommand.\nIP Source Guard\nIP Source Guard is a Layer 2 feature that works in conjunction with DHCP snooping. When \nIP Source Guard is enabled, all IP traffic on the port is initially blocked, with the exception \nof DHCP packets that are processed by the DHCP snooping feature (if enabled). After the \nend host receives a valid IP address from the DHCP server, or when a user configures a \nstatic IP source binding, a Port Access Control List (PACL) is applied on the port to restrict \nthe client IP traffic to specific source IP addresses that are configured in the binding \nconfiguration. The switch drops all IP traffic with a source IP address other than that in the \nIP source binding. \nAn important note to remember is that if you configure IP Source Guard on a trunk port \nwith a large number of VLANs that have DHCP snooping enabled, you might run out of \nACL hardware resources, and depending on your platform, some packets might be \nswitched in software. You can configure two levels of IP traffic filtering with IP Source \nGuard:\n•\nFiltering source IP addresses: Only IP traffic with a source IP address that matches \nthe IP source binding entry is permitted.\n•\nFiltering on Source IP and MAC address: This is based on source IP address and \nits associated MAC address.\nTo enable IP Source Guard, use the ip verify source vlan dhcp-snooping interface \nsubcommand, as shown in the following example:\ninterface GigabitEthernet1/1\n ip verify source vlan dhcp-snooping\nExample 7-2\nOuput of the show ip dhcp snooping command\nmyswitch#show ip dhcp snooping\nSwitch DHCP snooping is enabled\nDHCP snooping is configured on following VLANs:\n10,20,30,40,50\nInsertion of option 82 is enabled\nOption 82 on untrusted port is not allowed\nVerification of hwaddr field is enabled\nInterface                    Trusted     Rate limit (pps)\n------------------------     -------     ----------------\nGigabitEthernet1/1           no          100 \n"
        },
        {
            "page_number": 211,
            "text": "188\nChapter 7:  Proactive Security Framework\nTo verify the configuration, you can use the show ip verify source interface \ngigabitEthernet 1/1 command, as shown in the following example:\nmyswitch#show ip verify source interface gigabitEthernet 1/1\nInterface  Filter-type  Filter-mode  IP-address       Mac-address        Vlan\n---------  -----------  -----------  ---------------  -----------------  ----------\nGi1/1      ip-mac       active       10.10.1.1                           10  \nGi1/1      ip-mac       active       deny-all                            11-20  \nDigital Certificates and PKI\nDigital certificates and PKI are also technologies that are used for trust and identity. \nDigital certificates bind an identity to a pair of electronic keys that can be used to encrypt \nand sign digital information. A digital certificate makes it possible to verify a claim that \nsomeone has the right to use a given key. This verification helps to prevent people from \nusing phony keys to impersonate other users. Used in conjunction with encryption, digital \ncertificates provide a more complete security solution than traditional username and \npassword schemes. Digital certificates ensure the identity of all parties involved in a \ntransaction.\nThe following are some of the most common uses of digital certificates:\n•\nIPsec VPN tunnel authentication\n•\nSSL transactions\n•\nCode signing\n•\nApplication authentication (that is, e-mail, e-commerce, and so on)\nIKE\nIKE provides authentication mechanisms for IPsec VPN tunnels. This protocol is also an \nexample of identity and trust technologies.\nNOTE\nDetailed information on IKE authentication mechanisms is covered in Chapter 1.\nNetwork Admission Control (NAC)\nNAC is also an example of a trust and identity technology. As you learned in Chapters 1 \nand 2, NAC appliance and framework provide a solution to evaluate whether end-host \nworkstations are compliant with security policies before they enter the network. These \npolicies can include antivirus, antispyware software, operating system updates, security \npatches, and other preconfigured options. In addition, the role-based authentication features \nprovide more granular access to end hosts and users. \n"
        },
        {
            "page_number": 212,
            "text": "Visibility\n189\nRouting Protocol Authentication\nAnother example of a trust and identity technique is the implementation of routing protocol \nauthentication. Border Gateway Protocol (BGP), Enhanced Interior Gateway Routing \nProtocol (EIGRP), Open Shortest Path First (OSPF), Routing Information Protocol (RIP) \nand Intermediate System-to-Intermediate System Protocol (IS-IS) all support various forms \nof authentication mechanisms. \nNOTE\nThese authentication mechanisms are discussed in Chapter 2 in detail.\nStrict Unicast RPF \nStrict Unicast RPF is an antispoofing mechanism that verifies the source address of a packet \nreceived on a router interface by verifying the forwarding table of the router. If the source \naddress is reachable through the same interface on which the packet was received, the \nrouter processes the packet; if not, the packet is dropped. You can also categorize Unicast \nRPF as a trust and identity mechanism.\nNOTE\nUnicast RPF is discussed in Chapter 2.\nVisibility\nNetwork visibility is one of the most important pillars within the SAVE framework. In fact, \ntwo of the most important components of SAVE are visibility and control. The following \nare the most common technologies that can be used to obtain and maintain complete \nnetwork visibility:\n•\nAnomaly detection\n•\nIntrusion detection system/intrusion prevention system (IDS/IPS) \n[IOS, Cisco Security Agent (CSA), network-based intrusion detection \nsystem/network-based intrusion prevention system (NIDS/NIPS)]\n•\nCisco Network Analysis Module (NAM)\n•\nLayer 2 and Layer 3 information [Cisco Discovery Protocol (CDP), routing tables, \nCisco Express Forwarding (CEF) tables]\nThese are illustrated in Figure 7-8.\n"
        },
        {
            "page_number": 213,
            "text": "190\nChapter 7:  Proactive Security Framework\nFigure 7-8\nTechnologies That Help to Achieve and Maintain Complete Network Visibility\n Anomaly Detection\nAnomaly detection can be performed by various tools that provide insightful \ninformation on exactly what is happening within your network. These tools or \ntechnologies include the following:\n•\nNetFlow\n•\nArbor Peakflow SP and Peakflow X\n•\nCisco Anomaly Detector XT\nNOTE\nAnomaly detection technologies and solutions are discussed in Chapters 1 and 2.\nIDS/IPS\nIDSs and IPSs also provide visibility into what is happening on the network. Most of the \nnetwork IDS and IPS systems rely on signatures for detection and protection. For this \nreason, it is extremely important to keep signatures up-to-date and to tune the IDS/IPS \ndevices accordingly. Cisco IPS 6.0 now supports anomaly detection capabilities that allow \nyou to detect day-zero vulnerabilities more easily. \nVisibility\nAnomaly Detection\nIDS/IPS\nNAM\nLayer 2 and Layer 3 Info\nCisco Guard\nNetFlow\nIPS Sensors,\nAIP-SSM, IDSM\nCSA\nCDP, Routing Tables, CEF, etc.\n"
        },
        {
            "page_number": 214,
            "text": "Visibility\n191\nNOTE\nAn introduction to network IDS and IPS systems is covered in Chapter 1. Chapter 3 teaches \nyou how to use network IDS and IPS systems to successfully identify and classify security \nthreats. The configuration of IPS systems is covered within the case studies included in \nChapter 12.\nHost-based intrusion prevention systems, such as the Cisco Security agent, also provide \ninformation about the behavior of end-host systems by extending the visibility to each end \npoint (host or servers).\nCisco Network Analysis Module (NAM)\nThe Cisco NAM is an integrated network monitoring solution for the Cisco Catalyst 6500 \nseries switches. Ciso NAM is designed to give you visibility into the network by showing \nyou information about applications running on your network and the performance of these \napplications. The Cisco NAM solution includes a web-based traffic analyzer GUI that \npresents statistical information to the administrator. The Cisco NAM uses Management \nInformation Bases (MIB) for Remote Monitoring II (RMON II), Differentiated Services \nMonitoring (DSMON), Switch Monitoring (SMON), and other mechanisms to analyze and \nstore the collected data.\nNOTE\nThe following link provides detailed information about NAM: \nhttp://www.cisco.com/en/US/products/hw/modules/ps2706/ps5025/index.html. \nThe configuration guide is located at http://www.cisco.com/en/US/products/hw/switches/\nps708/products_configuration_guide_book09186a00805e081e.html.\nLayer 2 and Layer 3 Information (CDP, Routing Tables, CEF Tables)\nLayer 2 and Layer 3 routing features can provide insightful information and increase \nvisibility. Features such as CDP, CEF, and IP routing tables can give you topological \ninformation about the network. It is important to notice that in the hands of the enemy, tools \nlike CDP can be destructive. Therefore, it is recommended that you enable CDP only on \ntrusted interfaces. \nNOTE\nFor more information on best practices to use when implementing CDP, refer to Chapter 2.\n"
        },
        {
            "page_number": 215,
            "text": "192\nChapter 7:  Proactive Security Framework\nCorrelation\nIn previous chapters, you learned the different aspects of event correlation. For example, \nyou learned that the more complex the network and devices deployed, the more event \nmessages, alarms, and alerts these devices will generate. In the end, far more data is \ngenerated than anyone can easily scan, and it is located in numerous places. In this chapter, \nyou learn the importance of event correlation for maintaining good visibility of what is \nhappening in the network. This chapter also describes tools and technologies you can \ndeploy to successfully correlate events, while maintaining visibility and control of the \nnetwork. Event correlation tools enable you to efficiently use your staff time and skills, and \nthey prevent revenue loss resulting from downtime. The following are examples of \ncorrelation tools:\n•\nCisco Security Monitoring, Analysis, and Response System (CS-MARS)\n•\nArbor Peakflow SP and Peakflow X\n•\nCisco Security Agent Management Center (CSA-MC) basic event correlation\nThese tools are illustrated in Figure 7-9.\nFigure 7-9\nExample of Tools That Help You Maintain Network Visibility\nCorrelation\nCS-MARS\nArbor Peakflow SP and X\nCSA-MC\n"
        },
        {
            "page_number": 216,
            "text": "Instrumentation and Management     193\nCS-MARS\nCS-MARS supports events from routers, switches, firewalls, VPN devices, IPS/IDS \nsolutions, operating system logs, application logs, and many other items. It supports both \nCisco and non-Cisco devices.\nNOTE\nChapter 3 teaches how you can use CS-MARS to successfully identify and classify security \nthreats. The configuration of CS-MARS is covered within the case studies included in \nChapter 12.\nArbor Peakflow SP and Peakflow X\nArbor Peakflow SP (for service providers) and Peakflow X (for enterprises) are excellent \ntools that allow you to obtain network visibility. Based on information collected from \nrouters, such as interface statistics and NetFlow, Peakflow SP and Peakflow X can show you \ndetails of the traffic traversing throughout your network.\nNOTE\nFor more information about these tools, go to http://www.arbor.net.\nArbor has excellent white papers about anomaly detection and combating day-zero threats \nat http://www.arbor.net/resources_researchers.php.\nCisco Security Agent Management Console (CSA-MC) Basic \nEvent Correlation\nCSA-MC can also provide you with basic host-based event correlation. You can gain \nvisibility of what exactly is happening within each endpoint (user workstations and \nservers).\nInstrumentation and Management\nInstrumentation and management is also an important category within the SAVE \nframework. You should always implement protocols and mechanisms that achieve the \nmanagement of every network device. Having good instrumentation and management \nmechanisms in place not only allows you to provision configurations to your network \ndevices, but it also helps you to maintain control of your environment. Some examples of \nmanagement and instrumentation tools are as follows:\n•\nCisco Security Manager (CSM)\n•\nConfiguration logger and configuration rollback\n"
        },
        {
            "page_number": 217,
            "text": "194\nChapter 7:  Proactive Security Framework\n•\nEmbedded device managers \n•\nCisco IOS XR XML interface\n•\nSimple Network Management Protocol (SNMP) and remote monitoring (RMON)\n•\nSyslog\nThese tools are illustrated in Figure 7-10.\nFigure 7-10 Example of Instrumentation and Management Tools\nInstrumentation\nand Management\nCisco Security Manager\nConfiguration Logger\nand Rollback\nEmbedded Device Managers\nCisco IOS XR XML\nInterface\nXML\nSyslog\nSNMP and RMON\nASDM\nIDM\nSDM\n"
        },
        {
            "page_number": 218,
            "text": "Instrumentation and Management     195\nCisco Security Manager\nCSM helps you configure Cisco firewalls, IPS devices, and VPN tunnels easily. It not only \nsaves you time in the provisioning phase, but it can also be used to update enforcement \npolicies in firewalls and routers when needed. CSM achieves scalability through \npolicy-based management techniques that are used to simplify administration.\nConfiguration Logger and Configuration Rollback\nThe Cisco IOS configuration logger logs all changes that are manually entered at \nthe command-line prompt. In addition, it can notify registered clients about any changes \nto the log. \nNOTE\nThe contents of the configuration log are stored in the run-time memory; the contents of the \nlog are not persisted after reboots. The Configuration Logger Persistency feature allows you \nto keep the configuration commands entered by users after reloads. You can enable the \nConfiguration Logger Persistency feature by using the archive log config persistent save\ncommand.\nThe Cisco IOS Software configuration rollback feature allows you to keep a journal file \ncontaining a log of the changes and discard them if needed. The purpose of this feature is \nto revert (or roll back) to a previous configuration. You can use the configure replace\ncommand to roll back to a previous configuration state.\nNOTE\nMore information about the Cisco IOS configuration rollback feature is located at \nhttp://www.cisco.com/en/US/products/sw/iosswrel/ps5207/\nproducts_feature_guide09186a0080356ea5.html#wp1066264.\n Embedded Device Managers\nIn small environments, you can use embedded devices managers to configure and manage \nnetwork access devices such as routers, switches, firewalls, IPS devices, and others. Numerous \nCisco devices come with an embedded device manager. Examples include the following:\n•\nCisco Adaptive Security Device Manager (ASDM): Manages Cisco PIX and \nCisco Adaptive Security Appliance (ASA) security appliances\n•\nCisco IPS Device Manager (IDM): Manages Cisco IPS sensors, in addition to \nAdvanced Inspection and Prevention Security Services Module (AIP-SSM) for the \nCisco ASA\n•\nSecurity Device Manager (SDM): Manages Cisco IOS routers\n"
        },
        {
            "page_number": 219,
            "text": "196\nChapter 7:  Proactive Security Framework\nCisco IOS XR XML Interface\nThe Cisco IOS XR software supports an extensible markup language (XML)\napplication programming interface (API) that helps you develop external \nmanagement applications for routers that run Cisco IOS XR software. \nNOTE\nThe following site has detailed information about the Cisco IOS XR XML interface: \nhttp://www.cisco.com/en/US/products/ps5845/tsd_products_support_series_home.html\nSNMP and RMON\nSNMP allows you to exchange management information between network devices and \ncentral management servers. SNMP is the most commonly used network device \nmanagement protocol. \nNOTE\nIn Chapter 2, you learn the basics of SNMP and what is most important: how to secure it.\nThe RMON protocol provides you with freedom when selecting network-monitoring \nprobes and consoles with features that not only provide ease of management, but also can \nbe used for greater visibility and control of the network.\nSyslog\nIn Chapters 2 and 3, you learn how syslog can provide you with details on what is \nhappening in network devices, while also allowing you to achieve more control and \nvisibility of the network. Firewalls, routers, switches, and other networking devices can \nsend insightful information to administrators via syslog. The combination of syslog and \nevent correlation systems gives you powerful capabilities.\nIsolation and Virtualization\nThe fifth pillar in the SAVE framework addresses network isolation and virtualization. \nSeveral isolation and virtualization techniques and tools are available, including the \nfollowing:\n•\nCisco IOS Role-Based CLI Access (CLI Views)\n•\nAnomaly detection zones \n•\nNetwork device virtualization\n"
        },
        {
            "page_number": 220,
            "text": "Isolation and Virtualization     197\n•\nSegmentation with VLANs \n•\nSegmentation with firewalls\n•\nSegmentation with VRF/VRF-Lite\nThese techniques and tools are illustrated in Figure 7-11.\nFigure 7-11 Examples of Isolation and Virtualization Techniques and Tools\nAnother isolation technique is maintaining separation between the different network \nplanes. For example, keep the data plane separate from the control and management planes, \nby also implementing the necessary policies to protect each of them.\nCisco IOS Role-Based CLI Access (CLI Views)\nYou can consider the Cisco IOS routers Role-Based CLI Access feature a form of \nvirtualization. This feature, otherwise known as CLI Views, allows you to define a virtual \nset of operational commands and configuration capabilities that provide selective or partial \naccess to Cisco IOS exec and configuration mode commands. A view is a framework of \npolicies that defines which commands are accepted and which configuration information is \nvisible to the user based on his role.\nCisco IOS role-based CLI Access\nAnomaly Detection Zones\nNetwork Device Virtualization\nSegmentation with VLANs\nSegmentation with Firewalls\nSegmentation with VRF/VRF Lite\nIsolation\n"
        },
        {
            "page_number": 221,
            "text": "198\nChapter 7:  Proactive Security Framework\nNOTE\nThe following site has detailed information about this feature: \nhttp://www.cisco.com/en/US/products/ps6350/\nproducts_configuration_guide_chapter09186a0080455b96.html#wp1027184\nAnomaly Detection Zones\nThe Cisco Detector XT and the Cisco Guard XT allow you to configure zones to \ncategorize and define anomaly detection policies for more granularity and customization. \nThe following are examples of zones you can configure within the Cisco traffic \nanomaly detectors:\n•\nCollections of servers or clients\n•\nCollections of routers or other network access devices\n•\nNetwork links, subnets, or entire networks \n•\nSingle users or whole companies \n•\nInternet service providers\nNOTE\nThe following site provides step-by-step instructions on how to create zones in Cisco \nDetector and Guard implementations: \nhttp://www.cisco.com/en/US/products/ps5887/\nproducts_configuration_guide_chapter09186a00804bee78.html#wp1043192\nNetwork Device Virtualization\nSeveral networking devices support virtualization. You can take advantage of device \nvirtualization to segment and apply different policies within your infrastructure, while \nsaving money in hardware. For example, you can partition a single hardware device into \nmultiple virtual devices. In most cases, each virtual device acts as an independent device. \nThe following devices support virtualization:\n•\nCisco PIX\n•\nCisco ASA\n•\nCisco Firewall Services Module (FWSM) for the Catalyst 6500 series switches\n•\nCisco IPS sensors running version 6.x or later\n•\nThe Cisco Application Control Engine (ACE) family for the Cisco Catalyst 6500 \nseries switches\nThe Cisco PIX, Cisco ASA, and FWSM can be configured in multiple context mode in \nwhich each context has its own security policy, interfaces, and administrators. Having \n"
        },
        {
            "page_number": 222,
            "text": "Isolation and Virtualization     199\nmultiple contexts is similar to having multiple standalone devices. Figure 7-12 illustrates \nhow a Cisco FWSM is deployed with three contexts (admin, context-1, and context-2) to \nsegment different servers in a data center).\nFigure 7-12 Security Contexts in FWSM\nMany features are supported in Cisco ASA, Cisco PIX, and Cisco FWSM running in \nmultiple-context mode; however, some features are not supported, including VPN and \ndynamic routing protocols.\nNOTE\nChapter 10, “Data Center Security,” includes sample configurations of Cisco FWSM \nvirtualization to provide data center security. Chapter 12, “Case Studies,” also has \nconfiguration examples of virtualization in Cisco PIX and Cisco ASA security appliances.\nSegmentation with VLANs \nYou can achieve network segmentation and isolation in many ways. The use of VLANs \nis one of the most commonly used methods because of its simplicity and ease of \ndeployment. Figure 7-13 illustrates how you can isolate/segment different types of \ndevices just by using VLANs.\nAdmin Context\nContext-1\n(E-Commerce)\nContext-2\n(Database)\nDatabase Servers\nE-Commerce Servers\nManagement Servers\n"
        },
        {
            "page_number": 223,
            "text": "200\nChapter 7:  Proactive Security Framework\nFigure 7-13 Segmentation Using VLANs\nIn Figure 7-13, a set of web, database, Lightweight Directory Access Protocol (LDAP), \nand management servers are isolated by simply configuring four separate VLANs \n(VLANs 10, 20, 30, and 40, respectively).\nSegmentation with Firewalls\nIn many situations, you can simply segment or isolate parts of the network, servers, or \nusers by placing firewalls. Firewalls also provide more granular policy enforcement \nmechanisms. Sometimes you can use firewalls with VLAN segmentation, as illustrated \nin Figure 7-14.\nIn Figure 7-14, the same servers and the four separate VLANs are configured. In addition, \na pair of Cisco ASAs are placed to provide segmentation services while enforcing more \ngranular security policies.\nSegmentation with VRF/VRF-Lite\nYou can also use Multiprotocol Label Switching (MPLS) VPN routing and forwarding \n(VRF) or the MPLS VRF-Lite feature on Cisco IOS routers for network segmentation \npurposes. This concept is illustrated in Figure 7-15.\nVLAN 10\nVLAN 20\nVLAN 30\nVLAN 40\nWeb Servers\nDatabase Servers\nLDAP Servers\nManagement\nApplications\n"
        },
        {
            "page_number": 224,
            "text": "Isolation and Virtualization     201\nFigure 7-14 Segmentation Using VLANs and Firewalls for Policy Enforcement\nFigure 7-15 Segmentation Using VRF and VRF-Lite\nThe main challenge of implementing VRFs and VRF-Lite is that most enterprises do not \nrun MPLS within their corporate network. More importantly, their staffs do not have the \nskills to implement MPLS because it is a complicated routing technology. This \nsegmentation technique is mainly implemented by service providers.\nVLAN 10\nVLAN 20\nVLAN 30\nVLAN 40\nWeb Servers\nDatabase Servers\nLDAP Servers\nCisco ASAs\nManagement\nApplications\nVRF-1\nVRF-2\nVRF-3\nVRF-4\nWeb Servers\nDatabase Servers\nLDAP Servers\nCisco ASAs\nManagement\nApplications\n"
        },
        {
            "page_number": 225,
            "text": "202\nChapter 7:  Proactive Security Framework\n Policy Enforcement\nThe last pillar in the SAVE framework defines policy enforcement. You can enforce \npolicy in many ways. Figure 7-16 illustrates some examples of techniques and features \nthat allow you to enforce security policies within your organization:\nFigure 7-16 Policy Enforcement\nThe following examples are illustrated in Figure 7-16.\n•\nCisco Guard XT MVP: With the Cisco Guard XT, you can do per-flow-level attack \nanalysis, identification, and mitigation. This is an example of policy enforcement, \nbecause the Cisco Guard XT MVP architecture provides multiple layers of defense \nthat can block attack traffic, while allowing legitimate transactions to pass.\n•\nControl Plane Policing: In Chapter 2, you learn best practices when deploying \nControl Plane Policing (CoPP) in your network. CoPP is also used to enforce \npredefined policies to protect the control plane of Cisco IOS routers in your network.\n•\nEncryption policies: You can enforce security encryption policies that best fit your \nenvironment in IPsec site-to-site and remote access VPN tunnels.\n•\nFirewalls, packet filters, and ACLs: Firewalls, packet filters, and ACLs \n(including VLAN ACLs [VACLs] and policy-based ACLs in the Catalyst 6500) are \nthe methods most commonly used to enforce security policies for segmentation \nand protection of network resources.\n•\nNAC policy enforcement: You can configure NAC Appliance and NAC Framework \npolicies to ensure that only compliant machines can enter the network. Based on \nyour configured policies, you can quarantine and remediate noncompliant machines.\n•\nPolicy-based routing (PBR): You can also use PBR on routers and Layer 3 devices \nto define enforcement policies for traffic within your network.\nPolicy Enforcement\nCisco Guard XT MVP\nControl Plane Policing\nEncryption Policies in IPsec\nFirewalls, ACLs, Packet Filters\nNAC Policy Enforcement\nPolicy-based Routing\nRTBH\n"
        },
        {
            "page_number": 226,
            "text": "Visualization Techniques     203\n•\nRemotely triggered black holes (RTBH): In previous chapters, you learn how you \ncan block attack traffic or infected hosts using RTBH. RTBH is another example of \nhow you can reactively enforce policies within your network. \nVisualization Techniques\nThis section includes a few examples of how you can create topology maps and other \ndiagrams to visualize your network resources and apply SAVE. These diagrams give you \nthe basic idea so that you can then customize the diagrams to fit your organizational needs. \nYou can create circular diagrams like the one illustrated in Figure 7-17. Typically, \nthese types of diagrams include resources that surround a critical system or area of the \nnetwork you want to protect. In Figure 7-17, a cluster of database servers is illustrated in \nthe center of the diagram. Several layers describe the devices in the topology in relation \nto different sections of the network. \nFigure 7-17 Topology Map Visualization\n4948-A\n3750-A\n2821-1\nBranch1-2811-a\nInternet Router\nCisco ASA\n3750-B\n4948-B\nCore CAT 6K\nCore CAT 6K\nCore CAT 6K\nCore CAT 6K\nFWSM\nFWSM\nFWSM\nFWSM\n1\n2\n3\n4\nFinance\nDepartment\nCall\nCenter\nLA Branch Office\nInternet\n"
        },
        {
            "page_number": 227,
            "text": "204\nChapter 7:  Proactive Security Framework\nThe illustration in Figure 7-17 helps you visualize and understand the different layers of \nprotection you can apply within your network to protect the mission-critical systems. The \ndiagram in Figure 7-17 has four major sections that portray the path from and to the \nprotected system and the following sections of the network:\n1 Finance department users\n2 Internet\n3 Call Center\n4 Branch Office in Los Angeles, California (LA)\nYou can also visualize packet flows and understand how security policies can be applied to \neach network device to protect critical systems and the infrastructure as a whole. An \nexample is illustrated in Figure 7-18.\nFigure 7-18 Traffic Flow Visualization\n4948-A\n3750-A\n2821-1\nBranch1-2811-a\nInternet Router\nCisco ASA\n3750-B\n4948-B\nCore CAT 6K\nCore CAT 6K\nCore CAT 6K\nCore CAT 6K\nFWSM\nFWSM\nFWSM\nFWSM\n1\n2\n3\n4\nFinance\nDepartment\nCall\nCenter\nInternet\nLA Branch Office\n"
        },
        {
            "page_number": 228,
            "text": "Visualization Techniques     205\nFigure 7-18 illustrates an example of the packet flow when a user from the finance \ndepartment accesses the Internet. There you can see the devices that these packets touch and \nthe relation to the critical systems.\nYou can identify where you can apply the technologies that belong to each SAVE pillar. For \nexample, Figure 7-19 shows how you can apply technologies that enable you to gain and \nmaintain visibility of what is happening in your network.\nFigure 7-19 Visibility Techniques Applied\nFigure 7-19 shows you how you can enable syslog on devices such as the switches, routers, \nFWSM for the Cisco Catalyst 6500 series switches, and Cisco ASA. It also shows you \nplaces where you want to enable NetFlow, IPS services, and other features.\nFigure 7-20 shows where you can enforce policies to restrict access.\n4948-A\n3750-A\n2821-1\nBranch1-2811-a\nInternet Router\nCisco ASA\n3750-B\n4948-B\nCore CAT 6K\nCore CAT 6K\nCore CAT 6K\nCore CAT 6K\nFWSM\nFWSM\nFWSM\nFWSM\n1\n2\n3\n4\nFinance\nDepartment\nCall\nCenter\nLA Branch Office\nsyslog\nsyslog\nsyslog\nNetFlow\nNetFlow\nNetFlow\nIPS\nInternet\n"
        },
        {
            "page_number": 229,
            "text": "206\nChapter 7:  Proactive Security Framework\nFigure 7-20 Policy Enforcement Visualization\nYou can apply ACLs and IP inspection features on the Cisco ASA and the FWSM. In \naddition, you can apply VACLs on the access switches and antispoofing and \ninfrastructure ACLs on the Internet router and other routers within the network. You \ncan also enforce strict IPsec policies for the site-to-site connectivity between the main \noffice and the branch office.\nNOTE\nAntispoofing and infrastructure ACLs are discussed in Chapter 2, “Preparation Phase.” \nChapter 12, “Case Studies,” also provides some examples within the case studies it covers.\n4948-A\n3750-A\n2821-1\nBranch1-2811-a\nInternet Router\nCisco ASA\n3750-B\n4948-B\nCore CAT 6K\nCore CAT 6K\nCore CAT 6K\nCore CAT 6K\nFWSM\nFWSM\nFWSM\nFWSM\n1\n2\n4\nFinance\nDepartment\nCall\nCenter\nLA Branch Office\nVACLs\nVACLs\nACLs,\nInspects,\netc\nACLs,\nInspects,\netc\nIPsec\nPolicies\nAnti-\nSpoofing,\nInfrastructure\nACLs\nAnti-\nSpoofing,\nInfrastructure\nACLs\nInternet\n3\n"
        },
        {
            "page_number": 230,
            "text": "Summary     207\nYou can also create similar diagrams to visualize where you can apply the technologies and \nfeatures described on each of the pillars in SAVE. SAVE advocates the understanding of \ndevice roles and their appropriate configuration. For example, the Internet edge routers do \nnot have the same role as the other routers within the topology in the previous examples. \nDespite that, Internet edge routers can be the same model and run the same software \nversions as other routers, and their configuration should be modeled after their role.\nNOTE\nThe types of diagrams shown in Figures 7-18, 7-19, and 7-20 are not limited to only these \ntechnologies, features, and applications. You can customize them to your specific needs.\nSummary\nSAVE is a framework that was initially developed for service providers, but you can apply \nits practices to any organization. This chapter covers SAVE in detail. Examples of \ntechnologies within the six SAVE main categories are discussed. Visibility and control are \ntwo of the most important topics and concepts within SAVE. This chapter provides \nexamples of techniques and practices that can allow you to gain and maintain visibility and \ncontrol over the network during normal operations or during the course of a security \nincident or an anomaly in the network.\n"
        },
        {
            "page_number": 231,
            "text": ""
        },
        {
            "page_number": 232,
            "text": "P A R T III\nDefense-In-Depth Applied \nChapter 8\nWireless Security \nChapter 9\nIP Telephony Security \nChapter 10\nData Center Security \nChapter 11\nIPv6 Security \n"
        },
        {
            "page_number": 233,
            "text": "This chapter covers the following topics:\n•\nOverview of Cisco Unified Wireless Network Architecture\n•\nAuthentication and Authorization of Wireless Users\n•\nLightweight Access Point Protocol (LWAPP)\n•\nWireless Intrusion Prevention System Integration\n•\nManagement Frame Protection (MFP)\n•\nPrecise Location Tracking\n•\nNetwork Admission Control (NAC) in Wireless Networks\n"
        },
        {
            "page_number": 234,
            "text": "C H A P T E R 8\nWireless Security\nWireless networks are becoming more and more popular. Not only can you take advantage \nof wireless networking at the office, home, a hotel, and coffee shops, but also at airports, \ntrain stations, and many other places. Wireless networks increase productivity. Your \nemployees can save time by sending and receiving e-mail or accessing information on \nnetwork servers from a conference room or any location within your organization that has \nwireless connectivity. You can also implement a voice over wireless LAN (WLAN) \nsolution. With a WLAN, your employees can reach each other anywhere within your \norganization without having to rely on cellular coverage that can be spotty or nonexistent. \nNow the bad news: wireless networks are a major target for attackers. One of the biggest \nchallenges today is to make sure that the appropriate tools and mechanisms are used to \nprotect data in-transit across wireless networks. In addition, the wireless infrastructure \nneeds to be protected against attacks targeted to the wireless networking devices. Stories \nabound of attackers gaining access to wireless networks not only to steal information but \nalso to attack other networks.\nAfter reading this chapter, you will become familiar with some of the technologies, tools, \nand mechanisms that are typically used to protect your wireless network. You will also learn \nbest practices to use when securing the Cisco Unified Wireless Architecture.\nThe 802.11a, 802.11b, and 802.11g are the most widely deployed WLAN technologies \ntoday. Historically, 802.11 WLAN security includes the use of open or shared-key \nauthentication and static wired equivalent privacy (WEP) keys. This combination offers a \nrudimentary level of access control and privacy but each element can be compromised. \nThe low cost of wireless deployments makes them popular (that is, you do not have to worry \nabout expensive cabling solutions and portability issues). However, inexpensive equipment \nalso makes it easier for attackers to gain unauthorized access. Rogue access points and \nunauthorized, poorly secured networks compound the odds of a security breach. The best \npractices you learned in previous chapters play a crucial role when protecting the \ninfrastructure, analyzing risks, and building the most appropriate operational security \nprogram for your organization.\nIn this chapter, you will also learn the different authentication mechanisms in wireless \nnetworks. In addition, you will become familiar with advanced topics such as: \n•\nWireless intrusion detection and prevention services (IDS/IPS)\n"
        },
        {
            "page_number": 235,
            "text": "212\nChapter 8:  Wireless Security\n•\nPrecise location tracking \n•\nNetwork Admission Control (NAC) in wireless networks\nOverview of Cisco Unified Wireless Network \nArchitecture\nThe Cisco Unified Wireless Architecture is a multiservice solution designed for any type of \norganization. It can be deployed in your corporate offices, branches, retail stores, hospitals, \nmanufacturing plants, warehouses, educational institutions, financial institutions, \ngovernment agencies, and any other type of organization that needs wireless connectivity. \nIndustry standards including the IEEE 802.11 and the draft IETF Control and Provisioning \nof Wireless Access Points (CAPWAP) are supported.\nBecause the Cisco Unified Wireless Network is a multiservice solution, it supports data, \nvoice, and video applications. Some examples of data applications are as follows:\n•\nE-mail\n•\nInternet access\n•\nVirtual private network (VPN) access\n•\nInventory management applications\n•\nAsset tracking\n•\nMobile healthcare applications\nYou can also run Voice over IP (VoIP) over WLAN. The Cisco Unified Wireless Network \nArchitecture also supports video, such as video surveillance applications, video streaming \napplications for e-learning, and others. The Cisco Unified Wireless solution provides \ninteroperability with the Cisco Wireless IP Phones to provide comprehensive voice \ncommunications using Cisco Unified CallManager and Cisco Wi-Fi access points. The \nCisco Compatible Extensions program gives third-party manufacturers the ability to design \nindustry-standard and Cisco innovations into a wide variety of devices. Other advanced \nfeatures such as wireless intrusion detection and prevention, precise location tracking, and \nNetwork Admission Control (NAC) are also supported. \nYou can implement wireless networks in all sizes. For example, you can have merely a \ncouple of wireless access points or wireless routers within your organization, as illustrated \nin Figure 8-1.\nIn Figure 8-1, a wireless access point and a wireless router are accepting connections from \nend-user workstations, laptops, and wireless scanners. This approach is only appropriate for \nsmall environments. It is not feasible for medium and large organizations because it does \nnot provide centralized management and ease of deployment. The Cisco Unified Wireless \nNetwork solution provides centralized management that allows you to easily deploy \nWLAN configurations with the same level of security, scalability, and reliability to all \n"
        },
        {
            "page_number": 236,
            "text": "Overview of Cisco Unified Wireless Network Architecture     213\nwireless networking devices within your organization. Figure 8-2 illustrates the main \ncomponents of the Cisco Unified Wireless Network.\nFigure 8-1\nBasic Wireless Network\nWireless\nAccess Point\nWireless\nRouter\nInternet\n"
        },
        {
            "page_number": 237,
            "text": "214\nChapter 8:  Wireless Security\nFigure 8-2\nThe Cisco Unified Wireless Network Architecture \nThe following are the primary components of the Cisco Unified Wireless Network solution \n(as illustrated in Figure 8-2):\n•\nWLAN management: Centralized management enables configuration of the same \nlevel of security, scalability, and reliability features throughout your organization. You \ncan use the CiscoWorks Wireless LAN Solution Engine (WLSE) or the CiscoWorks \nWLSE express.\n•\nWireless LAN controllers: Provision of centralized intelligence for wireless access \npoint management.\n•\nAccess points: Devices to which mobile devices connect.\n•\nMobile clients: End-user workstations, laptops, personal assistant (PDAs), and other \nwireless devices that ensure peak performance and interoperability.\n•\nMobility services: Services such as voice over wireless LAN, wireless intrusion \ndetection and prevention, precise location tracking (Cisco WLAN Location \nAppliance), and others.\nLWAPP\nAccess\nPoint\nAccess\nPoint\nCisco WLAN\nManagement\nvia WLSE\nCisco WLAN\nLocation\nAppliance\nCisco WLAN\nController\nAccess Point\nMobile Clients\nMobile Clients\nMobile Clients\nLWAPP\n"
        },
        {
            "page_number": 238,
            "text": "Overview of Cisco Unified Wireless Network Architecture     215\nNOTE\nFor general information about the Cisco wireless devices, go to \nhttp://www.cisco.com/go/wireless.\nYou can deploy wireless access points within your organization in two modes: unified mode \n(as illustrated in Figure 8-2) and autonomous mode. In autonomous mode, a WLSE \nnetwork management appliance is deployed with autonomous access points. Some access \npoints act as domain controllers (WDS) for sets of access points communicating over the \nwired network using the Wireless LAN Context Control Protocol (WLCCP). This is \nillustrated in Figure 8-3.\nFigure 8-3\nAutonomous Wireless Access Points\nThe main difference between the unified and autonomous modes is that in unified mode, \naccess points operate with the Lightweight Access Point Protocol (LWAPP) and work \nin conjunction with Cisco wireless LAN controllers and the Cisco Wireless Control \nSystem (WCS). When configured with LWAPP, the access points can automatically detect \n"
        },
        {
            "page_number": 239,
            "text": "216\nChapter 8:  Wireless Security\nthe best-available Cisco wireless LAN controller and download appropriate policies and \nconfiguration information with no manual intervention. Autonomous access points are \nbased on Cisco IOS software and may optionally operate with the Cisco WLSE. \nAutonomous access points, along with the Cisco WLSE, deliver a core set of features and \nmay be field-upgraded to take advantage of the full benefits of the Cisco Unified Wireless \nNetwork as requirements evolve.\nYou can individually manage Cisco Aironet autonomous access points via the command-\nline interface (CLI), a web interface, the CiscoWorks WLSE, or CiscoWorks WLSE \nExpress. On the other hand, Cisco recommends that you upgrade any existing Cisco \nAironet access points operating autonomously to run LWAPP and operate them as \nlightweight access points to receive all the features, benefits, and mobility services of the \nCisco Unified Wireless Network.\nNOTE\nCisco provides free upgrade software for existing customers at \nhttp://tools.cisco.com/support/downloads/pub/MDFTree.x?butype=wireless.\nAuthentication and Authorization of Wireless Users\nThe 802.11 standard supports different types of authentication. The two most generic types \nare open and shared-key authentication. In most wireless networks, a service set ID (SSID) \nis specified to identify the wireless network. The basic mechanisms of 802.11 augment the \nidentification by using SSIDs with authentication mechanisms that prevent the client from \nsending data to and receiving data from the access point unless the client has the correct \nshared key. One of the most basic wireless authentication protocols is the wired equivalent \nprivacy (WEP) standard. The following section describes WEP in detail. \nWEP\nWEP, an optional encryption standard in 802.11 that most vendors support, is implemented \nin the MAC layer. WEP-enabled devices encrypt the payload of each 802.11 frame \nbefore transmission by using an RC4 stream cipher. The packets are then decrypted in the \nwireless access point. WEP encrypts only data between 802.11 stations. After the frame \nenters the wired side of the network, WEP no longer applies. \nDuring the encryption process, WEP arranges a key schedule (otherwise known as a seed)\nby concatenating the shared secret key supplied by the user of the sending station with a \nrandom-generated 24-bit initialization vector (IV). The IV lengthens the life of the secret \nkey because the station can change the IV for each frame transmission. WEP inputs the \nresulting seed into a pseudorandom number generator that produces a key-stream equal to \nthe length of the frame payload plus a 32-bit integrity check value (ICV), as illustrated in \nFigure 8-4.\n"
        },
        {
            "page_number": 240,
            "text": "Authentication and Authorization of Wireless Users     217\nFigure 8-4\nWEP Process\nThe following steps are illustrated in Figure 8-4:\n1 The ICV is calculated using CRC-32 and concatenated to the plaintext message. \n2 A random IV and the shared secret key are also concatenated producing the seed. \n3 This seed is the input to the WEP Pseudorandom Number Generator (PRNG). WEP \nuses RC4 PRNG of RSA Data Security to produce a pseudorandom sequence. \n4 The message is encrypted by using an XOR operation with the sequence generated in \nthe previous step. \n5 The encrypted message is sent to the other end.\nThe ICV is a check sum that the receiving station eventually recalculates and compares \nto the one sent by the sending station to determine whether the transmitted data underwent \nany form of tampering while in transient. If the receiving station calculates an ICV that does \nnot match the one found in the frame, the receiving station can reject the frame or flag the user. \nNOTE\nWEP shared secrets use 40-bit, 64-bit, or 128-bit keys.\nWEP has some limitations and has undergone extensive examination and criticism over the \npast years. In short, WEP is vulnerable because of its relatively short IVs and keys that \nSeed\nWEP\nPRNG\nIntegrity Check\nValue (ICV)\nIntegrity Algorithm\nKey\nSequence\nEncrypted\nMessage\nPlain Text\nMessage\nInitialization\nVector (IV)\nShared Key\n"
        },
        {
            "page_number": 241,
            "text": "218\nChapter 8:  Wireless Security\nremain static. For a large, busy network, this reoccurrence of IVs can happen within an hour \nor so. Because of this, you will have many frames or packets with similar key-streams. \nTechnically, an attacker can gather frames based on the same IV to determine the shared \nvalues among the wireless devices. This information can be key-stream or the shared secret \nkey. The static nature of the shared secret keys emphasizes this problem. In many cases, \nsystem administrators and users use the same keys for months or even years. This gives \nmischievous culprits plenty of time to monitor and attack the WEP-enabled networks. Now \nsome vendors deploy dynamic key distribution solutions based on 802.1X, which definitely \nimproves the security of wireless LANs. \nMany now recommend the use of IP security (IPsec) to ensure data confidentiality, \nintegrity, and authenticity. The only caveat is that when you deploy IPsec in a WLAN \nenvironment, you need to install an IPsec software client on every machine that connects to \nthe wireless network. \nWEP has several enhancements. The first one is the use of the Temporal Key Integrity \nProtocol (TKIP) .\nNOTE\nTKIP is often referred to as WEP Version 2. \nThe second enhancement is the use of the Advanced Encryption Standard (AES) encryption \nprotocol instead of RC4, which is used in older WEP implementations.\nThe Wi-Fi Protected Access (WPA) standard uses TKIP to provide additional security \nfeatures. WPA is discussed in the next section. \nWPA\nWPA (using TKIP) includes a per-packet keying (PPK) and message integrity check (MIC) \nand an extension of the initialization vector from 24 bits to 48 bits. WPA mitigates the WEP \nthreat by implementing different keys on a per-packet basis. It does this by hashing the \nIV and WEP keys to produce a temporal key. This temporal key is then combined with \nthe IV and fed to an XOR operation with the plaintext message. \nToday WPA combines TKIP and user authentication via IEEE 802.1x and the EAP \n(Extensible Authentication Protocol). This combination mitigates vulnerabilities from \nseveral angles and represents a significant security upgrade over WEP.\n"
        },
        {
            "page_number": 242,
            "text": "Authentication and Authorization of Wireless Users     219\nNOTE\nThe following site includes a whitepaper with detailed information about WEP, WPA, and \nother authentication mechanisms:\nhttp://www.cisco.com/en/US/netsol/ns340/ns394/ns348/ns386/\nnetworking_solutions_white_paper09186a00800b469f.shtml\n802.1x on Wireless Networks\nIn Chapter 1, “Technology Overview,” you learned the basics of the 802.1X. As a \nrefresher, 802.1x is a standard that defines the encapsulation methodologies for the \ntransport of the Extensible Authentication Protocol (EAP) protocol. \nNOTE\nEAP was originally defined in RFC 2284, which is now obsolete due to RFC 3748.\nThe 802.1X standard allows you to enforce access control when wired and wireless devices \nattempt to access the network. Figure 8-5 illustrates the main components of 802.1x.\nFigure 8-5\n802.1x in Wireless Networks\nThe following are the main components of 802.1x illustrated in Figure 8-5:\n•\nSupplicant: Software running on the client workstation\n•\nAuthenticator: The wireless access point\n•\nAuthentication Server: RADIUS server such as the Cisco Secure Access Control \nServer (ACS)\n•\nExternal Database: External database such as the Microsoft Active Directory, \nLightweight Directory Access Protocol (LDAP), or any Open Database Connectivity \n(ODBC) repository. \nNOTE\nThe Cisco comprehensive identity-based solution, which is based on 802.1x, is referred to \nas Identity Based Networking Services (IBNS).\nIdentity Store\n(Microsoft Active Directory,\nLDAP, ODBC, etc.)\nAuthentication Server\nAuthenticator\nWireless Client\nwith Supplicant\nRADIUS\nIdentity Store Integration\n802.1x\n"
        },
        {
            "page_number": 243,
            "text": "220\nChapter 8:  Wireless Security\nThe basic 802.1x authentication negotiation scheme is illustrated in Figure 8-6.\nFigure 8-6\n802.1x Authentication Negotiation Basics\nThe following are the steps illustrated in Figure 8-6:\n1 The client attempts to connect to the wireless network, and the wireless access point \nsends an EAP identity request to the client (supplicant).\n2 The user enters his credentials, and the client machine sends the EAP identity reply to \nthe wireless access point.\n3 Depending on the EAP method, the client starts an authentication exchange to the \nauthentication server. An EAP tunnel passes directly to the authentication server.\n4 The authentication server accepts or rejects the user and sends further information/\ninstructions based on the authentication and authorization of the user.\nAt the end of the session, the client sends an EAPOL Logout message.\nThe different types of EAP methods are categorized as follows:\n•\nChallenge/response based\n•\nCryptographic based\n•\nTunneling methods\n•\nGeneric token and one-time-passwords\nThe challenge-response-based EAP methods are the following:\n•\nEAP with Message Digest 5: Uses MD5 hashing for authentication exchange\n•\nCisco LEAP: Authentication based on usernames and passwords\n•\nEAP using the Microsoft Challenge Handshake Authentication Protocol Version 2 \n(MSCHAPv2)\nAuthentication Server\nAuthenticator\nWirless Client\nwith Supplicant\nEAP-Identity-Request\nRADIUS\n802.1x\n1\nEAP-Identity-Response\n2\nEAP-Auth Exchange\n3\n4\nEAP-Success/Failure\nAuth Exchange with Auth Server\n(EAP Method Dependent)\nAuthentication Successful/Rejected\nPolicy Instructions\nEAPOL-Logoff\n5\n"
        },
        {
            "page_number": 244,
            "text": "Authentication and Authorization of Wireless Users     221\nThe cryptographic-based EAP method is as follows: \n•\nEAP over Transport Layer Security (EAP-TLS): Uses x.509 digital certificates and \nTLS for authentication\nThe most common EAP tunneling methods are as follows:\n•\nProtected EAP (PEAP)\n•\nEAP Tunneling Transport Layer Security (EAP-TTLS)\n•\nEAP Flexible Authentication via Secure Tunneling (EAP-FAST): Designed not to \nrequire certificates \nThe EAP Generic Token Card (EAP-GTC) is an EAP method used for generic token cards \nand one-time passwords. \nNOTE\nEAP-GTC is defined in RFC 3748. It does not protect the authentication data in any way. \nThe following sections describe each EAP method.\nEAP with MD5\nWhen you configure EAP-MD5, both the client and the authentication server must have a \nshared secret established out-of-band. This shared secret is typically a password associated \nwith an identity/username. Figure 8-7 illustrates the primary steps within the EAP-MD5 \nauthentication method.\nFigure 8-7\nEAP-MD5\nAuthentication Server\nAuthenticator\nWireless Client\nwith Supplicant\nEAP-Identity-Request\n1\nEAP-Identity-Response\n(HASH)\n2\n4\n3\nEAP-Success/Failure\nAuth Exchange with Auth Server\nAuthentication Successful/Rejected\nPolicy Instructions\nAccess to the Network\n5\nAllow or Deny\n"
        },
        {
            "page_number": 245,
            "text": "222\nChapter 8:  Wireless Security\nThe following are the steps illustrated in Figure 8-7:\nStep 1\nA random challenge is sent to the supplicant from the wireless access point.\nStep 2\nThe client sends its response containing the hash of the challenge created \nusing the shared secret. \nStep 3\nThe RADIUS authentication server verifies the hash and accepts or \nrejects the authentication. \nStep 4\nThe wireless access point allows or disallows access based on the \nRADIUS authentication server decision. \nStep 5\nIf the authentication is successful, the client gains access to the network.\nBecause EAP-MD5 is purely an authentication protocol, it does not provide encryption \nafter the authentication process. Therefore, all the messages are transmitted in cleartext \nafter authentication. In addition, because it is only a client authentication protocol, the \nserver side is not authenticated. Subsequently, you cannot detect rogue wireless access \npoints if you implement EAP-MD5. The use of mutual authentication provides a means of \nreducing the risk of users installing rogue access points within the infrastructure, because \nmutual authentication also requires the client to authenticate the server and, most definitely, \nrogue devices will not do this. Another way you can try to protect against rogue access \npoints is to lock down your switches so that you can use only authorized MAC addresses \non your wired network. This is explained later in this chapter.\nTIP\nEAP-MD5 is vulnerable to dictionary and brute-force attacks when used with Ethernet and \nwireless.\nCisco LEAP\nCisco LEAP was initially developed to address the vulnerabilities that WEP showed. At that \ntime, it was an alternative protocol that allowed you to deploy wireless networks without \nrequiring a certificate infrastructure for clients by leveraging authentication mechanisms \nthat were already available within the infrastructure. The following are some of the benefits \npresented by using Cisco LEAP:\n•\n802.1x EAPOL messages are used within Cisco LEAP.\n•\nServer authentication is achievable.\n•\nThe client username and password are sent over MS-CHAP.\n•\nRADIUS is used as the authentication server.\n•\nLEAP provides mechanisms for deriving and distributing encryption keys.\nMany people are now migrating from Cisco LEAP to full 802.1x implementations.\n"
        },
        {
            "page_number": 246,
            "text": "Authentication and Authorization of Wireless Users     223\nEAP-TLS\nEAP-TLS provides several features. For example, it supports mutual authentication \nproviding an encrypted transport layer and the capability to change the keys dynamically. \nEAP-TLS requires the use of digital certificates. You need to keep this in mind when \nthinking about deploying EAP-TLS within your network. \nNOTE\nEAP-TLS is defined in RFC 2246.\nDuring the TLS handshake phase, the client and wireless device establish a session \nexchanging symmetric session keys used to encrypt the transport during the data transfer \nphase. TLS has two layers:\n•\nRecord layer: Includes information about fragmentation, MAC, and encryption\n•\nMessage layer: Includes four different types of messages\nThe following are the four message types:\n•\nChange cipher spec: This defines a change in the session context to be used by the \nrecord layer.\n•\nAlert message: There are approximately 26 different alert message subtypes. (They \ninclude access denied, close notify, decryption failed, and certificate revoked.)\n•\nHandshake protocol: During the handshake protocol, the client and the server \nexchange different hello messages; server authentication and key exchange messages; \nclient authentication and key exchange messages; and the finalization message to \nclose the session.\n•\nApplication data: This is the actual data that is transmitted over the TLS tunnel.\nEAP-TLS does not use all parts of the TLS record protocol; however, it uses the TLS \nhandshake for mutual authentication, for cipher suite negotiation, and for derivation of the \nsession keys. EAP-TLS was initially designed for PPP connections; however, in wireless \nimplementations, EAP-TLS is used as a strong and secure mechanism for mutual \nauthentication and key establishment; then the native WEP mechanisms of the wireless \ndevice are used to encrypt the data.\nPEAP\nMany people refer to PEAP as the true EAP-TLS in wireless implementations. PEAP uses \nEAP-TLS functionality by securing the open exchanges, but it keeps things simple. For \ninstance, PEAP requires only server-side certificates; however, it can still perform mutual \nauthentication between the client and the server. It also uses TLS for the secure tunnel and \n"
        },
        {
            "page_number": 247,
            "text": "224\nChapter 8:  Wireless Security\nlengthens the EAP-TLS exchange beyond the finished message to add client authentication \nand key exchange. One of the disadvantages of PEAP is that it is considered to be a \nchatty protocol. The PEAP protocol has two phases:\n•\nPhase 1: Used to establish a secure tunnel using the EAP-TLS with server \nauthentication\n•\nPhase 2: Authenticates the client based on EAP methods, exchange of arbitrary \ninformation, and other PEAP-specific means using the information established during \nPhase 1\nMany people use PEAP because it is simple to implement within a wireless infrastructure.\nEAP Tunneled TLS Authentication Protocol (EAP-TTLS)\nEAP-TTLS is basically the same as EAP-TLS; however, it extends the client authentication \nby the use of a method called tunneled authentication. With EAP-TTLS, the client does \nnot need a digital certificate (only the authentication server requires one), thereby \nsimplifying the client identity management. \nNOTE\nEAP-TTLS enables you to also use legacy authentication methods such as password-based \nmethodologies.\nEAP-FAST \nEAP-FAST was initially known as the Tunneled EAP (TEAP) and as LEAP Version 2. \nEAP-FAST is classified by many as the most comprehensive and secure EAP type suitable \nfor wireless implementations. It addresses the risks of man-in-the-middle and dictionary \nattacks. In addition, EAP-FAST reduces the hardware requirements, making it a flexible \ndeployment model and more attractive to many people.\nEAP-FAST authentication does not require the use of a specific encryption type. Instead, \nthe WLAN encryption type to be used is determined by the client wireless network \ninterface card capabilities. \nIf the client devices do not support WPA2 or WPA, you can deploy 802.1X authentication \nwith dynamic WEP keys, but, because of the well-known exploits against WEP keys, this \nWLAN encryption mechanism is not recommended. If you must support WEP-only clients, \nit is recommended that you employ a session-timeout interval which requires that the \nclients derive a new WEP key on a frequent interval. \n"
        },
        {
            "page_number": 248,
            "text": "Authentication and Authorization of Wireless Users     225\nTIP\n30 minutes is the recommended session interval for typical WLAN data rates.\nCisco has a comprehensive list of frequently asked questions about EAP-FAST at \nhttp://www.cisco.com/en/US/products/hw/wireless/ps4555/\nproducts_qanda_item09186a00802030dc.shtml.\nEAP-GTC\nEAP-GTC enables you to use hardware token cards as one-time-passwords. An example of \na hardware token card is the RSA SecurID solution.\nNOTE\nFor more information about RSA SecurID, go to http://rsa.com.\nYou can use EAP-GTC inside the TLS tunnel created by PEAP. You can use this EAP \nmethod to implement a two-factor authentication solution to avoid common password \ncompromises and combine it with your remote access VPN solution. For instance, a user \ncan use the token card for both wireless and remote access VPN authentication. If you are \njust starting to deploy a WLAN, you must decide whether token deployment is cost \neffective. Many people justify the cost of token deployment by using this authentication \nmechanism with other network infrastructure authentication, such as remote access VPN.\nIn summary, the two EAP methods that most people implement today are EAP-FAST \nand PEAP. EAP-FAST provides more flexibility when deployed with 802.1x or NAC. \nEAP-FAST is easy to implement, and it is not Cisco proprietary. It supports Windows \nsingle-sign-on and provides support for login script operation with any user database such \nas Microsoft Active Directory, Lightweight Directory Access Protocol (LDAP), and \none-time password (OTP). In addition, because EAP-FAST does not require certificates, \nyou can configure it easily and distribute it for Cisco Aironet client devices with the \nCisco Aironet Configuration Administration tool.\nTIP\nIt is recommended that you employ either WPA2 (AES-CCM) or WPA (TKIP) encryption, \nwhich are both dependent on the NIC card capabilities in the specific deployment. \n"
        },
        {
            "page_number": 249,
            "text": "226\nChapter 8:  Wireless Security\nConfiguring 802.1x with EAP-FAST in the Cisco Unified Wireless \nSolution\nThis section describes how to configure the wireless LAN context (WLC), the Cisco Secure \nServices Client (CSSC), and Cisco Secure Access Control Server (ACS) to perform 802.1x \nauthentication using EAP-FAST. Figure 8-8 illustrates the topology used in this \nconfiguration example.\nFigure 8-8\nConfiguring 802.1x with EAP-FAST on the Cisco Unified Wireless Solution\nFigure 8-8 shows a workstation with the CSSC connecting to a Cisco wireless access point \n(with IP address 172.18.85.123) in a lightweight configuration controlled by a WLC. The \nmanagement IP address of the WLC is 172.18.85.96, and the AP manager IP address is \n172.18.85.97. The WLC forwards all authentication requests to a Cisco Secure ACS.\nConfiguring the WLC\nComplete the following steps to configure the WLC to use the Cisco Secure ACS server for \nauthentication. Cisco Secure ACS validates the user credentials using the Windows \ndatabase. (The Cisco Secure ACS server configuration is covered in the next section.) \nStep 1\nLog in to the WLC as an administrator and click the Security tab; then \nclick New to add a new RADIUS server, as illustrated in Figure 8-9. You \nwill then see the screen shown in Figure 8-10.\nLWAPP\nControll Messages\nData Encapsulation\nWorkstation\nwith CSSC\nWireless Access Point\n172.18.85.123\nCisco Secure ACS\n172.18.85.181\nWireless LAN\nController\nManagement IP\n172.18.85.96\nAP Manager\n172.18.85.97\nLWAPP Tunnel\n"
        },
        {
            "page_number": 250,
            "text": "Authentication and Authorization of Wireless Users     227\nFigure 8-9\nAdding a RADIUS Server to the WLC\nFigure 8-10 RADIUS Server Configuration on the WLC\n"
        },
        {
            "page_number": 251,
            "text": "228\nChapter 8:  Wireless Security\nStep 2\nIn the screen shown in Figure 8-10, enter the RADIUS server \ninformation. In this case, the Cisco Secure ACS IP address is \n172.18.85.181. Enter a shared key to mutually authenticate the WLC and \nthe RADIUS server. In this example, the default RADIUS port UDP/\n1812 is used. Ports UDP/1645 (legacy) and UDP/1812 are supported by \nCisco Secure ACS for RADIUS authentication. Leave all other options \nwith the default values and click Apply.\nStep 3\nBy default, the WLC uses 802.1x for the security policies in WLANs. \nYou can also combine 802.1x with static WEP, WPA, and others. In this \nexample, 802.1x is used without WEP/WPA. To enable this \nconfiguration, navigate to the WLANs tab and edit the configured \nWLAN. (In this example, the WLAN SSID is named ciscotest.) Under \nSecurity Policies and Layer 2 Security, select 802.1x from the drop-\ndown menu, as shown in Figure 8-11.\nFigure 8-11 WLAN Layer 2 Security Policy\nStep 4\nScroll down on the same screen and choose the configured Cisco Secure \nACS server on the drop-down menu under the RADIUS Servers section,\nas shown in Figure 8-12. Click Apply.\n"
        },
        {
            "page_number": 252,
            "text": "Authentication and Authorization of Wireless Users     229\nFigure 8-12 Selecting the Configured RADIUS Server\nThe next section shows you how to configure the Cisco Secure ACS server.\nConfiguring the Cisco Secure ACS Server for 802.1x and EAP-FAST\nComplete the following steps to configure the Cisco Secure ACS server for 802.1x \nauthentication using the EAP-FAST method. You first add the WLC as AAA client on the \nCisco Secure ACS server. \nTo add the WLC as a AAA client on Cisco Secure ACS, click the Network Configuration \nradio button. You can create a network device group to maintain a collection of AAA clients \nand AAA servers, or you can use the default Not Assigned network device group. In this \nexample, the WLC is added to the Not Assigned default group. Click the Not Assigned\ngroup.\nStep 1\nClick Add Entry. The screen shown in Figure 8-13 is displayed. \nStep 2\nComplete the form by entering the hostname and IP address of the WLC.\n(WLC is the hostname, and 172.18.85.96 is the management IP address \nof the WLC in this example.) \n"
        },
        {
            "page_number": 253,
            "text": "230\nChapter 8:  Wireless Security\nFigure 8-13 Adding an AAA Client into Cisco Secure ACS\nStep 3\nEnter the shared secret to be used between the Cisco Secure ACS server \nand the WLC. (In this example, the key is 1qaz@WSX.)\nStep 4\nChoose RADIUS (Cisco Airspace) under the drop-down menu in the \nAuthenticate Using section.\nStep 5\nClick Submit + Apply.\nStep 6\nIn this example, the Cisco Secure ACS server queries an external \nWindows 2003 server for authentication credentials. Navigate through \nthe radio button sequence as follows. Click External User Databases > \nDatabase Configuration > Windows Database > Configure.\nStep 7\nUnder the Windows EAP Settings, check the Enable password change \ninside PEAP or EAP-FAST checkbox, as illustrated in Figure 8-14.\nStep 8\nClick Submit.\nStep 9\nNavigate to External User Databases > Unknown User Policy and \nclick the Check the following external user databases radio button.\nStep 10 Click the Windows Database from External Databases to Selected\nDatabases, as shown in Figure 8-15.\nStep 11 Click Submit.\n"
        },
        {
            "page_number": 254,
            "text": "Authentication and Authorization of Wireless Users     231\nFigure 8-14 Windows EAP Settings\nFigure 8-15 Selecting the Windows Database on the Unknown User Policy\n"
        },
        {
            "page_number": 255,
            "text": "232\nChapter 8:  Wireless Security\nStep 12 Next, you have to enable EAP-FAST support on the Cisco Secure ACS \nServer. To do this, navigate via the radio buttons to System\nConfiguration > Global Authentication Setup > EAP-FAST \nConfiguration. The screen in Figure 8-16 is displayed.\nFigure 8-16 Enabling EAP-FAST on Cisco Secure ACS\nStep 13 Check Allow EAP-FAST.\nStep 14 In this example, the recommended (default) values for Active master \nkey TTL (1 month), Retired master key TTL (3 months), and Tunnel\nPAC TTL (1 week) are selected.\nStep 15 The Authority ID Info text is shown on some EAP-FAST client \nsoftware; in this case, cisco is the text configured and displayed. This can \nbe anything you want. On the other hand, the CSSC (used in this \nscenario) does not display this descriptive text for the PAC authority. \nHowever, the word cisco will be displayed if any other client (802.1x \nsupplicant) is used.\nStep 16 Check the Allow anonymous in-band PAC provisioning checkbox. \nThis enables Automatic PAC Provisioning for EAP-FAST-enabled clients.\nStep 17 The CSSC supports EAP-FAST Version 1a, which uses MS-CHAPv2 for \nauthentication. Scroll down and check EAP-MSCHAPv2 under the \nAllowed inner methods section, as shown in Figure 8-17.\n"
        },
        {
            "page_number": 256,
            "text": "Authentication and Authorization of Wireless Users     233\nFigure 8-17 EAP-MSCHAPv2 and EAP-FAST Master Server Configuration\nStep 18 Check the EAP-FAST master server check box to configure this \nCisco Secure ACS server as the master. The Actual EAP-FAST Master \nserver status line will say Master. Any other Cisco Secure ACS servers \n(if present in your organization) will use this server as the master PAC \nauthority to avoid the need to provision unique keys for each Cisco \nSecure ACS in a network.\nStep 19 Click Submit + Restart.\nConfiguring the CSSC \nThis section shows how to configure the CSSC to authenticate to the wireless network using \nEAP-FAST. Complete the following steps to configure the CSSC.\nStep 1\nLaunch the CSSC and click Create Network.\nStep 2\nThe Network Profile screen shown in Figure 8-18 is displayed. Under \nNetwork Configuration Summary and Authentication, click Modify.\n"
        },
        {
            "page_number": 257,
            "text": "234\nChapter 8:  Wireless Security\nFigure 8-18 CSSC Network Profile Screen\nStep 3\nThe Network Authentication screen shown in Figure 8-19 is displayed. \nTurn on authentication by clicking the radio button labeled Turn On\nunder the Authentication Methods section, as illustrated in Figure 8-19. \nIn this example, the Use Username as Identity button is selected, \nbecause the user credentials are being used for authentication.\nStep 4\nUnder the Protocol list, check FAST and click the Configure button.\nStep 5\nThe Configure EAP Method screen shown in Figure 8-20 is displayed. \nUnder the Tunneled Method, you can choose Any Method to allow the \nCSSC to use any EAP method offered by the wireless infrastructure. In \nthis example, the EAP-MSCHAPv2 method is selected, because we are \ndoing external authentication to a Windows Active Directory user \ndatabase. If, however, you choose the Any Method option, it will work, \nbut in some cases, you may want to be selective to force the use of only \none EAP method. (In this case, the method is EAP-MSCHAPv2.)\nStep 6\nLeave all other default values as they are, and click OK.\nStep 7\nClick OK in the Network Authentication screen. \n"
        },
        {
            "page_number": 258,
            "text": "Authentication and Authorization of Wireless Users     235\nFigure 8-19 CSSC Network Authentication Screen\nFigure 8-20 CSSC Configure EAP Method Screen\nStep 8\nOnly wireless networks that have SSIDs enabled for broadcast are visible \nwithin the CSSC. In this example, the WLC is configured not to \nbroadcast the SSID. Consequently, you must manually define the SSID \nin the CSSC. To define the SSID in CSSC, click the Add button under the \nAccess Devices section of the Network Profile screen. The SSID used \npreviously is ciscotest.\nStep 9\nClick Add Access.\n"
        },
        {
            "page_number": 259,
            "text": "236\nChapter 8:  Wireless Security\nStep 10 Click OK.\nStep 11 The CSSC attempts to connect to your wireless network. If it does not \nautomatically make this attempt, click Connect from the CSSC main \nscreen.\nStep 12 You are prompted for your user credentials, and if successfully \nauthenticated, you are granted access to the network.\nLightweight Access Point Protocol (LWAPP)\nIn the Cisco Unified Wireless Architecture, a wireless LAN controller (WLC) is used to \nmanage the wireless access point configuration and firmware creating an LWAPP tunnel. \nLWAP provides the control messaging protocol and data encapsulation. In other words, the \nwireless client data packets are encapsulated between the access point and the WLC. \nFigure 8-21 illustrates how a WLC controls a wireless access point over an LWAPP tunnel.\nFigure 8-21 LWAPP Tunnel\nThe following steps are illustrated in Figure 8-21:\n1 The wireless client sends a packet to the wireless access point.\n2 The wireless access point decrypts the packet and encapsulates it with an LWAPP \nheader, forwarding it to the WLC. \n3 The WLC removes the LWAPP header and forwards the packet to its destination in \nthe corporate wired network. \nControl Messages\nData Encapsulation\nWireless\nClient\nLWAPP Tunnel\nLightweight Wireless Access\nPoints Controlled by a\nCentralized WLAN Controller\nIngress/Egress\nPoint to Wired\nNetwork\n(802.1Q Trunk)\nWireless LAN\nController\n1\n2\n3\nCorporate Wired Network\nLWAPP\n"
        },
        {
            "page_number": 260,
            "text": "Lightweight Access Point Protocol (LWAPP)     237\nNOTE\nWhen a client on the corporate wired network sends replies to the wireless client, the packet \nfirst goes into the WLC where it is encapsulated with an LWAPP header and forwarded \nto the appropriate wireless access point. Subsequently, the access point removes the \nLWAPP header and encrypts the packet if necessary.\nThe LWAPP control messages are encrypted using the AES-CCM encryption method. The \nshared encryption key is derived and exchanged when the access point joins the WLC. \nNOTE\nThe payload of the encapsulated LWAPP data is not encrypted. Therefore, you should \nfollow infrastructure protection best practices to protect the wired network.\nThe following are the major steps or stages used in the LWAPP:\nStep 1\nDiscovery: The wireless access point looks for a controller. The LWAPP \nDiscovery Response from the controller contains the following important \ninformation from the WLC:\n— Controller name (sysName)\n— Controller type\n— Controller capacity\n— Current wireless access point load in the WLC\n— Master controller status information used for redundancy\n— Access point manager IP address and the number of access points \njoined to the manager\n(a) When the AP is powered on, if a static IP address has not \nbeen previously configured, the AP issues a DHCP \nDISCOVER to get an IP address. \n(b) If Layer 2 mode is supported, the AP attempts a Layer 2 \nLWAPP Discovery by sending an Ethernet broadcast \nmessage.\n(c) If Layer 2 mode is not supported or the AP fails to find a \nWLC, the AP attempts a Layer 3 LWAPP Discovery.\n(d) If a Layer 3 LWAPP Discovery also fails, the AP reboots \nand retries the first step.\n"
        },
        {
            "page_number": 261,
            "text": "238\nChapter 8:  Wireless Security\nStep 2\nJoin: The wireless access point attempts to establish a secured \nrelationship with a controller.\nStep 3\nImage Data: The wireless access point downloads code from the WLC \nwhen needed.\nStep 4\nConfig: The wireless access point receives the configuration from the \nWLC.\nStep 5\nRun: The wireless access point and the WLC are operating normally, and \nservice data is exchanged.\nStep 6\nReset: The wireless access point clears the current state, and this process \nstarts over again.\nThe WLC provides support for radio resource management (RRM). The following are \nsome of the advantages of RRM:\n•\nContinuous analysis of RF environment\n•\nDynamic channel and power management\n•\nCoverage hole detection and correction\n•\nCoverage resiliency\nThe WLCs elect a radio frequency (RF) group leader who analyzes RF data and neighbor \nrelationships to make more optimized decisions about the RF environment for wireless \ninfrastructure. Multiple RF domains can coexist within a single RF Group. These RF \ndomains can be intercontroller or intracontroller, as illustrated in Figure 8-22.\nFigure 8-22 Multiple RF Domains\nWLC-1\nAP-1\nWLC-2\nAP-2\nAP-3\nLogical Rf\nSub-Group B\nLogical Rf\nSub-Group A\nRf-Group 1\nRf-Group 2\nWLC-3\nAP-4\nAP-5\nLogical Rf\nSub-Group C\nLWAPP\nLWAPP\nLWAPP\nLWAPP\nLWAPP\n"
        },
        {
            "page_number": 262,
            "text": "Wireless Intrusion Prevention System Integration     239\nWhy is this important to security? A good wireless network design that includes network \nresiliency is important for the overall security of your wireless network. The WLC has a \nbuilt-in understanding of the signal strength that exists between lightweight access points \nwithin the same network. These controllers can use this information to create a dynamic \noptimal RF topology for the network. When a Cisco LWAPP-enabled access point boots up, \nit immediately looks for a wireless LAN controller within the network. After it finds a \nwireless LAN controller, the LWAPP-enabled access point sends out encrypted “neighbor” \nmessages. These neighbor messages include the MAC address and signal strength of any \nneighboring access points. In a single wireless LAN controller network, the controller uses \nthis neighbor information to determine the relative spatiality of the access points in the \nnetwork. The controller then tunes each access point channel and optimal signal strength \nfor optimal coverage and capacity.\nWhen wireless LAN controllers are clustered in the network, a default controller is chosen. \nAll the controllers feed the default controller information to their registered access points. \nThe default controller correlates information for all the access points in the network and \nthen pushes out the optimal channel and power for every access point on the network. The \nalgorithms built into the Cisco Unified Wireless Network architecture prevent the \ninterruption of wireless connectivity. \nWireless Intrusion Prevention System Integration\nYou can integrate Cisco IPS sensors with the Cisco Unified Wireless Solution. This \nincludes the Cisco IPS sensors, the Cisco Adaptive Security Appliance (ASA), Advanced \nInspection and Prevention Security Services Module (AIP-SSM), the Catalyst 6500 \nIntrusion Detection/Prevention Services Module Version 2 (IDSM-2), and the IPS modules \nfor Cisco IOS routers. When you integrate IPS with the Cisco Unified Wireless Solution, \nthe WLC talks to the Cisco IPS sensor via its management port using the Security Device \nEvent Exchange (SDEE) protocol over TCP port 443. The WLC supports up to five IPS \nsensors.\nNOTE\nThe WLC also supports the use of a certain limited number of IPS signatures that you \ncan enable to detect security threats within your wireless network. However, the \ncombination of an external IPS device with the WLC provides more granular inspection \nand detection. \nThe WLC Software Release Version 4.x and later supports shunning (blocking) from the \nIPS sensors. A shun request needs to be sent to the WLC from the Cisco IPS device to \ntrigger the client blacklisting or exclusion behavior available on the controller. The WLC \nqueries the Cisco IPS device at a configured query rate to retrieve all the shun events. This \nis illustrated in Figure 8-23.\n"
        },
        {
            "page_number": 263,
            "text": "240\nChapter 8:  Wireless Security\nFigure 8-23 IPS Sensor Integration\nThe following steps are illustrated in Figure 8-23:\nStep 1\nAn infected client sends malicious traffic over the wireless network \n(through access point 1 (AP1)). \nStep 2\nThe WLC sends the traffic to be inspected by the IPS device (IPS \nSensor1).\nStep 3\nThe IPS device sends a shun request to the WLC to block the offending \nclient.\nStep 4\nThe client is blocked (shunned).\nNOTE\nThe shunned client status is maintained on each controller in the mobility group even if any \nor all of the controllers are reset. On the controller, clients are disabled based on a MAC \naddress, even though the shun request that the IPS initiates uses the client IP address as its \ndestination. Therefore, although a client remains disabled for the duration of the controller \nexclusion time and is re-excluded if it reacquires its previous DHCP address, that client is \nno longer disabled if the IP address of the client that is shunned changes Here is an example. \nThe client connects to the same network, and the DHCP lease timeout has not expired.\nWLC\nAP-2\nAP-1\n1\n4\n3\n2\nSDEE\nIPS Sensor1\nInfected Client\nMalicious\nTraffic\nLWAPP\nLWAPP\n"
        },
        {
            "page_number": 264,
            "text": "Wireless Intrusion Prevention System Integration     241\nConfiguring IDS/IPS Sensors in the WLC\nYou can configure IDS/IPS using the WLC web management console or through the CLI. \nThis section demonstrates how to use the web management console to add IDS/IPS sensors. \nStep 1\nConnect the Cisco IPS device to the same switch where the WLC resides.\nStep 2\nMirror the WLC ports that carry the wireless client traffic to the Cisco \nIPS device. You do this because the Cisco IPS device must receive a copy \nof every packet to be inspected on the wireless network. The Cisco IPS \ndevice provides a downloadable signature file that you can customize. \nWhen a signature is triggered, the Cisco IPS device generates the alarm \nwith a shunning event action. The WLC polls the Cisco IPS device for \nalarms. When an alarm is detected with the IP address of a wireless \nclient, which is associated to the WLC, the IPS device puts the client into \nthe exclusion list. The WLC generates a trap and notifies the WCS. The \nWLC removes the user from the exclusion list after the specified period \n(60 seconds by default).\nStep 3\nLog in to the WLC as an administrator. \nStep 4\nTo add the Cisco IPS device to the WLC, navigate to the Security tab. \nUnder CIDS, click Sensors.\nStep 5\nClick New.\nStep 6\nThe screen shown in Figure 8-24 is displayed. Enter the sensor IP \naddress. The IP address of the IPS device in this example is \n172.18.85.149. The WLC uses SDEE, and the default port is 443. Enter \nthe username and password of the Cisco IPS device.\nIn this example, the query interval is configured for 15 seconds. This \nquery interval is safe to use in most environments. Enter the Cisco IPS \ndevice SHA1 fingerprint. You can obtain this by invoking the show tls \nfingerprint command on the Cisco IPS device, as follows:\nExample 8-1 IPS-sensor# show tls fingerprint\nMD5: B8:A7:74:B5:62:AB:C8:15:5C:FE:E6:4C:0C:42:39:CE\nSHA1: AC:6A:FA:FC:BE:05:D1:09:31:53:21:DC:36:A0:1A:B6:6A:DA:00:AF\nThe highlighted line shows the fingerprint that is entered into the WLC \nconfiguration. You must omit the colons (:) within the hexadecimal \nfingerprint. The fingerprint must be 40 characters in length.\n"
        },
        {
            "page_number": 265,
            "text": "242\nChapter 8:  Wireless Security\nFigure 8-24 Adding IPS Sensors\nStep 1\nClick Apply.\nStep 1\nNavigate to WLANs and click Edit on the configured WLANs that you \nwant to monitor. Make sure that Client Exclusion is enabled. The default \nclient exclusion timeout is 60 seconds. On the other hand, the client \nexclusion persists as long as the IPS shun (block) remains active. The \ndefault block time in the Cisco IPS devices is 30 minutes.\nUploading and Configuring IDS/IPS Signatures\nSeveral signatures come with the WLC by default. You can view the standard signatures by \nnavigating to Security > Wireless Protection Policies and then clicking Standard\nSignatures. This is illustrated in Figure 8-25.\nYou can also upload a signature file from the WLC to customize the signatures. To do this, \nnavigate to Commands > Upload File > Signature File. To download the modified \nsignature file, navigate to Commands > Download File > Signature File. After you \ndownload (or push) the edited signature file to the WLC, all registered wireless access \npoints are refreshed in real time with the new signature configuration.\n"
        },
        {
            "page_number": 266,
            "text": "Management Frame Protection (MFP)     243\nFigure 8-25 WLC Standard Signatures\nWhen customizing signatures, you must use the following format:\nName = <str>, Ver = <int>, Preced = <int>, FrmType = <frmType-type>, Pattern = \n<pattern-format>,\nFreq = <int>, Interval = <int>, Quiet = <int>, Action = <action-val>, Desc = <str> \nNOTE\nThe maximum length of each line is 1000 characters. The WLC will not correctly parse any \nlines longer than 1000 characters.\nYou can view the custom signatures by navigating to Security > Wireless Protection \nPolicies and then clicking Custom Signatures.\nManagement Frame Protection (MFP)\nManagement Frame Protection (MFP) enables authentication of all 802.11 management \nframes between the WLC and wireless access points. MFP protects against direct and man-\nin-the-middle attacks. It also detects and reports potential phishing attacks. MFP has three \nmain functions: \n•\nFrame protection: This enables the wireless access point to protect the management \nframes by adding a message integrity check information element (MIC-IE) to each frame. \n"
        },
        {
            "page_number": 267,
            "text": "244\nChapter 8:  Wireless Security\n•\nFrame validation: The wireless access point validates every management frame that \nit receives from other access points in the network. \n•\nEvent reporting: The wireless access point notifies the WLC when it detects an \nanomaly. The WLC can also report these events via SNMP traps to management \nservers. \nYou can enable MFP globally. However, you can disable it on individual WLANs and \naccess points. In other words, you can selectively enable or disable MFP on specific \nwireless access points or WLANs. \nTo enable MFP globally, navigate to Security > Wireless Protection Policies. Then click \nAP Authentication/MFP and choose Management Frame Protection from the \nProtection Type pull-down menu. You can view the MFP statistics under Security > \nWireless Protection Policies > Management Frame Protection.\nPrecise Location Tracking\nThe Cisco Wireless Location Appliance uses RF fingerprinting technology to track mobile \ndevices to within a few meters. This allows you to gain visibility into the location of people \nand assets. In addition, RF fingerprinting technology enables you to respond to security \nissues and thereby gain insight into the location and movement of people and assets, as well \nas locating rogue wireless access points.\nThe Cisco Wireless Location Appliance supports two location tracking options:\n•\nOn-demand location tracking: The user queries the location of the person or \nwireless device.\n•\nSimultaneous location tracking: This automatically tracks up to thousands of \n802.11 wireless devices by adding a Cisco Wireless Location Appliance in \nconjunction with a Cisco WCS.\nTIP\nIt is recommended that you become familiar with the different methodologies used for \nlocation tracking and that you deploy these solutions within your network. Conventionally, \nmany have used three different methods for locating wireless users or devices: closest \naccess point, triangulation, and RF fingerprinting. As previously mentioned, the Cisco \nWireless Location Appliance uses RF fingerprinting. A whitepaper explaining each \nmethodology is located at http://www.cisco.com/en/US/products/ps6386/\nproducts_white_paper0900aecd80477957.shtml.\n"
        },
        {
            "page_number": 268,
            "text": "Network Admission Control (NAC) in Wireless Networks     245\nNetwork Admission Control (NAC) in Wireless \nNetworks\nNetwork Admission Control (NAC) was initially designed as two separate solutions: the \nNAC Framework and NAC Appliance (formerly known as Cisco Clean Access). The most \ncommonly deployed NAC solution for wireless networks is the NAC Appliance. This \nsection covers how to integrate the Cisco NAC Appliance into the Cisco Unified Wireless \nsolution.\nAs mentioned in previous chapters, the NAC Appliance has three major components:\n•\nClean Access Server (CAS)\n•\nClean Access Manager (CAM)\n•\nClean Access Agent\nIn the example illustrated in Figure 8-26, the CAS is configured inline and managed by the \nCAM (172.18.85.181). All wireless traffic will pass through the server before it can reach \nthe corporate network or the Internet. The goal in this example is to separate guest users \nfrom employees. The guest users will have only limited access to the Internet via HTTP and \nHTTPs. The employees will have access to the corporate resources.\nTwo SSIDs are configured in the Figure 8-26 example:\n•\nGUESTNET: Used by guests\n•\nCORPACCESS: Used by employees\nThe WLC is configured to broadcast the GUESTNET SSID, but not the CORPACCESS.\nTIP\nAs a best practice, it is recommended that you use different SSIDs for your employees and \nguest wireless users. For your employees (internal users), you can also use 802.1X \nauthentication and strong encryption (WPA with TKIP/MIC or WPA2 with AES). \nThe following sections provide the step-by-step procedures for configuring the NAC \nAppliance (CAM and CAS), the WLC, and the NAC Agent configuration.\n"
        },
        {
            "page_number": 269,
            "text": "246\nChapter 8:  Wireless Security\nFigure 8-26 Cisco NAC Appliance Integration to Cisco Unified Wireless Solution\nNAC Appliance Configuration\nIt is recommended that you configure the CAS in the Real-IP gateway mode for wireless \nnetwork deployments. When the CAS is configured in the Real-IP gateway mode, it handles \nall routing between the unprotected and protected networks. In this example, the untrusted \n(unprotected) interface resides in the 10.10.10.0/24 subnet, and the trusted (protected) \ninterface resides in the 192.168.40.0/24 subnet.\nComplete the following steps to configure the NAC Appliance solution to protect the \ncorporate resources by performing security posture checks for wireless users. In addition, \nenforce policy for guest users so that they are only able to access the Internet while \nUn-trusted\n10.10.10.2\nGuest Clients\n10.20.1.x/24\nEmployees\n10.30.1.x/24\nCAS\nTrusted\n192.168.40.2\nCAM\n172.18.85.181\nWLC\n172.18.85.96\nACS\n172.18.85.181\nASA\nInternet\nCorporate\nNetwork\nAP-1\nAP-2\nLWAPP\nLWAPP\n"
        },
        {
            "page_number": 270,
            "text": "Network Admission Control (NAC) in Wireless Networks     247\nemployees can access corporate resources. Noncompliant clients will be quarantined and \nremediated.\nStep 1\nThe CAS is always configured via the CAM. Log in to the CAM with an \nadministrator account.\nStep 2\nAfter you are logged in to the CAM, navigate to the Device Management\nsection in the menu on the left, and click CCA Servers.\nStep 3\nTo add a new CAS, click the New Server tab and enter the CAS \ninformation, as illustrated in Figure 8-27. In this example, the CAM will \naccess the CAS via the trusted interface (IP address 192.168.40.2).\nFigure 8-27 Adding a New CAS in the CAM\nStep 4\nEnter a server location description. The description can be any word or \nphrase that describes the location of the CAS. In this example, the \nlocation description is Wireless Network.\nStep 5\nThe goal in this example is to configure the CAS in Real-IP gateway \nmode. Choose Real-IP Gateway from the drop-down menu.\nStep 6\nClick Add Clean Access Server.\nStep 7\nTo access the CAS, click the Manage icon under Device Management \n> CCA Servers, as illustrated in Figure 8-28.\n"
        },
        {
            "page_number": 271,
            "text": "248\nChapter 8:  Wireless Security\nFigure 8-28 Accessing the CAS via the CAM\nStep 8\nVerify the IP addressing information, and verify that the CAS is \nconfigured with the Real-IP Gateway option by clicking the Network\ntab, as shown in Figure 8-29.\nStep 9\nIn this example, the trusted interface IP address is 192.168.40.2, and the \ndefault gateway is the Cisco ASA (192.168.40.1). Enter this information \nunder the Trusted Interface section, as illustrated in Figure 8-29.\nStep 10 Enter the IP address information for the untrusted interface. In this \nexample, the untrusted interface IP address is 10.10.10.2, and the default \ngateway is 10.10.10.1. Both the trusted and untrusted interfaces are \nconfigured with a 24-bit subnet mask (255.255.255.0).\nStep 11 Enter your DNS information under the DNS section, as illustrated in \nFigure 8-30. In this example, the CAS name is cas1, the domain name is \ncisco.com, and the IP address of the DNS server is 172.18.108.40.\nStep 12 In this example, you will create two users: guest and employee1. To \ncreate the local database, navigate to User Management > Local Users\nand enter the user information, as illustrated in Figure 8-31.\nStep 13 The next step is to create the user roles. To enter a new user role, go to \nUser Management > User Roles > New Role and enter the user role \ninformation, as illustrated in Figure 8-32.\n"
        },
        {
            "page_number": 272,
            "text": "Network Admission Control (NAC) in Wireless Networks     249\nFigure 8-29 Real-IP Gateway Configuration\nFigure 8-30 Entering DNS Server Information\n"
        },
        {
            "page_number": 273,
            "text": "250\nChapter 8:  Wireless Security\nFigure 8-31 Adding Local Users\nFigure 8-32 User Roles\n"
        },
        {
            "page_number": 274,
            "text": "Network Admission Control (NAC) in Wireless Networks     251\nIn Figure 8-32, the guest user role is configured. The user role name \nis Guest Role, and the role description is Wireless Guest Role. For \nguest users, at the After Successful Login Redirect to field, click to \nchoose this URL, and enter the URL to which you want the guest user \nredirected. In this case, guest users will be redirected to a site called \nguestaccess.cisco.com with further instructions and disclaimers. All \nother options are left with default values.\nStep 14 You can configure traffic policies to be applied to each user role by \nclicking the Policies icon by the specific role, as illustrated in Figure 8-33.\nFigure 8-33 User Role Policies\nStep 15 By default, all traffic is denied. To enter a new policy, click the Add\nPolicy link, as illustrated in Figure 8-34.\nStep 16 Enter the policy information. In this example, all guest users are allowed \nto access the Internet via HTTP (TCP port 80) and HTTPs (TCP port \n443). DNS traffic (UDP port 53) also needs to be allowed. Figure 8-35 \nshows how to configure a new policy to allow HTTP traffic.\nStep 17 All internal traffic is denied. In this case, all internal networks can be \nsummarized into two major subnets: 192.168.0.0/16 and 172.18.0.0/16. \nFigure 8-36 shows how all the guest user policies are configured.\n"
        },
        {
            "page_number": 275,
            "text": "252\nChapter 8:  Wireless Security\nFigure 8-34 Adding a New Policy\nFigure 8-35 Allowing HTTP for Guest Users\n"
        },
        {
            "page_number": 276,
            "text": "Network Admission Control (NAC) in Wireless Networks     253\nFigure 8-36 All Guest Users Policies\nNotice how traffic to HTTP and HTTPS to all destinations is allowed by \nthe first few policy entries. This is done because you cannot map the \nwhole Internet for guest users. However, specific deny statements for all \nUDP and TCP traffic to internal networks are denied. In addition, a catch-\nall deny statement is included at the end.\nYou can assign users to different roles by editing the previously created \nusers.\nStep 18 Configure a host-based policy for access to remediation sites when users \nare quarantined. Navigate to User Management > User Roles > Traffic \nControl > Host and choose Agent Quarantine Role in the drop-down \nmenu, as illustrated in Figure 8-37. Then select the sites you want your \nquarantined clients to be able to access for remediation.\nIn Figure 8-37, access is allowed to update.microsoft.com (the Microsoft \nupdate site) and to an internal remediation server.\nStep 19 You can create or customize a login page for the wireless users by going \nto Administration > User Pages and choosing Add at the Login Page\ntab. You can edit the web login portal page content by going to \nAdministration > User Pages > Login Page > Edit > Content.\n"
        },
        {
            "page_number": 277,
            "text": "254\nChapter 8:  Wireless Security\nFigure 8-37 Host-Based Policy for Remediation Access\nStep 20 To enable basic network scanning for guest user workstations, go to \nNetwork Scanner > Scan Setup to determine which user role and \noperating system to use. This is illustrated in Figure 8-38. \nStep 21 Select the operating system options under the Plugins, Options, and\nVulnerability tabs.\nStep 22 You can also configure a user agreement page for web login users by \nnavigating to the User Agreement tab.\nStep 23 To establish employee roles for posture assessment, you must create a \nrequirement rules mapping by going to Device Management > Clean \nAccess > Clean Access Agent > Requirements > Requirement-Rules.\nFor instance, a user can choose to perform Windows HotFixes checks for \nWindows-based systems.\nStep 24 For employees, you should require the use of the NAC Agent (Clean \nAccess Agent) by clicking Require use of Clean Access Agent.\nAfter users are successfully logged in, you will see them under Monitoring > Online \nUsers.\n"
        },
        {
            "page_number": 278,
            "text": "Network Admission Control (NAC) in Wireless Networks     255\nFigure 8-38 Scanner Setup\nWLC Configuration\nThis section includes the steps necessary to configure the WLC for the NAC Appliance \nsolution to work. Complete the following steps to configure the WLC.\nStep 1\nAs a best practice, it is recommended that you configure separate VLANs \nfor guest and internal users. To do this, you need to configure two new \npseudointerfaces. Log in to the WLC, navigate to Controller > \nInterfaces, and click New to add a new interface. Enter the name for the \nnew interface and the VLAN you want to assign. This is illustrated in \nFigure 8-39. In this example, the interface for guest users is called guest\nand assigned to VLAN Id 123.\nStep 2\nThe next screen (shown in Figure 8-40) allows you to enter the interface \nconfiguration parameters, such as IP address, subnet mask, default \ngateway, DHCP server information, and others. In this case, the guest \ninterface is configured with the IP address 10.20.1.2 with a 24-bit subnet \nmask. The default gateway and DHCP server is 10.20.1.1.\n"
        },
        {
            "page_number": 279,
            "text": "256\nChapter 8:  Wireless Security\nFigure 8-39 Adding a New Dynamic Guest Interface in the WLC\nFigure 8-40 WLC Guest Interface Configuration\n"
        },
        {
            "page_number": 280,
            "text": "Network Admission Control (NAC) in Wireless Networks     257\nStep 3\nAdd another interface for employees (internal users).\nStep 4\nUnder Controller > General, make sure that Layer 3 is selected in the \nLWAPP Transport Mode drop-down menu, as illustrated in Figure 8-41.\nFigure 8-41 LWAP Setting\nStep 5\nIn the Default Mobility Domain Name field, enter RFGroup1.\nStep 6\nCreate a guest wireless LAN interface named guest and assign an SSID. \n(In this example, we also name it guest.)\nStep 7\nConfigure the WLAN with open authentication and DHCP address \nassignment required. Enter guest as the wireless LAN interface SSID\nunder the WLANs > Edit window. Click the check box to require DHCP\nAddr. Assignment, as illustrated in Figure 8-42.\nStep 8\nRepeat Steps 6 and 7 to create and configure a WLAN for internal users. \nStep 9\nTo add the RADIUS server information for 802.1X authentication, navigate \nto Security > AAA> RADIUS Authentication. In this case, you use the \nsame server that you configured previously in this chapter (172.18.85.181).\nStep 10 The CAS uses RADIUS accounting packets to trigger the security \nposture of wireless users. Configure the CAS as the RADIUS Accounting \nserver by going to Security > AAA> RADIUS Accounting > New. Add \nthe CAS information, as illustrated in Figure 8-43.\n"
        },
        {
            "page_number": 281,
            "text": "258\nChapter 8:  Wireless Security\nFigure 8-42 Guest WLAN Configuration\nFigure 8-43 Adding the CAS as a RADIUS Accounting Server \n"
        },
        {
            "page_number": 282,
            "text": "Summary     259\nAfter you complete these steps, you will be able to authenticate using a wireless client. \nGuest users will be redirected to a web-based login, and regular employees will use the \nCisco Clean Access Agent to connect to the network.\nSummary\nWireless access is a core part of the infrastructure in most organizations. When developing \na wireless implementation, take into consideration the unique security challenges that \nwireless connectivity brings. Implementing best practice wireless security techniques is a \nmust for any organization. This chapter included best practices when deploying wireless \nnetworks. It also covered different types of authentication mechanisms, including 802.1x. \nIn addition, it included an overview of LWAP, location services, MFP, and other wireless \nfeatures that need to be taken into consideration when designing security within your \nwireless infrastructure. \nThis chapter also covered step-by-step configuration examples of the integration of IPS on \nCisco wireless networks. In addition, it provided guidance on how to integrate the Cisco \nNAC Appliance and the Cisco Unified Wireless Network solution.\n"
        },
        {
            "page_number": 283,
            "text": "This chapter covers the following topics:\n•\nProtecting the IP Telephony Infrastructure\n•\nSecuring the IP Telephony Applications\n•\nProtecting Against Eavesdropping and Other Attacks\n"
        },
        {
            "page_number": 284,
            "text": "C H A P T E R 9\nIP Telephony Security\nCisco alone has sold more than 4.5 million IP phones and 3 million Cisco Unity unified \nmessaging licenses. The company has more than 20,000 IP Communications customers. \nIP telephony or Voice over IP (VoIP) deployments are growing dramatically on a daily \nbasis. Consequently, the need to secure IP telephony networks is also growing by the \nminute. IP telephony security threats generally fall into one of two categories. The \nfirst category includes risks that are aimed to hijack listening or unauthorized listening to \nvoice conversations (phone tapping). The second category includes risks that can \ncompromise IP telephony communications with direct attacks to the network infrastructure, \nservers, and other systems, such as denial of service (DoS) attacks. \nThis chapter covers several best practices and strategies for building your infrastructure \nto successfully identify threats and react to them in a manner that is appropriate to \neach severity level. It shows how integrated security features must be implemented from \nend to end across all network elements to increase voice security. IP telephony security \nhas four major elements:\n•\nNetwork infrastructure: Routers, switches, firewalls, and other infrastructure \ncomponents\n•\nCall processing systems: Call management, control, and accounting\n•\nEndpoints: IP phones, IP communicator software, video terminals, and so on\n•\nApplications: Unified messaging software, conferencing applications, contact, and a \ncustom tool\nThis chapter offers you different techniques to protect each element. \nIP telephony security requires the collaboration of security, network intelligence, and \nother services to minimize the impact of attacks and risks. With the collaboration \nof security technologies and network services, you can deploy Defense-in-Depth security \nthat encompasses the entire network, including voice systems. \n"
        },
        {
            "page_number": 285,
            "text": "262\nChapter 9:  IP Telephony Security\n Protecting the IP Telephony Infrastructure \nThe first step in IP telephony security is to make sure that you apply the best practices \nlearned in previous chapters to protect the infrastructure as a whole. As previously \nmentioned, all the infrastructure components are networking devices deployed within your \norganization, such as:\n•\nRouters\n•\nSwitches\n•\nFirewalls\n•\nVoice gateways\n•\nGatekeepers\nFigure 9-1 illustrates a common IP telephony deployment in a medium-to-large enterprise. \nIn Figure 9-1, several infrastructure components are depicted within a headquarters main \noffice topology, which demonstrates a layered approach. Within the main office segment \nof the figure, notice the different access, distribution, and core layers. A group of \napplication servers, a Cisco Unified CallManager cluster, and Cisco Unity servers are \ndeployed to provide different VoIP services to the organization. Within the illustrated \ntopology, IP telephony endpoints include both regular IP phones and wireless phones, \nas well as IP conferencing systems. A voice gateway is deployed to connect to the \npublic switched telephone network (PSTN).\nIn this figure, voice services are also provided to branch offices, telecommuters, and remote \naccess users. Although Figure 9-1 provides a high-level topology, it represents a \nhighly available, fault-tolerant infrastructure that is based on common infrastructure \nguidelines. A well-designed infrastructure is essential for easier deployment of IP \ntelephony and its integration with applications such as video streaming and video \nconferencing. As you learned in previous chapters, resiliency and high availability are \ncrucial for security. As a best practice when designing your network infrastructure, \nalways think about high availability, connectivity options for phones (such as in-line \npower), and quality of service (QoS) mechanisms. Make sure that you understand the \ncall patterns for your organization. \nTIP\nYou can obtain VoIP provisioning recommendations and best practices listed in the \nwhitepaper at http://www.cisco.com/en/US/products/sw/voicesw/ps556/\nproducts_implementation_design_guide_chapter09186a008063743a.html.\n"
        },
        {
            "page_number": 286,
            "text": "Protecting the IP Telephony Infrastructure     263\nFigure 9-1\nCommon IP Telephony Deployment\nCallManager Cluster\nApplications\nUnity Servers\nU\nU\nIP\nIP\nIP\nIP\nCORE\nConference Rooms\nWireless\nHeadsets\nIP\nIP\nIP\nIP Phones\nV\nV\nIP WAN\nPSTN\nBranch\nOffice\nTelecommuters/Remote Users\nMain\nOffice\nVoice\nGateway\nInternet\nV\n"
        },
        {
            "page_number": 287,
            "text": "264\nChapter 9:  IP Telephony Security\nFigure 9-2 illustrates a typical regional site, branch office, or small enterprise deployment. \nFigure 9-2\nBranch or Small Enterprise IP Telephony Deployment\nIn Figure 9-2, a Cisco IOS Software router running Cisco Unified Communications \nManager Express is deployed. The Cisco Unified Communications Manager Express \n(formerly known as the Cisco CallManager Express) is an optional software feature that \nenables Cisco routers to deliver Key System or Hybrid PBX functionality for branch offices \nor small businesses. Also deployed is Cisco Unity Express, which is a Linux-based \napplication that runs on Cisco IOS Software routers, using either Network Module (NM) \nor Advanced Integration Module (AIM) hardware to provide basic automated attendant \nand voice mail features. \nV\nV\nIP\nIP\nIP\nIP\nIP\nIP\nBranch\nOffice\nInternet\nWorkstations\nand IP Phones \nWorkstations\nand IP Phones \nUnity\nExpress\nCallManager\nExpress\nCisco ASA\n"
        },
        {
            "page_number": 288,
            "text": "Protecting the IP Telephony Infrastructure     265\nNOTE\nBest practices to secure Cisco Unified CallManager, Cisco Unified Communications \nManager Express, Cisco Unity, and Unity Express are covered later in this chapter in the \nsection “Securing the IP Telephony Applications.”\nAll the infrastructure security recommendations you learned in previous chapters (such as \nChapter 2, “Preparation Phase”) apply to IP telephony networks. It is, therefore, important \nthat you follow those guidelines. For example, disable unnecessary services, implement \ninfrastructure access control lists (ACL), and protect the control plane. This section shows \nyou several other best practices and outline recommendations that are applicable strictly to \nvoice implementations.\nYou should take a layered approach when securing your IP telephony infrastructure. Build \nsecurity layer upon layer starting at the ports that your workstations and IP phones connect \n(access layer), and work your way to the distribution, core, and data center. Figure 9-3 \nillustrates the different layers within an enterprise network.\nThe following layers are illustrated in Figure 9-3:\n1 Access layer: Access switches provide connectivity to user workstations and IP \nphones. The access layer can also include wireless access points with wireless \nhandsets or workstations with voice software.\n2 Distribution layer: This is the segment of the network where LAN-based routers \nand Layer 3 switches reside. These devices ensure that packets are properly routed \nbetween subnets and VLANs in your enterprise. \n3 Core: The core typically consists of two or more high-end Layer 3 switches or routers \nthat glue the network together as a whole.\n4 Data center distribution layer: The distribution layer at the data center typically \nincludes firewall or other security components (that is, intrusion detection systems \n[IDS] or intrusion prevention systems [IPS]). In Figure 9-3, two Catalyst 6500 \nswitches with Firewall Services Modules (FWSM) are depicted.\n5 Data center access layer: This layer includes access switches to which all the servers \nare connected. Figure 9-3 shows applications, Cisco Unified CallManager, and \nCisco Unity servers connected to access switches at the data center.\n"
        },
        {
            "page_number": 289,
            "text": "266\nChapter 9:  IP Telephony Security\nFigure 9-3\nLayered Approach to Securing IP Telephony Infrastructures\nIn the following sections, you will learn best practices for securing each infrastructure layer.\nAccess Layer\nThe first recommendation, and one of the most important, is that you enable two VLANs \nat the access layer—one VLAN for data traffic and another VLAN for voice traffic. \nApplications\nUnity Servers\nData Center \nAccess Layer\nData Center \nDistribution Layer\nCore\nDistribution Layer\nAccess Layer\nCallManager Cluster\nIP \nIP \nIP \nV\n1\n2\n3\n4\n5\n"
        },
        {
            "page_number": 290,
            "text": "Protecting the IP Telephony Infrastructure     267\nThe voice VLAN in the Catalyst Switches that are running Catalyst Operating System \n(CatOS) is also known as an Auxiliary VLAN. Figure 9-4 illustrates this recommendation.\nFigure 9-4\nAccess Layer and VLAN Assignment\nIn Figure 9-4, several IP phones are connected to two Cisco Catalyst 3750 switches. \nUser workstations are then connected to the IP phones. The voice VLAN in the 3750-1 \nswitch is VLAN 10, and the data VLAN is VLAN 100. Similarly, the voice VLAN in the \n3750-2 switch is VLAN 11, and the data VLAN is VLAN 101.\nTIP\nWhen deploying access switches for voice networks, it is recommended that you use \nswitches capable of running the following features:\n• Inline power or Power over Ethernet (PoE)\n• Multiple queue support \n• 802.1p and 802.1Q \n• Fast link convergence\nThe separation of voice and data VLANs is recommended for many reasons. One of the \nmajor reasons is for address space conservation as well as for voice device protection from \nexternal networks. It is strongly recommended that voice endpoints be addressed using \nDistribution Switches\n3750-2\n3750-1\nVoice VLAN 11\nVoice VLAN 10\nData VLAN 100\nData VLAN 101\nV\nIP\nIP\nV\n"
        },
        {
            "page_number": 291,
            "text": "268\nChapter 9:  IP Telephony Security\nRFC 1918 private subnet addresses. By separating voice and data VLANs, you can also \nimplement QoS trust boundary configurations that are strictly for voice devices. \nIn addition, the use of separate voice and data VLANs can help you dramatically when \nresponding to security incidents. This is why previous chapters stressed the importance \nof good addressing schemes. For example, if you are responding to a security incident \nsuch as a worm or a DoS attack, you can easily identify what addresses represent IP phones \nand what addresses represent user workstations. Subsequently, you can use VLAN access \ntagging control mechanisms such as VLAN access control lists (VACL), 802.1Q, \nand 802.1p to provide protection for voice devices from malicious traffic. Last, but \nnot least, are the ease of management and configuration benefits (that is, simplified QoS \nconfiguration schemes). \nAnother recommendation is that you enable root guard or the PortFast bridge protocol \ndata unit (BPDU) guard feature on all access switches. This rules out the possibility \nof someone introducing a rogue switch that might attempt to become the Spanning Tree \nroot. You can enable PortFast BPDU guard on a global basis on Cisco switches running \nCatOS, as shown in the following example.\nConsole> (enable) set spantree portfast bpdu-guard enable \nThe next example shows how to enable PortFast BPDU guard on Cisco switches running \nCisco IOS Software.\nmyswitch(config)# spanning-tree portfast bpduguard \nWhen a switch running BPDU guard disables one of its ports, it remains disabled until it is \nmanually enabled. On the other hand, you can configure a port to re-enable itself \nautomatically from the “errdisable” state on CatOS-enabled switches, as shown in the \nfollowing example. \nConsole> (enable) set errdisable-timeout interval 450 \nConsole> (enable) set errdisable-timeout enable bpdu-guard\nThe timeout interval in this example is set to 450 seconds. The default timeout interval is \n300 seconds and, by default, the timeout feature is disabled. The following example \nshows how to configure the automatic re-enabling of a disabled port on a switch running \nCisco IOS Software.\nmyswitch(config)# errdisable recovery cause bpduguard\nmyswitch(config)# errdisable recovery interval 450\nYou can also enable port security or dynamic port security to protect against MAC flooding \nattacks. For instance, if you have an IP phone attached to a switch port and then a \nworkstation connected directly to the IP phone, it is recommended that you limit the \nnumber of learned MAC addresses to two: one for the IP phone and one for the workstation \nbehind the phone. Limit the learned MAC addresses to one in case you have only an \nIP phone connected to the switch port. This configuration is typically used in lobbies, \ncommon areas, and conference rooms. Protecting against MAC flooding attacks is \nimportant in publicly accessed areas of your organization such as lobbies because you do \n"
        },
        {
            "page_number": 292,
            "text": "Protecting the IP Telephony Infrastructure     269\nnot want outsiders to be able to plug in laptops to an IP phone or disconnect the IP phone \nand plug in a laptop. Example 9-1 shows how to configure an access port with dynamic port \nsecurity for a port on which an IP phone resides and a user workstation is plugged into the \ndata port on the phone. \nIn the previous example, port security is enabled on the interface GigabitEthernet1/12. \nNotice the way the VLAN assignment is configured. The voice VLAN is VLAN 10, and the \ndata VLAN is VLAN 100. Port security is configured to restrict learning to a maximum of \nthree MAC addresses—one for the phone itself, another for the integrated PC port on the \nphone, and the third for a PC connected on the phone.\nTIP\nThe switchport port-security violation restrict command enables the switch to learn up \nto the maximum number of MAC addresses and then stop learning any new MAC \naddresses. The default setting is to disable the port. If you keep the default setting and the \nmaximum number of MAC addresses is exceeded, the port becomes disabled, and the \nphone loses power (in case of inline power). In addition, the recommended port security \naging time is 2 minutes.\nIt is also recommended that you enable the DHCP snooping feature to prevent rogue DHCP \nserver attacks and DHCP starvation attacks. Attackers can use different tools to create a \nDHCP starvation attack (the most common is called Gobbler) by making numerous DHCP \nrequests until you run out of IP addresses. Subsequently, legitimate workstations cannot \nreceive an IP address from your DHCP server successfully. You can enable DHCP snooping \nglobally or on a per-interface basis. The following example shows how to configure DHCP \nsnooping globally on a switch running Cisco IOS Software. An IP phone is connected to \nthe switch, and a user workstation is plugged into the data port on the phone.\nmyswitch(config)#ip dhcp snooping vlan 10, 100\nmyswitch(config)#ip dhcp snooping\nExample 9-1\nDynamic Port-Security\nmyswitch#configure terminal\nmyswitch(config)#interface GigabitEthernet1/12\nmyswitch(config-if)# switchport access vlan 100\nmyswitch(config-if)# switchport mode access\nmyswitch(config-if)# switchport voice vlan 10\nmyswitch(config-if)# switchport port-security\nmyswitch(config-if)# switchport port-security maximum 3\nmyswitch(config-if)# switchport port-security violation restrict\nmyswitch(config-if)# switchport port-security aging time 2\nmyswitch(config-if)# switchport port-security aging type inactivity\n"
        },
        {
            "page_number": 293,
            "text": "270\nChapter 9:  IP Telephony Security\nIn the previous example, DHCP snooping is enabled on VLAN 10 (voice VLAN) \nand VLAN 100 (data VLAN). The following example shows how DHCP snooping is \nenabled on a specific port/interface.\nmyswitch(config)#interface GigabitEthernet 1/48\nmyswitch(config-if)#ip dhcp snooping limit rate 10\nmyswitch(config-if)#ip dhcp snooping trust\nDHCP snooping is a DHCP security feature that provides network security by filtering \nuntrusted DHCP messages and by building and maintaining a DHCP snooping \nbinding database (also referred to as a DHCP snooping binding table).\nDHCP snooping acts like a firewall between untrusted hosts and DHCP servers. You can \nuse DHCP snooping to differentiate between untrusted interfaces connected to the end user \nand trusted interfaces connected to the DHCP server or another switch. For DHCP \nsnooping to function properly, all DHCP servers must be connected to the switch through \ntrusted interfaces.\nAnother feature that you can enable to protect the access layer of your voice-enabled \nnetwork is the Dynamic Address Resolution Protocol (ARP) Inspection (DAI). DAI \nis commonly used to prevent gratuitous ARP attacks. Workstations bind a MAC address \nto an IP address in an ARP cache. When the system sends out an ARP request, the device \nthat owns the IP address in that request replies with its IP and MAC address information \nto the system that originated the request. On the other hand, gratuitous ARP is an \nunsolicited ARP reply, in which a system tells the rest of the Layer 2 adjacent systems \nthat it owns a specific IP and MAC address. Networking devices commonly use this \ntechnique. For example, when the Cisco PIX or the Cisco Adaptive Security Appliances \n(ASA) fail over, it sends a gratuitous ARP to other devices on the network to advertise \nthe assumed IP addresses. On the other hand, attackers can use gratuitous ARP to \nspoof the identity of another system. You can use DAI to inspect all ARP requests \nand replies (gratuitous and nongratuitous) to avoid these types of exploits on untrusted \nports.\nNOTE\nYou must enable DHCP snooping to use DAI.\nYou can enable DAI globally and then on a per-interface basis. The following example \nshows how to configure DAI globally on a switch running Cisco IOS Software.\nmyswitch#configure terminal\nmyswitch(config)#ip arp inspection vlan 10,100\nmyswitch(config)#ip dhcp snooping database tftp://172.18.108.26/dai/dai_db\nIn the previous example, DAI is enabled on VLANs 10 and 100. The switch is configured \nto save the DHCP snooping database on a TFTP server (172.18.108.26) under a directory \n"
        },
        {
            "page_number": 294,
            "text": "Protecting the IP Telephony Infrastructure     271\ncalled dai and a file called dai_db. You can also enable DAI on a per-interface basis, \nas shown in the following example:\nmyswitch(config)#interface GigabitEthernet 1/12\nmyswitch(config-if)#ip arp inspection limit rate 15\nIn the previous example, the ip arp inspection command is configured with the limit rate\noption to specify the maximum number of ARP packets per second allowed on the \nGigabitEthernet 1/12 interface. The switch disables that port when it detects more than 15 \nARP packets per second. \nNOTE\nIf you do not want to disable the phone when the port receives more then 15 ARP messages \nin a second, you can set the rate limit to none which allows the phone to stay up.\nMany people are becoming more concerned with unauthorized network access, and \npotentially, even unauthorized placement of IP phones. More advanced features such as \n802.1x and Network Admission Control (NAC) can also be implemented. In 802.1x \nenvironments in which user workstations are plugged in to the back of IP phones, the \nuse of automatic port control on Cisco Catalyst switches is recommended. To enable \n802.1x automatic port control on switches running Cisco IOS Software, use the \ndot1x port-control auto command. On switches running CatOS, use the \nset port dot1x <m/p> port-control auto command. 802.1x and IP telephony are only \nsupported with the use of Cisco IP phones. You must use multi-VLAN access ports \n(separate VLANs for voice and data) based on the configurations shown in the previous \nexamples in this chapter. \nWhen you enable 802.1x on a switch port where a Cisco IP phone resides, authentication \nis done based only on Cisco Discovery Protocol (CDP). It is important to notice that no \nvoice or data packets are allowed before CDP packets are processed. This varies on a \nper-platform basis. For instance, on a Catalyst 6500 running CatOS, packets other than \nExtensible Authentication Protocol over LAN (EAPOL) or CDP are dropped by the \nsoftware at the in-band driver level. The voice VLAN Spanning Tree state is set to \n“forwarding,” and the disabling of learning of other MAC addresses is done on the line \ncards by setting the appropriate bits in port header control registers. On the other hand, \nCisco Catalyst 3750 switches put phones addresses in the TCAM after detecting CDP \npackets to allow voice traffic through. In addition, an ACL to catch all EAPOL packets is \nused. The hardware drops any other packets sent from unknown source addresses when they \nhit the catchall entry in the TCAM, triggering an address learning violation in the switch. \nIn short, in 802.1x environments, CDP is absolutely necessary for IP phone operation; \nwithout it, an IP phone is unusable. In contrast, when you use the Cisco NAC Framework \nsolution in Layer 2 IP (NAC-L2-IP), EAP over UDP (EoU) is used. EOU provides a \ndifferent type of architecture and access control environment than 802.1x because EoU acts \n"
        },
        {
            "page_number": 295,
            "text": "272\nChapter 9:  IP Telephony Security\nat Layer 3, and 802.1x is strictly Layer 2. In NAC-L2-IP, the security posture check \nis triggered after an ARP packet is detected or by the use of DHCP snooping. Cisco \nswitches support EoU in an IP telephony environment. In most cases, it is recommended \nthat you use NAC-L2-IP. Based primarily on CDP, you can exempt Cisco IP phones \nfrom any EOU rules. An alternative to this approach includes a configured static exception \nor use of the Generic Authorization Message Exchange (GAME) protocol with an external \naudit server.\nIt is recommended that you exempt IP phones from the NAC posture entirely. Example 9-2 \ndemonstrates how to configure an exception policy for Cisco IP phones on a switch \nrunning Cisco IOS Software.\nIn the previous example, an identity profile is configured for EoU, and the device authorize\ncommand is used to “authorize” or exempt all Cisco IP phones from NAC posture checks. \nThis is done by using the CDP information from the Cisco IP phone. The identity policy \nnamed allow-my-phones is configured with an access list to catch all traffic.\nNOTE\nRefer to the Cisco Press book Network Admission Control Volume II for detailed NAC \nconfiguration examples and troubleshooting guides.\nYou can configure Cisco IP phones to allow an administrator to get statistics and device \ninformation through a built-in web server that runs on each phone. Administrators can use \nthis feature for debugging and to obtain the remote status of the phone. This built-in web \nserver is also used to receive application information from the Cisco Unified CallManager. \nYou can enable or disable web access globally or on each phone specifically. It is \nrecommended that you control web access to the phones. If you completely disable web \naccess, troubleshooting voice-related issues can be more difficult to solve. Alternatively, \nyou can restrict access by configuring ACLs or VACLs only, allowing an administrative \nnetwork or subnet in different parts of the network (in most cases, as close as possible \nto the phone).\nExample 9-2\nException Policy for Cisco IP Phones\nidentity profile eapoudp\n device authorize type cisco ip phone policy allow-my-phones\nidentity policy allow-my-phones\n access-group allow-my-phones\nip access-list extended allow-my-phones\n permit ip any any\n"
        },
        {
            "page_number": 296,
            "text": "Protecting the IP Telephony Infrastructure     273\nNOTE\nAs previously mentioned in this book, it is extremely important that you have a separate \nnetwork segment or subnet dedicated to administrative access and applications.\nDistribution Layer\nAt the distribution layer, you can apply enforcement mechanisms (such as ACLs) based on \nyour security policies for the IP telephony–enabled network. For example, you can \nconfigure Layer 3 ACLs so that they do not allow traffic from the nonvoice VLANS to \naccess the voice gateway and voice applications in the network. Typically, voice application \nservers (such as Cisco Unified CallManager and Cisco Unity) are protected by firewalls in \nthe distribution layer of the data center. On the other hand, you can create ACL templates \nto strategically deploy within your distribution layer to restrict access from nonvoice \nVLANs. This method simplifies the ACLs at Layer 3 compared to the ACLs at Layer 2 or \nVLAN ACLs. Figure 9-5 shows the two access switches you saw in the previous examples, \nin which IP phones in the 192.168.10.0/24 and 192.168.11.0/24 networks reside \n(voice VLANs 10 and 11). The user workstations are in VLANs 100 (IP range \n192.168.100.0/24) and 101 (IP range 192.168.101.0/24).\nThe goal is to restrict access from nonvoice segments to the voice gateway (10.10.10.100) \nand to the CallManager cluster (172.18.124.0/24). You can use a simple ACL in your \ndistribution switches, as demonstrated in Example 9-3.\nDepending on your security policy and your environment, you will allow or restrict access \nto additional services. Of course, in your data center, you will have more granular ACLs \nallowing or denying traffic based on your security policy.\nHigh availability is crucial in the distribution layer. Use the Hot Standby Router Protocol \n(HSRP) at the distribution layer to ensure high availability in the event of a failure.\nExample 9-3\nACL in Distribution Switch\naccess-list 100 deny ip 192.168.100.0 0.0.0.255 host 10.10.10.100\naccess-list 100 deny ip 192.168.101.0 0.0.0.255 host 10.10.10.100\n! the lines above deny all nonvoice devices to send traffic to the voice \n! gateway\naccess-list 100 deny ip 192.168.100.0 0.0.0.255 172.18.124.0 0.0.0.255\naccess-list 100 deny ip 192.168.101.0 0.0.0.255 172.18.124.0 0.0.0.255\n! the access list entries above deny all nonvoice devices to send \n! traffic to the Cisco Unified CallManager servers\naccess-list 100 permit ip 192.168.100.0 0.0.0.255 any\naccess-list 100 permit ip 192.168.101.0 0.0.0.255 any\n"
        },
        {
            "page_number": 297,
            "text": "274\nChapter 9:  IP Telephony Security\nFigure 9-5\nDistribution Layer Access List\nNOTE\nThe following link contains numerous step-by-step examples of methods for configuring \nHSRP on Cisco Catalyst switches and Cisco IOS Software routers:\nhttp://www.cisco.com/en/US/partner/tech/tk648/tk362/tk321/\ntsd_technology_support_sub-protocol_home.html\nGateway Load Balancing Protocol (GLBP) is another redundancy mechanism. GLBP is \nnow Stateful Switchover (SSO) aware. GLBP can detect when a router is failing over to the \nDistribution Switches\n3750-2\n3750-1\nVoice VLAN 11\n192.168.11.0/24\nVoice VLAN 10\n192.168.10.0/24\nVoice Gateway\n10.10.10.100\nData VLAN 100\n192.168.100.0/24\nData VLAN 101\n192.168.101.0/24\nV\nIP\nIP\nV\nCallManager Cluster\n(172.18.124.0/24)\nCORE\n"
        },
        {
            "page_number": 298,
            "text": "Securing the IP Telephony Applications     275\nsecondary Route Processor (RP) and continue in its current GLBP group state. Prior to \nbeing SSO aware, GLBP was not able to detect that a second RP was installed and \nconfigured to take over if the primary RP failed. When the primary failed, the GLBP device \nwould stop participating in the GLBP group and, depending on its role, could trigger \nanother router in the group to take over as the active router. With this enhancement, GLBP \ndetects the failover to the secondary RP, and no change occurs to the GLBP group. If the \nsecondary RP fails and the primary is still not available, the GLBP group detects this and \nre-elects a new active GLBP router.\nAt the distribution layer, you can also enable NetFlow to gain complete visibility of what \nis happening in your network. As you learned in previous chapters, NetFlow brings \nunmatched telemetry features that allow you to maintain visibility of your network \ntraffic.\nCore\nA number of books are required to fully cover how to design the core of your network. \nHowever, for the purpose of this chapter and this book, the most important thing \nyou need to remember is the need for high availability and the ability to route/switch \ntraffic as fast as possible with little need for traffic filtering in your core. You can use \nfeatures such as Control Plane Policing (CoPP) to protect the control plane of your core \nrouters. In addition, you should implement the routing protocol security best practices \nlearned in previous chapters and all other Network Foundation Protection (NFP) \nstrategies.\nSecuring the IP Telephony Applications \nIn this section, you learn how to protect IP telephony applications such as:\n•\nCisco Unified CallManager\n•\nCisco Unified Communications Manager Express\n•\nCisco Unity\n•\nCisco Unity Express\n•\nCisco Personal Assistant\nSecuring these applications starts with the development of a well-defined application \nsecurity policy that describes all the processes required to ensure server and application \nsecurity and assumes that you deployed the recommended network infrastructure best \npractices described earlier in this chapter. This policy not only includes design \nguidelines, but also operational practices, such as patch management, antivirus \nprotection, and in-depth protection with the Cisco Security Agent (CSA). In the \nfollowing sections, you learn best practices for increasing the security of the previously \nmentioned applications.\n"
        },
        {
            "page_number": 299,
            "text": "276\nChapter 9:  IP Telephony Security\nProtecting Cisco Unified CallManager\nServer and operating system best practices apply when protecting the \nCisco Unified CallManager. Just as with any other critical application, you should make \nmajor configuration changes within a maintenance window to avoid the disruption of voice \nservices. However, some standard security policies for application servers might not be \nadequate for IP telephony servers. For example, on e-mail and web servers, you can \neasily resend an e-mail message or refresh a web page. On the other hand, voice \ncommunications are real-time events. Consequently, your user population will quickly \nnotice any disruption of service. \nThe first step is to restrict activities on IP telephony servers (such as the \nCisco Unified CallManager) that might be considered normal on application servers within \na network. For instance, you should browse the Internet on CallManager servers. This \nsounds obvious, however, many administrators fail to do this.\nPatch management is one of the most crucial aspects of application security. Cisco provides \na well-defined patch system for the Cisco Unified CallManager solution. You should \napply only patches that Cisco provides and not patch the system using an operating system \nvendor patch (unless Cisco has approved it). \nNOTE\nYou can download all Cisco Unified CallManager patches from \nhttp://www.cisco.com/kobayashi/sw-center/sw-voice.shtml.\nAdditional information templates show you how to increase the hardening of the operating \nsystem in the Utils\\SecurityTemplates directory on your Cisco Unified CallManager \nserver. \nIt is important to know that Cisco Unified CallManager 5.x does not support the use of \nantivirus software. However, an unmanaged version of the Cisco Security Agent provides \nsecurity features above and beyond traditional antivirus solutions. As you learned in \nprevious chapters, CSA looks at the server traffic and the way the running applications \nbehave. It then enforces security mechanisms when something is considered abnormal. \nFor instance, CSA prevents any virus or malware that tries to be installed on the system. \nIt prevents the infection before it happens. You can also deploy the full version of CSA \nto provide granular configuration of security policies within the servers. In addition, \nyou can monitor all CSA event logs from a centralized location (from the \nCSA Management Control, or CSA-MC).\nNOTE\nUse of CSA is highly recommended not only for Cisco Unified CallManager but to protect \nany servers and endpoints within your organization.\n"
        },
        {
            "page_number": 300,
            "text": "Securing the IP Telephony Applications     277\nIn addition, you may want to protect all your servers in your data center with a firewall. The \nFWSM for the Cisco Catalyst 6500 series switches is typically deployed at the data center. \nYou should configure strict policies on the specific traffic that is allowed to communicate \nto the Cisco Unified CallManager servers. As a best practice, only allow traffic from \nyour voice VLANs/subnets and traffic from your administrative subnets.\nNOTE\nDetailed information on how to protect your data center is covered in Chapter 10, “Data \nCenter Security.”\nProtecting Cisco Unified Communications Manager \nExpress (CME)\nAs previously discussed in this chapter, the Cisco Unified CME is an entry-level VoIP \nsolution that runs on Cisco IOS Software routers. It is designed for small businesses \nand autonomous small enterprise branch offices. CME enables you to provide voice, data, \nand IP telephony services on a single platform. Because it is an integrated solution \nwithin Cisco IOS Software routers, all the best practices of router security that you learned \nin Chapter 2 apply when securing the Cisco Unified CME solution. These best practices \ninclude the following:\n•\nConfigure enable secret passwords or encrypted passwords within the configuration.\n•\nConfigure administrator access privileges within Cisco IOS Software.\n•\nRestrict access to VTY lines for remote administration access.\n•\nUse RADIUS or TACACS+ servers for authentication and authorization of \nadministrative sessions.\n•\nConfigure RADIUS or TACACS+ accounting. \n•\nConfigure a fallback user account for administrative access when the external \nauthentication server is not available.\n•\nConfigure Secure Shell (SSH) access instead of Telnet.\n•\nControl the access of Simple Network Management Protocol (SNMP) sessions.\n•\nUse all other best practices listed in Chapter 2 that protect the control plane and \nmanagement plane.\nIn addition to the common infrastructure protection best practices, you should only allow \nIP phones in the trusted domain for registration. You can use the strict-match option in \nthe ip source-address command if your local segment is a trusted domain. This allows \nonly locally attached IP phones to register, as demonstrated in the following example:\nCME(config-telephony)#ip source-address 192.168.10.1 port 2000 \n"
        },
        {
            "page_number": 301,
            "text": "278\nChapter 9:  IP Telephony Security\nAnother good practice is to block port 2000 (from external untrusted networks) to prevent \nunauthorized Skinny Call Control Protocol (SCCP) phones from registering to your \nCisco Unified CME. You can use an ACL as demonstrated in the following example:\naccess-list 100 deny tcp any any eq 2000 \nAlways use Secure Socket Layer (SSL) and HTTPS to access the web-based admin console, \nas shown in the following:\nip http server \nip http secure-server \nTIP\nYou can also use ip http authentication to perform external RADIUS or TACACS+ server \nfor HTTPS authentication.\nConfigure Class of Restrictions (COR) is used to prevent toll fraud. Typically, it is \nrecommended that you configure different classes of service to control the destinations that \nusers can call. For example, you can configure different levels of permissions that allow \nspecific users to dial only local numbers and 911 for any emergencies. In the following \nexample, two different types of users are configured (users and superusers). Superusers are \nallowed to dial any numbers, and regular users have access to all resources with the \nexception of toll (1-900 numbers), directory assistance (411), and international calling. \nThis is achieved with the configuration shown in Example 9-4.\nExample 9-4\nProtecting Against Toll Fraud Using COR \ndial-peer cor custom\nname 911\nname 1800\nname local-call\nname ld-call\nname 411\nname int-call\nname 1900\n!different dial-peer names are assigned for the different services; additionally, \n  different COR\n!lists for each service are configured below.\n!\ndial-peer cor list call911\nmember 911\n! \ndial-peer cor list call1800\nmember 1800\n!\ndial-peer cor list calllocal\nmember local-call\n!\ndial-peer cor list callint\nmember int-call\n"
        },
        {
            "page_number": 302,
            "text": "Securing the IP Telephony Applications     279\n!\ndial-peer cor list callld\nmember ld-call\n!\ndial-peer cor list call411\nmember 411\n!\ndial-peer cor list call1900\nmember 1900\n!\ndial-peer cor list user\nmember 911\nmember 1800\nmember local-call\nmember ld-call\n!the previous COR list allows regular users (user) to access/use 911, 1800, local \n  calls, and !caller ID services\n!\ndial-peer cor list superuser\nmember 911\nmember 1800\nmember local-call\nmember ld-call\nmember 411\nmember int-call\nmember 1900\ndial-peer voice 9 pots\ncorlist outgoing callld\ndestination-pattern 91..........\nport 1/0\nprefix 1\n!the previous COR list allows superusers to access/use all available services\n!\ndial-peer voice 911 pots\ncorlist outgoing call911\ndestination-pattern 9911\nport 1/0\nprefix 911\n!\ndial-peer voice 11 pots\ncorlist outgoing callint\ndestination-pattern 9011T\nport 2/0\nprefix 011\n!\ndial-peer voice 732 pots\ncorlist outgoing calllocal\ndestination-pattern 9732.......\nport 1/0\nprefix 732\n!\ncontinues\nExample 9-4\nProtecting Against Toll Fraud Using COR (Continued)\n"
        },
        {
            "page_number": 303,
            "text": "280\nChapter 9:  IP Telephony Security\nYou can configure the Cisco IOS Software Firewall on the same router that runs \nCisco Unified CME. On the other hand, you must pay attention to certain requirements needed \nfor Cisco Unified CME to work in your environment. For example, SCCP support is needed \nfor locally generated Skinny traffic. SCCP is a Cisco proprietary lite-version of H.323 for \ncall signaling, control, and media communication. H.323 uses Q.931, H.225, and H.245 \nfor call setup, management, and control. H.323 requires a TCP connection for H.245 \nsignaling that does not have a well-known port associated with it. The H.245 port is \ndynamically negotiated. NAT and stateful firewalls can break H.323.\ndial-peer voice 800 pots\ncorlist outgoing call1800\ndestination-pattern 91800.......\nport 1/0\nprefix 1800\n!\ndial-peer voice 802 pots\ncorlist outgoing call1800\ndestination-pattern 91877.......\nport 1/0\nprefix 1877\n!\ndial-peer voice 805 pots\ncorlist outgoing call1800\ndestination-pattern 91888.......\nport 1/0\nprefix 1888\n!\ndial-peer voice 411 pots\ncorlist outgoing call411\ndestination-pattern 9411\nport 1/0\nprefix 411\n!\ndial-peer voice 806 pots\ncorlist outgoing call1800\ndestination-pattern 91866.......\nport 1/0\nprefix 1866\nephone-dn 1\nnumber 2000\ncor incoming user\nEphone-dn 2\nnumber 2001\ncor incoming superuser\nExample 9-4\nProtecting Against Toll Fraud Using COR (Continued)\n"
        },
        {
            "page_number": 304,
            "text": "Securing the IP Telephony Applications     281\nNOTE\nCisco IOS Software supports unidirectional firewall policy configurations between \ngroups of interfaces which have been known as zones since Version 12.4(6)T. Previously, \nall inspect rules had to be applied to specific interfaces on routers running the \nCisco IOS Firewall feature set. All inbound and outbound traffic was inspected based \non the direction to which the inspect rule was applied.\nSince Version 12.4(11)T, Cisco IOS Software Firewalls have supported H.225 Registration, \nAdmission, and Status (RAS) signaling. H.323 uses the H.225 standard for call setup.\nProtecting Cisco Unity\nThe Cisco Unity solution provides advanced voice mail and messaging features. In \nthis section, you will learn tips for increasing the security of the Cisco Unity solution. \nCisco Unity runs over the Microsoft Windows operating system (OS). The first step in \nprotecting the Cisco Unity system is to have a good patch management procedure. Microsoft \nhas different recommendations for installing and securing Windows Server 2003 and \nWindows 2000 Server systems. For Windows Server 2003, refer to the article “Checklists; \nWindows Server 2003, Standard Edition” at http://technet.microsoft.com/en-us/default.aspx. \nFor the Windows 2000 Server, refer to the article “Installing and Securing a New \nWindows 2000 System,” which is available on the same website. \nTIP\nMake sure that the latest supported Cisco Unity service pack and all updates \nrecommended by Microsoft are installed on the server. All supported \nservice packs and recommended updates are listed at \nhttp://www.cisco.com/univercd/cc/td/doc/product/voice/c_unity/cmptblty/msupdate.htm. \nYou can use security templates to help increase the security of the system. On the other \nhand, you should always apply all security policies to the Windows server only after the \nCisco Unity installation is completed. Some security templates can affect the operation \nof Cisco Unity. The following Windows 2000 Server settings are recommended to \nrestrict and audit access to the Cisco Unity server. To change these settings, go to \nStart > Programs > Administrative Tools > Local Security Policy on the Windows 2000 \nserver, and perform the following functions:\nStep 1\nSet the Audit account login events option to Failure.\nStep 2\nSet the Audit account management option to Success, Failure.\n"
        },
        {
            "page_number": 305,
            "text": "282\nChapter 9:  IP Telephony Security\nStep 3\nSelect Failure under the Audit directory service access option.\nStep 4\nSet the Audit login events option to Failure.\nStep 5\nUnder Audit object access, select No auditing.\nStep 6\nUnder the Audit policy change, select Success, Failure.\nStep 7\nUnder the Audit privilege use option, select Failure.\nStep 8\nUnder Audit system events, select No auditing.\nStep 9\nUnder the Act as part of the operating system option, enter the account \nused to install Cisco Unity.\nStep 10 Under the Access this computer from the network, select the following \noptions: Backup Operators, Power Users, Users, Administrators, \nservername\\IWAM, domainname\\ISUR_servername.\nStep 11 Only allow Backup Operators and Administrators under the \nShut down the system option.\nIt is important that you know the TCP and User Datagram Protocol (UDP) ports used by \nCisco Unity. Table 9-1 lists all the TCP and UDP ports and their usage.\nTable 9-1\nTCP and UDP Ports Used by Cisco Unity \nProtocols/Ports\nService\nUsage\nTCP 25\nSimple Mail Transfer \nProtocol (SMTP)\nAllowed inbound and outbound by \nMicrosoft Exchange when \ninstalled on the Cisco Unity \nserver.\nTCP and UDP 53\nDomain Name System \n(DNS)\nAllowed outbound for access \nname resolution. Used inbound if \nthe DNS server is running on the \nCisco Unity server. It is \nrecommended that for your DNS \nserver, you use a server other than \nthe system on which Cisco Unity \nis installed.\nUDP 67\nDHCP/Bootstrap Protocol \n(BOOTP)\nAllowed outbound if you are using \nDHCP instead of static IP \naddresses. It is recommended that \nyou use static addressing for the \nserver.\n"
        },
        {
            "page_number": 306,
            "text": "Securing the IP Telephony Applications     283\nUDP 68\nDHCP/BOOTP\nAllowed inbound if you are using \nDHCP instead of static IP \naddresses, which is used by the \nCisco Unity server to receive \nDHCP or BOOTP replies.\nTCP 80\nHTTP\nAllowed bidirectional to access \nthe Cisco Unity web console. \nHTTPS access is recommended.\nTCP 135\nMicrosofts Remote \nProcedural Call (MS-RPC)\nUsed to negotiate access to the \nMedia Master, Cisco Unity \nViewMail for Microsoft Outlook, \nthe Exchange server, and other \nDistributed Component Object \nModel (DCOM) services.\nUDP 137\nNetwork Basic Input/Output \nSystem (NetBIOS)\nNetBIOS Name Service. Used for \nNetBIOS name resolution or \nWINS resolution.\nUDP 138\nNetBIOS\nNetBIOS Datagram Service. Used \nwhen browsing Windows \nnetworks.\nTCP 139\nNetBIOS\nUsed to access Windows file \nshares and perform NetBIOS over \nTCP/IP connections.\nUDP 161\nSNMP\nUsed to send SNMP notifications \nand to provide SNMP information \nwhen the host agent is queried.\nUDP 162\nSNMP Trap\nUsed to send SNMP traps.\nTCP 389\nLightweight Directory \nAccess Protocol (LDAP) \nwith AD-DC\nAllowed outbound to access \nLDAP directory services.\nConfigurable (typically it \nis set to TCP 390 or any \nunused TCP port)\nLDAP with Exchange 5.5\nUsed to access LDAP directory \nservices.\ncontinues\nTable 9-1\nTCP and UDP Ports Used by Cisco Unity (Continued)\nProtocols/Ports\nService\nUsage\n"
        },
        {
            "page_number": 307,
            "text": "284\nChapter 9:  IP Telephony Security\nTCP 443\nHTTP/SSL\nUsed to perform system \nadministration on a remote \nCisco Unity server when it is \nconfigured for HTTP/SSL.\nTCP 445\nSMB\nUsed outbound to access Windows \nfile shares and perform NetBIOS \nover TCP/IP connections. Used \ninbound to access Cisco Unity \nreports and Microsoft Windows \nfile shares.\nTCP 636\nLDAP/SSL\nUsed to access LDAP directory \nservices over SSL.\nTCP 691\nSMTP/link-state \nadvertisement (LSA)\nUsed when the Exchange server is \nrunning on the Cisco Unity server \nand the Exchange server is \naccepting SMTP with LSA.\nTCP 1432\nTelecommunications \nDevelopment Symposium \n(TDS) proxy \n(CiscoUnityTdsProxy)\nUsed by local processes to access \nthe SQL Server or Microsoft SQL \nServer Desktop Engine (MSDE) \ndatabase.\nTCP 1433 (default)\nMS-SQL-S\nUsed to access the SQL Server or \nMSDE database and to perform \nreplication when Cisco Unity \nfailover is configured.\nUDP 1434\nMS-SQL-M\nUsed to access the SQL Server or \nMSDE database.\nTCP 2000\nSkinny (SCCP)\nUsed to access \nCisco CallManager.\nTCP 2443\nSecure Skinny (SCCPS)\nUsed to access Cisco CallManager \nvia an encrypted channel.\nTCP 3268\nLDAP with AD-GC\nUsed to access LDAP directory \nservices when the global catalog \nserver is on another server.\nTable 9-1\nTCP and UDP Ports Used by Cisco Unity (Continued)\nProtocols/Ports\nService\nUsage\n"
        },
        {
            "page_number": 308,
            "text": "Securing the IP Telephony Applications     285\nTCP 3269\nLDAP/SSL with AD-GC\nUsed to access LDAP directory \nservices over SSL when the global \ncatalog server is on another server.\nTCP 3372\nMicrosoft Distributed \nTransaction Coordinator \n(MSDTC)\nUsed to access the SQL Server or \nMSDE database when \nCisco Unity failover is configured.\nTCP 3389\nWindows Terminal Services\nUsed to remotely perform system \nadministration on a Cisco Unity \nserver.\nTCP 3653\nNode Manager\nUsed to send manual keepalive \npackets (or “pings”) between the \nprimary and secondary servers \nwhen Cisco Unity failover is \nconfigured.\nTCP 4444\nKerberos authentication\nUsed to perform Kerberos \nauthentication.\nTCP 5060 (default)\nSession Initiation Protocol \n(SIP)\nUsed when the Cisco Unity server \nis connecting to SIP endpoints or \nSIP proxy servers.\nTCP 8005\nServer Life Cycle (JMX)\nUsed to access the Tomcat server.\nTCP 8009\nApache JServ Protocol (AJP)\nUsed by Internet Information \nServer (IIS).\nTCP and UDP dynamic \n(in the range of 1024 \nthrough 65535)\nDCOM\nUsed by the Media Master to play \nand record voice messages, and \nused when the Cisco Unity server \nis a domain controller supporting \nmember servers.\nDynamic UDP ports \n(in the range of 1024 \nthrough 65535)\nMessaging Application \nProgramming Interface \n(MAPI) notifications\nUsed in inbound direction to \nnotify Cisco Unity of changes to \nsubscriber mailboxes when \nExchange is the message store.\nUDP dynamic (in the \nrange of 22800 through \n32767)\nReal-Time Protocol (RTP)\nUsed when sending and receiving \nVoIP traffic with SCCP or SIP \nendpoints.\nTable 9-1\nTCP and UDP Ports Used by Cisco Unity (Continued)\nProtocols/Ports\nService\nUsage\n"
        },
        {
            "page_number": 309,
            "text": "286\nChapter 9:  IP Telephony Security\nUse the information in Table 9-1 to restrict and allow access to firewalls that protect your \nCisco Unity servers. \nCisco Unity uses Microsoft SQL Server. An important recommendation is to make sure that \nyou increase the security of your Microsoft SQL Server 2000 installation. Make sure you \nselect Windows Authentication Mode when you install Microsoft SQL Server, as \ndocumented in the Cisco Unity installation guide. In addition, make sure that you pay \nattention to the following guidelines:\n•\nUse a strong password for the SQL administrator (SA) account.\n•\nRestrict client access to Microsoft SQL Server 2000 by only allowing the Cisco Unity \nservice accounts to access the Microsoft SQL Server 2000 directories, folders, and \nfiles. You can also grant this access to a highly privileged account designated for use \nby a system administrator.\n•\nDetach the default Northwind and Pubs databases.\nAt a minimum, Internet Explorer (IE) 6.0 with Service Pack 1 must be installed on the \nCisco Unity server. Use IE on the Cisco Unity server for Cisco Unity administration \nonly. It is not expected that you will use IE on the Cisco Unity server to browse the Internet \nand other external resources. On the other hand, in some cases, you may have to access \nthe Microsoft or Cisco websites to obtain patches and hotfixes.\nTIP\nAs part of securing IE, refer to Microsoft Knowledge Base article 826955 at \nhttp://support.microsoft.com/kb/826955. It includes instructions on how to reduce the \nchance of being exposed to a worm like Blaster or Nachi.\nCisco Unity uses IIS 5.0 and later. Always make sure that you install the latest cumulative \nupdate patches for IIS 5.0 on the Cisco Unity server. \nTIP\nYou can also use the guidelines specified in the “Secure Internet Information Services 5 \nChecklist,” which is available on the Microsoft TechNet website, with one exception: \ngrant Full Control access to Cisco Unity directories, folders, and files only to Cisco Unity \nservice accounts and the local server administrators group. \n"
        },
        {
            "page_number": 310,
            "text": "Securing the IP Telephony Applications     287\nIn addition, it is recommended that you pay attention to the following best practices:\n•\nDelete all IIS default sample files, folders, and websites. \n•\nDisable all default IIS COM objects. \n•\nRemove unused script mappings. Cisco Unity uses only the ASA and ASP script \nmappings.\n•\nDo not follow Microsoft recommendations regarding parent paths. The Parent Paths\noption should remain enabled on the Cisco Unity server.\nTIP\nCisco Unity uses Microsoft Message Queuing (MSMQ) 2.0. It is recommended that you do \nnot change the default MSMQ setting of Local Use Only.\nWithin Cisco Unity, each application has its own authentication capabilities and \nmechanisms, and you should become familiar with each of these authentication methods. \nCisco has a detailed explanation of each application authentication mechanism at \nhttp://www.cisco.com/univercd/cc/td/doc/product/voice/c_unity/unity40/usg/ex/usg006.htm.\nProtecting Cisco Unity Express\nAs mentioned previously in this chapter, Cisco Unity Express is a Linux-based application \nthat runs on Cisco IOS Software routers with either an NM or an AIM. No external \ninterfaces exist on the Cisco Unity Express hardware. In reality, a physical Fast Ethernet \ninterface does exist; however, it is software disabled. All traffic to the Cisco Unity Express \nhardware must pass through the router. On the other hand, you can access \nCisco Unity Express via the router command-line interface (CLI) using the \nservice-module service-engine x/y session command in enable mode. The Cisco Unity Express \nmodule also has a CLI, but you cannot configure a password on it. \nTo protect the Cisco Unity Express application, you should first apply all router security \nbest practices that you learned previously in this book to the router itself. In addition, you \nshould only allow SSH access, instead of Telnet, to the router. Cisco Unity Express does \nnot support SSH. However, the communication between the router and Cisco Unity Express \nis via the router backplane and is not exposed to external interfaces. Therefore, SSH access \nto the router is sufficient.\n"
        },
        {
            "page_number": 311,
            "text": "288\nChapter 9:  IP Telephony Security\nThe initial versions of Cisco Unity Express did not support HTTPS. However, login to the \nCisco Unity Express GUI is password protected. One major limitation is that the login \ninformation currently travels in cleartext across the IP network. To provide additional \nprotection, you can use an IP Security (IPsec) tunnel to communicate to the router. \nHowever, HTTPS is supported on the Cisco Unified Communications Manager Express \nand Cisco Unity Express since Cisco IOS Software Version 12.2(15)ZJ2. To enable HTTPS \naccess to the Cisco Unity Express application, you must enable the secure HTTP server on \nCisco IOS Software with the following two commands:\nip http server\nip http secure-server\nYou should also use ACLs on the router to restrict access to only the protocols and ports \nthat the Cisco Unity Express software uses. The following are the protocols and ports that \nCisco Unity Express uses:\n•\nSSH for administrative access: TCP port 22\n•\nDNS: UDP or TCP port 53\n•\nTFTP: UDP port 69\n•\nFTP: TCP port 21 for control and TCP port 20 for data (Active FTP only)\n•\nHTTP: TCP port 80 for the Cisco IP phones\n•\nHTTPS: TCP port 443 for administrative access to the GUI\n•\nSyslog: UDP port 514\n•\nSIP: UDP port 5060\n•\nRTP: UDP port range from port 16384 to port 32767\n•\nNTP: UDP port 123\nCisco Unity Express runs on Linux; however, access to the Linux operating system \nor to the Linux kernel is not direct. The Linux operating system is entirely embedded. Apply \nonly the patches that Cisco provides. The same goes for SQL and LDAP support. \nCisco Unity Express includes a SQL server and LDAP directory services; however, direct \naccess does not exist to the SQL server or the LDAP directory. \nAs with the full version of Cisco Unity, you should also ensure that two servers are \nconfigured correctly: first, configuration of authentication to the FTP server that is used for \nsoftware installation; and second, configuration of the FTP server that is used for backup \nand restore. Never leave the backup and restore FTP server password configured \npermanently on the Cisco Unity Express module. In addition, because mailbox PINs do not \nexpire, a best practice is to change all passwords periodically, forcing users to reset their \nPINs to a new setting.\n"
        },
        {
            "page_number": 312,
            "text": "Securing the IP Telephony Applications     289\nProtecting Cisco Personal Assistant\nThis section covers the most common best practices to harden the Cisco Personal Assistant. \nThe recommendations to increase the security of the Cisco Personal Assistant server can be \nsummarized into two major areas:\n•\nOperating environment\n•\nSecurity policies\nNOTE\nThe Cisco Personal Assistant operating environment is made up of several third-party \nproducts. You should follow the security guidelines documented by each of these \nthird-party product vendors. This chapter covers several general guidelines on securing \nthe Cisco Personal Assistant operating environment.\nHardening the Cisco Personal Assistant Operating Environment\nThe Cisco Personal Assistant operating environment third-party components needed \nare mainly Microsoft products. Other third-party components, such as Nuance ASR and \nReal-Speak TTS, are also needed. \nNOTE\nThe following site includes a detailed list of all Cisco Personal Assistant operating \nenvironment components: \nhttp://www.cisco.com/en/US/products/sw/voicesw/ps2026/prod_maintenance_guides_list.html\nSeveral of the Cisco Personal Assistant operating environment components are configured \nby default with minimum security. It is extremely important that customers increase \nthe level of security protection for each of those systems. One of the major flaws is \nthat Microsoft IIS is vulnerable until the Windows 2000 installation on the Cisco Personal \nAssistant server is complete. You have two options: disable IIS, or wait to install it \nuntil after Windows 2000 Service Pack 4 is installed. The recommended method is to install \na bundled Windows 2000 installation CD with Service Pack 4. \n"
        },
        {
            "page_number": 313,
            "text": "290\nChapter 9:  IP Telephony Security\nNOTE\nIt is recommended that you go query the Microsoft TechNet website \n(http://technet.microsoft.com/en-us/default.aspx) for IIS vulnerabilities on a periodic \nbasis. Also, you can always go to http://tools.cisco.com/security/center/home.x \nfor a list of the latest (vendor-neutral) vulnerabilities.\nYou can apply Microsoft-provided security policies to the Cisco Personal Assistant server; \nhowever, you should never apply any of these policies until the Cisco Personal Assistant \ninstallation is complete. Some security templates can affect the operation of the \nCisco Personal Assistant.\nThe following are several general guidelines to use when you harden IIS on the Cisco \nPersonal Assistant server:\n•\nAlways make sure that the most current cumulative update patches for IIS 5.0 are \ninstalled on the server. \n•\nAlways remove all IIS sample files, folders, and web applications. This is specified in \nthe complete IIS 5.0 security checklist available on the Microsoft TechNet website. \n•\nRefer to the recommendations described in the complete IIS 5.0 security checklist \navailable on the Microsoft TechNet website to disable all default IIS COM objects. \nHowever, do not disable the File System Object (FSO) and Parent Paths. These are \nenabled by default and are needed for the operation of the Cisco Personal Assistant \nserver.\n•\nYou can also use the Microsoft IIS Lockdown and URLScan tools. However, it is \nextremely important that you not disable support for Active Server Pages (.asp) or the \nScripts Virtual directory. You can download these tools from the Microsoft TechNet \nwebsite.\nOne of the requirements of the Cisco Personal Assistant is to have IE Version 6.0 with \nService Pack 1. However, it is strongly recommended that you use IE on the server for the \nadministration of the Cisco Personal Assistant only. \nMicrosoft recommends that you subscribe to the Security Notification Service; however, \nsecurity experts advise against subscribing on the server. To subscribe to that service, drop \nIE security settings to a lower protection level. \n"
        },
        {
            "page_number": 314,
            "text": "Securing the IP Telephony Applications     291\nCisco Personal Assistant Server Security Policies\nIt is recommended that you change several security policies and server settings from their \ndefault values. It is also recommended that you enable auditing to track the way the Cisco \nPersonal Assistant server is being accessed. The following values are recommended for the \nAudit Policies and User Rights Assignments under the Local Policies:\nStep 1\nSet Audit account logon events to Failure.\nStep 2\nSet Audit account management to Success, failure.\nStep 3\nConfigure Audit directory service access to Failure.\nStep 4\nSet Audit logon events to Failure.\nStep 5\nSet Audit object access to No auditing.\nStep 6\nLeave Audit policy change at its default value (Success, failure).\nStep 7\nSet Audit privilege use to Failure.\nStep 8\nLeave Audit system events at its default value No auditing.\nStep 9\nUnder Access this computer from the network, allow only \nBackup operators, Power users, Users, Administrators, \nuservername\\IWAM, and domainname\\ISUR_servername. In other \nwords, leave all default values except Everyone.\nStep 10 Under Shut down the system, only allow \nBackup operators and Administrators.\nThe following is the recommended list of settings that you can modify by using the \nWindows Local Security Policy utility on the Cisco Personal Assistant server.\nStep 1\nUnder Additional restrictions for anonymous connections, select \nDo not allow enumeration of SAM accounts and shares.\nStep 2\nDisable the Allow system to be shut down without having to log on \noption.\nStep 3\nDisable the Audit use of Backup and Restore privilege option. \nStep 4\nDisable the Clear virtual memory pagefile when system shuts down \noption.\nStep 5\nUnder Digitally sign client communication (always), select the default \nDisabled value.\nStep 6\nEnable the Digitally sign client communication (when possible)\noption.\n"
        },
        {
            "page_number": 315,
            "text": "292\nChapter 9:  IP Telephony Security\nStep 7\nDisable the Digitally sign server communication (always) option.\nStep 8\nEnable the Digitally sign server communication (when possible)\noption.\nStep 9\nDisable Ctrl-Alt-Del requirement for login.\nStep 10 Enable the Do not display last user name in logon screen option.\nStep 11 Under the LAN manager authentication level option, select \nSend NTLM response only.\nStep 12 Set Number of previous logons to cache (in case domain controller is \nnot available) to 5 logons. This is strictly dependent on your security \npolicy and your environment. \nStep 13 Enable the Prevent system maintenance of computer account \npassword option.\nStep 14 Set the Prompt user to change password before expiration to 7 days \ninstead of the 14 days default value. This is strictly dependent on your \nsecurity policy and your environment; however, as a rule of thumb, 7 \ndays is appropriate for most environments.\nStep 15 Enable the Restrict CD-ROM access to locally logged-on users only \noption.\nStep 16 Enable the Restrict floppy access to locally logged-on users only\noption.\nStep 17 Enable the Secure Channel: Digitally encrypt or sign secure channel \ndata (always) option.\nStep 18 Enable the Secure Channel: Require strong (Windows 2000 or later) \nsession key option.\nStep 19 Disable the Send unencrypted password to connect to third-party \nSMB [small and medium-sized business] servers option.\nStep 20 Set the Smart card removal behavior option to Lock workstation.\nStep 21 Under Unsigned driver installation behavior, select the \nDo not allow installation option.\nStep 22 Under Unsigned non-driver installation behavior, select the \nSilently succeed / Warn but allow installation option.\n"
        },
        {
            "page_number": 316,
            "text": "Protecting Against Eavesdropping Attacks     293\nFor any other Windows security–related information, see the Microsoft \nTechNet site.\nProtecting Against Eavesdropping Attacks\nEavesdropping attacks are also known as phone tapping attacks. The main goal is for an \nattacker to listen, copy, or record a conversation. An example of an eavesdropping attack is \nan incident reported back in 2006. The phones of about 100 Greek politicians and offices \n(including the U.S. embassy in Athens and the Greek prime minister) were compromised \nby a malicious code embedded in Vodafone mobile phone software. The attackers tapped \ninto their conference call system. Basically, by using several prepaid mobile phones, the \nattackers “joined the conference call” and recorded their conversations.\nThe Cisco ASA, Cisco PIX, and IOS Firewalls provide several features that support the \nstateful processing of signaling protocols, H.323, and SIP. These devices monitor the \nspecific connection request and required resources and permit only what is specifically \nnecessary for the operation of the system, thereby protecting against session hijacking and \nspoofing.\nThe Cisco ASA and Cisco PIX security appliances support H.323 inspection by making \nsure that only compliant transactions are allowed between IP telephony devices, such as \nCisco CallManager and other non-Cisco products. Cisco ASA and Cisco PIX support \nH.323 Versions 3 and 4. They also support multiple calls on the same call signaling channel. \nExample 9-5 demonstrates how you can configure an H.323 inspection policy map on a \nCisco ASA or Cisco PIX security appliance running Version 7.2 or later.\nExample 9-5\nDynamic Port-Security\nmy_asa(config)# regex phone1 “5551234567”\nmy_asa(config)# regex phone2 “5553213212”\nmy_asa(config)# class-map type inspect h323 match-all voice-traffic\nmy_asa(config-pmap-c)# match called-party regex phone1\nmy_asa(config-pmap-c)# match calling-party regex phone2\nmy_asa(config)# policy-map type inspect h323 h323-policy-map\nmy_asa(config-pmap)# parameters\nmy_asa(config-pmap-p)# class voice_traffic\nmy_asa(config-pmap-p)# rtp-conformance enforce-payloadtype\nmy_asa(config-pmap-c)# drop\nciscoasa(config)# service-policy h323-policy-map interface inside\n"
        },
        {
            "page_number": 317,
            "text": "294\nChapter 9:  IP Telephony Security\nIn Example 9-5, two regular expression entries are configured for two specific phone \nnumbers (5551234567 and 5553213212). This is an optional step, but it gives you the \nflexibility to inspect traffic based on a specific caller or called party. A class map called \nvoice-traffic is configured to inspect all traffic between the two previously defined phone \nnumbers. The class map is applied to a policy map called h323-policy-map. All \nnoncompliant traffic is dropped. The rtp-conformance enforce-payloadtype parameter is \nused to ensure that all transit RTP packets comply with protocol specifications. Finally, the \npolicy map is applied to the inside interface using the service-policy command.\nIPS and IDS devices can also be placed in strategic areas within the network to detect \nunusual traffic, such as an attempt to execute an unusual command, or a malformed packet \nindicating some form of protocol manipulation.\nA good way to protect your voice traffic in untrusted environments is by the use of the \nvoice- and video-enabled VPN (V3PN) solution. V3PN provides secure site-to-site \nconnectivity to transport voice, video, and data. With V3PN, you can enable remote branch \noffices and teleworkers to use IP telephony services while reducing business operations \ncosts.\nNOTE\nThe following white paper includes detailed information about V3PN design and \nimplementation:\nhttp://www.cisco.com/application/pdf/en/us/guest/netsol/ns171/c649/\nccmigration_09186a008074f2d8.pdf\nMedia encryption using Secure Real-Time Transport Protocol (SRTP) delivers protection \nby encrypting the voice conversation, rendering it unintelligible to internal or external \neavesdroppers who have gained access to the voice domain. Designed for voice packets, \nSRTP supports the AES encryption algorithm and is an Internet Engineering Task Force \n(IETF) RFC 3711 standard. Media encryption on Cisco access routers works with both \nCisco CallManager and the media encryption feature on Cisco IP phones, enabling \ncustomers to place secure analog phone or fax calls between an IP phone and the PSTN \ngateway depending on the gateway interface type. The SRTP-encrypted voice packets \nare almost indistinguishable from RTP voice packets, allowing features like QoS and \ncompression to be implemented without additional development or manipulation. Voice \nencryption keys derived by Cisco Unified CallManager are securely sent by encrypted \nsignaling path to Cisco Unified IP phones through the use of Transport Layer Security (TLS) \nand to gateways over IPsec-protected links.\n"
        },
        {
            "page_number": 318,
            "text": "Summary     295\nSummary\nIP telephony solutions are being deployed at a fast rate in many organizations. The cost \nsavings introduced with VoIP are significant. On the other hand, these benefits can be \nheavily impacted if you do not have the appropriate security mechanisms in place. This \nchapter covers several best practices for securing IP telephony networks. It discusses how \nto protect voice-enabled networks by protecting infrastructure components. It also covered \nhow to secure different IP telephony components, such as the Cisco Unified CallManager, \nCisco Unified CME, Cisco Unity, Cisco Unity Express, and Cisco Unified Personal \nAssistant. Finally, it covered several mechanisms that are used to combat voice \neavesdropping and other attacks.\n"
        },
        {
            "page_number": 319,
            "text": "This chapter covers the following topics:\n•\nProtecting the Data Center Against Denial of Service (DoS) Attacks and Worms\n•\nData Center Segmentation and Tiered Access Control\n•\nDeploying Network Intrusion Detection and Prevention Systems\n•\nDeploying the Cisco Security Agent (CSA) in the Data Center\n"
        },
        {
            "page_number": 320,
            "text": "C H A P T E R 10\nData Center Security\nData centers comprise some of the most critical assets within any organization. Typically, \napplications, databases, and management servers reside in the data center. For this reason, \nit is extremely important to have the appropriate defense mechanisms in place to protect \nthe data center against security threats. Attacks against data center assets can result in lost \nbusiness applications and the theft of confidential information. This chapter covers several \nbest practices and recommendations used to increase the security of your data center. These \ntopics include protecting against denial of service (DoS) attacks, worms, information theft, \nand other security threats. The recommendations in earlier chapters are put into action in \nthis chapter to provide an in-depth defense mechanism against existing and new threats.\nProtecting the Data Center Against Denial of Service \n(DoS) Attacks and Worms\nYou can implement different mechanisms and technologies on infrastructure components \nto help mitigate the effects of DoS and worms on your network. The following are some \nexamples:\n•\nSYN cookies in firewalls and load balancers\n•\nIntrusion Prevention Systems (IPSs) and Intrusion Detection Systems (IDSs)\n•\nCisco NetFlow in the data center\n•\nCisco Guard\n•\nData center infrastructure protection\nSYN Cookies in Firewalls and Load Balancers\nA commonly used distributed denial of service (DDoS) attack is known as SYN-flooding.\nIn this type of attack, the attacker sends a series of TCP SYN packets that typically originate \nfrom spoofed IP addresses. The constant flood of SYN packets can prevent servers within \nthe data center from handling legitimate connection requests. You can use firewalls and \n"
        },
        {
            "page_number": 321,
            "text": "298\nChapter 10:  Data Center Security\nsecurity appliances such as the Cisco ASA and the Cisco PIX enabled with the SYN \ncookies algorithm to combat SYN flood attacks. In large data centers, the Cisco Firewall \nServices Module (FWSM), for the Catalyst 6500 series switches, is typically used for \nthis same purpose. Figure 10-1 demonstrates how TCP synchronization message (SYN) \ncookies work in the Cisco Adaptive Security Appliance (ASA), the Cisco PIX, and the \nFWSM for the Cisco Catalyst 6500 switches. In this example, a Cisco FWSM is used.\nFigure 10-1 SYN Cookies in FWSM\nThe following steps are illustrated in Figure 10-1:\n1 A client machine attempts a TCP connection to a web server behind the FWSM and \nsends the initial SYN packet to the firewall.\n2 When the embryonic (half-open) connection limit is reached, the Cisco ASA, Cisco \nPIX, or Cisco FWSM can act as a proxy for the server and generate a SYN-ACK \nresponse to the client SYN request. The SYN-ACK reply has a “cookie” in the \nsequence (SEQ) field of the TCP header. The cookie is a message digest 5 algorithm \n(MD5) authentication of the source and destination IP addresses and port numbers. \nAll the connection requests are rebuilt from these cookies.\n3 The acknowledgement (ACK) packet SEQ field has the value of the cookie+1. In this \ncase, when the FWSM receives an ACK from the client, it “authenticates” the client \nand allows the connection to the server.\n4 The FWSM sends its own SYN packet to the server.\n5 The server replies with an ACK.\n6 The FWSM sends its SYN-ACK to the server, and the connection is built.\nOn the Cisco FWSM, you can use the show np command to view SYN cookie statistics. \nExample 10-1 shows the output of the show np 2 syn command on an FWSM.\nExample 10-1 Output of show np 2 syn Command \nFWSM# show np 2 syn\n-------------------------------------------------------------------------------\n             Fast Path Syn Cookie Statistics Counters (NP-2)                  \n-------------------------------------------------------------------------------\nSYN_COOKIE: Syn cookie secret wheel index                        : 16\nSYN_COOKIE: Total number of SYNs intercepted                     : 231356987\nSYN_COOKIE: Total number of ACKs intercepted                     : 204\nSYN_COOKIE: Total number of ACKs dropped after lookup            : 0\nSYN\nSYN\nACK+Cookie\nSYN/ACK+Cookie\nWeb\nServer\nFWSM\nACK\nSYN/ACK\nTCP\nClient\n3\n2\n1\n4\n5\n6\n"
        },
        {
            "page_number": 322,
            "text": "Protecting the Data Center Against Denial of Service (DoS) Attacks and Worms     299\nIn the highlighted line in Example 10-1, you can see that the total number of intercepted \nSYN packets is 231356987. This is most definitely indicative of a SYN flood.\nLoad-balancing solutions such as the Cisco Content Switching Module (CSM) also support \nSYN cookies. You can deploy the CSM in inline mode or one-arm mode. Figure 10-2 \nillustrates a CSM configured in inline mode. Traffic from certain applications cannot be \nload-balanced because of the nature of those applications. In Figure 10-2, the traffic that \ncannot be load-balanced is labeled as direct traffic.\nFigure 10-2 CSM in Inline Mode\nIn Figure 10-2, the CSM is configured with both physical interfaces that are connected to \nthe network with all traffic passing through the CSM. Figure 10-3 illustrates the one-arm \nCSM design.\nThe CSM uses a virtual IP address. In a “one-arm” design, you can combine it with a \nCisco FWSM. One of the major benefits of using a CSM one-arm design in combination \nwith the Cisco FWSM is that the CSM protects against DoS attacks directed at its virtual \nIP address, and the Cisco FWSM protects against attacks directed at non-load-balanced servers.\nThe use of SYN cookies has certain limitations. For example, SYN cookies cannot carry \nTCP options that are set up in SYN packets; SYN cookies can carry only an encoding of \nthe maximum segment size (MSS) value of the server. Some TCP options are used for \nperformance and scalability (for example, large windows, selective acknowledgement, and \nso on). Another limitation of SYN cookies is that they do not protect against established \nconnection attacks.\nSYN_COOKIE: Total number of ACKs successfully validated          : 193\nSYN_COOKIE: Total number of ACKs Dropped: Secret Expired         : 11\nSYN_COOKIE: Total number of ACKs Dropped: Invalid Sequence       : 0\nSYN_COOKIE: Total number of Syn Cookie Entries inserted by NP3   : 12\nSYN_COOKIE: ACKs dropped: Syn cookie ses not yet established     : 0\nSYN_COOKIE: Leaf allocation failed                               : 0\nSYN_COOKIE: Leaf insertion failed                                : 2088\nExample 10-1 Output of show np 2 syn Command (Continued)\nBalanced Traffic\nDirect Traffic\nCSM\nClient\nWeb Servers\nClient\n"
        },
        {
            "page_number": 323,
            "text": "300\nChapter 10:  Data Center Security\nFigure 10-3  CSM in One-Arm Mode\nNOTE\nEstablished connection attacks are attacks that exploit vulnerabilities after a connection has \nbeen established such as a buffer overflow to a specific application.\nIntrusion Prevention Systems (IPS) and Intrusion \nDetection Systems (IDS)\nIn earlier chapters, you learned the difference between IDS and IPS devices. IDS and \nIPS appliances and modules are usually placed in the data center distribution center \nnot only to alert an administrator when a security threat has been detected, but also \nto take action and protect the data center assets. In small environments, one or more \nIDS/IPS appliances (such as the Cisco 4200 sensors) can be placed in the data center. \nThe Cisco Catalyst 6500 IDS/IPS module (IDSM) is used in larger environments. \nThe Cisco Security Agent (CSA) provides host-based prevention services that help you \nprotect the servers in the data center from attacks that exploit OS and application \nvulnerabilities. These two technology solutions (network and host-based) complement each \nother. Despite the fact that both solutions provide intrusion prevention mechanisms \nthat guard against direct attacks, the technologies are different in numerous ways. Later \nsections in this chapter cover the deployment of both network and host-based IPS \nsolutions. The benefits and limitations of each solution are discussed in their respective \nsections.\nBalanced Traffic\nDirect Traffic\nCSM\nClient\nWeb Servers\nClient\n"
        },
        {
            "page_number": 324,
            "text": "Protecting the Data Center Against Denial of Service (DoS) Attacks and Worms     301\nCisco NetFlow in the Data Center\nCisco NetFlow provides network traffic visibility that can help in identifying and classifying \npotential DDoS attempts and other security threats. In addition, it provides valuable \ninformation about application usage that can be beneficial for network planning and traffic \nengineering. You can enable NetFlow in data center infrastructure devices, such as your \ndistribution switches or routers. A new version of NetFlow called Flexible NetFlow is now \navailable on Cisco IOS routers starting with IOS Version 12.4(9)T. Cisco is working to \nprovide this functionality in other platforms such as the Catalyst 6500 series switches.\nNOTE\nYou can use the Cisco Feature Navigator tool to find information about platform support. \nTo access this tool, go to http://tools.cisco.com/ITDIT/CFN/jsp/index.jsp.\nWith Flexible NetFlow, you can configure a range of parameters for traffic analysis and \ndata export on a networking device. For instance, you can define your own records by \nspecifying the key and nonkey fields to customize the data collection to your specific \nrequirements. In previous versions of NetFlow, a flow was based on a set of seven IP \npacket attributes:\n•\nSource IP\n•\nDestination IP\n•\nSource port\n•\nDestination port\n•\nLayer 3 Protocol\n•\nType of Service (ToS) byte\n•\nInput interface\nFlexible NetFlow adds the ability to check other information, such as the number of bytes \nand packets in a flow. You can also create custom records for functions like quality of \nservice (QoS), bandwidth monitoring, application and end user traffic profiling, and \nsecurity monitoring.\nThe main limitation is that, currently, Flexible NetFlow is not supported in the \nCisco Catalyst 6500. In most cases, it is recommended that you enable NetFlow at the data \ncenter distribution switches. In large data centers, Cisco Catalyst 6500 switches are used \nas distribution switches. However, the benefits of NetFlow Versions 5 and 9 are still \nextremely valuable, because NetFlow is one of the most helpful tools for identifying and \nclassifying security threats. In addition, you can use network monitoring tools such as the \nCisco Security Monitoring, Analysis, and Response System (CS-MARS) to analyze \nNetFlow and other telemetry data from many different network devices.\n"
        },
        {
            "page_number": 325,
            "text": "302\nChapter 10:  Data Center Security\nCisco Guard\nThe Cisco Detector and Cisco Guard provide anomaly detection and attack mitigation \nfeatures. You can place them in large data centers to divert traffic directed at the target host \nfor analysis and filtering, so that legitimate transactions can still be processed while \nillegitimate traffic is dropped. On the other hand, in most cases small, medium, and large \nenterprises place their Cisco Guard at their Internet edge or subscribe to managed services \nprovided by service providers.\nNOTE\nThe managed service solution is called Clean Pipes. Cisco has detailed information \nabout the Clean Pipes solution at http://www.cisco.com/en/US/netsol/ns615/\nnetworking_solutions_sub_solution.html.\nData Center Infrastructure Protection\nThe infrastructure protection best practices that you learned in Chapter 2, “Preparation \nPhase,” also apply in the data center. For example, you should harden control protocols as \na basic security precaution on all applicable devices in the data center. In addition, you \nshould disable unnecessary services on infrastructure components and implement \ndevice protection mechanisms, such as infrastructure access control lists (iACLs) and \nControl Plane Policing (CoPP). These device protection mechanisms will help you greatly \nin case of worm outbreaks, DDoS, or even in case of an anomaly other than a security threat \n(that is, a misconfigured application).\nTIP\nRemember to implement basic best-practice recommendations such as hardening device \nauthentication, hardening Simple Network Management Protocol (SNMP), using Network \nTime Protocol (NTP), and all others that you learned in Chapter 2.\nYou can also develop configuration templates for data center access switch ports where \nservers reside. Basic Layer 2 security mechanisms, such as limits on the number of MAC \naddresses that the server can originate on a port, can be included in the configuration \ntemplate. You can also disable the Cisco Discovery Protocol (CDP) when it is not needed; \nbe careful, however, because certain applications use CDP for legitimate transactions. \nExample 10-2 shows a basic template.\nExample 10-2 Data Center Access Switch Port Template \ninterface GigabitEthernet2/4\n no ip address\n switchport\n switchport access vlan 100\n"
        },
        {
            "page_number": 326,
            "text": "Data Center Segmentation and Tiered Access Control     303\nThe highlighted commands in Example 10-2 enable port security and BPDU guard and \ndisable CDP. \nNOTE\nAn important point about port security is that it does not interoperate well with virtual \nservers because they may carry multiple MAC addresses of virtual hosts. You should also \nbe careful when implementing port security with certain server failover mechanisms. In \nsome environments, servers with multiple network interface cards (NIC) may share the \nsame MAC address between interfaces when a failover occurs.\nFor antispoofing protection, you can also enable Unicast Reverse Path Forwarding \n(Unicast RPF) in routers, security appliances such as the Cisco ASA, or in the \nCisco FWSM. In the data center, it is most common to deploy Unicast RPF on the firewalls \n(Cisco ASA or FWSM). With Unicast RPF, if traffic enters the outside or untrusted interface \nfrom an address that is known to the routing table, but it resides on the inside interface, \nthe firewall drops the packet. Similarly, if traffic enters the inside interface from an \nunknown source address, the firewall drops the packet to prevent spoofed attacks. \nYou can enable Unicast RPF on the Cisco ASA, Cisco PIX, or Cisco FWSM with the \nip verify reverse-path command, as shown in the following example:\nFWSM(config)#ip verify reverse-path interface outside\nFWSM(config)#ip verify reverse-path interface inside\nIn the previous example, Unicast RPF is enabled in the outside and inside interfaces. \nBecause firewalls require traffic path symmetry, in most cases, Unicast RPF can provide \ngreat benefits without impacting traffic flow. \nData Center Segmentation and Tiered \nAccess Control \nBy isolating different types of servers and services, you can use segmentation and tiered \naccess control in your data center to provide a multilayered architecture while adding \nsecurity. The easiest way to segment your data center is to configure different Layer 2 \ndomains or VLANs. In addition, you can use firewalls for policy enforcement between each \n switchport mode access\n spanning-tree portfast\n switchport port-security maximum 2\n switchport port-security violation shutdown\n spanning-tree bpduguard enable\n no cdp enable\nExample 10-2 Data Center Access Switch Port Template (Continued)\n"
        },
        {
            "page_number": 327,
            "text": "304\nChapter 10:  Data Center Security\nsegment. By using private VLANs, you can also use segmentation that is local to the \nVLAN. This helps in preventing a compromised or infected server from affecting adjacent \nsystems. In a multitier architecture, you separate systems based on the different functions \nthey handle. For example, you can separate the presentation, business logic, and database \nlayers, as illustrated in Figure 10-4.\nFigure 10-4 Multitier Server Segmentation Example\nIn Figure 10-4, a web server farm is separated from the application and the database servers. \nThis is done to protect the application and the database in case the web servers are \ncompromised.\nYou can also segment the data center by separating other types of application servers and \ndevices. It is a best practice to separate all your management servers. For example, \nApplication Servers\nWeb/Front-End Servers\nDatabase Servers\nCorporate\nNetwork\n"
        },
        {
            "page_number": 328,
            "text": "Data Center Segmentation and Tiered Access Control     305\nyour management segment can include your TACACS+, RADIUS, SNMP, and any \nconfiguration management servers such as CiscoWorks, Cisco Security Manager, \nCS-MARS, and others.\nFigure 10-5 shows how management servers can also be separated from the rest of the data \ncenter.\nFigure 10-5 Management Servers Segmented\nAs previously mentioned, you can segment your data center simply by configuring separate \nVLANs; however, this does not truly provide a complete solution that allows you to \nenforce your security policies between each boundary. Therefore, you can configure \nfirewalls to provide additional security while allowing the necessary traffic to pass between \nsegments.\nCorporate\nNetwork\nManagement Servers\nWeb/Front-End Servers\nApplication Servers\nDatabase Servers\n"
        },
        {
            "page_number": 329,
            "text": "306\nChapter 10:  Data Center Security\nNOTE\nYou can also segment your data center by configuring Virtual Routing and Forwarding \n(VRF) interfaces with Multiprotocol Label Switching (MPLS) or by using VRF-Lite. This \nis more suitable for large environments and requires your staff to be familiar with more \nadvanced routing features such as MPLS. The next section explains how to achieve \nsegmentation using separate VLANs and the Cisco FWSM for policy enforcement and \nadditional protection.\nSegmenting the Data Center with the Cisco FWSM\nIn this section, you will learn how to take advantage of some of the Cisco FWSM features \nto segment your data center. It covers the modes of operation of the FWSM, design \nconsiderations, and configuration steps.\nCisco FWSM Modes of Operation and Design Considerations\nYou can use the Cisco FWSM not only to segment your data center, but also to enforce \npolicy and to provide additional security benefits such as stateful and deep packet \ninspection. You can configure the Cisco FWSM in two different modes:\n•\nRouted mode: The default behavior. The Cisco FWSM in routed mode acts as a \nLayer 3 device supporting features such as Network Address Translation (NAT) and \nrouting protocols. In most cases, when a Cisco FWSM is deployed in routed mode in \nthe data center, it becomes the default gateway for a majority of the servers. \n•\nTransparent mode: The Cisco FWSM acts as a Layer 2 device. One of the major \nbenefits of transparent mode is that you do not have to worry about readdressing your \ninfrastructure when deploying a new firewall within your data center, because the \nfirewall acts as a bridge between the external and internal network. On the other hand, \nwhen you are operating in transparent mode, the FWSM does not support features \nsuch as NAT routing protocols and some specific inspections engines that depend\non NAT.\nNOTE\nRouted and transparent modes are also supported in the Cisco ASA and the Cisco PIX \nsecurity appliances. In smaller environments, you can deploy the Cisco ASA at \nthe data center. The configuration is identical except that the Cisco FWSM runs in the \nCatalyst 6500 series switches or in the Cisco 7600 series routers; therefore, specific \nconfiguration steps are needed in the switch or the router. This subject is covered later \nin this section.\nFigure 10-6 shows a Cisco FWSM configured in transparent mode.\n"
        },
        {
            "page_number": 330,
            "text": "Data Center Segmentation and Tiered Access Control     307\nFigure 10-6 Cisco FWSM in Transparent Mode\nIn Figure 10-6, the Cisco FWSM outside interface resides on VLAN 100, and the inside \ninterface resides on VLAN 101. Both interfaces belong to the same network subnet \n(10.10.10.0/24). The Cisco FWSM must have a management IP address configured for \ntraffic to pass through it when configured in transparent mode. In this example, the \nmanagement IP address is 10.10.10.123.\nYou can take advantage of the virtualization capabilities of the Cisco FWSM to segment \nyour data center. You can partition the Cisco FWSM into multiple virtual firewalls, known \nas security contexts. Each of these virtual firewalls has its own configuration enforcing \nseparate security policies to each segment in the data center. \n(Outside)\nVlan 100\n10.10.10.0/24\n(Inside)\nVlan 101\n10.10.10.0/24\nFWSM\n(Management IP: 10.10.10.123)\n"
        },
        {
            "page_number": 331,
            "text": "308\nChapter 10:  Data Center Security\nNOTE\nWhen you have multiple virtual security contexts configured, it is similar to having multiple \nstandalone firewalls. Many features are supported when you configure the Cisco FWSM \nwith multiple contexts, including routing tables, firewall features, and management. \nHowever, certain features are not supported, including dynamic routing protocols.\nThe Cisco ASA and Cisco PIX security appliances also support virtual firewalls. Their \nbehavior is similar to the Cisco FWSM.\nFigure 10-7 illustrates the four modes of operations of the Cisco FWSM:\n•\nSingle context routed mode\n•\nSingle context transparent mode\n•\nMultiple context routed mode\n•\nMultiple context transparent mode\nFigure 10-7 Cisco FWSM Modes of Operation\nFigure 10-8 shows a Cisco FWSM configured with three different contexts. Each context \nincludes its own configuration to protect each data center segment.\nFWSM\nMulticontext\nMode\nRouted\nTransparent\nSingle Mode\nRouted\nTransparent\n"
        },
        {
            "page_number": 332,
            "text": "Data Center Segmentation and Tiered Access Control     309\nFigure 10-8 Cisco FWSM Contexts\nIn Figure 10-8, the Cisco FWSM contexts separate the web servers, applications servers, \nand database servers. The following are the context names:\n•\nWebservers\n•\nAPPservers\n•\nDBservers\nThe inside interface of context Webservers resides in VLAN 10. The inside interface of \ncontext APPservers is in VLAN 20, and the context DBserver inside interface is in VLAN 30.\nConfiguring the Cisco Catalyst Switch\nIn the Cisco Catalyst switch, you must create the necessary VLANs and assign those to the \nCisco FWSM. Example 10-3 shows the commands used to create VLANs 10, 20, 30, \nand 40 in the Cisco Catalyst 6500 switch.\nWeb Servers\nApplication Servers\nDatabase Servers\nContext Webservers\nVLAN 10\nContext APPservers\nVLAN 20\nContext DBservers\nVLAN 30\nFWSM\nOutside Interface VLAN 40\n"
        },
        {
            "page_number": 333,
            "text": "310\nChapter 10:  Data Center Security\nEach VLAN entry is configured with a descriptive name based on the data center segment. \nYou then have to assign the VLANs to the Cisco FWSM. Example 10-4 shows how you \ncan create firewall VLAN groups and then assign the group to the Cisco FWSM.\nIn Example 10-4, a VLAN group with ID of 1 is configured. This VLAN group \nincludes VLANs 10, 20, 30, and 40 and is applied to the Cisco FWSM with the \nfirewall module 2 vlan-group 1 command. The number 2 indicates that the \nCisco FWSM resides on the second slot in the Cisco Catalyst 6500 switch.\nTIP\nFor security reasons, by default, only one switch virtual interface (SVI) can exist between \nthe switch and the Cisco FWSM. You might also choose to use multiple SVIs in routed \nmode so that you do not have to share a single VLAN for the outside interface. You can use \nthe firewall multiple-vlan-interfaces command to allow you to add more than one \nSVI to the Cisco FWSM. In this example, the outside interfaces of each context reside on \nVLAN 40.\nCreating Security Contexts in the Cisco FWSM\nWhen you configure the Cisco FWSM in multiple context modes, you add and manage \nall security contexts in the system space or system configuration mode. By default, a \ncontext named admin is created. The admin context is just like any other context, except \nthat when a user logs into the admin context, that user has system administrator rights \nand can access the system and all other contexts. The admin context is not restricted in any \nExample 10-3 Creating the VLANs in the Switch\nvlan 10\nname webservers\n!\nvlan 20\nname appservers\n!\nvlan 30\nname dbservers\n!\nvlan 40\nname tocorpnetwork\nExample 10-4 Assigning the VLANs to the Cisco FWSM\nfirewall multiple-vlan-interfaces\nfirewall module 2 vlan-group 1\nfirewall vlan-group 1 10,20,30,40\n"
        },
        {
            "page_number": 334,
            "text": "Data Center Segmentation and Tiered Access Control     311\nway and can be used as a regular context. However, because logging into the admin context \ngrants you administrator privileges over all contexts, you might need to restrict access to \nthe admin context for appropriate users. \nTIP\nThe admin context configuration must reside on flash memory and not on a remote system. \nIf your system is already in multiple context mode, or if you convert from single mode, the \nadmin context is created automatically as a file on the internal flash memory called \n“admin.cfg.” This context is named “admin.” If you do not want to use admin.cfg as the \nadmin context, you can change the admin context.\nBecause the default mode in the Cisco FWSM is single routed mode, to start creating \nsecurity context, you need to change the FWSM to multiple mode. You can use the \nmode multiple command from configuration mode to enable multiple mode, as shown here:\nFWSM(config)# mode multiple\nNOTE\nAfter you enter the mode multiple command, you are prompted to reboot the \nCisco FWSM.\nExample 10-5 shows the context configuration on the Cisco FWSM that was pictured in the \nprevious example.\nExample 10-5 Creating the Security Contexts\ncontext webservers\n  description Webserver segment\n  allocate-interface vlan40 int1\n  allocate-interface vlan10 int2\n  config-url disk:/webservers.cfg\n!\ncontext appservers\n  description Application server segment\n  allocate-interface vlan50 int1\n  allocate-interface vlan20 int2\n  config-url disk:/appservers.cfg\n!\ncontext dbservers\n  description Database servers segment\n  allocate-interface vlan60 int1\n  allocate-interface vlan30 int2\n  config-url disk:/dbservers.cfg\n"
        },
        {
            "page_number": 335,
            "text": "312\nChapter 10:  Data Center Security\nThe contexts webservers, appservers, and dbservers are defined in Example 10-5. Each \nsecurity context or virtual firewall has two interfaces.\nIn this example, the configuration of each security context is stored locally and not on an \nexternal server. After the contexts have been created, you can change to any of them by \nusing the changeto context command, as shown here:\nFWSM(config)# changeto context webservers\nFWSM/webservers(config)#\nNotice that the prompt changes with the hostname followed by the context name you are \ncurrently configuring.\nConfiguring the Interfaces on Each Security Context\nThe interface identifiers on each security context that were previously created were int1 for \nthe outside interface and int 2 for the inside interface. Figure 10-9 shows the IP address \nconfiguration of the interfaces on each security context (virtual firewall). \nFigure 10-9 IP Address Configuration on Each Virtual Firewall\nContext Webservers\nContext APPservers\nContext DBservers\nMSFC\nFWSM\nOutside Interface\n10.10.10.1\nVLAN 40\nOutside Interface\n10.10.10.2\nVLAN 50\nOutside Interface\n10.10.10.3\nVLAN 60\nInside Interface\n192.168.10.1\nVLAN 10\nInside Interface\n192.168.20.1\nVLAN 20\nInside Interface\n192.168.30.1\nVLAN 30\n"
        },
        {
            "page_number": 336,
            "text": "Data Center Segmentation and Tiered Access Control     313\nExample 10-6 shows the configuration of the interfaces on the Webservers security context.\nExample 10-7 shows the configuration of the interfaces on the APPservers security context.\nExample 10-8 shows the configuration of the interfaces on the DBservers security context.\nConfiguring Network Address Translation\nThe goal is to configure static NAT for each server residing on each security context. \nThree systems reside in the web server segment (context webservers). This is illustrated in \nFigure 10-10.\nExample 10-6 webservers Security Context IP Address Configuration\ninterface int1\n nameif outside\n security-level 0\n ip address 10.10.10.1 255.255.255.0\n!\ninterface int2\n nameif inside\n security-level 100\n ip address 192.168.10.1 255.255.255.0\nExample 10-7 appservers Security Context IP Address Configuration\ninterface int1\n nameif outside\n security-level 0\n ip address 10.10.10.2 255.255.255.0\n!\ninterface int2\n nameif inside\n security-level 100\n ip address 192.168.20.1 255.255.255.0\nExample 10-8 dbservers Security Context IP Address Configuration\ninterface int1\n nameif outside\n security-level 0\n ip address 10.10.10.3 255.255.255.0\n!\ninterface int2\n nameif inside\n security-level 100\n ip address 192.168.30.1 255.255.255.0\n"
        },
        {
            "page_number": 337,
            "text": "314\nChapter 10:  Data Center Security\nFigure 10-10 webserver IP Address Configuration\nTable 10-1 lists the physical IP addresses of each web server with the statically translated \naddress.\nExample 10-9 shows the static NAT configuration for each server on the webservers \nsecurity context.\nTable 10-1\nWeb Servers NAT Mapping\nWeb Server Name\nTranslated  IP Address\nPhysical IP Address\nWeb-Server 1\n10.10.10.51\n192.168.10.51\nWeb-Server 2\n10.10.10.52\n192.168.10.52\nWeb-Server 3\n10.10.10.53\n192.168.10.53\nExample 10-9 webservers Context NAT Configuration\nstatic (inside,outside) 10.10.10.51 192.168.10.51 netmask 255.255.255.255\nstatic (inside,outside) 10.10.10.52 192.168.10.52 netmask 255.255.255.255\nstatic (inside,outside) 10.10.10.53 192.168.10.53 netmask 255.255.255.255\nOutside Interface\n10.10.10.1\nVLAN 40\nInside Interface\n192.168.10.1\nVLAN 10\nContext\nWebservers\nWeb-Server 1\n192.168.10.51\nWeb-Server 2\n192.168.10.52\nWeb-Server 3\n192.168.10.53\n"
        },
        {
            "page_number": 338,
            "text": "Data Center Segmentation and Tiered Access Control     315\nTwo application servers are in the data center as illustrated in Figure 10-11. They are \nprotected by the virtual firewall (context) called APPservers.\nFigure 10-11 Application Servers IP Address Configuration\nTable 10-2 lists the physical IP addresses of each application server along with the statically \ntranslated address. \nExample 10-10 shows the static NAT configuration for each server on the appservers \nsecurity context.\nTable 10-2\nApplication Servers NAT Mapping\nServer Name\nTranslated IP Address\nPhysical IP Address\nAPP-Server 1\n10.10.20.71\n192.168.20.71\nAPP-Server 2\n10.10.20.72\n192.168.20.72\nExample 10-10 appservers Context NAT Configuration\nstatic (inside,outside) 10.10.20.71 192.168.20.71 netmask 255.255.255.255\nstatic (inside,outside) 10.10.20.72 192.168.20.72 netmask 255.255.255.255\nAPP-Server 1\n192.168.20.71\nAPP-Server 2\n192.168.20.72\nOutside Interface\n10.10.10.2\nVLAN 40\nInside Interface\n192.168.20.1\nVLAN 20\nContext\nAPPservers\n"
        },
        {
            "page_number": 339,
            "text": "316\nChapter 10:  Data Center Security\nThe data center has two database servers, as illustrated in Figure 10-12. They are protected \nby the virtual firewall (context) called DBservers.\nFigure 10-12 Database Servers IP Address Configuration\nTable 10-3 lists the physical IP addresses of each application server along with the statically \ntranslated address. \nExample 10-11 shows the static NAT configuration for each server on the DBservers security \ncontext.\nTable 10-3\nDatabase Servers NAT Mapping\nServer Name\nTranslated IP Address\nPhysical IP Address\nDB-Server 1\n10.10.30.101\n192.168.30.101\nDB-Server 2\n10.10.30.102\n192.168.30.102\nExample 10-11 dbservers Context NAT Configuration\nstatic (inside,outside) 10.10.30.101 192.168.30.101 netmask 255.255.255.255\nstatic (inside,outside) 10.10.30.102 192.168.30.102 netmask 255.255.255.255\nDB-Server 1\n192.168.30.101\nDB-Server 2\n192.168.30.102\nOutside Interface\n10.10.10.3\nVLAN 40\nInside Interface\n192.168.30.1\nVLAN 20\nContext\nDBservers\n"
        },
        {
            "page_number": 340,
            "text": "Data Center Segmentation and Tiered Access Control     317\nControlling Access with ACLs\nIt is recommended that you configure ACLs on both interfaces of each security context \nfor more granular security policy enforcement. You can tune the ACLs based on your \nsecurity policies and application usage. The ACLs that are configured on each of the \nsecurity contexts in this example only allow the necessary traffic for each server \nand application.\nTable 10-4 lists the protocols and ports that need to be allowed on the webservers security \ncontext. \n1\nSSH = Secure Shell\n2\nSCP = Secure Copy Protocol\n3\nDNS = Domain Name System\n4\nUDP = User Datagram Protocol\nUsers connect to the web servers via HTTP and HTTPS; therefore, this traffic is allowed on \nthe outside interface in the webservers context. The web servers are Linux-based machines. \nThe administrator transfers files over SCP and connects to the server command-line \ninterface (CLI) via SSH. In addition, the administrator uses a custom management \napplication to install software and patches on the systems (Mgmt-App). This traffic from \nthe management network (10.10.100.0/24) needs to be allowed. \nThe web servers themselves need to access an application called App-X running on the \nservers in the APPservers context over TCP port 987. DNS resolution and SYSLOG must \nalso be allowed to external servers. Example 10-12 shows the ACLs configured in the \nWebservers context allowing the previously mentioned ports and protocols.\nTable 10-4\nProtocols and Ports Used by the webservers\nUsage/Application\nProtocol or Port\nAllowed by ACL\nHTTP\nTCP 80\ninbound-traffic\nHTTPS\nTCP 443\ninbound-traffic\nSSH1/SCP2\nTCP 22\ninbound-traffic\nMgmt-App\nTCP 890\ninbound-traffic\nApp-X\nTCP 987\noutbound-traffic\nDNS3\nUDP4 53\noutbound-traffic\nSYSLOG\nUDP 514\noutbound-traffic\nExample 10-12 webservers Context ACL Configuration \naccess-list inbound-traffic remark INBOUND TRAFFIC TO WEBSERVERS\naccess-list inbound-traffic extended permit tcp any host 10.10.10.51 eq www\naccess-list inbound-traffic extended permit tcp any host 10.10.10.51 eq https\ncontinues\n"
        },
        {
            "page_number": 341,
            "text": "318\nChapter 10:  Data Center Security\nIn Example 10-12, ACLs are configured to allow the traffic specified in Table 10-4. The \nACL named inbound-traffic is applied to the outside interface, and the ACL named \naccess-list inbound-traffic extended permit tcp 10.10.100.0 255.255.255.0 host \n  10.10.10.51 eq ssh\naccess-list inbound-traffic extended permit tcp 10.10.100.0 255.255.255.0 host \n  10.10.10.51 eq 890\naccess-list inbound-traffic extended permit tcp any host 10.10.10.52 eq www\naccess-list inbound-traffic extended permit tcp any host 10.10.10.52 eq https\naccess-list inbound-traffic extended permit tcp 10.10.100.0 255.255.255.0 host \n  10.10.10.52 eq ssh\naccess-list inbound-traffic extended permit tcp 10.10.100.0 255.255.255.0 host \n  10.10.10.52 eq 890\naccess-list inbound-traffic extended permit tcp any host 10.10.10.53 eq www\naccess-list inbound-traffic extended permit tcp any host 10.10.10.53 eq https\naccess-list inbound-traffic extended permit tcp 10.10.100.0 255.255.255.0 host \n  10.10.10.53 eq ssh\naccess-list inbound-traffic extended permit tcp 10.10.100.0 255.255.255.0 host \n  10.10.10.53 eq 890\naccess-group inbound-traffic in interface outside\n!\naccess-list outbound-traffic remark OUTBOUND TRAFFIC FROM WEBSERVERS\naccess-list outbound-traffic extended permit tcp  host 192.168.10.51 host \n  10.10.20.71 eq 987\naccess-list outbound-traffic extended permit tcp  host 192.168.10.51 host \n  10.10.20.72 eq 987\naccess-list outbound-traffic extended permit udp  host 192.168.10.51 host \n  10.10.111.11 eq 53\naccess-list outbound-traffic extended permit udp  host 192.168.10.51 host \n  10.10.111.12 eq 53\naccess-list outbound-traffic extended permit udp  host 192.168.10.51 host \n  10.10.100.100 eq 514\naccess-list outbound-traffic extended permit tcp  host 192.168.10.52 host \n  10.10.20.71 eq 987\naccess-list outbound-traffic extended permit tcp  host 192.168.10.52 host \n  10.10.20.72 eq 987\naccess-list outbound-traffic extended permit udp  host 192.168.10.52 host \n  10.10.111.11 eq 53\naccess-list outbound-traffic extended permit udp  host 192.168.10.52 host \n  10.10.111.12 eq 53\naccess-list outbound-traffic extended permit udp  host 192.168.10.52 host \n  10.10.100.100 eq 514\naccess-list outbound-traffic extended permit tcp  host 192.168.10.53 host \n  10.10.20.71 eq 987\naccess-list outbound-traffic extended permit tcp  host 192.168.10.53 host \n  10.10.20.72 eq 987\naccess-list outbound-traffic extended permit udp  host 192.168.10.53 host \n  10.10.111.11 eq 53\naccess-list outbound-traffic extended permit udp  host 192.168.10.53 host \n  10.10.111.12 eq 53\naccess-list outbound-traffic extended permit udp  host 192.168.10.53 host \n  10.10.100.100 eq 514\naccess-group outbound-traffic in interface inside\nExample 10-12 webservers Context ACL Configuration (Continued)\n"
        },
        {
            "page_number": 342,
            "text": "Data Center Segmentation and Tiered Access Control     319\noutbound-traffic is applied to the inside interface. Notice that the web server IP addresses \nin the inbound-traffic ACL are the translated addresses. However, because the \noutbound-trafficACL is applied to the inside interface, the physical IP addresses are used \nas the source. The web servers must access two DNS servers. The primary DNS server is \n10.10.111.11, and the secondary is 10.10.111.12. The IP address of the SYSLOG server is \n10.10.100.100.\nTable 10-5 lists the necessary protocols and ports that need to be allowed on the appservers \nsecurity context. \nThe web servers communicate with the application (App-X) running on the servers in the \nAPPservers context over TCP port 987. Similar to the web servers, the administrator transfers \nfiles over SCP and connects to the server CLI via SSH. In addition, the administrator uses a \ncustom management application to install software and patches on the systems (Mgmt-App). \nThis management traffic from the management network (10.10.100.0/24) needs to be \nallowed. The application servers connect to the database servers running MySQL over \nTCP port 3306. DNS resolution and SYSLOG must also be allowed to external servers.\nExample 10-13 shows the ACLs configured in the appservers context allowing the ports and \nprotocols listed in Table 10-6.\nTable 10-5\nProtocols and Ports Used by the appservers\nUsage/Application\nProtocol and/or port\nAllowed by ACL\nApp-X\nTCP 987\ninbound-traffic\nSSH/SCP\nTCP 22\ninbound-traffic\nMgmt-App\nTCP 890\ninbound-traffic\nMySQL\nTCP 3306\noutbound-traffic\nDNS\nUDP 53\noutbound-traffic\nSYSLOG\nUDP 514\noutbound-traffic\nExample 10-13 appservers Context ACL Configuration \naccess-list inbound-traffic remark INBOUND TRAFFIC TO APPSERVERS\naccess-list inbound-traffic extended permit tcp host 10.10.10.51 host 10.10.20.71 \n  eq 987\naccess-list inbound-traffic extended permit tcp host 10.10.10.52 host 10.10.20.71 \n  eq 987\naccess-list inbound-traffic extended permit tcp host 10.10.10.53 host 10.10.20.71 \n  eq 987\naccess-list inbound-traffic extended permit tcp host 10.10.10.51 host 10.10.20.72 \n  eq 987\naccess-list inbound-traffic extended permit tcp host 10.10.10.52 host 10.10.20.72 \n  eq 987\naccess-list inbound-traffic extended permit tcp host 10.10.10.53 host 10.10.20.72 \n  eq 987\ncontinues\n"
        },
        {
            "page_number": 343,
            "text": "320\nChapter 10:  Data Center Security\nIn Example 10-13, ACLs are configured to allow the traffic specified in Table 10-5. The \nACL named inbound-traffic is applied to the outside interface, and the ACL named \noutbound-traffic is applied to the inside interface.\nTable 10-6 lists the necessary protocols and ports that need to be allowed on the DBservers \nsecurity context. \naccess-list inbound-traffic extended permit tcp 10.10.100.0 255.255.255.0 host \n  10.10.20.71 eq 22\naccess-list inbound-traffic extended permit tcp 10.10.100.0 255.255.255.0 host \n  10.10.20.72 eq 22\naccess-list inbound-traffic extended permit tcp 10.10.100.0 255.255.255.0 host \n  10.10.20.71 eq 890\naccess-list inbound-traffic extended permit tcp 10.10.100.0 255.255.255.0 host \n  10.10.20.72 eq 890\naccess-group inbound-traffic in interface outside\n! \naccess-list outbound-traffic remark OUTBOUND TRAFFIC FROM APPSERVERS\naccess-list outbound-traffic extended permit tcp  host 192.168.20.71 host \n  10.10.30.101 eq 3306\naccess-list outbound-traffic extended permit tcp  host 192.168.20.72 host \n  10.10.30.101 eq 3306\naccess-list outbound-traffic extended permit tcp  host 192.168.20.71 host \n  10.10.30.102 eq 3306\naccess-list outbound-traffic extended permit tcp  host 192.168.20.72 host \n  10.10.30.102 eq 3306\naccess-list outbound-traffic extended permit udp  host 192.168.20.71 host \n  10.10.111.11 eq 53\naccess-list outbound-traffic extended permit udp  host 192.168.20.72 host \n  10.10.111.11 eq 53\naccess-list outbound-traffic extended permit udp  host 192.168.20.71 host \n  10.10.111.12 eq 53\naccess-list outbound-traffic extended permit udp  host 192.168.20.72 host \n  10.10.111.12 eq 53\naccess-list outbound-traffic extended permit tcp  host 192.168.20.71 host \n  10.10.100.100 eq 514\naccess-list outbound-traffic extended permit tcp  host 192.168.20.72 host \n  10.10.100.100 eq 514\naccess-group outbound-traffic in interface inside\nTable 10-6\nProtocols and Ports Used by the dbservers\nUsage/Application\nProtocol and/or port\nAllowed by ACL\nMySQL\nTCP 3306\ninbound-traffic\nSSH)/SCP\nTCP 22\ninbound-traffic\nMgmt-App\nTCP 890\ninbound-traffic\nDNS\nUDP 53\noutbound-traffic\nSYSLOG\nUDP 514\noutbound-traffic\nExample 10-13 appservers Context ACL Configuration (Continued)\n"
        },
        {
            "page_number": 344,
            "text": "Data Center Segmentation and Tiered Access Control     321\nThe application servers communicate with the MySQL database running on the servers in \nthe DBservers context over TCP port 3306. Linux-based servers also exist, and the \nadministrator transfers files over SCP and connects to the server CLI via SSH. As with the \nother servers, the administrator uses the custom management application to install software \nand patches on the systems (Mgmt-App). This management traffic from the management \nnetwork (10.10.100.0/24) needs to be allowed. DNS resolution and SYSLOG must also be \nallowed to external servers.\nExample 10-14 shows the ACLs configured in the APPservers context allowing the ports \nand protocols listed in Table 10-6.\nIn Example 10-14, ACLs are configured to allow the traffic specified in Table 10-6. The \nACL named inbound-traffic is applied to the outside interface, and the ACL named \noutbound-traffic is applied to the inside interface. \nExample 10-14 dbservers Context ACL Configuration\naccess-list inbound-traffic remark INBOUND TRAFFIC TO DATABASE SERVERS\naccess-list inbound-traffic extended permit tcp host 10.10.20.71 host 10.10.30.101 \n  eq 3306\naccess-list inbound-traffic extended permit tcp host 10.10.20.72 host 10.10.30.101 \n  eq 3306\naccess-list inbound-traffic extended permit tcp host 10.10.20.71 host 10.10.30.102 \n  eq 3306\naccess-list inbound-traffic extended permit tcp host 10.10.20.72 host 10.10.30.102 \n  eq 3306\naccess-list inbound-traffic extended permit tcp 10.10.100.0 255.255.255.0 host \n  10.10.30.101 eq 22\naccess-list inbound-traffic extended permit tcp 10.10.100.0 255.255.255.0 host \n  10.10.30.102 eq 22\naccess-list inbound-traffic extended permit tcp 10.10.100.0 255.255.255.0 host \n  10.10.30.101 \neq 890\naccess-list inbound-traffic extended permit tcp 10.10.100.0 255.255.255.0 host \n  10.10.30.102 \neq 890\naccess-group inbound-traffic in interface outside\n!\naccess-list outbound-traffic remark OUTBOUND TRAFFIC FROM DATABASE SERVERS\naccess-list outbound-traffic extended permit udp  host 192.168.30.101 host \n  10.10.111.11 eq 53\naccess-list outbound-traffic extended permit udp  host 192.168.30.102 host \n  10.10.111.11 eq 53\naccess-list outbound-traffic extended permit udp  host 192.168.30.101 host \n  10.10.111.12 eq 53\naccess-list outbound-traffic extended permit udp  host 192.168.30.102 host \n  10.10.111.12 eq 53\naccess-list outbound-traffic extended permit tcp  host 192.168.30.101 host \n  10.10.100.100 eq 514\naccess-list outbound-traffic extended permit tcp  host 192.168.30.102 host \n  10.10.100.100 eq 514\naccess-group outbound-traffic in interface inside\n"
        },
        {
            "page_number": 345,
            "text": "322\nChapter 10:  Data Center Security\nVirtual Fragment Reassembly\nThe Cisco FWSM, Cisco ASA, and Cisco PIX security appliances drop fragments. \nHowever, many different applications generate fragments. If you enable fragment \nforwarding, you open yourself to fragment attacks (like the ones defined in RFC 1858). You \ncan use the Virtual Fragment Reassembly feature to protect against this type of attack. You \nenable Virtual Fragment Reassembly with the fragment command. In the following \nexample, the Cisco FWSM is limiting its fragment buffer size to 200 packets on its outside \nand inside interfaces.\nfragment size 200 outside \nfragment size 200 inside \nTIP\nBy using the chain and timeout options in the fragment command, you can also define \nthe maximum number of fragments to be chained together and the length of time the \nCisco FWSM waits for the fragments to arrive before discarding them.\nDeploying Network Intrusion Detection \nand Prevention Systems \nYou can use network IDS/IPS appliances in small-to-medium organizations or the \nCisco IDSM-2 for the Cisco Catalyst 6500 series switches in larger organizations. The \nimplementation of each solution depends on the size of your data center and its \nrequirements. When designing a network IDS/IPS solution for the data center, for both \nscalability and manageability, you should reduce the amount of traffic that is sent to the \nsensor. You should also avoid sending duplicate frames to the IDS/IPS sensors or modules. \nAt the same time, you should avoid the situation in which you must change existing ACLs \nor VACLs before being able to implement an IDS/IPS solution. In most cases, you want \nto create several SPAN sessions to be able to send the traffic to multiple IDS/IPS devices. \nThis section includes several best practices to use when you deploy an IDS/IPS solution \nin your data center.\nSending Selective Traffic to the IDS/IPS Devices\nDepending on the size of your data center, you may use one or more IPS/IDS devices. In \nlarge data centers, you can use several IDSMs to monitor the activity within your server \nfarms. Figure 10-13 illustrates a data center with three different IDSMs installed on each \nCisco Catalyst 6500 along with the Cisco FWSM. \n"
        },
        {
            "page_number": 346,
            "text": "Deploying Network Intrusion Detection and Prevention Systems     323\nFigure 10-13 IDSMs Deployed in the Data Center\nIn some cases, exposing IPS/IDS sensors to all the traffic that flows within a data center can \noversubscribe the IPS/IDS devices. To avoid performance problems in the data center, some \nadministrators prefer to use only IDS features (promiscuous inspection) instead of inline \nIPS services. Others prefer to limit the number of protocols or the type of traffic to which \na sensor is assigned. For example, in the high-level data center topology illustrated in \nFigure 10-13, you can selectively send traffic from each data center segment to specific \nIDSMs. For instance, you may want to send all web-related traffic on the webservers \nsegment to the first IDSM. Similarly, you may want to send all traffic that traverses the \napplication server segment to the second IDSM, and traffic destined and originated by the \ndatabase servers to the third IDSM. This is illustrated in Figure 10-14.\nCorporate\nNetwork\nIDSMs\nIDSMs\nApplication Servers\nWeb/Front-End Servers\nDatabase Servers\n"
        },
        {
            "page_number": 347,
            "text": "324\nChapter 10:  Data Center Security\nFigure 10-14 Sending Selective Traffic to the IDS/IPS Devices\nBased on VLAN information, you can use a SPAN session to differentiate traffic \non multiple ports. This is supported on the Cisco Catalyst 6500 starting from \nCisco IOS Versions 12.2(18)SXD and 12.1(24)E. You can configure a single SPAN session \nto capture traffic from the three VLANs and send traffic from each VLAN to a specific \nIDSM or external sensor. With this configuration, the IDS/IPS devices can inspect \nclient-to-server traffic, locally switched traffic, and server-to-server routed traffic.\nAlternatively, you can use VACL capture. You do this by simply configuring three VACLs \nwith the forward capture action and assigning them to the three different segments. You \nassign IDSM-A to the web servers segment, IDSM-B to the application servers segment, \nand IDSM-C to the database segment. \nIn certain trunk environments, the use of VACLs achieves half the goal of this design. The \nIDSMs may still experience substantial noise traffic. In addition to this, you have to modify \nthe security VACLs that might already be in place in the data center to include the capture \naction for the traffic that you want to monitor. To address this problem, you can use RSPAN \nand VACL redirect together. You can configure RSPAN to create a copy of the traffic from \nall the ports connecting the Catalyst 6500 to the core and to the server farms. All these \nframes are locally copied onto an RSPAN VLAN which is a special VLAN that is equally \nvisible to three IDSMs. Then you configure VACL redirection. This does not permit or deny \nthe traffic, it simply redirects the traffic to the desired IDSM. One VACL entry specifies  that \nIDSM-C\nIDSM-B\nIDSM-A\nApplication Servers\nWeb/Front-End Servers\nDatabase Servers\n"
        },
        {
            "page_number": 348,
            "text": "Deploying the Cisco Security Agent (CSA) in the Data Center     325\ntraffic to the web servers on the RSPAN VLAN be redirected to IDSM-1; another VACL \nentry specifies that traffic destined to the application servers on the RSPAN  VLAN be \nredirected to IDSM-2; the same applies for the database server traffic to  IDSM-3. \nNOTE\nYou can find a detailed white paper on how to use RSPAN with VACLs for granular traffic \nanalysis at http://www.cisco.com/warp/public/cc/pd/si/casi/ca6000/prodlit/rspan_wp.pdf.\nMonitoring and Tuning \nMonitoring tools such as CS-MARS help not only to identify and detect security threads, \nbut also to reduce steps in the tuning process. Tuning is the process of managing and \nminimizing the number of false positives and false negatives that the network IDS/IPS \ndevice reports. As you learned in previous chapters, a false positive is a benign network \nactivity mistakenly identified as malicious by the sensor. A false negative is malicious \nnetwork activity mistakenly identified as benign or not detected by the sensor. To tune \nsensors, you enable, disable, or modify the signatures used in the network. The tuning \nprocess is one of the most crucial operational tasks that you perform when increasing the \nsecurity of your data center. In Chapter 3, “Identifying and Classifying Security Threats,” \nyou learned best practices to use when deploying IDS/IPS devices. These same best \npractices apply in the data center.\nDeploying the Cisco Security Agent (CSA) \nin the Data Center\nCSA provides several security features that are more robust than a traditional antivirus or a \npersonal firewall. CSA not only protects against viruses, worms, and direct attacks, but it \nalso protects against day-zero threats. CSA plays an important role in data center security.\nCSA Architecture\nIn the CSA solution architecture, a central management center maintains a database of \npolicies and information about the workstations and servers on which the CSA software is \ninstalled. Agents register with the Cisco Security Agent Management Center (CSA-MC). \nSubsequently, the CSA-MC checks its configuration database and deploys a configured \npolicy for that particular system. \nNOTE\nStarting with CSA Version 5.1, the CSA-MC is a standalone system. Prior to Version 5.1, \nCSA-MC was part of the Cisco Works VPN and Security Management System (VMS).\n"
        },
        {
            "page_number": 349,
            "text": "326\nChapter 10:  Data Center Security\nThe CSA software constantly monitors all activity on the end host and polls to the CSA-MC \nat configurable intervals for policy updates. The agent sends events and alerts to the global \nevent manager of the CS-AMC. The global event manager inspects the event logs and then \nalerts the administrator or triggers the agent to take action based on the specific alert. \nNOTE\nAll the communication between the agents and the CSA-MC is via Secure Socket Layer (SSL). \nThe administrator also connects to the CSA-MC via SSL to manage and monitor the agents. \nConfiguring Agent Kits\nAs previously mentioned, CSA-MC comes with preconfigured agent kits that can be used to \nfulfill initial security needs. However, CSA-MC allows you to create custom agent kits to fit \nyour specific requirements. For example, you can create different agent kits for the various \nservers within your data center. To create a new agent kit, complete the following steps:\nStep 1\nChoose Systems > Agent Kits from the CSA-MC console.\nStep 2\nClick New at the bottom of the page displayed. A dialog box appears asking \nyou to specify the operating system on which the agent kit will be applied.\nStep 3\nEnter a name and description for the new agent kit. For example, you can \ncreate agent kits for the web servers, application, and database servers in \nthe examples in the previous sections.\nStep 4\nSelect the groups that will be associated with this agent kit. You can \nselect from predefined groups designed for different type of servers.\nStep 5\nOptionally, you can select to reboot the system after the CSA installation \nis complete. You can also select a quiet install to avoid end-user \ninteraction.\nStep 6\nClick Make Kit to create the new agent kit. \nStep 7\nClick Generate Rules to generate all pending rules. A new window \nappears with information about the rule generation. After you have made \nthe appropriate selections, click Generate.\nStep 8\nAll rules and configuration changes are applied at this point. A summary \nwindow appears if the rule generation completes successfully.\nPhased Deployment\nWhen you start your CSA deployment, select the initial hosts on which CSA will be \ninstalled based on the following guidelines:\n•\nSelect at least one host per each distinct application or server environment.\n•\nDuring the pilot, make the test host a mirror sample of the production systems.\n"
        },
        {
            "page_number": 350,
            "text": "Summary     327\n•\nWhen installing CSA on servers, use a test machine for each server type to ensure that \nthere is no negative impact from the CSA agent software installation.\n•\nCreate a group for each type of application environment to be protected. \nBuilding and tuning of CSA policies is a continuous task. You need to have the proper staff \nand procedures to minimize the administrative burden. The security staff is responsible not \nonly for maintaining the CSAMC policies, but also for creating and organizing appropriate \nexception rules and for monitoring user activity. You can organize the exception rules as \nfollows:\n•\nCreate a global exception policy to allow legitimate traffic and application behavior \nthat is required on all the systems within the organization. Subsequently, add these \nglobal exception rules to this exception policy.\n•\nCreate one exception policy for each group. \n•\nApply these policies to their respective groups and collect all necessary data to \ncomplete any additional tuning.\nThe following summarizes the steps that your security staff should use when deploying the \nagent kits throughout the organization:\nStep 1\nDeploy the CSA agents in test mode throughout your organization.\nStep 2\nCollect and analyze results. Subsequently, start policy tuning (as \nneeded).\nStep 3\nEnable protection mode.\nStep 4\nMake sure that your security, operations, and engineering staff members \nare comfortable with the support of your deployment.\nSummary\nIn most cases, data centers are equipped with surveillance cameras, biometric locks, \nauthorization-based access policies, strict security personnel, and other physical security \noptions. However, data centers that use such precautions, and are therefore prepared for \nphysical intrusions, often do not deploy the necessary technologies and tools to combat \ncyberattacks. A good balance between physical and network security is crucial. \nThis chapter covered several best practices to use when deploying Defense-in-Depth \nstrategies to secure the data center. It discussed several tools and mechanisms to help you \nprotect the data center against DoS, worms, and other security outbreaks. You learned \nseveral tips for segmenting your data center in a multilayered architecture. This chapter also \ncovered some tips for deploying network IDS/IPS solutions and CSA in the data center. \n"
        },
        {
            "page_number": 351,
            "text": "This chapter covers the following topics:\n•\nReconnaissance\n•\nFiltering in IPv6\n•\nSpoofing\n•\nHeader Manipulation and Fragmentation \n•\nBroadcast Amplification or Smurf Attacks\n•\nIPv6 Routing Security\n•\nIPsec in IPv6\n"
        },
        {
            "page_number": 352,
            "text": "C H A P T E R 11\nIPv6 Security\nInternet Protocol Version 6 (IPv6) is often called the next generation protocol and is \ndesigned to replace the widely deployed Internet Protocol Version 4 (IPv4). Despite that, \nIPv6 has only been implemented in a few places, but it is expected to grow over time. For \nexample, Microsoft Windows Vista includes support for IPv6. \nIPv6 enables easier support and maintenance of service provider networks than previous \nversions. The large address space improves the usage of online support systems and enables \nthe inexpensive provision of address space to end users. Many service providers in Europe, \nAsia, and the United States are currently working on providing IPv6 services to enterprises \nand small businesses. This chapter includes several IPv6 security topics. It also provides a \ncomparison with IPv4 from a threat and mitigation perspective.\nNOTE\nThis chapter requires a basic knowledge of the IPv6 protocol.\nIPv6 is defined in RFC 2460, “Internet Protocol, Version 6 (IPv6) Specification.” The \nfollowing are some of the main differences between IPv6 and IPv4: \n•\nExpanded addressing: The IP address size is increased in IPv6 to 128 bits from the \n32 bits supported in IPv4. This introduces considerable flexibility while supporting \nmore levels of addressing hierarchy. Multicast routing scalability is also improved by \nthe addition of a “scope” field to multicast addresses. \n•\nSimplified header format: Several of the header fields used in IPv4 are not used \nin IPv6. These fields include check sum, Internet header length (IHL), identification \nflag, and fragment offset.\n•\nImproved support for extensions and options: IPv6 encodes information into \nseparate headers.\n•\nFragmentation performed at the end hosts: Unlike IPv4 packets, routers do not \nperform packet fragmentation on IPv6 packets. IPv6 supports payloads that are longer \nthan 64 Kilobytes (KB).\n•\nAuthentication: IPv6 supports built-in authentication and confidentiality.\n"
        },
        {
            "page_number": 353,
            "text": "330\nChapter 11:  IPv6 Security\nTIP\nSeveral sites include good information about IPv6, including the following:\n• Cisco IPv6 information on IOS: http://www.cisco.com/go/ipv6\n• IPv6 Forum: http://www.ipv6forum.com\n• 6Net IPv6 International Research: http://www.6net.org\n• Internet2 IPv6 Working Group: http://ipv6.internet2.edu\nThe first thing you need to learn about IPv6 security is the different types of security threats \nthat may affect your IPv6 deployment. This chapter covers the most common types of \nthreats in IPv6 and other security topics, such as:\n•\nReconnaissance\n•\nFiltering in IPv6 \n•\nSpoofing\n•\nHeader manipulation and fragmentation \n•\nBroadcast amplification or smurf attacks\n•\nIPv6 routing security\n•\nIPsec and IPv6\nReconnaissance\nReconnaissance in IPv6 is not as easy to perform as in IPv4 networks. Do not forget that \nIPv6 has many more addresses than IPv4 (2^64 to be exact, or 128-bit addresses). \nPerforming a network scan for that many addresses is not feasible for an attacker because \nit takes a considerable amount of time to scan millions of addresses. \nAttackers use different techniques to gain more visibility of your network. Inevitably, many \nnetwork administrators may adopt addresses that are easy to remember to assign to network \ndevices (for example, ::10, ::20, ::F00D). Attackers may use these types of addresses in \nspecific scans or reconnaissance methodologies. Instead of standardizing on host addresses, \ntry something that is more difficult for attackers to guess. For example, you may want to \nuse something like ::DEE1 for default gateways. Some people refer to this technique as \nsecurity through obscurity. That technique can be beneficial, because it does not require \nadministrative complications. Standardizing on a short, fixed pattern for interfaces that \nshould not be directly accessed from the outside allows for a short filter list at the border \nrouters.\nBecause Domain Name System (DNS) is still used to map systems to IPv6 addresses on \nexternal and internal networks, an attacker can obtain information on your IPv6 network \naddresses if he compromises the DNS infrastructure/application. \n"
        },
        {
            "page_number": 354,
            "text": "Filtering in IPv6     331\nJust as for IPv4, it is recommended that you filter all IPv6 services at the perimeter router \nor firewall in an effort to protect the internal networks. \nPrivacy becomes a problem when you use DHCPv6 on an IPv6 network. An IPv6 address \nhas two parts. The first part is the subnet prefix, and the second part is a local identifier. This \nidentifier is typically derived from your MAC address. The subnet prefix is a fixed 64-bit \nlength for all current definitions. DHCP is not suitable for some IPv6 environments because \nyou can technically get an IPv6 address via DHCPv6 in your corporate network and then \nget the same address when you are at home or at a hotel. Attackers can track you down \nwith the use of web cookies that can retain your address information. That is why it is \nrecommended that you use IPv6 Privacy Extensions for external communication. \nRFC 3041 defines the use of IPv6 Privacy Extensions.\nFiltering in IPv6 \nFiltering of unauthorized access in IPv6 is similar to IPv4. This section includes examples \nof IPv6 access control lists (ACL), in addition to best practices when filtering ICMPv6 \nunnecessary packets and extension headers.\nFiltering Access Control Lists (ACL)\nYou can configure the filters or ACLs using Layer 3 and Layer 4 information. You can \nconfigure an IPv6 ACL in a Cisco IOS router using the ipv6 access-list command. The \ncommand uses the permit and deny subcommands with the following options:\nipv6 access-list command and its subcommands\npermit protocol {source-ipv6-prefix/prefix-length | any | host source-ipv6-address} \n[operator [port-number]] {destination-ipv6-prefix/prefix-length | any | host \ndestination-ipv6-address} [operator [port-number]] [dest-option-type [doh-number | \ndoh-type]] [dscp value] [flow-label value] [fragments] [log] [log-input] [mobility] \n[mobility-type [mh-number | mh-type]] [reflect name [timeout value]] [routing] \n[routing-type routing-number] [sequence value] [time-range name]\ndeny protocol {source-ipv6-prefix/prefix-length | any | host source-ipv6-address} \n[operator [port-number]] {destination-ipv6-prefix/prefix-length | any | host \ndestination-ipv6-address} [operator [port-number]] [dest-option-type [doh-number | \ndoh-type]] [dscp value] [flow-label value] [fragments] [log] [log-input] [mobility] \n[mobility-type [mh-number | mh-type]] [routing] [routing-type routing-number] \n[sequence value] [time-range name] [undetermined-transport]\nExample 11-1 shows an ACL in a Cisco IOS router allowing HTTP traffic (TCP port 80) \nfrom a trusted IPv6 host and denying all other traffic.\nExample 11-1 IPv6 Access Control List\nipv6 access-list outside_acl\n permit tcp 2001:1234:0300:0101::/32 any eq 80\ninterface FastEthernet 0/0\n ipv6 traffic-filter outside_acl in\n"
        },
        {
            "page_number": 355,
            "text": "332\nChapter 11:  IPv6 Security\nIn the previous example, the ACL name is outside_acl, and it is applied inbound to the \nFastEthernet 0/0 interface.\nNOTE\nStandard IPv6 ACLs are supported starting with Cisco IOS Version 12.2(2)T and \n12.0(21)ST and later.\nIn the Cisco ASA and Cisco PIX security appliances, the IPv6 ACLs are similar to IOS. \nTo create an IPv6 ACL to allow the same host to pass HTTP traffic on the Cisco ASA or \nCisco PIX, use the ipv6 access-list command, as shown in the following example:\nipv6 access-list asa_outside_acl permit tcp 2001:1234:0300:0101::/32 any eq www – \naccess-group asa_outside_acl in interface outside\nNotice that the IPv6 access list is applied to the outside interface using the access-group\ncommand just as for IPv4 access lists.\nNOTE\nIPv6 has been supported on the Cisco PIX since Version 7.0. The Cisco ASA supports IPv6 \nin all versions, because the first version of Cisco ASA software is 7.0.\nICMP Filtering\nYou may also want to filter unnecessary ICMPv6 messages, just as with ICMPv4. It is \nrecommended that you configure your ICMPv6 filters and policies in a manner that is \nsimilar to your ICMPv4 policies, with the following additions:\n•\nICMPv6 Type 2: Packet too big\n•\nICMPv6 Type 4: Parameter problem\n•\nICMPv6 Type 130-132: Multicast listener\n•\nICMPv6 Type 133/134: Router solicitation and router advertisement\n•\nICMPv6 Type 135/136: Neighbor solicitation and neighbor advertisement \nMake sure that, if you need to allow these options, you only allow trusted sources and deny \neverything else. \nExtension Headers in IPv6\nIn IPv6, IP options are replaced with extension headers. An attacker may use these \nextension headers to evade your security configuration. All devices running IPv6 must \naccept packets with a routing header. In some cases, it may be possible for end-host devices \n"
        },
        {
            "page_number": 356,
            "text": "Header Manipulation and Fragmentation     333\nto also process routing headers and forward the packet somewhere else. Attackers can \ntake advantage of this and use routing headers to evade the ACLs configured on your \nrouters and firewalls.\nAs a best practice, you should designate specific devices that are allowed to act as Mobile \nIPv6 (MIPv6) home agents. MIPv6 is a protocol developed as a subset of IPv6 to support \nmobile connections. You should typically only assign the default router for a specific subnet \nto act as an MIPv6 home agent. If MIPv6 is not needed, packets with the routing header can \neasily be dropped at your firewalls and routers without relying on the end host not to \nforward the packets. \nSpoofing\nOne of the most common techniques that attackers use is spoofing. Spoofing is the \ntechnique of modifying your source IP address or the ports to appear as your packets are \ninitiated from another location. From a Layer 3 spoofing perspective, IPv6 presents a huge \nbenefit because the allocations of IPv6 addresses are designed to easily be summarized \nallowing service providers to at least ensure that their own customers are not using \naddresses outside their allocated range. You can use filtering techniques such as those \ndefined in RFC 2827. \nThe following are the most common best practices suggested to protect against IPv6 Layer 3 \nand Layer 4 spoofing:\n•\nImplement filtering techniques as defined in RFC 2827. In Chapter 2, “Preparation \nPhase,” you learned how to create antispoofing ACLs for your IPv4. You should do \nthe same for your IPv6 addresses by denying all traffic from your own network range \nto be sourced from outside your networks. \n•\nIn an IPv6 subnet, an attacker has numerous options to select an IP address to spoof. \nIt is critical to have tools to determine the true physical source of the traffic within \nyour network. This generally entails some combination of Layer 2 and Layer 3 \ninformation gleaned from switches and routers.\nHeader Manipulation and Fragmentation \nIPv6 is susceptible to fragmentation and other header manipulation attacks. With these \ntypes of attacks, the attacker uses fragmentation to evade network intrusion detection \nsystems (IDS), intrusion prevention systems (IPS), and firewalls. \nAn attacker can also use out-of-order fragments to try to avoid an IDS/IPS device that is \ndeployed to detect attacks based on the enabled signatures on the system. RFC 2460 \nprohibits fragmentation of IPv6 packets by intermediary network devices. \n"
        },
        {
            "page_number": 357,
            "text": "334\nChapter 11:  IPv6 Security\nAs is the case with IPv4, you should always deny IPv6 fragments destined to an \ninternetworking device whenever possible. On the other hand, you should test this in the \nlab and make sure that this does not cause problems with specific applications in your \nparticular network environment.\nThe combination of multiple extension headers and fragmentation in IPv6 creates the \npotential that the Layer 4 protocol will not be included in the first packet of a fragment set. \nMake sure that your IDS/IPS system or any other security monitoring device accounts for \nthis possibility and reassembles fragments. Today, Cisco IPS/IDS devices support multiple \nextension headers and fragmentation.\nBroadcast Amplification or Smurf Attacks\nBroadcast amplification attacks are typically referred to as smurf attacks. These are denial \nof service (DoS) attacks where the attacker sends an echo-request message with a \ndestination address of a subnet broadcast and a spoofed source address using the host IP \naddress of the victim. This causes all the devices on the subnet to respond to the spoofed \nsource IP address and flood the victim with echo-reply messages. RFC 2463 prohibits \nIP-directed broadcasts within IPv6. In addition, it states that an ICMPv6 message should \nnot be generated as a response to a packet with an IPv6 multicast destination address, a \nlink-layer multicast address, or a link-layer broadcast address. \nSmurf attacks should not be a threat if all the devices within your network are compliant \nwith RFC 2463. On the other hand, you should always implement ingress filtering of \npackets with IPv6 multicast source addresses. \nIPv6 Routing Security\nSome routing protocols change in respect to security in IPv6; however; others do not. This \nsection lists the routing protocols that change as well as those that remain the same. \nBorder Gateway Protocol (BGP) continues to have authentication mechanisms such as \nMD5 authentication but what, if anything, changes with IPv6? The Intermediate \nSystem-to-Intermediate System (IS-IS) protocol was extended in a draft specification to \nsupport IPv6. In IPv4, the simple password authentication of IS-IS was not encrypted. \nHowever, RFC 3567 defines the IS-IS cryptographic authentication. IS-IS in IPv6 also \nsupports this cryptographic authentication mechanism. \nThe Open Shortest Path First Version 3 (OSPFv3) protocol changed to support IPv6. The \nauthentication fields were removed from the header of OSPF messages/packets. Another \nprotocol that removed authentication capabilities was the Routing Information Protocol \nNext-Generation (RIPng). For this reason, it is recommended that you use traditional \n"
        },
        {
            "page_number": 358,
            "text": "IPsec and IPv6\n335\nauthentication mechanisms for BGP and IS-IS. OSPF for IPv6 requires the use of IPsec to \nenable authentication. It is always a best practice to use OSPF in conjunction with IPsec to \nsecure routing protocol updates in OSPF for IPv6.\nNOTE\nCisco IOS routers support the use of IPv6 IPsec to authenticate OSPFv3 starting with \nVersions 12.3(4)T, 12.4, and later.\nIPsec and IPv6\nIPsec is available with IPv6. IPv6 headers have no security mechanisms themselves, just as \nin IPv4. Administrators rely on the IPsec protocol suite for security. The same security risks \nfor man-in-the-middle attacks in Internet Key Exchange (IKE) in IPv4 are present in IPv6. \nMost people recommend using IKE main mode negotiations when the use of preshared \nkeys is required. On the other hand, IKE Version 2 (IKEv2) is expected to address this issue \nin the future. IKEv2 supports different peer authentication options with built-in support for \nasymmetric user authentication through the Extensible Authentication Protocol (EAP).\nThe IPv6 IPsec packet format is basically the same as in IPv4. Figure 11-1 illustrates an \nIPv6 packet where Authentication Header (AH) and Encapsulation Security Payload (ESP) \nprotocols are used. IPv6 AH and ESP extension headers are used to provide authentication \nand confidentiality to IPv6 packets.\nFigure 11-1 IPv6 IPsec Packet\nCisco IOS supports IPv6 IPsec for VPN tunnels starting with IOS Version 12.4(4)T. \nFigure 11-2 illustrates a topology where two Cisco IOS routers are configured to terminate \na site-to-site IPv6 IPsec tunnel. The IPv6 address of the router in New York is \n2EEE:1001::DCBA:BBAA:DDCC:4321, and the IPv6 address of the router in London is \n2EEE:2002::ABCD:AABB:CCDD:1234.\nIPv6\nHeader\nAH\nHeader\nESP\nHeader\nIPv6\nHeader\nPayload\nESP Encrypted\nESP HMAC Authenticated\nAH Authenticated\nPadding\nESP\nAuth\n"
        },
        {
            "page_number": 359,
            "text": "336\nChapter 11:  IPv6 Security\nFigure 11-2 IPv6 IPsec Configuration Example\nVirtual tunnel interfaces (VTI) are configured on each router in this example. \nExample 11-2 shows the configuration of the router in New York. Notice that the \nconfiguration is almost identical to the IPv4 VTI implementation. In this example, routers \nuse preshared keys with SHA for hashing, and Diffie-Hellman group 1 for Phase 1. \nAH-SHA-HMAC and ESP-3DES are used for Phase 2.\nExample 11-3 shows the configuration of the router in London. Notice that the \nconfiguration is almost identical for the exception of the IP addresses. \nExample 11-2 New York Router Configuration\ncrypto isakmp policy 1\n  authentication pre-share\n!\ncrypto isakmp key 1qaz2wsx address ipv6 2EEE:2002::ABCD:AABB:CCDD:1234/128\n!\ncrypto ipsec transform-set 3des ah-sha-hmac esp-3des \n!\n!\ncrypto ipsec profile myprofile\n  set transform-set 3des \n!\nipv6 cef\n!\ninterface Tunnel0\n  ipv6 address 2EEE:1001::/64 eui-64\n  ipv6 enable\n  ipv6 cef\n  tunnel source FastEthernet0\n  tunnel destination 2EEE:2002::ABCD:AABB:CCDD:1234\n  tunnel mode ipsec ipv6\n  tunnel protection ipsec profile myprofile\n2EEE:1001::DCBA:BBAA:DDCC:4321\n2EEE:2002::ABCD:AABB:CCDD:1234\nNew York\nLondon\nIPsec Tunnel\nInternet\n"
        },
        {
            "page_number": 360,
            "text": "Summary     337\nThe IKE and IPsec Security Associations (SA) are negotiated and established before the \nline protocol for the tunnel interface is changed to the UP state. The remote IKE peer is \nthe same as the tunnel destination address; the local IKE peer will be the address picked \nfrom the tunnel source interface, which has the same IPv6 address scope as the tunnel \ndestination address.\nSummary\nThis chapter introduced security topics in IPv6. Although it is assumed that you already \nhave a basic understanding on IPv6, this chapter covered fundamental topics of IPv6 \nincluding how to filter IPv6 traffic in infrastructure devices such as the Cisco ASA and \nCisco IOS routers. When deploying IPv6 on your network, you should pay attention to \nseveral security considerations. These considerations include the use of authorization for \nautomatically assigned addresses and configurations, protection of IP packets, host \nprotection from scanning and attacks, and control of traffic that is exchanged with the \nInternet. In many cases, these security considerations also exist for IPv4 traffic. \nUnderstanding the IPv6 security threats is a must for every security professional. This \nchapter included the most common IPv6 security threats and the best practices adopted by \nmany organizations to protect their IPv6 infrastructure. \nMany IPv6-enabled devices also support IPsec. This chapter covered how to configure \nCisco IOS routers to terminate IPsec in IPv6 networks. It provided sample configurations \nto enhance the learning.\nExample 11-3 London Router Configuration\ncrypto isakmp policy 1\n  authentication pre-share\n!\n!\ncrypto isakmp key 1qaz2wsx address ipv6 2EEE:1001::DCBA:BBAA:DDCC:4321/128\n!\ncrypto ipsec transform-set 3des ah-sha-hmac esp-3des \n!\ncrypto ipsec profile myprofile\n  set transform-set 3des \n!\nipv6 cef\n!\ninterface Tunnel0\n  ipv6 address 2EEE:2002::/64 eui-64 – \n  ipv6 enable\n  ipv6 cef\n  tunnel source FastEthernet0\n  tunnel destination 2EEE:1001::DCBA:BBAA:DDCC:4321\n  tunnel mode ipsec ipv6\n  tunnel protection ipsec profile myprofile\n"
        },
        {
            "page_number": 361,
            "text": ""
        },
        {
            "page_number": 362,
            "text": "P A R T IV\nCase Studies \nChapter 12\n Case Studies \n"
        },
        {
            "page_number": 363,
            "text": "This chapter covers the following topics:\n•\nCase Study of a Small Business\n•\nCase Study of a Medium-Sized Enterprise\n•\nCase Study of a Large Enterprise\n"
        },
        {
            "page_number": 364,
            "text": "C H A P T E R 12\nCase Studies\nHaving Defense-in-Depth mechanisms and tools in place is important to any organization \nregardless of its size. This chapter includes three different case studies explaining how a \nsmall (Company-A), medium (Company-B), and large enterprise (Company-C) apply the \nbest practices learned in all previous chapters. These case studies provide you with an \nin-depth and objective analysis of security technologies and techniques applied in different \nenvironments. The intent is to help you identify and implement practical security strategies \nthat are both flexible and scalable.\n Case Study of a Small Business\nThis section uses Company-A as an example. Company-A is a small web development \ncompany based in Raleigh, North Carolina. Its office in Raleigh hosts 35 employees. The \nuser population is composed of sales, marketing, finance personnel, and several web \ndevelopers. Figure 12-1 illustrates the network architecture and topology of the Raleigh \noffice of Company-A.\nThe Raleigh office has a simple network architecture. Client workstations are connected to \nan access switch and then connected to the Cisco Adaptive Security Appliance (ASA) \ninside interface. The Cisco ASA outside interface connects directly to a router provided \nby the Internet service provider (ISP) of Company-A. The ISP completely manages this \nrouter; Company-A has no control over it. A third interface on the Cisco ASA hosts a \ndemilitarized zone (DMZ) hosting several servers. These servers include web, e-mail, and \nFTP applications.\n"
        },
        {
            "page_number": 365,
            "text": "342\nChapter 12:  Case Studies\nFigure 12-1 Raleigh Office of Company-A\nBecause this is a simple topology, all security policies are enforced in the Cisco ASA. The goal \nis to protect the internal and DMZ hosts from external threats, while allowing the following:\n•\nClient workstations must be able to access the web server at the DMZ (10.10.20.10) \nover HTTP and HTTPS. Clients should also be able to put and get files via FTP to the \nsame server at 10.10.20.10.\n•\nClient workstations must be able to access the Internet over HTTP and HTTPS. No \nother protocol access is allowed to the Internet.\n•\nClient workstations must be able to check their e-mail on the e-mail server at the \nDMZ (10.10.20.20).\n•\nThe web server should be reachable from outside Internet clients over HTTP and \nHTTPS only. The Cisco ASA should do static Network Address Translation (NAT) for \nthe web server to be reachable via a public IP address from the Internet.\nInternet\nClient Workstations\nInside\n10.10.10.1\nOutside\n209.165.200.225\nASA\nManagement 10.10.30.1\nDMZ\n10.10.20.1\nWeb/FTP\n.10\nEmail\n.20\nCompany-A\nRaleigh Office\nISP Router\n"
        },
        {
            "page_number": 366,
            "text": "Case Study of a Small Business\n343\n•\nThe e-mail server should be able to receive e-mail from external hosts over the \nSimple Mail Transfer Protocol (SMTP). The Cisco ASA should do static NAT for the \ne-mail server to be reachable via a public IP address from the Internet.\n•\nThe client workstations will be translated to the external public IP address of the \nCisco ASA using Port Address Translation (PAT).\nRaleigh Office Cisco ASA Configuration\nThe following sections cover the steps necessary to complete the goals listed earlier.\nConfiguring IP Addressing and Routing\nThis section demonstrates how to configure the interfaces and default gateway on the Cisco \nASA using the Adaptive Security Device Manager (ASDM). The following are the \nconfiguration steps:\nStep 1\nWorking with a new Cisco ASA installation, the administrator logs in via \nthe command-line interface (CLI) and sets the management interface \nIP address (10.10.30.1) and other interface configuration with the \nfollowing commands.\nCo-A-ASA1# configure terminal\nCo-A-ASA1(config)# interface Management0/0\nCo-A-ASA1(config-if)# nameif management\nCo-A-ASA1(config-if)# security-level 80 \nCo-A-ASA1(config-if)# ip address 10.10.30.1 255.255.255.0\nCo-A-ASA1(config-if)# no shutdown\nCo-A-ASA1(config-if)# exit\nCo-A-ASA1(config)#\nStep 2\nThe administrator enables ASDM access only from machines on the \nmanagement network with the following commands:\nCo-A-ASA1(config)# http server enable\nCo-A-ASA1(config)# http 10.10.30.0 255.255.255.0 management\nCo-A-ASA1(config)# asdm location 10.10.30.0 255.255.255.0 management\nStep 3\nThe next step is to configure the outside, inside, and DMZ interfaces. The \nadministrator connects to the Cisco ASA via ASDM and clicks \nConfiguration > Device Setup > Interfaces, as illustrated on Figure 12-2.\nStep 4\nThe administrator selects the GigabitEthernet0/0 interface and clicks \nthe Edit button. The screen illustrated in Figure 12-3 is shown. The \nadministrator enters the interface name (outside), the IP address \nconfiguration (209.165.200.225), subnet mask (255.255.255.0), and a \ndescription for the outside interface.\n"
        },
        {
            "page_number": 367,
            "text": "344\nChapter 12:  Case Studies\nFigure 12-2 Configuring the Cisco ASA Interfaces on ASDM\nFigure 12-3 Outside Interface Configuration\n"
        },
        {
            "page_number": 368,
            "text": "Case Study of a Small Business\n345\nStep 5\nSimilarly, the GigabitEthernet0/1 interface is configured as the inside \ninterface, as shown in Figure 12-4. The security level for the inside \ninterface is set to 100.\nFigure 12-4 Inside Interface Configuration\nStep 6\nThe GigabitEthernet0/2 interface is configured as the dmz interface, as \nshown in Figure 12-5. The security level of the dmz interface is set to 50.\nStep 7\nThe next step is to configure the default route of the Cisco ASA to point \nto the ISP router (209.165.200.226). To configure the default route, \nnavigate to Configuration > Device Setup > Routing > Static Routes\nand click Add. The screen shown in Figure 12-6 is displayed. Choose the \noutside interface from the drop-down menu, and enter 0.0.0.0 for the IP \naddress and 0.0.0.0 for the Mask. The Gateway IP is 209.165.200.226,\nand the metric is 1. Leave all the other options with their default value.\n"
        },
        {
            "page_number": 369,
            "text": "346\nChapter 12:  Case Studies\nFigure 12-5 DMZ Interface Configuration\nFigure 12-6 Inside Interface Configuration\n"
        },
        {
            "page_number": 370,
            "text": "Case Study of a Small Business\n347\nConfiguring PAT on the Cisco ASA\nThe next step is to configure PAT for internal users to be able to communicate to the \nInternet. Complete the following steps to configure PAT on the Cisco ASA.\nStep 1\nTo configure PAT, go to Configuration > Firewall > NAT Rules, click \nAdd, and choose Add Dynamic NAT Rule from the drop-down menu, \nas illustrated in Figure 12-7. \nFigure 12-7 Configuring PAT for Internal Users\nStep 2\nThe screen shown in Figure 12-8 is displayed. Under the Original\nsection, choose the inside interface from the drop-down menu.\nStep 3\nExpand the Source option to select the inside source address space. This \nis illustrated in Figure 12-9. Select the inside network (10.10.10.0/24)\nand click OK.\n"
        },
        {
            "page_number": 371,
            "text": "348\nChapter 12:  Case Studies\nFigure 12-8 Adding a Dynamic NAT Rule\nFigure 12-9 Selecting the Source\n"
        },
        {
            "page_number": 372,
            "text": "Case Study of a Small Business\n349\nStep 4\nUnder the Translated section, click the Manage button to add a global \naddress pool.\nStep 5\nThe screen shown in Figure 12-10 is displayed. Under the IP Addresses \nto Add section, click Port Address Translation (PAT) using IP \nAddress of the interface and click the Add button to include it under the \nAddress pools, as shown in Figure 12-10.\nFigure 12-10 Configuring PAT to Use the Outside Interface Address\nStep 6\nClick OK and apply your changes to the Cisco ASA.\nConfiguring Static NAT for the DMZ Servers\nThe DMZ servers must be statically translated with a public IP address. Table 12-1 lists the \nIP address mapping of the DMZ servers.\nComplete the following steps to configure static NAT for the DMZ web and e-mail servers.\nStep 1\nNavigate to Configuration > Firewall > NAT Rules, click Add, and \nchoose Add Static NAT Rule from the drop-down menu, as illustrated \nin Figure 12-11.\nTable 12-1\nIP Address Mapping of DMZ Servers\nServer\nInside IP Address\nTranslated Address\nWeb server\n10.10.20.10\n209.165.200.227\nE-mail server\n10.10.20.20\n209.165.200.228\n"
        },
        {
            "page_number": 373,
            "text": "350\nChapter 12:  Case Studies\nFigure 12-11 Adding a Static NAT Rule\nStep 2\nThe screen shown in Figure 12-12 is displayed. First configure static \nNAT for the web server. Under the Original section, choose the dmz\ninterface from the drop-down menu, and enter the web server physical IP \naddress (10.10.20.10) as the source.\nFigure 12-12 Adding a Static NAT Rule\n"
        },
        {
            "page_number": 374,
            "text": "Case Study of a Small Business\n351\nStep 3\nUnder the Translated section, choose the outside interface from the \ndrop-down menu.\nStep 4\nClick the Use IP address option, and enter the public address to which \nthe web server will be translated (209.165.200.227).\nStep 5\nClick OK.\nStep 6\nRepeat the same procedure for the e-mail server.\nConfiguring Identity NAT for Inside Users\nThe inside users must be able to communicate with the DMZ servers. The goal is to \nconfigure identity NAT for inside users when communicating to the DMZ servers. \nComplete the following steps to configure identity NAT for inside users.\nStep 1\nNavigate to Configuration > Firewall > NAT Rules, click Add, as \nillustrated in Figure 12-13.\nFigure 12-13 Configuring Identity NAT for the Inside Network on the DMZ\nStep 2\nUnder the Original section, choose the inside interface from the drop-\ndown menu, and the inside network as the source (10.10.10.0/24).\nStep 3\nUnder the Translated section, choose the dmz interface from the \ndrop-down menu, and select the same inside network (10.10.10.0/24) as \nthe translated IP address, as shown in Figure 12-13.\n"
        },
        {
            "page_number": 375,
            "text": "352\nChapter 12:  Case Studies\nStep 4\nClick OK.\nStep 5\nApply the changes to the Cisco ASA.\nControlling Access\nNext, you need to configure policies on the Cisco ASA to control access and achieve the \nfollowing goals.\n•\nThe web server should be reachable from outside Internet clients over the HTTP and \nHTTPS protocols only. \n•\nThe e-mail server should be able to receive e-mail from external hosts over the SMTP \nonly.\nComplete the following steps to configure access rules on the Cisco ASA.\nStep 1\nNavigate to Configuration > Firewall > Access Rules, click Add. In\nFigure 12-14 the Access Rule configuration is displayed.\nFigure 12-14 Configuring Access Rules \nStep 2\nFirst, the access rule to allow Internet users to reach the web server at the \nDMZ is configured. Under Action, click Permit.\nStep 3\nUnder source, select any.\n"
        },
        {
            "page_number": 376,
            "text": "Case Study of a Small Business\n353\nStep 4\nUnder destination, enter the IP address of the web server \n209.165.200.227.\nStep 5\nSelect HTTP (TCP/HTTP) under the service.\nStep 6\nOptionally, you can enter a description for this access rule, as illustrated \nin Figure 12-14.\nStep 7\nClick OK.\nStep 8\nRepeat the same steps to allow HTTPS (TCP port 443) access to the web \nserver and SMTP (TCP port 25) access to the e-mail server.\nCisco ASA Antispoofing Configuration\nThe Company-A security administrator wants to protect the infrastructure from spoofed \nsources. The administrator enables Unicast Reverse Path Forwarding (Unicast RPF) to \nprotect against IP spoofing attacks by ensuring that all packets have a source IP address that \nmatches the correct source interface according to the routing table. To enable Unicast RPF, \nnavigate to Configuration > Firewall > Advanced > Anti-spoofing. Select the desired \ninterface, and click Enable, as illustrated in Figure 12-15.\nFigure 12-15 Configuring Unicast RPF\n"
        },
        {
            "page_number": 377,
            "text": "354\nChapter 12:  Case Studies\nBlocking Instant Messaging\nThe security administrator is now tasked by his management to come up with a solution to \nprevent internal users from using Yahoo! and MSN instant messaging (IM) programs. The \nsolution is to configure the Cisco ASA to block this traffic and log it. The security \nadministrator completes the following steps to achieve this goal.\nStep 1\nThe first step is to configure an inspect map on the Cisco ASA. To do \nthis, navigate to Configuration > Firewall > Objects > Inspect Maps > \nInstant Messaging (IM).\nStep 2\nClick Add.\nStep 3\nThe Add Instant Messaging (IM) Inspect screen is displayed.\nStep 4\nEnter a name and an optional description for the new inspect map \nconfiguration. In this example, the inspect map name is IM.\nStep 5\nClick Add to add a new inspection criterion.\nStep 6\nThe screen is shown in Figure 12-16 is displayed.\nFigure 12-16 Adding an Instant Messaging Inspect Map\nStep 7\nUnder Match Criteria, click Single Match.\nStep 8\nUnder Match Type, click Match.\nStep 9\nUnder Criterion, select Protocol.\nStep 10 Check both protocols (Yahoo! Messenger and MSN Messenger).\n"
        },
        {
            "page_number": 378,
            "text": "Case Study of a Small Business\n355\nStep 11 Under the Actions sections, leave the default of Drop Connection and \nLog enabled. \nStep 12 Click OK.\nStep 13 Navigate to Configuration > Firewall > Service Policy Rules and click \nAdd. The first screen of the Configuration Wizard is displayed, as \nillustrated in Figure 12-17.\nFigure 12-17 Adding a New Service Policy Rule\nStep 14 In this example, the service policy will be applied only to the inside \ninterface. To do this, click Interface under the Create a Service Policy \nand Apply To section.\nStep 15 Select the inside interface, and enter a name, as shown in \nFigure 12-17.\nStep 16 Click Next.\nStep 17 The Traffic Classification Criteria screen is displayed, as shown in \nFigure 12-18. Click Use class-default as the traffic class.\nStep 18 Click Next.\n"
        },
        {
            "page_number": 379,
            "text": "356\nChapter 12:  Case Studies\nFigure 12-18 Traffic Classification Criteria Screen\nStep 19 The Rule Actions screen is shown, as illustrated in Figure 12-19.\nFigure 12-19 Rule Actions Screen\n"
        },
        {
            "page_number": 380,
            "text": "Case Study of a Small Business\n357\nStep 20 Under the Protocol Inspection tab, check IM and click Configure.\nStep 21 Select the previously configured inspection map (IM).\nStep 22 Click OK on the Select IM Inspect Map screen.\nStep 23 Click Finish to end the wizard.\nStep 24 Apply the configuration to the Cisco ASA.\nExample 12-1 shows the Cisco ASA CLI configuration for Company-A.\nExample 12-1\nCLI Configuration of the Cisco ASA at the Raleigh Office \nCo-A-ASA1# show running-config\n: Saved\n:\nASA Version 8.0(1)\n!\nhostname Co-A-ASA1\nenable password 8Ry2YjIyt7RRXU24 encrypted\nnames\n!\n!outside interface configuration\ninterface GigabitEthernet0/0\n description outside interface connected to the Internet\n nameif outside\n security-level 0\n ip address 209.165.200.225 255.255.255.0\n!\n!inside interface configuration\ninterface GigabitEthernet0/1\n description inside interface connected to corporate network\n nameif inside\n security-level 100\n ip address 10.10.10.1 255.255.255.0\n!\n!dmz interface configuration\ninterface GigabitEthernet0/2\n description dmz interface where web, email, and FTP servers reside\n nameif dmz\n security-level 50\n ip address 10.10.20.1 255.255.255.0\n!\ninterface GigabitEthernet0/3\n shutdown\n no nameif\n no security-level\n no ip address\n!\n!management interface configuration\ninterface Management0/0\n nameif management\n security-level 80\ncontinues\n"
        },
        {
            "page_number": 381,
            "text": "358\nChapter 12:  Case Studies\n ip address 10.10.30.1 255.255.255.0\n!\n!ACL controlling access to the web and e-mail server\naccess-list outside_access_in extended permit tcp any host 209.165.200.228 eq smtp\naccess-list outside_access_in_ remark Allowing HTTP to the webserver \naccess-list outside_access_in_ extended permit tcp any host 209.165.200.227 eq www\naccess-list outside_access_in_ remark Allowing HTTPS to the webserver\naccess-list outside_access_in_ extended permit tcp any host 209.165.200.227 eq https\naccess-list outside_access_in_ remark Allowing SMTP to the email server \naccess-list outside_access_in_1 extended permit tcp any host 209.165.200.228 eq smtp\n!\npager lines 24\nmtu outside 1500\nmtu inside 1500\nmtu dmz 1500\nmtu management 1500\n!\n!Unicast RPF Configuration\nip verify reverse-path interface outside\nip verify reverse-path interface inside\nip verify reverse-path interface dmz\n!\nno failover\nicmp unreachable rate-limit 1 burst-size 1\nno asdm history enable\narp timeout 14400\n!\n!PAT Configuration for inside users\nnat-control\nglobal (outside) 1 interface\nnat (inside) 1 10.10.10.0 255.255.255.0\n!\n!Static NAT configuration for web and e-mail servers\nstatic (dmz,outside) 209.165.200.227 10.10.20.10 netmask 255.255.255.255\nstatic (dmz,outside) 209.165.200.228 10.10.20.20 netmask 255.255.255.255\n!\n!Static identity NAT configuration for inside network at the DMZ\nstatic (inside,dmz) 10.10.10.0 10.10.10.0 netmask 255.255.255.0\n!\n!ACL is applied to the outside interface\naccess-group outside_access_in_1 in interface outside\nroute outside 0.0.0.0 0.0.0.0 209.165.200.226 1\ntimeout xlate 3:00:00\ntimeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 icmp 0:00:02\ntimeout sunrpc 0:10:00 h323 0:05:00 h225 1:00:00 mgcp 0:05:00 mgcp-pat 0:05:00\ntimeout sip 0:30:00 sip_media 0:02:00 sip-invite 0:03:00 sip-disconnect 0:02:00\ntimeout uauth 0:05:00 absolute\ndynamic-access-policy-record DfltAccessPolicy\nhttp server enable\nhttp 10.10.30.0 255.255.255.0 management\nno snmp-server location\nno snmp-server contact\nExample 12-1\nCLI Configuration of the Cisco ASA at the Raleigh Office (Continued)\n"
        },
        {
            "page_number": 382,
            "text": "Case Study of a Small Business\n359\nsnmp-server enable traps snmp authentication linkup linkdown coldstart\nno crypto isakmp nat-traversal\ntelnet timeout 5\nssh 10.10.30.0 255.255.255.0 management\nssh timeout 5\nconsole timeout 0\nthreat-detection basic-threat\nthreat-detection statistics access-list\n!\nclass-map inspection_default\n match default-inspection-traffic\n!\n!\npolicy-map type inspect dns preset_dns_map\n parameters\n  message-length maximum 512\n!\n!policy map to block Yahoo! and MSN IM.\npolicy-map type inspect im IM\n description Blocking Instant Messanging\n parameters\n match protocol msn-im yahoo-im\n  drop-connection log\npolicy-map global_policy\n class inspection_default\n  inspect dns preset_dns_map\n  inspect ftp\n  inspect h323 h225\n  inspect h323 ras\n  inspect netbios\n  inspect rsh\n  inspect rtsp\n  inspect skinny\n  inspect esmtp\n  inspect sqlnet\n  inspect sunrpc\n  inspect tftp\n  inspect sip\n  inspect xdmcp\n!\n!Service policy map to block IM\npolicy-map inside-policy\n description Service Policy to block IM for Inside Users\n class class-default\n  inspect im IM\n!\n!global service policy\nservice-policy global_policy global\n!\n!service policy for IM applied to the inside interface only\nservice-policy inside-policy interface inside\nExample 12-1\nCLI Configuration of the Cisco ASA at the Raleigh Office (Continued)\n"
        },
        {
            "page_number": 383,
            "text": "360\nChapter 12:  Case Studies\nAtlanta Office Cisco IOS Configuration\nCompany-A opened a small branch office in Atlanta, Georgia. This new office has only \n4 salesmen and 12 web developers. The Atlanta office network topology is simple. \nA Cisco IOS Software router with the IOS Firewall features set is configured to protect the \ninternal network. This is illustrated in Figure 12-20.\nFigure 12-20 Atlanta Office Network Topology\nThe router has only two interfaces enabled. The inside interface resides on the 10.100.10.0/\n24 network, and the outside interface faces the Internet.\nLocking Down the Cisco IOS Router\nThe security administrator at Company-A must configure the router appropriately to \nincrease the security of the Atlanta office network. The administrator uses the Security \nDevice Manager (SDM) to configure the router and perform a security audit. Using SDM, \nthe administrator can configure the router quickly using the best practices recommended \nin Chapter 2, “Preparation Phase.”\nInternet\nClient Workstations\nOutside\n209.165.200.231\nInside\n10.100.10.1\nRouter with\nIOS Firewall\nCompany-A\nAtlanta Office\n"
        },
        {
            "page_number": 384,
            "text": "Case Study of a Small Business\n361\nYou can complete the following steps to perform a security audit and fix any discrepancies \nfound on the Cisco IOS router.\nStep 1\nLog in to the Cisco IOS router using SDM.\nStep 2\nNavigate to Configure > Security Audit, and click the Perform security \naudit button, as illustrated in Figure 12-21. Alternatively, you can \nperform a one-step lockdown to configure default recommendations by \nclicking the One-step lockdown button. In this example, the \nstep-by-step option is selected, which allows you to customize your \nconfiguration.\nFigure 12-21 Performing a Security Audit with SDM\nStep 3\nThe Security Audit Wizard welcome screen shown in Figure 12-22 is \ndisplayed.\nStep 4\nClick Next.\nStep 5\nThe Security Audit Interface Configuration screen shown in \nFigure 12-23 is displayed. In this example, a Cisco 871 router is used. \nThe outside interface is FastEthernet4, and the inside interface is \nVlan 1.\n"
        },
        {
            "page_number": 385,
            "text": "362\nChapter 12:  Case Studies\nFigure 12-22 Security Audit Wizard Welcome Screen\nFigure 12-23 Security Audit Wizard Interface Configuration Screen\n"
        },
        {
            "page_number": 386,
            "text": "Case Study of a Small Business\n363\nStep 6\nClick Next.\nStep 7\nSDM performs the audit to make sure that the recommended settings are \nconfigured on the router. As illustrated in Figure 12-24, the router fails \non numerous items.\nFigure 12-24 Security Audit Wizard Interface Configuration Screen\nSDM allows you to save a report that lists all the configuration \nchecks that have passed or failed. The report is illustrated in \nFigure 12-25.\n"
        },
        {
            "page_number": 387,
            "text": "364\nChapter 12:  Case Studies\nFigure 12-25 Security Audit Report\nStep 8\nSDM asks you to enter a new enable secret password and to configure a \nlogin banner, as illustrated in Figure 12-26.\nStep 9\nAfter you enter the new enable secret password and login banner, click \nNext.\nStep 10 SDM allows you to configure an administrative account, as shown in \nFigure 12-27. To configure a new account, click Add.\n"
        },
        {
            "page_number": 388,
            "text": "Case Study of a Small Business\n365\nFigure 12-26 Configuring a New Enable Secret Password and Login Banner\nFigure 12-27 Creating an Administrative Account\n"
        },
        {
            "page_number": 389,
            "text": "366\nChapter 12:  Case Studies\nStep 11 Enter the username and password, as shown in Figure 12-27. In this \nexample, a user named companyAadmin is created. \nStep 12 Click OK after entering the username and password.\nStep 13 Click Next to continue with the Security Audit Wizard.\nStep 14 In the next screen, SDM allows you to enable logging and configure a \nsystem log (SYSLOG) server, as illustrated in Figure 12-28. \nFigure 12-28 Configuring Logging\nStep 15 In this example, the logging level is set to informational (level 6), and \nthe SYSLOG server IP address is 10.100.10.222.\nStep 16 Click Next.\nStep 17 The Advanced Firewall Configuration Wizard welcome screen is \ndisplayed, as shown in Figure 12-29.\nStep 18 Click Next.\nStep 19 Check the inside and outside interfaces. In this example, FastEthernet4\nis the outside interface, and Vlan1 is the inside interface. This is \nillustrated in Figure 12-30.\n"
        },
        {
            "page_number": 390,
            "text": "Case Study of a Small Business\n367\nFigure 12-29 Advanced Firewall Configuration Wizard Welcome Screen\nFigure 12-30 IOS Firewall Inside and Outside Interface Selection\nStep 20 Click Next.\n"
        },
        {
            "page_number": 391,
            "text": "368\nChapter 12:  Case Studies\nStep 21 The screen shown in Figure 12-31 is displayed. In this screen, SDM \nallows you to enable predefined application security policies. You can use \nthe slider to select the security level. In this example, the security level is \nset to High.\nFigure 12-31 Application Security Policies\nStep 22 Click Next.\nStep 23 The SDM Wizard allows you enter the primary and secondary DNS \nservers for name resolution, as illustrated in Figure 12-32. In this \nexample, the primary DNS server is 10.100.10.21, and the secondary \nDNS server is 10.100.10.22.\nStep 24 Click Next after entering the DNS server information.\nStep 25 A summary screen lists the configuration changes, as illustrated in \nFigure 12-33. Click Finish to send the configuration changes to the Cisco \nIOS router.\n"
        },
        {
            "page_number": 392,
            "text": "Case Study of a Small Business\n369\nFigure 12-32 DNS Server Configuration\nFigure 12-33 Security Audit Wizard Summary Screen \n"
        },
        {
            "page_number": 393,
            "text": "370\nChapter 12:  Case Studies\nExample 12-2 shows the CLI configuration of the router at the Atlanta office after \ncompleting the previous steps. \nExample 12-2\nCLI Configuration of the Cisco IOS Router at the Atlanta Office \ncompany-A-ios-fw#show running-config\nBuilding configuration...\nCurrent configuration : 8080 bytes\n!\nversion 12.4\nno service pad\nservice tcp-keepalives-in\nservice tcp-keepalives-out\nservice timestamps debug datetime msec localtime show-timezone\nservice timestamps log datetime msec localtime show-timezone\nservice password-encryption\nservice sequence-numbers\n!\nhostname company-A-ios-fw\n!\nboot-start-marker\nboot-end-marker\n!\nno logging buffered\nlogging console critical\nenable secret 5 $1$XlSV$Pa0oIYeuSY5CZOGXXOJjF/\n!\naaa new-model\n!\naaa authentication login local_authen local\naaa authorization exec local_author local\n!\naaa session-id common\nno ip source-route\nip cef\n!\n!\nip tcp synwait-time 10\nno ip bootp server\nip name-server 10.100.10.21\nip name-server 10.100.10.22\nip ssh time-out 60\nip ssh authentication-retries 2\n!\nparameter-map type protocol-info msn-servers\n server name messenger.hotmail.com\n server name gateway.messenger.hotmail.com\n server name webmessenger.msn.com\n!\nparameter-map type protocol-info aol-servers\n server name login.oscar.aol.com\n server name toc.oscar.aol.com\n server name oam-d09a.blue.aol.com\n!\n"
        },
        {
            "page_number": 394,
            "text": "Case Study of a Small Business\n371\nparameter-map type protocol-info yahoo-servers\n server name scs.msg.yahoo.com\n server name scsa.msg.yahoo.com\n server name scsb.msg.yahoo.com\n server name scsc.msg.yahoo.com\n server name scsd.msg.yahoo.com\n server name cs16.msg.dcn.yahoo.com\n server name cs19.msg.dcn.yahoo.com\n server name cs42.msg.dcn.yahoo.com\n server name cs53.msg.dcn.yahoo.com\n server name cs54.msg.dcn.yahoo.com\n server name ads1.vip.scd.yahoo.com\n server name radio1.launch.vip.dal.yahoo.com\n server name in1.msg.vip.re2.yahoo.com\n server name data1.my.vip.sc5.yahoo.com\n server name address1.pim.vip.mud.yahoo.com\n server name edit.messenger.yahoo.com\n server name messenger.yahoo.com\n server name http.pager.yahoo.com\n server name privacy.yahoo.com\n server name csa.yahoo.com\n server name csb.yahoo.com\n server name csc.yahoo.com\n!\nparameter-map type regex sdm-regex-nonascii\n pattern [^\\x00-\\x80]\n!\n!\n!\n!\nusername companyAadmin password 7 02050D4808095E731F \n!\n!\nclass-map type inspect smtp match-any sdm-app-smtp\n match  data-length gt 5000000\nclass-map type inspect http match-any sdm-app-nonascii\n match  req-resp header regex sdm-regex-nonascii\nclass-map type inspect imap match-any sdm-app-imap\n match  invalid-command\nclass-map type inspect match-any sdm-cls-insp-traffic\n match protocol dns\n match protocol https\n match protocol icmp\n match protocol imap\n match protocol pop3\n match protocol tcp\n match protocol udp\nclass-map type inspect match-all sdm-insp-traffic\n match class-map sdm-cls-insp-traffic\nclass-map type inspect match-all sdm-protocol-pop3\n match protocol pop3\ncontinues\nExample 12-2\nCLI Configuration of the Cisco IOS Router at the Atlanta Office (Continued)\n"
        },
        {
            "page_number": 395,
            "text": "372\nChapter 12:  Case Studies\nclass-map type inspect match-any sdm-cls-icmp-access\n match protocol icmp\n match protocol tcp\n match protocol udp\nclass-map type inspect match-any sdm-cls-protocol-im\n match protocol ymsgr yahoo-servers\n match protocol msnmsgr msn-servers\n match protocol aol aol-servers\nclass-map type inspect pop3 match-any sdm-app-pop3\n match  invalid-command\nclass-map type inspect http match-any sdm-http-blockparam\n match  request port-misuse im\n match  request port-misuse p2p\n match  request port-misuse tunneling\n match  req-resp protocol-violation\nclass-map type inspect match-all sdm-protocol-im\n match class-map sdm-cls-protocol-im\nclass-map type inspect match-all sdm-icmp-access\n match class-map sdm-cls-icmp-access\nclass-map type inspect match-all sdm-invalid-src\n match access-group 100\nclass-map type inspect http match-any sdm-app-httpmethods\n match  request method bcopy\n match  request method bdelete\n match  request method bmove\n match  request method bpropfind\n match  request method bproppatch\n match  request method connect\n match  request method copy\n match  request method delete\n match  request method edit\n match  request method getattribute\n match  request method getattributenames\n match  request method getproperties\n match  request method index\n match  request method lock\n match  request method mkcol\n match  request method mkdir\n match  request method move\n match  request method notify\n match  request method options\n match  request method poll\n match  request method post\n match  request method propfind\n match  request method proppatch\n match  request method put\n match  request method revadd\n match  request method revlabel\n match  request method revlog\n match  request method revnum\n match  request method save\n match  request method search\nExample 12-2\nCLI Configuration of the Cisco IOS Router at the Atlanta Office (Continued)\n"
        },
        {
            "page_number": 396,
            "text": "Case Study of a Small Business\n373\n match  request method setattribute\n match  request method startrev\n match  request method stoprev\n match  request method subscribe\n match  request method trace\n match  request method unedit\n match  request method unlock\n match  request method unsubscribe\nclass-map type inspect match-all sdm-protocol-http\n match protocol http\nclass-map type inspect match-all sdm-protocol-smtp\n match protocol smtp\nclass-map type inspect match-all sdm-protocol-imap\n match protocol imap\n!\n!\npolicy-map type inspect sdm-permit-icmpreply\n class type inspect sdm-icmp-access\n  inspect\n class class-default\n  pass\npolicy-map type inspect http sdm-action-app-http\n class type inspect http sdm-http-blockparam\n  log\n  reset\n class type inspect http sdm-app-httpmethods\n  log\n  reset\n class type inspect http sdm-app-nonascii\n  log\n  reset\n class class-default\npolicy-map type inspect smtp sdm-action-smtp\n class type inspect smtp sdm-app-smtp\n  reset\n class class-default\npolicy-map type inspect imap sdm-action-imap\n class type inspect imap sdm-app-imap\n  log\n  reset\n class class-default\npolicy-map type inspect pop3 sdm-action-pop3\n class type inspect pop3 sdm-app-pop3\n  log\n  reset\n class class-default\npolicy-map type inspect sdm-inspect\n class type inspect sdm-invalid-src\n  drop log\n class type inspect sdm-protocol-http\n  inspect\n  service-policy http sdm-action-app-http\ncontinues\nExample 12-2\nCLI Configuration of the Cisco IOS Router at the Atlanta Office (Continued)\n"
        },
        {
            "page_number": 397,
            "text": "374\nChapter 12:  Case Studies\n class type inspect sdm-protocol-smtp\n  inspect\n  service-policy smtp sdm-action-smtp\n class type inspect sdm-protocol-imap\n  inspect\n  service-policy imap sdm-action-imap\n class type inspect sdm-protocol-pop3\n  inspect\n  service-policy pop3 sdm-action-pop3\n class type inspect sdm-protocol-im\n  drop log\n class type inspect sdm-insp-traffic\n  inspect\n class class-default\npolicy-map type inspect sdm-permit\n class class-default\n!\nzone security out-zone\nzone security in-zone\nzone-pair security sdm-zp-self-out source self destination out-zone\n service-policy type inspect sdm-permit-icmpreply\nzone-pair security sdm-zp-out-self source out-zone destination self\n service-policy type inspect sdm-permit\nzone-pair security sdm-zp-in-out source in-zone destination out-zone\n service-policy type inspect sdm-inspect\n!\n!\n!\n!\n!\ninterface Null0\n no ip unreachables\n!\ninterface FastEthernet0\n!\ninterface FastEthernet1\n!\ninterface FastEthernet2\n!\ninterface FastEthernet3\n!\ninterface FastEthernet4\n description $FW_OUTSIDE$\n ip address 209.165.200.231 255.255.255.0\n no ip redirects\n no ip unreachables\n no ip proxy-arp\n zone-member security out-zone\n ip route-cache flow\n duplex auto\nExample 12-2\nCLI Configuration of the Cisco IOS Router at the Atlanta Office (Continued)\n"
        },
        {
            "page_number": 398,
            "text": "Case Study of a Small Business\n375\n speed auto\n!\ninterface Vlan1\n description $FW_INSIDE$\n ip address 10.100.10.1 255.255.255.0\n no ip redirects\n no ip unreachables\n no ip proxy-arp\n zone-member security in-zone\n ip route-cache flow\n!\nip route 0.0.0.0 0.0.0.0 209.165.200.225\n!\nip http server\nno ip http secure-server\n!\nlogging trap informational \nlogging 10.100.10.222\naccess-list 100 remark SDM_ACL Category=128\naccess-list 100 permit ip host 255.255.255.255 any\naccess-list 100 permit ip 127.0.0.0 0.255.255.255 any\naccess-list 100 permit ip 209.165.200.0 0.0.0.255 any\naccess-list 101 remark VTY Access-class list\naccess-list 101 remark SDM_ACL Category=1\naccess-list 101 permit ip 10.100.10.0 0.0.0.255 any\naccess-list 101 deny   ip any any\nno cdp run\n!\n!\n!\ncontrol-plane\n!\nbanner login ^C*** THIS IS A RESTRICTED SYSTEM, UNAUTHORIZED ACCESS^C\n!\nline con 0\n login authentication local_authen\n no modem enable\n transport output telnet\nline aux 0\n login authentication local_authen\n transport output telnet\nline vty 0 4\n access-class 101 in\n authorization exec local_author\n login authentication local_authen\n transport input telnet ssh\n!\nscheduler max-task-time 5000\nscheduler allocate 4000 1000\nscheduler interval 500\nend\nExample 12-2\nCLI Configuration of the Cisco IOS Router at the Atlanta Office (Continued)\n"
        },
        {
            "page_number": 399,
            "text": "376\nChapter 12:  Case Studies\nConfiguring Basic Network Address Translation (NAT)\nThe router administrator needs to configure basic NAT for internal users to access the \nInternet. The following steps are completed to enable basic NAT on the Cisco IOS router.\nStep 1\nLog in to the router using SDM.\nStep 2\nNavigate to Configure > NAT and click Basic NAT, as illustrated in \nFigure 12-34.\nFigure 12-34 Configuring Basic NAT \nStep 3\nClick the Launch the selected task button to start the NAT \nConfiguration Wizard.\nStep 4\nThe NAT Configuration Wizard welcome screen appears. Click Next.\nStep 5\nThe screen shown in Figure 12-35 is displayed. \n"
        },
        {
            "page_number": 400,
            "text": "Case Study of a Small Business\n377\nFigure 12-35 Basic NAT Configuration Wizard \nStep 6\nChoose the interface that connects to the Internet from the drop-down \nmenu. FastEthernet4 is selected in this example.\nStep 7\nIn this example, the inside network will be translated to the public IP \naddress of the outside interface.\nStep 8\nClick Next.\nStep 9\nThe wizard displays a summary screen listing the configuration changes. \nClick Finish.\nConfiguring Site-to-Site VPN \nUsers at the office in Atlanta need to securely access resources in the Raleigh office. The \nsecurity administrator configures a site-to-site IPsec tunnel between the Cisco ASA in \nRaleigh and the Cisco IOS router in Atlanta.\nThe following are the steps that need to be completed to configure the Cisco IOS router in \nAtlanta to terminate a site-to-site IPsec tunnel with the Cisco ASA in Raleigh.\nStep 1\nLog in to the router using SDM.\nStep 2\nNavigate to Configure > VPN and choose Site-to-Site VPN, as \nillustrated in Figure 12-36.\n"
        },
        {
            "page_number": 401,
            "text": "378\nChapter 12:  Case Studies\nFigure 12-36 Configuring a Site-to-Site VPN Using SDM \nStep 3\nClick Create a Site to Site VPN and click the Launch the selected task\nbutton.\nStep 4\nThe Site-to-Site VPN Wizard welcome screen is displayed, as \nillustrated in Figure 12-37. The Quick setup option allows you to easily \nconfigure a site-to-site VPN tunnel to another Cisco router with minimal \ninteraction. In this case, the router will be creating a site-to-site VPN \ntunnel to a Cisco ASA, then the Step by step wizard is selected. This \noption lets you customize the configuration.\nStep 5\nClick Next.\nStep 6\nThe screen shown in Figure 12-38 is displayed. Select the interface that \nwill terminate the VPN tunnel. In this example, FastEthernet4 (the \noutside interface of the router) is selected.\n"
        },
        {
            "page_number": 402,
            "text": "Case Study of a Small Business\n379\nFigure 12-37 SDM Site-to-Site VPN Wizard Welcome Screen \nFigure 12-38 Configuring the VPN Interface, Remote Peer, and Preshared Keys \n"
        },
        {
            "page_number": 403,
            "text": "380\nChapter 12:  Case Studies\nStep 7\nIn this case, the VPN peer (Cisco ASA) is configured with a static IP \naddress. Choose Peer with static IP address from the drop-down menu \nand enter the IP address of the peer (209.165.200.225). Preshared keys \nare used in this example for tunnel authentication.\nStep 8\nClick Next.\nStep 9\nThe next screen allows you to configure an Internet Key Exchange (IKE) \n(as illustrated in Figure 12-39). This policy must match the IKE policy \non the Cisco ASA. Click Add to enter a new IKE policy.\nFigure 12-39 Configuring the IKE Policy with SDM \nStep 10 In this case, a new policy is configured to use preshared keys for \nauthentication. The selected encryption protocol is Advanced Encryption \nStandard AES_256. Diffie-Hellman (DH) Group 2 is used. The IKE \nhashing algorithm is Secure Hash Algorithm SHA_1. The default \n24-hour lifetime for IKE is selected.\nStep 11 Click Next.\nStep 12 The next screen enables you to configure the IPsec policies. Click Add\nto add a new transform-set (IPsec phase two policies).\nStep 13 The dialog box illustrated in Figure 12-40 appears allowing you to \nconfigure the IPsec policies.\n"
        },
        {
            "page_number": 404,
            "text": "Case Study of a Small Business\n381\nFigure 12-40 Configuring the IPsec Phase Two Policies with SDM \nStep 14 Enter a name for the new transform set. In this case, the name is \ntunnel-to-asa.\nStep 15 The Encapsulatation Security Payload (ESP) protocol is used in \nthis example. The integrity algorithm used in this example is \nESP_SHA_HMAC, and the encryption algorithm is ESP_AES_256.\nThe Cisco ASA configuration must match these settings to establish the \nsite-to-site IPsec VPN tunnel.\nStep 16 Tunnel mode is used in this example to encrypt both the payload (data) \nand IP header.\nStep 17 Click OK to add the new transform-set.\nStep 18 Click Next.\nStep 19 The screen shown in Figure 12-41 is displayed. It allows you to select the \ntraffic you would like to protect.\nStep 20 Click Protect all traffic between the following subnets.\nStep 21 Configure the local and remote networks (the networks that will be able \nto communicate over the VPN tunnel). In this case, the local network \nis 10.100.10.0/24, and the remote network is 10.10.10.0/24.\nStep 22 Click Next.\n"
        },
        {
            "page_number": 405,
            "text": "382\nChapter 12:  Case Studies\nFigure 12-41 Traffic to Protect \nStep 23 A summary screen listing the configuration changes is displayed. Click \nFinish to apply the changes.\nStep 24 Because NAT/PAT was configured on the router, SDM shows a warning \nmessage asking you if you would like to bypass NAT for the traffic over \nthe VPN tunnel. The warning screen is shown in Figure 12-42.\nFigure 12-42 SDM Warning Screen \nStep 25 Click Yes to bypass NAT for the tunnel traffic.\n"
        },
        {
            "page_number": 406,
            "text": "Case Study of a Small Business\n383\nExample 12-3 shows the CLI VPN configuration of the router.\nThe next task is to configure the Cisco ASA in the Raleigh office to terminate the \nsite-to-site VPN tunnel. Complete the following steps to complete this task.\nStep 1\nLog in to the Cisco ASA using ASDM.\nStep 2\nFrom the main ASDM menu, choose Wizards > IPsec VPN Wizard, as \nshown in Figure 12-43.\nStep 3\nThe VPN Wizard starts by allowing you to select the tunnel type, as \nillustrated in Figure 12-44. Click Site-to-Site.\nExample 12-3\nCLI VPN Configuration of the Router\n!Phase 1 IKE policy\ncrypto isakmp policy 2\n encr aes 256\n authentication pre-share\n group 2\ncrypto isakmp key cisco123 address 209.165.200.225\n!\n!Phase 2 policy\ncrypto ipsec transform-set tunnel-to-asa esp-aes 256 esp-sha-hmac\n!\n!crypto-map configuration for the Tunnel to the Cisco ASA\ncrypto map SDM_CMAP_1 1 ipsec-isakmp\n description Tunnel to209.165.200.225\n set peer 209.165.200.225\n set transform-set tunnel-to-asa\n match address 102\n! \n!ACL defining tunnel traffic\naccess-list 102 remark SDM_ACL Category=4\naccess-list 102 remark IPSec Rule\naccess-list 102 permit ip 10.100.10.0 0.0.0.255 10.10.10.0 0.0.0.255\n!\n!Outside Interface Configuration\ninterface FastEthernet4\n description $FW_OUTSIDE$\n ip address 209.165.200.231 255.255.255.0\nip nat outside\ncrypto map SDM_CMAP_1\n!\n!NAT Configuration – bypassing NAT for tunnel traffic\nip nat inside source route-map SDM_RMAP_1 interface FastEthernet4 overload\n!\nroute-map SDM_RMAP_1 permit 1\n match ip address 105\naccess-list 105 remark SDM_ACL Category=2\naccess-list 105 remark IPSec Rule\naccess-list 105 deny   ip 10.100.10.0 0.0.0.255 10.10.10.0 0.0.0.255\naccess-list 105 permit ip 10.100.10.0 0.0.0.255 any\n"
        },
        {
            "page_number": 407,
            "text": "384\nChapter 12:  Case Studies\nStep 4\nChoose the outside interface as the VPN tunnel interface from the \ndrop-down menu.\nFigure 12-43 Launching the ASDM IPsec VPN Wizard \nFigure 12-44 ASDM VPN Wizard—VPN Tunnel Type \n"
        },
        {
            "page_number": 408,
            "text": "Case Study of a Small Business\n385\nStep 5\nIn this example, the Cisco ASA will be configured to allow inbound IPsec \nsessions to bypass all configured access control lists (ACL).\nStep 6\nClick Next.\nStep 7\nThe screen shown in Figure 12-45 is displayed. Here you can enter the \nremote site peer information.\nFigure 12-45 ASDM VPN Wizard—Remote Peer Information \nStep 8\nEnter the peer IP address (209.165.200.231 in this example). \nStep 9\nUnder Authentication Method, click Pre-shared key and enter the \npreshared key. In this example, the preshared key is 1qazXSW2.\nStep 10 By default, the IP address of the remote peer is used as the tunnel group \nname. Leave the default configuration.\nStep 11 Click Next.\nStep 12 The screen shown in Figure 12-46 is displayed. Here you can enter the \nIKE policy information.\nStep 13 The IKE policy parameters must match those configured in the router. In \nthis case, the same encryption protocol, authentication hashing \nalgorithm, and DH group are configured.\nStep 14 Click Next.\n"
        },
        {
            "page_number": 409,
            "text": "386\nChapter 12:  Case Studies\nFigure 12-46 ASDM VPN Wizard—IKE Policy \nStep 15 The screen shown in Figure 12-47 is displayed. Here you can enter the \nIPsec phase 2 information.\nFigure 12-47 ASDM VPN Wizard—IPsec Encryption and Authentication \n"
        },
        {
            "page_number": 410,
            "text": "Case Study of a Small Business\n387\nStep 16 The IPsec encryption and authentication protocol parameters must match \nthose configured in the router, as shown in Figure 12-47.\nStep 17 Click Next.\nStep 18 The screen shown in Figure 12-48 is displayed. This screen allows you \nto enter the local and remote networks that will communicate over the \nIPsec site-to-site VPN tunnel.\nFigure 12-48 ASDM VPN Wizard—Hosts and Networks \nStep 19 Under Action, click Protect.\nStep 20 Enter the local network information. In this case, the inside-network/24\nis selected.\nStep 21 Enter the remote network information. The 10.100.10.0/24, atlanta-\noffice remote network is selected in this example.\nStep 22 Check the Exempt ASA side host/network from address translation\noption and choose the inside interface from the drop-down menu to \nbypass NAT for tunnel traffic.\nStep 23 Click Next.\nStep 24 The summary screen shown in Figure 12-49 is displayed.\nStep 25 Click Finish to apply the changes to the Cisco ASA.\n"
        },
        {
            "page_number": 411,
            "text": "388\nChapter 12:  Case Studies\nFigure 12-49 ASDM VPN Wizard—Summary Screen\nExample 12-4 shows the Cisco ASA CLI site-to-site VPN configuration.\nExample 12-4\nCisco ASA CLI Site-to-Site VPN Configuration \n!IKE Enabled on the outside interface\ncrypto isakmp enable outside\n!\n!IKE Policy (phase one policy)\ncrypto isakmp policy 10\n authentication pre-share\n encryption aes-256\n hash sha\n group 2\n lifetime 86400\n!\n!Phase 2 policy and crypto map configuration\ncrypto ipsec transform-set ESP-AES-256-SHA esp-aes-256 esp-sha-hmac\ncrypto map outside_map 20 match address outside_20_cryptomap\ncrypto map outside_map 20 set peer 209.165.200.231\ncrypto map outside_map 20 set transform-set ESP-AES-256-SHA\n!\n!Crypto map is applied to the outside interface\ncrypto map outside_map interface outside\n"
        },
        {
            "page_number": 412,
            "text": "Case Study of a Medium-Sized Enterprise     389\nCase Study of a Medium-Sized Enterprise\nCompany-B is a medium-sized software development company based in Chicago, Illinois. \nThis organization has 1200 employees and 75 contractors at a call center in a partner \noffice (Partner-A). Figure 12-50 illustrates a high-level overview of the Chicago office \nfor Company-B.\nTwo routers (R1 and R2) reside at the Internet Edge followed by two Cisco ASAs with the \nAdvanced Inspection and Prevention Security Services Module (AIP-SSM). The AIP-SSM \nprovides intrusion prevention system (IPS) functionality. Web, e-mail, and DNS servers \nreside at a DMZ network. A Cisco Secure Monitoring, Analysis, and Response System \n(CS-MARS), a Cisco Secure Access Control Server (ACS), and a Simple Network \nManagement Protocol (SNMP) server reside in the management network.\nCompany-B has three major user groups in the Chicago office:\n•\nSales\n•\nEngineering\n•\nFinance\nCompany-B’s security manager has learned the techniques and methodologies discussed \nearlier on this book. The security manager develops a strategic plan to implement best \npractices to increase the security of their network infrastructure. The following sections \ninclude several tasks that the security manager of Company-B completes to increase the \nsecurity of the network and its components. \n!\n!ACL used by the crypto map to define the traffic that will be encrypted\naccess-list outside_20_cryptomap extended permit ip 10.10.10.0 255.255.255.0 \nobject-group atlanta-office\n!\n!Tunnel group configuration for the site-to-site tunnel\ntunnel-group 209.165.200.231 type ipsec-l2l\ntunnel-group 209.165.200.231 ipsec-attributes\n pre-shared-key *\n!\n!Bypassing NAT for the VPN tunnel traffic\nnat (inside) 0 access-list inside_nat0_outbound\naccess-list inside_nat0_outbound extended permit ip 10.10.10.0 255.255.255.0 \nobject-group atlanta-office\n!\n!Object Group defining the Atlanta office remote network\nobject-group network atlanta-office\n network-object 10.100.10.0 255.255.255.0\nExample 12-4\nCisco ASA CLI Site-to-Site VPN Configuration (Continued)\n"
        },
        {
            "page_number": 413,
            "text": "390\nChapter 12:  Case Studies\nFigure 12-50 High-Level Overview of Company-B Chicago Office\nFinance\nEngineering\nSales\nManagement Network\nACS SNMP  CS-MARS\nR1\nR2\nR3\nR4\nInternet\nPartner-1\nDMZ\nWeb, E-mail, DNS\nIPsec\nASA-1\n(w AIP-SSM)\nASA-2\n(w AIP-SSM)\nCAT 6K-1\nCAT 6K-2\nCompany-B\nChicago Office\n"
        },
        {
            "page_number": 414,
            "text": "Case Study of a Medium-Sized Enterprise     391\nProtecting the Internet Edge Routers\nOn the Internet edge routers (R1 and R2), the administrator configures an ACL to deny \npackets from illegal sources (RFC 1918 and RFC 3330 addresses). In addition, this ACL \ndenies traffic with source addresses belonging within the internal address space of \nCompany-B (that is, 209.165.201.0/24) that is entering from an external source. \nExample 12-5 shows the ACL configuration.\nNOTE\nIn addition, the administrator performs a security audit using SDM and makes the necessary \nchanges, as the Company-A administrator.\nConfiguring the AIP-SSM on the Cisco ASA\nTwo Cisco ASAs protect the Chicago office internal network. The IP address configuration \nof both Cisco ASAs is illustrated in Figure 12-51.\nFigure 12-51 Cisco ASAs at the Chicago Office\nExample 12-5\nAntispoofing ACL\naccess-list 100 deny ip host 0.0.0.0 any\naccess-list 100 deny ip 127.0.0.0 0.255.255.255 any\naccess-list 100 deny ip 192.0.2.0 0.0.0.255 any\naccess-list 100 deny ip 224.0.0.0 31.255.255.255 any\naccess-list 100 deny ip 10.0.0.0 0.255.255.255 any\naccess-list 100 deny ip 172.16.0.0 0.15.255.255 any\naccess-list 100 deny ip 192.168.0.0 0.0.255.255 any\naccess-list 100 deny ip any 209.165.201.0 0.0.0.255\naccess-list 100 permit ip any any\nAIP-SSM\nManagement\n10.200.30.1\nDMZ\n10.200.20.1\nASA-1\nOutside\n209.165.201.1\nInside\n10.200.10.1\nSSM Management\n10.200.30.3\nAIP-SSM\nManagement\n10.200.30.2\nDMZ\n10.200.20.2\nASA-2\nOutside\n209.165.201.2\nInside\n10.200.10.2\nSSM Management\n10.200.30.4\n"
        },
        {
            "page_number": 415,
            "text": "392\nChapter 12:  Case Studies\nThe following are the IP addresses of each of the interfaces of the primary Cisco ASA \n(ASA-1):\n•\nOutside: 209.165.201.1\n•\nInside: 10.200.10.1\n•\nDMZ: 10.200.20.1\n•\nManagement: 10.200.30.1\n•\nAIP-SSM Management interface: 10.200.30.3\nThe following are the IP addresses of each of the interfaces of the secondary Cisco ASA \n(ASA-2):\n•\nOutside: 209.165.201.2\n•\nInside: 10.200.10.2\n•\nDMZ: 10.200.20.2\n•\nManagement: 10.200.30.2\n•\nAIP-SSM management interface: 10.200.30.4\nThe administrator configures the necessary access and address translation for internal \nservices in a procedure that is similar to the steps you learned previously in this chapter. \nAfter performing these basic configuration steps, the security administrator initializes the \nAIP-SSM. To verify that the ASA-1 recognizes the AIP-SSM, the administrator uses the \nshow module command, as shown in Example 12-6.\nThe highlighted lines show that the module is running IPS Software Version 6.0(2)E1 and \nthat it is operational.\nThe administrator logs into ASA-1 via the CLI and connects to the AIP-SSM using the \nsession 1 command. This puts him on the AIP-SSM CLI. To initialize the AIP-SSM, the \nadministrator uses the setup command, as demonstrated in Example 12-7.\nExample 12-6\nOutput of the show module Command\ncompanyB-ASA1# show module\nMod Card Type                                    Model              Serial No.\n--- -------------------------------------------- ------------------ -----------\n  0 ASA 5520 Adaptive Security Appliance         ASA5520-K8         JMX1113L0Y4\n  1 ASA 5500 Series Security Services Module-10  ASA-SSM-10         JAB101502D9\nMod MAC Address Range                 Hw Version   Fw Version   Sw Version\n--- --------------------------------- ------------ ------------ ---------------\n  0 001a.6d7c.8c95 to 001a.6d7c.8c99  2.0          1.0(11)2     8.0(2)\n  1 0016.c79f.78c1 to 0016.c79f.78c1  1.0          1.0(10)0     6.0(2)E1\nMod SSM Application Name           Status           SSM Application Version\n--- ------------------------------ ---------------- --------------------------\n  1 IPS                            Up               6.0(2)E1\nMod Status             Data Plane Status     Compatibility\n--- ------------------ --------------------- -------------\n  0 Up Sys             Not Applicable\n  1 Up                 Up\n"
        },
        {
            "page_number": 416,
            "text": "Case Study of a Medium-Sized Enterprise     393\nExample 12-7\nInitializing ASA-1 AIP-SSM \nsensor# setup\n    --- System Configuration Dialog ---\nAt any point you may enter a question mark '?' for help.\nUse ctrl-c to abort configuration dialog at any prompt.\nDefault settings are in square brackets '[]'.\nCurrent Configuration:\nservice host\nnetwork-settings\nhost-ip 10.1.9.201/24,10.1.9.1\nhost-name sensor\ntelnet-option disabled\nftp-timeout 300\nlogin-banner-text\nexit\ntime-zone-settings\noffset 0\nstandard-time-zone-name UTC\nexit\nsummertime-option disabled\nntp-option disabled\nexit\nservice web-server\nport 443\nexit\nCurrent time: Mon May 14 18:26:51 2007\nSetup Configuration last modified: Mon May 14 17:45:30 2007\nContinue with configuration dialog?[yes]: yes\nEnter host name[sensor]: companyB-AIP-SSM1\nEnter IP interface[10.1.9.201/24,10.1.9.1]: 10.200.30.3/24,10.200.30.1\nEnter telnet-server status[disabled]:\nEnter web-server port[443]:\nModify current access list?[no]: yes\nCurrent access list entries:\n  No entries\nPermit: 10.200.30.0/24\nPermit:\nModify system clock settings?[no]: no\nModify virtual sensor “vs0” configuration?[no]: yes\nCurrent interface configuration\n  Command control: GigabitEthernet0/0\n  Unused:\n    GigabitEthernet0/1\n  Monitored:\n    None\nAdd Monitored interfaces?[no]: yes\nInterface[]: GigabitEthernet0/1\nInterface[]:\nThe following configuration was entered.\nservice host\nnetwork-settings\ncontinues\n"
        },
        {
            "page_number": 417,
            "text": "394\nChapter 12:  Case Studies\nIn Example 12-7, the administrator configures the AIP-SSM hostname, IP address, and \nsubnet mask of the management interface, in addition to the default gateway. The \nadministrator allows management access only from machines in the 10.200.30.0/24 \nmanagement network. Also, the GigabitEthernet0/1 interface is enabled for traffic \ninspection. Finally, the administrator saves the configuration and exits the interactive \nsetup session.\nConfiguring Active-Standby Failover on the Cisco ASA\nMaintaining appropriate redundancy mechanisms within infrastructure devices is \nextremely important for any organization. The Cisco ASA supports active-active and \nactive-standby failover. \nNOTE\nWhen the active unit fails, it changes to the standby state while the standby unit changes \nto the active state. The unit that becomes active takes ownership of the IP addresses and \nMAC addresses of the failed unit. The unit that is now in standby state takes over the \nstandby IP addresses and MAC addresses. Because network devices see no change in the \nMAC-to-IP address pairing, no ARP entries change or time out anywhere on the network.\nhost-ip 10.200.30.3/24,10.200.30.1\nhost-name companyB-AIP-SSM1\ntelnet-option disabled\naccess-list 10.200.30.0/24\nftp-timeout 300\nno login-banner-text\nexit\ntime-zone-settings\noffset 0\nstandard-time-zone-name UTC\nexit\nsummertime-option disabled\nntp-option disabled\nexit\nservice web-server\nport 443\nexit\nservice analysis-engine\nvirtual-sensor vs0\nphysical-interface GigabitEthernet0/1\nexit\nexit\n[0] Go to the command prompt without saving this config.\n[1] Return back to the setup without saving this config.\n[2] Save this configuration and exit setup.\nEnter your selection[2]: 2\nConfiguration Saved.\nExample 12-7\nInitializing ASA-1 AIP-SSM (Continued)\n"
        },
        {
            "page_number": 418,
            "text": "Case Study of a Medium-Sized Enterprise     395\nWhen a pair of Cisco ASAs is configured in active-active failover mode, both appliances \nare actively passing traffic at the same time. In contrast, when configured in active-standby \nmode, the primary appliance is the active one and the secondary appliance is in standby \nand does not pass traffic. After the primary fails, the secondary takes over and begins to \npass traffic.\nThe network security team of Company-B evaluates both options. They decide to \nimplement active-standby failover because, for active-active to work, the appliances must \nbe configured in multicontext mode. Active-active requires a minimum of two security \ncontexts on each appliance. Company-B has a site-to-site VPN tunnel to a business partner \n(Partner-A). The Cisco ASA does not support VPN when configured in multicontext mode.\nThe following are the steps taken to configure active-standby failover on the Cisco ASAs.\nStep 1\nLog in to the Cisco ASA using ASDM.\nStep 2\nOn the main toolbar, click Wizards and choose High Availability and \nScalability Wizard, as illustrated in Figure 12-52.\nFigure 12-52 Launching the High Availability and Scalability Wizard\nStep 3\nThe screen shown in Figure 12-53 is displayed. Click Configure \nActive/Standby failover.\n"
        },
        {
            "page_number": 419,
            "text": "396\nChapter 12:  Case Studies\nFigure 12-53 Configuring Active/Standby Failover\nStep 4\nClick Next.\nStep 5\nEnter the IP address of the secondary appliance, as shown in Figure 12-54. \nThe IP address of the secondary appliance management interface is \n10.200.30.2 in this case. ASDM completes several compatibility and \nconnectivity checks on the secondary appliance. These steps are listed \nwithin the ASDM screen shown in Figure 12-54. If successful, ASDM \nallows you to proceed to the next step. However, if issues exist, \nASDM marks each check that failed. You must fix any errors before \nproceeding further.\nStep 6\nClick Next.\nStep 7\nThe screen shown in Figure 12-55 is displayed. This screen allows you \nto configure a dedicated interface for failover communication between \nthe two appliances. Choose an available interface from the drop-down \nmenu. In this case, the interface selected is GigabitEthernet0/3.\nStep 8\nEnter a name for the failover interface. In this example, the interface is \ncalled failover for simplicity. This is an arbitrarily name.\n"
        },
        {
            "page_number": 420,
            "text": "Case Study of a Medium-Sized Enterprise     397\nFigure 12-54 Failover Peer Connectivity and Compatibility Check\nFigure 12-55 Configuring the Failover LAN Link\n"
        },
        {
            "page_number": 421,
            "text": "398\nChapter 12:  Case Studies\nStep 9\nAssign an IP address for this interface, in addition to a standby IP \naddress, as shown in Figure 12-55. In this example, the active IP address \nis 10.200.40.1, and the secondary is 10.200.40.2.\nStep 10 Configure a subnet mask for this interface. A 30-bit (255.255.255.252)\nsubnet mask is configured in this example.\nStep 11 You can optionally encrypt the failover communication data exchanged \nby both appliances. To enable encryption, select the Use 32 hexadecimal \ncharacter key option under Communication Encryption.\nStep 12 Enter a 32 hexadecimal character key.\nStep 13 Click Next.\nStep 14 You can configure stateful failover to maintain connection status, \ntranslation, and other information on the standby appliance to avoid \ninterruption of services when a failover occurs. You can configure a \ndedicated interface or use the previously configured failover interface for \nthis communication. On busy networks where numerous connections are \nbuilt and torn down at a fast pace, a dedicated interface is suggested. In \nthis case, all other interfaces on the Cisco ASAs are used for other \npurposes, and the stateful failover traffic of Company-B does not present \nan oversubscription risk based on tests that the administrator performed in \nthe lab prior to deployment. The administrator configures the failover \nLAN link interface as the stateful failover link, as shown in Figure 12-56.\nFigure 12-56 Configuring the Stateful Failover Link\n"
        },
        {
            "page_number": 422,
            "text": "Case Study of a Medium-Sized Enterprise     399\nStep 15 You must configure a standby IP address for each interface that is enabled \non the Cisco ASA. The standby appliance uses these IP addresses. \nThe screen shown in Figure 12-57 allows you to configure the standby \nIP address for each interface.\nFigure 12-57 Configuring the Standby IP Addresses\nStep 16 Click Next.\nStep 17 A summary screen showing the configuration items to be sent to the \nsecurity appliance is displayed. Click Finish to apply the changes.\nExample 12-8 includes the CLI commands sent to the primary appliance.\nExample 12-8\nFailover Configuration on the Primary ASA\nfailover\nfailover lan unit primary\nfailover lan interface failover GigabitEthernet0/3\nfailover key *****\nfailover link failover GigabitEthernet0/3\nfailover interface ip failover 10.200.40.1 255.255.255.252 standby 10.200.40.2 \ninterface GigabitEthernet0/3\n description LAN/STATE Failover Interface\nmonitor-interface dmz\nmonitor-interface inside\nmonitor-interface outside\nmonitor-interface management\n"
        },
        {
            "page_number": 423,
            "text": "400\nChapter 12:  Case Studies\nExample 12-9 includes the CLI commands sent to the secondary appliance.\nYou will see the message shown in Example 12-10 after the secondary appliance is \nconfigured and the configuration replication is performed.\nConfiguring AAA on the Infrastructure Devices\nThe network administrator configures authentication, authorization, and accounting (AAA) \nfor administrative access to all routers within the network. The network administrator uses \ncommand authorization to enforce which commands users can invoke and execute in the \nrouters. Example 12-11 shows a AAA configuration template used for all routers within the \norganization:  \nThe aaa new-model command enables the AAA security services. The aaa authentication\ncommand defines the default method list. Incoming logins on all interfaces (by default) use \nTACACS+ for authentication. If no TACACS+ server responds, the network access server \nuses the information contained in the local username database for authentication. The \ntacacs-server host command identifies the TACACS+ server as having an IP address of \n172.18.85.181. The tacacs-server key command defines the shared encryption key to be \n1qaz2wsx.\nThe administrator also configures AAA on the Cisco ASAs for Telnet, Secure Shell (SSH), \nHTTPS, and serial console access. The commands used are shown in Example 12-12. \nExample 12-9\nFailover Configuration on the Secondary ASA\nfailover\nfailover lan unit secondary\nfailover lan interface failover GigabitEthernet0/3\nfailover key *****\nfailover interface ip failover 10.200.40.1 255.255.255.252 standby 10.200.40.2 \ninterface GigabitEthernet0/3\nno shutdown\nExample 12-10 Failover Configuration Replication Confirmation\ncompanyB-ASA1#..\n        Detected an Active mate\nBeginning configuration replication from mate.\ncompanyB-ASA1# End configuration replication from mate.\nExample 12-11 AAA Configuration on Routers \naaa new-model\naaa authentication login default group tacacs+ local\ntacacs-server host 172.18.85.181\ntacacs-server key 1qaz2wsx\n"
        },
        {
            "page_number": 424,
            "text": "Case Study of a Large Enterprise     401\nIn this example, authentication is performed using an external TACACS+ server (that is, \nCisco Secure ACS).\nCisco Secure ACS is used as the TACACS+ server. The following steps are taken to add the \nrouters and the Cisco ASAs as authentication clients on Cisco Secure ACS:\nStep 1\nLog in to the Cisco Secure ACS web admin console.\nStep 2\nChoose Network Configuration on the left, and click Add Entry to add \nan entry for the Cisco ASAs or routers in either the TACACS+ or \nRADIUS server database. \nStep 3\nChoose the server database according to the routers and Cisco ASA \nconfigurations. Because TACACS+ is used in this example, choose \nTACACS+ (Cisco IOS) under the Authenticate Using drop-down \nmenu.\nStep 4\nConfigure the shared key. This key is used for authentication between the \nauthentication client (router or Cisco ASA) and Cisco Secure ACS.\nCase Study of a Large Enterprise\nCompany-C is a large enterprise that offers numerous information technology products and \nservices. Over the past few years, this company has been growing at a fast pace. Recently, \nCompany-C acquired Company-A and Company-B. The Raleigh and Atlanta offices of \nCompany-A became branch offices, and the Chicago office of Company-B became a \nregional office, as illustrated in Figure 12-58. The headquarters is located in New York City.\nExample 12-12 Cisco ASA AAA Configuration\n!The following commands define a TACACS+ server and limit the number of failed \nattempts to 4.The server group name is svrgrp \n!\naaa-server svrgrp protocol tacacs+\n max-failed-attempts 4\n!\n!The TACACS+ server (172.18.85.101) and a shared secret (1qaz2wsx) are defined. The \ntimeout is set to 5 seconds.\naaa-server svrgrp host 172.18.85.101 1qaz2wsx timeout 5\n!\n!Telnet authentication\naaa authentication telnet console svrgrp\n!\n!Serial console port authentication \naaa authentication serial console svrgrp\n!\n!HTTPS authentication for ASDM connections\naaa authentication secure-http-client\n"
        },
        {
            "page_number": 425,
            "text": "402\nChapter 12:  Case Studies\nFigure 12-58 Company-C High-Level Network Topology\nSi\nInternet\nCompany-B\nChicago Office\nIPsec Tunnel\nSi\nSi\nSi\nExecutives\nSales\nEngineering\nFinance\nCall Center\nCore\nData Center\nCompany-A\nAtlanta Office\nIPsec Tunnel\nCompany-A\nRaleigh Office\nIPsec Tunnel\nASA VPN\nCluster\n"
        },
        {
            "page_number": 426,
            "text": "Case Study of a Large Enterprise     403\nThe following is a high-level explanation of the New York office topology:\n•\nAt the Internet edge, a pair of Cisco Catalyst 6500 switches is deployed with FWSMs.\n•\nA cluster of Cisco ASAs is configured for IPsec- and SSL-based remote access VPN.\n•\nCisco routers are configured to terminate IPsec site-to-site VPN tunnels to the branch \noffices and the regional office.\n•\nThe user population includes the following:\n— A call center of more than 100 customer service representatives\n— The executive floor\n— Sales representatives\n— Engineering\n— Finance\n•\nA large data center is also located at the New York office.\nWith the dramatic growth, Company-C staff members initiate several corporate \ninitiatives and projects to increase the security of the network. The following sections \ninclude information about different techniques and methodologies that Company-C staff \nmembers use.\nCreating a New Computer Security Incident Response Team (CSIRT)\nCompany-C management starts the process to create a Computer Security Incident \nResponse Team (CSIRT). The CSIRT will comprise staff members from different \ndepartments within an organization:\n•\nGlobal information technology (IT)\n•\nInformation Security (InfoSec)\n•\nOperation Security (OpSec)\n•\nBusiness analysis team\nTIP\nIn some large organizations, the CSIRT may be a full-time staff. Deciding whether the staff \nmembers should be full-time or not depends on your organizational needs and budget. What \nis important is to clearly identify who needs to be involved at each level of the CSIRT \nplanning, implementation, and operation. For instance, one of the most challenging tasks is \nthe process of identifying the staff members who will be performing security incident \nresponse functions.\nIn addition, you must identify which internal and external organizations will interface with \nthe CSIRT. Evangelize and communicate the CSIRT responsibilities accordingly with \nthese entities.\n"
        },
        {
            "page_number": 427,
            "text": "404\nChapter 12:  Case Studies\nThe new CSIRT team develops and documents roles and responsibilities for all CSIRT \nmembers and their functions. Each member has a different background and qualifications. \nThese roles and responsibilities are assigned based on the experience and strengths of \neach member.\nCreating New Security Policies\nThe executive team of Company-C also delegates the tasks of creating new security policies \nwithin the organization.  Since Company-C acquired Company-A and Company-B new \npolicies need to be defined and followed. The following are the new policies that are \ncreated:\n•\nPhysical security\n•\nPerimeter security\n•\nDevice security\n•\nRemote access VPN\n•\nPatch management\n•\nChange management\n•\nInternet access policy\nPhysical Security Policy\nThe physical security policy is created to protect and preserve information, physical \nassets, and human assets by reducing the exposure to various physical threats. A new \nemployee badge system is deployed to deny unauthorized access and to track authorized \nentry. Card access and monitoring devices will be used to ensure that sensitive information \nis not compromised and access to control office work areas is monitored. The building \nfacility manager will ensure that appropriate monitoring devices allow monitoring of \nprimary accesses and that each individual is screened for access. In addition, a video \nsurveillance system must be implanted and appropriately managed. This video system \nshould function with an existing Ethernet switched environment, and it should reduce the \ncomplexity while lowering the cost of deploying video surveillance. It also provides video \nsurveillance system owners with the flexibility to design solutions tailored to their \nunique requirements.\nPerimeter Security Policy\nThe company already has perimeter configuration guidelines that are implemented within \nthe organization. However, these guidelines were never documented in an organized \nfashion. The staff members at Company-C create a detailed perimeter security policy.\n"
        },
        {
            "page_number": 428,
            "text": "Case Study of a Large Enterprise     405\nDevice Security Policy\nJust as with perimeter security, the company already has device configuration guidelines \nthat are implemented within the organization. However, these guidelines were never \ndocumented in an organized fashion. The staff members at Company-C create  a detailed \ndevice security policy. These devices include infrastructure devices such as routers, \nswitches, and other equipment.\nRemote Access VPN Policy\nThe remote access VPN policy defines the appropriate use of remote access VPN \n(including IPsec and SSL-based remote access VPNs). The policies include the process of \nhow employees request remote access VPN and how administrators create, modify, and \ndelete remote access accounts. In this case, Company-C uses generic token cards with \none-time passwords (OTP) for remote access. When Company-C staff members start \ndeveloping the remote access VPN policy, they are trying to clarify answers to the \nfollowing questions:\n•\nDoes a remote access security policy exist? \n•\nIs the security policy frequently reviewed and revised to reflect technology changes, \noutmoded approaches, or new product or service offerings affecting company/\ncustomer relationships and system interaction? \n•\nDoes the remote access policy specify guidelines for the selection and implementation \nmechanisms that control access among authorized users and corporate computers \nand networks? \n•\nDoes the remote access policy conform to all existing corporate communications \nguidelines?\n•\nDoes the remote access policy address the physical protection of the communications \nmedium, devices, computers, and data storage at the remote site? \n•\nDoes the security policy require the classification of the functions, applications, and \ndata to determine the levels of security needed to protect the asset? \n•\nDoes a policy exist to obtain access to important proprietary information at remote \nsites?\n•\nDoes a policy exist for reporting unauthorized activity? \n•\nDoes a policy exist that defines appropriate personal use of company equipment? \n•\nDo remote access users have to sign a form stating they know and understand the \nremote access policies? \n•\nIs there a formal, complete, and tested disaster recovery plan in place for the remote \nsites?\n"
        },
        {
            "page_number": 429,
            "text": "406\nChapter 12:  Case Studies\nPatch Management Policy\nThe patch management policy establishes requirements for a secure patch management \nprogram for all Company-C networks to prevent disruption of service and unauthorized use \nbecause of vulnerabilities in unpatched systems. The patch management program shall be \nused to create a consistently configured environment that ensures security against known \nvulnerabilities in operating systems and application software. A key component of patch \nmanagement is the intake and selection of information regarding both security issues and \npatch release. The patch cycle shall be used to facilitate the application of standard patch \nreleases and updates. This cycle can be time or event based. For example, the schedule can \nmandate that system updates occur quarterly, or a cycle may be driven by the release of \nservice packs or maintenance releases. Testing of software patches is crucial. Company-C \ncreates a patch test process within this policy. After a patch has been determined valid, it \nshall be placed in a test environment that closely mirrors the production environment. \nCritical applications and supported operating platforms must be fully accounted for while \ntesting the patch infrastructure. \nChange Management Policy\nChange management practices are applied to the patch management process and any other \nconfiguration or system changes within the whole infrastructure. After a configuration or a \nsystem has been identified for change, a request-for-change must be submitted, and the \nconfiguration should be modified according to the procedures that the change management \nprocess has established.\nInternet Usage Policy\nThe Internet usage policy allows for reasonable use of the Internet by outlining the \npermitted and prohibited behaviors and defining violations. This policy should apply to all \nInternet users who access the Internet through the computing or networking resources. This \nincludes permanent, full-time, and part-time employees; contract workers; temporary \nagency workers; business partners; and vendors. The Internet users of your organization are \nexpected to be familiar with and to comply with this policy, which should also require the \nuse of common sense and good judgment while using Internet services.\nDeploying IPsec Remote Access VPN\nCompany-C deploys a cluster of Cisco ASAs to provide IPsec remote access VPN services. \nFigure 12-59 illustrates the topology listing the Cisco ASAs and their corresponding IP \naddresses.\n"
        },
        {
            "page_number": 430,
            "text": "Case Study of a Large Enterprise     407\nFigure 12-59 Remote Access VPN Cisco ASAs\nThe following are the IP addresses of each interface on the first Cisco ASA (ASA-1):\n•\nManagement interface: 10.250.30.1\n•\nInside interface: 10.250.10.1\n•\nOutside interface: 209.165.202.129\nThe following are the IP addresses of each interface on the second Cisco ASA (ASA-2):\n•\nManagement interface: 10.250.30.2\n•\nInside interface: 10.250.10.2\n•\nOutside interface: 209.165.202.130\nInternet\nCorporate\nNetwork\nRemote Access\nVPN ASA Cluster\nVirtual IP 209.165.202.131\nASA-2\nASA-1\nManagement IP: 10.250.30.1\nOutside: 209.165.202.129\nInside: 10.250.10.1\nManagement IP: 10.250.30.2\nOutside: 209.165.202.130\nInside: 10.250.10.2\nRemote Users\n"
        },
        {
            "page_number": 431,
            "text": "408\nChapter 12:  Case Studies\nThe following sections demonstrate how the Cisco ASAs are configured for IPsec and SSL \nremote access VPN.\nConfiguring IPsec Remote Access VPN\nThe administrator completes the following steps to configure IPsec remote access VPN on \nthe Cisco ASAs:\nStep 1\nLog in to the Cisco ASA using ASDM.\nStep 2\nOn the main menu, choose Wizards.\nStep 3\nSelect the IPsec VPN Wizard.\nStep 4\nThe IPsec VPN Wizard starts. Specify the tunnel type as shown in \nFigure 12-60.\nFigure 12-60 Configuring the Tunnel Type\nStep 5\nAll remote access VPN clients will be connecting to the outside interface. \nChoose the outside interface from the VPN Tunnel Interface drop-down \nmenu, as shown in Figure 12-60.\nStep 6\nEnable inbound IPsec sessions to bypass all configured ACLs, as shown \nin Figure 12-60.\n"
        },
        {
            "page_number": 432,
            "text": "Case Study of a Large Enterprise     409\nStep 7\nClick Next.\nStep 8\nThe screen shown in Figure 12-61 is displayed. Under VPN Client Type,\nclick Cisco VPN Client, Release 3.x or higher, or other Easy VPN \nRemote product.\nFigure 12-61 Remote Access VPN Client Type\nStep 9\nClick Next.\nStep 10 The screen shown in Figure 12-62 is displayed. Configure a preshared \nkey and a VPN tunnel group, as shown in Figure 12-62. In this example, \nthe preshared key is 1qaz2wsx, and the tunnel group is IPSEC-RA-\nGROUP.\nStep 11 Click Next.\nStep 12 The screen shown in Figure 12-63 is displayed. In this example, the \nCisco ASAs are configured for external authentication to a RADIUS \nserver. The AAA server group name is RADIUS-Server, as shown in \nFigure 12-63.\n"
        },
        {
            "page_number": 433,
            "text": "410\nChapter 12:  Case Studies\nFigure 12-62 VPN Client Authentication Method and Tunnel Group Name\nFigure 12-63 Client Authentication\n"
        },
        {
            "page_number": 434,
            "text": "Case Study of a Large Enterprise     411\nStep 13 Click Next.\nStep 14 The screen shown in Figure 12-64 is displayed. This screen allows you \nto configure an IP address pool used for remote access VPN connections. \nClick New to add a new pool.\nFigure 12-64 IPsec Remote Access VPN IP Address Pool\nStep 15 Specify a name for the IP address pool. In this example, the name of the \npool is IPSec-Pool.\nStep 16 Configure the starting and ending IP addresses, in addition to a subnet \nmask. In this example, the address range in the pool is from 10.250.50.1\nto 10.250.50.254, with a 24-bit subnet mask (255.255.255.0).\nStep 17 Click Next.\nStep 18 The screen shown in Figure 12-65 is displayed. This screen allows you \nto configure the primary and secondary DNS and WINS servers, in \naddition to the domain name. In this example, the primary DNS server is \n172.18.124.12; the secondary DNS server is 172.18.124.13; the primary \nWINS server is 172.18.124.14; and the secondary WINS server is \n172.18.124.15. The domain name is companyc.com.\n"
        },
        {
            "page_number": 435,
            "text": "412\nChapter 12:  Case Studies\nFigure 12-65 DNS and WINS Server Configuration\nStep 19 Click Next.\nStep 20 The screen shown in Figure 12-66 is displayed. This screen allows \nyou to configure the IKE policy used by remote access VPN \nconnections. In this example, the encryption algorithm used is \nAES-256. SHA is used for authentication, and the Diffie-Hellman \n(DH) group used is 5.\nStep 21 Click Next.\nStep 22 The screen shown in Figure 12-67 is displayed. This screen allows you \nto configure the IPsec encryption and authentication parameters. In this \nexample, the encryption protocol used is AES-256, and SHA is used for \nIPsec Phase 2 authentication.\n"
        },
        {
            "page_number": 436,
            "text": "Case Study of a Large Enterprise     413\nFigure 12-66 Remote Access VPN IKE Policy\nFigure 12-67 Remote Access VPN IPsec Encryption and Authentication\n"
        },
        {
            "page_number": 437,
            "text": "414\nChapter 12:  Case Studies\nStep 23 Click Next.\nStep 24 The screen shown in Figure 12-68 is displayed. This screen allows you \nto configure the Cisco ASA to bypass NAT for remote access VPN \nconnections. In this case, the inside network is selected (10.250.10.0/24).\nThe inside 10.250.10.0/24 network will not be translated \nwhen communicating with remote access VPN clients.\nFigure 12-68 Bypassing NAT and Configuring Split Tunneling\nStep 25 The screen shown in Figure 12-68 also allows you to configure split \ntunneling for remote access VPN connections. To enable split tunneling, \nselect Enable split tunneling to let remote users have simultaneous \nencrypted access to the resources defined earlier, and unencrypted access \nto the Internet option.\nStep 26 Click Next.\nStep 27 A summary screen appears. Click Finish to apply the changes to the \nCisco ASA.\n"
        },
        {
            "page_number": 438,
            "text": "Case Study of a Large Enterprise     415\nConfiguring Load-Balancing\nThe administrator configures load-balancing on each security appliance. The following are \nthe steps to configure load-balancing for remote access VPN.\nStep 1\nLog in to the Cisco ASA using ASDM.\nStep 2\nOn the main menu, choose Wizards.\nStep 3\nChoose the High Availability and Scalability Wizard.\nStep 4\nThe High Availability and Scalability Wizard starts. The screen shown in \nFigure 12-69 is displayed. Click Configure VPN Cluster Load \nBalancing, as shown in Figure 12-69.\nFigure 12-69 High Availability and Scalability Wizard\nStep 5\nClick Next.\nStep 6\nThe screen shown in Figure 12-70 is displayed. Enter the cluster IP \naddress. The cluster IP address is the virtual address that VPN clients will \nuse to connect to the cluster. In this example, the cluster IP address is \n209.165.202.131.\n"
        },
        {
            "page_number": 439,
            "text": "416\nChapter 12:  Case Studies\nFigure 12-70 VPN Cluster Load-Balancing Configuration\nStep 7\nEnter a UDP port for load-balancing communication between all Cisco \nASAs within the cluster. In this example, the default UDP port (9023)\nis used.\nStep 8\nOptionally, you can encrypt all VPN load-balancing traffic. Check the \nEnable IPsec encryption option to enable encryption.\nStep 9\nConfigure a preshared secret. In this example, the preshared secret is \n2wsx1qaz.\nStep 10 The priority is set to 5. The higher the priority, the more commonly that \nthis ASA will become the master of the cluster.\nStep 11 The public interface is the outside interface in this example. The private \ninterface is the inside interface, as shown in Figure 12-70.\nStep 12 Click Next.\nStep 13 A summary screen is displayed.\nStep 14 Click Finish to apply the configuration to the Cisco ASA.\n"
        },
        {
            "page_number": 440,
            "text": "Case Study of a Large Enterprise     417\nExample 12-13 shows the Cisco ASA remote access VPN and load-balancing CLI \nconfiguration.\nExample 12-13 Cisco ASA Remote Access VPN and Load-Balancing Configuration \nhostname asa-1\n!\ninterface GigabitEthernet0/0\n description Outside interface connected to the Internet\n nameif outside\n security-level 0\n ip address 209.165.202.129 255.255.255.0\n!\ninterface GigabitEthernet0/1\n description Inside interface connected to corporate network\n nameif inside\n security-level 100\n ip address 10.250.10.1 255.255.255.0\n!\ninterface Management0/0\n nameif management\n security-level 0\n ip address 10.250.30.1 255.255.255.0\n management-only\n!\n!Split tunneling ACL\naccess-list IPSEC-RA-GROUP_splitTunnelAcl standard permit 10.250.10.0 255.255.255.0\n!ACL to bypass NAT for remote access VPN connections\naccess-list inside_nat0_outbound extended permit ip 10.250.10.0 255.255.255.0 \n10.250.50.0 255.255.255.0\n !\n !IP address pool for remote access VPN clients\nip local pool IPSec-Pool 10.250.50.1-10.250.50.254 mask 255.255.255.0\n!\n!NAT configuration\nnat (inside) 0 access-list inside_nat0_outbound\n!\n!RADIUS Configuration for remote access VPN authentication\naaa-server RADIUS-Server protocol radius\naaa-server RADIUS-Server (management) host 172.18.85.181\n timeout 5\n key cisco123\n!\n!Crypto map configuration\ncrypto ipsec transform-set ESP-AES-256-SHA esp-aes-256 esp-sha-hmac\ncrypto dynamic-map SYSTEM_DEFAULT_CRYPTO_MAP 65535 set transform-set ESP-AES-256-\nSHA \ncrypto map outside_map 65535 ipsec-isakmp dynamic SYSTEM_DEFAULT_CRYPTO_MAP\ncrypto map outside_map interface outside\ncontinues\n"
        },
        {
            "page_number": 441,
            "text": "418\nChapter 12:  Case Studies\nReacting to a Security Incident\nIt is 4:00 a.m. (0400) on Christmas day, and the CSIRT team hotline rings with a call from \none of the database administrators. The network is congested, and no transactions are \npossible to the most critical application in the organization from different sections of the \norganization. The CSIRT collects all available information from the database administrator \nand completes the steps described in the following sections.\n!\n!ISAKMP enabled on the outside interface\ncrypto isakmp enable outside\n!ISAKMP policy for Remote Access VPN\ncrypto isakmp policy 10\n authentication pre-share\n encryption aes-256\n hash sha\n group 5\n lifetime 86400\n!\n!Load-balancing Configuration\nvpn load-balancing\n cluster key 2wsx1qaz\n cluster ip address 209.165.202.131\n cluster encryption\n participate\n!\n!Remote Access Group Configuration\ngroup-policy IPSEC-RA-GROUP internal\ngroup-policy IPSEC-RA-GROUP attributes\n wins-server value 172.18.124.14 172.18.124.15\n dns-server value 172.18.124.12 172.18.124.13\n vpn-tunnel-protocol IPSec\n split-tunnel-policy tunnelspecified\n split-tunnel-network-list value IPSEC-RA-GROUP_splitTunnelAcl\n default-domain value companyc.com\ntunnel-group IPSEC-RA-GROUP type remote-access\ntunnel-group IPSEC-RA-GROUP general-attributes\n address-pool IPSec-Pool\n authentication-server-group RADIUS-Server\n default-group-policy IPSEC-RA-GROUP\ntunnel-group IPSEC-RA-GROUP ipsec-attributes\n pre-shared-key *\nExample 12-13 Cisco ASA Remote Access VPN and Load-Balancing Configuration (Continued)\n"
        },
        {
            "page_number": 442,
            "text": "Case Study of a Large Enterprise     419\nIdentifying, Classifying, and Tracking the Security Incident or Attack\nOne of the members of the CSIRT collects NetFlow data from the data center distribution \nswitch and correlates this data with CS-MARS. He notices that most of the traffic is \nHTTP (TCP port 80). This traffic is originating from known sources in the sales department \n(floor) in the New York office and from unknown sources. The CSIRT team works with a \nnetwork administrator and discovers that the unknown sources are IP addresses belonging \nto the Atlanta branch office network. However, this process took almost an hour. \nReacting to the Incident\nThe CSIRT team works with the network administrators in the Atlanta and New York \noffices to configure an ACL on the router in the Atlanta office and a VACL on the access \nswitch in the sales floor. This ACL only blocks HTTP traffic from the offending machines. \nThe malicious traffic has been contained, but it is possible that other machines have been \ninfected.\nThe CSIRT team works with the desktop support group and server administrators. After \ndoing research and forensics on the traffic, they discover that the traffic pattern is similar to \na published vulnerability on security intelligence sites such as Cisco Security Center and \nUS-CERT. However, their network IPS and other mechanisms were not able to detect \nthe threat because the necessary signatures were not installed.\nThe server administrators and desktop support representatives download a security patch \nfrom the operating system vendor. Subsequently, they install this operating system patch \non the affected machines. They also push this update via their patch management system to \nall machines within the organization. In addition, the correct signatures are installed on \nthe IPS systems within the organization.\nPostmortem\nThe CSIRT creates a postmortem including the following information:\n•\nTotal amount of labor spent working on the incident\n•\nElapsed time from the beginning of the incident to its resolution\n•\nElapsed time for each stage of the incident-handling process \n•\nTime it took the incident response team to respond to the initial report of the incident\n•\nEstimated monetary damage from the incident\n•\nLessons learned\n•\nAction plan\n"
        },
        {
            "page_number": 443,
            "text": "420\nChapter 12:  Case Studies\nThe lessons learned section in the postmortem is documented, including all items that will \nimprove the incident response process and the proactive preparation of resources and \nprocesses to better defend against new threats. In this example, the following are areas that \nshould be improved and are taken into an action plan:\n•\nThe incident identification process was successful because the correct tools and \nmechanisms were in place. However, the identification of the Atlanta office IP address \nspace was not obvious, and the process was delayed for more than an hour. Better \ndocumentation and diagrams should be prepared to avoid this in the future. The \nCSIRT team, in addition to network administrators, should have this information \naccessible when responding to an attack.\n•\nIPS signatures were not upgraded because of a bad tuning and update process. A new \nprocess is developed to address this caveat.\n•\nACLs were deployed manually to contain and mitigate the attack. The network \nengineering teams will evaluate and create other tools and technologies, such as \nremotely triggered black holes (RTBH) or more appropriate mechanisms, to \nquarantine infected sources in a more effective fashion.\nEach item on this action plan is assigned an owner and a due date.\nSummary\nThis chapter covered three case studies: a small business, a medium-sized enterprise, \nand a large enterprise. It demonstrated some of the most common applications and \nprocedures discussed within this book. However, each of the previous chapters \npresented detailed instructions on how to proactively and reactively defend against \nsecurity threats.\nVarious configuration examples were included in this chapter. The examples included \ninfrastructure protection mechanisms and practices, basic firewall configuration, \nsite-to-site and remote access VPNs, and a basic example of a CSIRT responding to \na security incident. Security threats such as distributed denial of service (DDoS) \nattacks, worms, and others can result in significant loss of time and money for many \norganizations. It is highly recommended that you consider the extent to which the \norganization could afford a significant service outage and take steps commensurate \nwith the risk.\n"
        },
        {
            "page_number": 444,
            "text": "Summary     421\nThe network security lifecycle requires specialized support and a commitment to best \npractice standards. In this book, you learned best practices drawn upon disciplined \nprocesses, frameworks, expert advice, and proven technologies that will help you protect \nyour infrastructure and organization. You learned the complete security lifecycle of a \nnetwork, from strategy development to operations and optimization. You must take a \nproactive approach to security, an approach that starts with an assessment to identify and \ncategorize your risks. In addition, you need to understand the network security technical \ndetails relating to security policy and incident response procedures. This book covered \nnumerous best practices that will help you orchestrate a long-term strategy for your \norganization.\n"
        },
        {
            "page_number": 445,
            "text": ""
        },
        {
            "page_number": 446,
            "text": "I N D E X\nNumerics\n802.1x, 219\naccess layer (IP telephony), 271\nauthentication negotiation schemes, 220\nauthenticators, 26\ncomponents of, 219\nconfiguring Secure ACS Servers, 229, 232–233\nconfiguring with EAP-FAST in Unified \nWireless Solutions, 226\nEAP methods, 220–221\nIEEE 802.1x, 26\nsupplicants, 26\nA\nAAA\nidentity and trust (SAVE framework), 183–184\ninfrastructure devices, configuring\nmedium-sized business case studies, \n400–401\nAAA (Authentication, Authorization, \nAccounting), 23\nidentity management solutions/systems, 26\nIBNS, 26\nIEEE 802.1x, 26\nRADIUS, 23, 25\nTACACS+, 25\naaa authorization command, 65\naaa new-model command, 65\naccess control\nsmall business case study, 352\naccess layer (IP telephony), 265, 272\n802.1x, 271\nARP, 270\nBPDU, 268\nDAI, 270\nDHCP snooping, 269–270\nNAC, 271\nport security, 268–269\nroot guards, 268\nVLAN assignment, 267\naccess-class command\ninteractive access control (infrastructure \nsecurity), 62\naccounting, 23\nACL\nblocking unauthorized hosts/users from routers, \n6\nexception ACL, configuring, 64\nACL (Access Control Lists), 157\ncontrolling FWSM access via, 317–321\niACL (infrastructure Access Control Lists)\ninfrastructure security policy enforcement, \n82\nIPv6 filtering, 331–332\nrACL (receive Access Control Lists)\ninfrastructure security, 78–80\nVACL, 157\naction plans, building, 173–174\nactive-standby failovers\nASA, configuring on\nmedium-sized business case studies, \n394–396, 398–399\nAES (Advanced Encryption Standard) \nencryption protocol\nWEP, 218\nAIP-SSM\nASA, configuring on\nmedium-sized business case studies, \n391–394\nAironet AP (Access Points)\nmanaging, 216\nanalyzing data\npostmortems, 169\nanomaly detection\nIPS devices, 137–138\nvisibility (SAVE framework), 190\nanomaly detection systems, 22\nanomaly detection zones\nisolation and virtualization (SAVE framework), \n198\nanomaly/telemetry detection\nCS-MARS, 121–122, 125\nGuard XT, 127, 129–131\nIPS, 137–138\nNAM, 125–126\n"
        },
        {
            "page_number": 447,
            "text": "424\nNetFlow, 108\nCisco platform support, 108\ncollecting CLI statistics, 112–114\nEgress NetFlow, 111\nenabling, 111–112\nflows, elements of, 109\nflows, exporting data from, 110\nflows, obtaining additional information \nfrom, 109–110\nIngress NetFlow, 111\nIPFIX WG, 110\nNDE packet templates, 110\nopen source monitoring tools, 126–127\nSNMP, 118–119\nenabling IOS router/switch logging, \n119–121\nenabling logging on ASA security \nappliances, 121\nenabling logging on PIX security \nappliances, 121\nSYSLOG, 115\nenabling IOS router/switch logging, \n115–116\nenabling logging on ASA security \nappliances, 117–118\nenabling logging on CATOS running \ncatalyst swtiches, 117\nenabling logging on PIX security \nappliances, 117–118\nTAD XT, 127–128, 131\nanomaly-based analysis, 21\nantispoofing\nsmall business case study, 353\nantispoofing techniques, 141\nAP (Access Points)\nAironet\nmanaging, 216\nautonomous mode, 215\nLWAPP, 215\nunified mode, 215\nUnified Wireless Architectures, 215\nARP (Address Resolution Protocol)\naccess layer (IP telephony), 270\nproxy ARP\ninfrastructure security, disabling for, 73\nASA\nactive-standby failovers, configuring\nmedium-sized business case studies, \n394–396, 398–399\nAIP-SSM, configuring\nmedium-sized business case studies, \n391–394\nASA security appliances\nenabling SYSLOG logging on, 117–118, 121\nAtlanta Office Cisco IOS configuration (small \nbusiness case studies)\nconfiguring, 360\nlocking down IOS routers, 360, 363, 366, \n368, 370–375\nNAT configuration, 376\nsite-to-site VPN, 377, 380–381, 383, 385, \n387, 389\nattacks\nlarge business case studies, 419–420\nauthentication, 23\nHTTP\ninfrastructure security, 63\nRADIUS, 23, 25\nrouting protocols\nidentity and trust (SAVE framework), 189\ninfrastructure security, 68–69\ntunneled authentication, 224\nwireless networks, 216\n802.1x, 219–221, 226, 229, 232–233\nconfiguring CSSC, 233–234, 236\nconfiguring WLC, 226, 228\nEAP-FAST, 224–226, 229, 232–233\nEAP-GTC, 225\nEAP-MD5, 221–222\nEAP-TLS, 223\nEAP-TTLS, 224\nLEAP, 222\nPEAP, 223, 225\nWEP, 216–218\nWPA, 218\nauthentication banners\nconfiguring\ninfrastructure security, 62\nAuthentication Servers (802.1x), 219\nauthenticators (802.1x), 26, 219\nauthorization, 23\nanomaly/telemetry detection\n"
        },
        {
            "page_number": 448,
            "text": " 425\nauto secure command\ninfrastructure security, 84–85\nautonomous mode (AP), 215\nAutopsy (Linux forensics tool), 162–163\nAutoSecure (Cisco IOS)\ninfrastructure security, 84–88\nB\nbackscatter, 146\nbanners\nauthentication banners\nconfiguring for infrastructure security, 62\nbase metrics (CVSS), 51\nBGP (Border Gateway Protocol)\nrouters\nhop-by-hop tracebacks, 146\nblack-box penetration testing, 46\nbogon addresses, 37\nBOOTP servers\ninfrastructure security, disabling for, 73\nbotnets\nhop-by-hop tracebacks, 145\nBGP routers, 146\nShadowserver.com website, 145\ntracebacks, 150\nbots, 99\nBPDU (Bridge Protocol Data Units)\nIP telephony\naccess layer, 268\nbroadcast amplification attacks. See smurf \nattacks, 334\nC\nCAM (Clean Access Manager), NAS Appliance, \n27, 31\nCAS (Clean Access Servers), NAC Appliance, \n27–28\nCentralized Deployment mode, 31\nEdge Deployment mode, 30\nReal IP mode, 29\nVirtual Gateway mode, 28\ncase studies\nlarge businesses, 401, 403\nCSIRT, 403\nincident response, 419–420\nIPsec remote access VPN, \n406, 408, 411–412, 415–417\nload-balancing, 415–417\nsecurity policy creation, 404–406\nmedium-sized businesses, 389\nconfiguring AAA on infrastructure devices, \n400–401\nconfiguring active-standby failovers on \nASA, 394–396, 398–399\nconfiguring AIP-SSM on ASA, 391–394\nInternet edge routers, 391\nsmall businesses, 341–343, 360\naccess control, 352\nantispoofing configuration, 353\nIdentity NAT, 351\nIM, 354–355, 357–359\nIP addressing/routing, 343\nlocking down IOS routers, 360, 363, 366, \n368, 370–375\nNAT configuration, 376\nPAT, 347\nsite-to-site VPN, 377, 380–381, 383, 385, \n387, 389\nStatic NAT, 349\ncatalyst switches\nCATOS running switches\nenabling SYSLOG logging on, 117\nCATOS (Catalyst Operating System)\ncatalyst switches\nenabling SYSLOG logging on, 117\nCDP\nvisibility (SAVE framework), 191\nCDP (Cisco Discovery Protocol)\ninfrastructure security, disabling for, 71\nCEF tables\nvisibility (SAVE framework), 191\nCentralized Deployment mode (CAS), 31\nchange management policies\nlarge business case studies, 406\nchangeto context command\nFWSM configuration for data center \nsegmentation, 312\nchangeto context command\n"
        },
        {
            "page_number": 449,
            "text": "426\nchecklists\nincident-handling policies, 154–155\nCIRCA (Cisco Incident Response \nCommunications Arena), 54\nCisco Catalyst switches\ndata center segmentation, configuring for, \n309–310\nCisco Guard\nactive verification\nidentity and trust (SAVE framework), 185\ndata center security, 302\nCisco IOS\nAutoSecure\ninfrastructure security, 84–88\nCisco Personal Assistant\nsecuring, 289\nhardening operating environment, \n289–290\nserver security policies, 291–293\nCisco Security Center, 50\nCisco Unified CallManager (IP telephony), \nsecuring, 276–277\nCisco Unified CME (Communications Manager \nExpress)\nsecuring, 277–281\nCisco Unity\nsecuring, 281–282, 286–287\nTCP/UDP ports, 282–285\nCisco Unity Express\nsecuring, 287–288\nclassifying security threats\nCS-MARS, 121–122, 125\nGuard XT, 127, 129–131\nIDS, 131\nsignature updates, 131–132\ntuning, 133–134, 136\nIPS, 131\nanomaly detection, 137–138\nIDM, 132\nsignature updates, 131–132\ntuning, 133–134, 136\nNAM, 125–126\nNetFlow, 108\nCisco platform support, 108\ncollecting CLI statistics, 112–114\nEgress NetFlow, 111\nenabling, 111–112\nflows, elements of, 109\nflows, exporting data from, 110\nflows, obtaining additional information \nfrom, 109–110\nIngress NetFlow, 111\nIPFIX WG, 110\nNDE packet templates, 110\nnetwork visibility, 101, 103, 106–107\nopen source monitoring tools, 126–127\nSNMP, 118–119\nenabling IOS router/switch logging, \n119–121\nenabling logging on ASA security \nappliances, 121\nenabling logging on PIX security \nappliances, 121\nSYSLOG, 115\nenabling IOS router/switch logging, \n115–116\nenabling logging on ASA security \nappliances, 117–118\nenabling logging on CATOS running \ncatalyst switches, 117\nenabling logging on PIX security \nappliances, 117–118\nTAD XT, 127–128, 131\nClean Access Agents (NAC appliance), 27\nCLI\nNetFlow statistics\ncollecting, 112–114\nCLI Views\nenable view command, 65\ninfrastructure security, 64–65\nisolation and virtualization (SAVE framework), \n197\nLawful intercept views, 64\nparser view command, 65\nRoot views, 64\nSuperviews, 64\nusername command, 65\ncollaboration (incident-handling policies/\nprocedures), 153\ncollecting data\npostmortems, 169\nComputer Fraud and Abuse Act, 156\nconfidentiality\npenetration tests, 48\nchecklists\n"
        },
        {
            "page_number": 450,
            "text": " 427\nconfiguration logger (IOS)\ninstrumentation and management (SAVE \nframework), 195\nconfiguration rollback feature (IOS)\ninstrumentation and management (SAVE \nframework), 195\nConfigure EAP Method screen (CSSC), 234\nconfiguring\nauthentication banners\ninfrastructure security, 62\nexception ACL, 64\nNAT\nsmall business case study, 376\nCOPM (Cisco Operational Process Model), \nthreat modeling, 45\nCOPM (Cisco Operational Process Model). See \nSAVE, 177\nCoPP (Control Plane Policing)\nCPU traffic\ninfrastructure security, 80\ncore layer (IP telephony), 265, 275\ncorrelation (SAVE framework), 192\nCSA-MC, 193\nCS-MARS, 193\nPeakflow SP, 193\nPeakflow X, 193\nCPU\nCoPP\ninfrastructure security, 80\nfiltering traffic sent to\ninfrastructure security, 78\ninterrupt time\nprocessors versus (infrastructure \nsecurity), 78\npacket registration\ninfrastructure security, 78\nprocessors\ninterrupt time versus (infrastructure \nsecurity), 78\nrACL\ninfrastructure security, 78–80\nrate limiting traffic\ninfrastructure security, 78\nscheduler allocate command\ninfrastructure security, 81\nscheduler interval command\ninfrastructure security, 81\nCPU threshold notifications, 76\ncrystal-box (grey-box) penetration testing, 46\nCSA (Cisco Security Agent), 11\nendpoint security, 92–94\nCSA (Cisco Security Agents)\ndata centers, deploying for, 325\nconfiguring agent kits, 326\nCSA architectures, 325–326\nphased deployments, 326–327\nCSA-MC (Cisco Security Agent Mangement \nConsole)\ncorrelation (SAVE framework), 193\nCSIRT\npostmortems\nlarge business case studies, 419–420\nCSIRT (Computer Security Incident Response \nTeams), 52\nincident response collaborative teams, 54\nlarge business case studies, 403\nresponsiblities of, 54\nselecting personnel for, 53\ntasks of, 54\nCSM\ndata center security\nSYN cookies, 299\nCSM (Cisco Security Manager)\ninstrumentation and management (SAVE \nframework), 195\nCS-MARS\ncorrelation (SAVE framework), 193\ntracebacks, 148\nCS-MARS (Cisco Security Monitoring, Analysis \nand Response System), 121–122, 125\nCSSC\nConfigure EAP Method screen, 234\nconfiguring\nwireless networks, 233–234, 236\nNetwork Authentication screen, 234\nNetwork Profile screen, 233\nCVSS (Common Vulnerability Scoring System), \n50\nbase metrics, 51\nenvironmental metrics, 52\ntemporal metrics, 51\nCVSS (Common Vulnerability Scoring System)\n"
        },
        {
            "page_number": 451,
            "text": "428\nD\nDAI (Dynamic Address Inspection)\naccess layer (IP telephony), 270\ndark IP addresses, 37\ndata analysis\npostmortems, 169\ntelemetry\ninfrastructure security, 89\ndata centers, 297\nCSA, deploying, 325\nconfiguring agent kits, 326\nCSA architectures, 325–326\nphased deployments, 326–327\nDoS attacks, 297\nCisco Guard, 302\nFlexible NetFlow, 301\nIDS, 300\nIPS, 300\nNetFlow, 301\nSYN cookies, 297–299\ninfrastructure protection, 302–303\nnetwork intrusion detection/prevention systems, \ndeploying, 322\nmonitoring, 325\nsending selective traffic to IDS/IPS \ndevices, 322, 324\ntuning, 325\nsegmentation, 303–304\nFWSM, 306–314, 316–322\ntiered access control, 303–304\nworms, 297\nCisco Guard, 302\nFlexible NetFlow, 301\nIDS, 300\ninfrastructure protection, 302–303\nIPS, 300\nNetFlow, 301\ndata collection\npostmortems, 169\ndata transmission\ntelemetry\ninfrastructure security, 89\ndeep packet inspection, 10\ndeep-packet inspection, 9\ndevice authorize command, 272\ndevice security policies\nlarge business case studies, 405\nDHCP\nsnooping\nidentity and trust (SAVE framework), \n186–187\nDHCP snooping\naccess layer (IP telephony), 269–270\ndiagrams (networks)\nhigh-level enterprise diagrams, 101, 103\nlayered diagrams, 106\ndigital certificates\nidentity and trust (SAVE framework), 188\nDirected Broadcasts (IP)\ninfrastructure security, disabling for, 72\ndistance vector protocols (IGP), 67\ndistribution layer (IP telephony), 265, 273\nGLBP, 274\nHSRP, 273–274\ndistribution layer switches\nNetFlow\nconfiguring at, 103\nDMZ (demilitarized zones), 10\nDMZ servers\nStatic NAT\nsmall business case study, 349\ndocumentation\nincident-handling policies, 154–155\nDoS (Denial of Service) attacks\ndata center security, 297\nCisco Guard, 302\nFlexible NetFlow, 301\nIDS, 300\ninfrastructure protection, 302–303\nIPS, 300\nNetFlow, 301\nSYN cookies, 297–299\ndot-dot attacks\ntracebacks, 148\ndotlx port-control auto command, 271\nDREAD model (threat modeling), 44–45\nE\nEAP methods\n802.1x, 220–221\nDAI (Dynamic Address Inspection)\n"
        },
        {
            "page_number": 452,
            "text": " 429\nEAP-FAST, 224–225\nconfiguring 802.1x in Unified Wireless \nSolutions, 226\nconfiguring Secure ACS Servers, 229, 232–233\nEAP-GTC, 225\nEAP-MD5, 221–222\nEAP-TLS, 223\nEAP-TTLS (EAP Tunneled TLS Authentication \nProtocol), 224\neavesdropping attacks\nIP telephony, 293–294\nEdge Deployment mode (CAS), 30\nEGP (Exterior Gateway Protocols), 67\nEgress NetFlow, 111\nenable view command, 65\nEnCase (Guidance Software), 165\nendpoint security\nCSA, 92–94\npatch management, 90–91\nengineering (social), 49\nEnterprise\ntracebacks, 147\nCS-MARS, 148\ndot-dot attacks, 148\nenvironmental metrics (CVSS), 52\nescalation procedures (incident-handling policies/\nprocedures), 154\nescalation procedures (NAC), 97\nethical hacking. See penetration testing, 46\nexception ACL, configuring, 64\nexec-timeout command\nmodifying idle timeouts, 63\nextension headers\nIPv6, 332\nexternal databases (802.1x), 219\nF\nfailovers\nactive-standby failovers\nmedium-sized business case studies, 394–\n396, 398–399\nfeedback\nlooped feedback\npostmortems, 167\nfiltering\nCPU traffic\ninfrastructure security, 78\nIPv6, 331\nACL, 331–332\nroutes\ninfrastructure security, 69\nFinger Protocol\ninfrastructure security, disabling for, 72\nfirewalls, 5\ndata center security\nSYN cookies, 297–299\nnetwork firewalls, 6\ndeep packet inspection, 10\nDMZ, 10\nNAT, 7–8\npacket filters, 7\nrouter configurations, 6\nstateful firewalls, 9\npersonal firewalls, 11\nCSA, 11\nsegmentation\nisolation and virtualization (SAVE \nframework), 200\nFIRST (Forum for Incident Response and \nSecurity Teams)\ntracebacks, 142\nFlexible NetFlow\ndata center security, 301\nforensics, 160\nLinux forensics tools, 162–163\nnetstat command, 163\npstree command, 163\nlog files, 161\nWindows forensics tools\nEnCase, 165\nSysternals, 164\nfragment command\nFWSM, data center segmentation, 322\nfragmentation\nIPv6, 333\nFWSM\ndata center segmentation, 306, 308\nconfiguring Cisco Catalyst switches, \n309–310\nconfiguring NAT, 313–314, 316\nFWSM\n"
        },
        {
            "page_number": 453,
            "text": "430\nconfiguring security context interfaces, \n312–313\ncontrolling access via ACL, 317–321\ncreating security contexts, 310–312\nRouted mode, 306\nTransparent mode, 306–307\nVirtual Fragment Reassembly, 322\nFWSM (Firewall Services Module)\ndata center security\nSYN cookies, 298\nG\nGLBP (Gateway Load Balancing Protocol)\ndistribution layer (IP telephony), 274\ngrey-box (crystal-box) penetration testing, 46\nset port dotlx, 271\nGuard (Cisco)\nactive verification\nidentity and trust (SAVE framework), 185\nGuard XT (Traffic Anomaly Detectors XT)\nidentifying/classifying security threats, 127, \n129–131\nH\nhacking\nethical hacking. See penetration testing, 46\nheaders\nextension headers\nIPv6, 332\nmanipulation attacks\nIPv6, 333\nheuristic-based analysis, 21\nHigh Availability (NAC Appliance), 31\nhigh-level enterprise diagrams, 101, 103\nHIPAA (Health Industry Portability and \nAccountability Act), 156\nhop-by-hop tracebacks, 142\nbotnets, 145\nBGP routers, 146\nzombies, 145\nHSRP (Hot Standby Router Protocol)\ndistribution layer (IP telephony), 273–274\nHTTP\nauthentication\ninfrastructure security, 63\nI\niACL (infrastructure Access Control Lists)\ninfrastructure security policy enforcement, 82\nIB (in-band) mode (NAC appliance), 29\niBGP (interal Border Gateway Protocol), 36\nIBNS (Identity-Based Networking Services), 26\nIC3 (Internet Crime Complaint Center), 156\nICMP\nredirect messages\ninfrastructure security, disabling for, 73\nICMP filtering\nIPv6, 332\nICV (Integrity Check Values), 216–217\nIDENT (Indentity Protocol)\ninfrastructure security, disabling for, 74\nidentifiers (local)\nIPV6, 331\nidentifying security threats\nCS-MARS, 121–122, 125\nGuard XT, 127, 129–131\nIDS, 131\nsignature updates, 131–132\ntuning, 133–134, 136\nIPS, 131\nanomaly detection, 137–138\nIDM, 132\nsignature updates, 131–132\ntuning, 133–134, 136\nNAM, 125–126\nNetFlow, 108\nCisco platform support, 108\ncollecting CLI statistics, 112–114\nEgress NetFlow, 111\nenabling, 111–112\nflows, elements of, 109\nflows, exporting data from, 110\nflows, obtaining additional information \nfrom, 109–110\nIngress NetFlow, 111\nIPFIX WG, 110\nNDE packet templates, 110\nFWSM\n"
        },
        {
            "page_number": 454,
            "text": " 431\nnetwork visibility, 101, 103, 106–107\nopen source monitoring tools, 126–127\nSNMP, 118–119\nASA security appliances, enabling logging \non, 121\nIOS router/switch logging, enabling, \n119–121\nPIX security appliances, enabling logging \non, 121\nSYSLOG, 115\nASA security appliances, enabling logging \non, 117–118\nCATOS running catalyst switches, \nenabling logging on, 117\nIOS router/switch logging, enabling, \n115–116\nPIX security appliances, enabling logging \non, 117–118\nTAD XT, 127–128, 131\nidentity and trust (SAVE framework), 183\nAAA, 183–184\nCisco Guard active verification, 185\nDHCP snooping, 186–187\ndigital certificates, 188\nIKE, 188\nIP Source Guard, 187–188\nNAC, 188\nrouting protocol authentication, 189\nstrict Unicast RPF, 189\nidentity management solutions/systems, 26\nIBNS, 26\nIEEE 802.1x, 26\nIdentity NAT\nsmall business case study, 351\nidle timeouts\nmodifying, 63\nIDM (IPS Device Manager)\nsignature updates, 132\nIDS\ndata center network intrusion detection/\nprevention systems\nsending selective traffic to, 322, 324\nIP telephony eavesdropping attacks, 294\nvisibility (SAVE framework), 190–191\nIDS (Intrusion Detection Systems), 19, 22\nanomaly-based analysis, 21\ndata center security, 300\nheuristic-based analysis, 21\nidentifying/classifying security threats, 131\nsignature updates, 131–132\ntuning, 133–134, 136\npattern matching, 20\nprotocol analysis, 21\nsignatures, 20\nIEEE 802.1x, 26\nIGP (Interior Gateway Protocols)\ndistance vector protocols, 67\nlink state protocols, 67\nIKE\nidentity and trust (SAVE framework), 188\nIM (Instant Messaging)\nsmall business case study, 354–355, 357–359\nIMS (Internet Motion Sensor), security \nintelligence, 50\nincident response\nlarge business case studies, 419–420\nincident response collaborative teams (CSIRT), \n54\nIncident Response Reports, 169\nLessons Learned section, 171\nratings systems, 173\nincident-handling\nACL, 157\nVACL, 157\nforensics, 160\nLinux forensics tools, 162–163\nlog files, 161\nWindows forensics tools, 164–165\nlaw enforcement, 155\nComputer Fraud and Abuse Act, 156\nHIPAA, 156\nIC3, 156\nInfragard, 156\nU.S. Department of Justice website, 156\npolicies/procedures\nchecklists, 154–155\ncollaboration, 153\ndocumentation, 154–155\nescalation procedures, 154\npatch management, 154\nprivate VLAN, 158\nRTBH, 158, 160\nInfragard, 156\nInfragard\n"
        },
        {
            "page_number": 455,
            "text": "432\ninfrastructure devices\nAAA, configuring on\nmedium-sized business case studies, \n400–401\ninfrastructure security, 57\nautomated security tools\nCisco IOS AutoSecure, 84–88\nSDM, 88–89\ndisabling unnecessary services, 70\nBOOTP servers, 73\nCDP, 71\nFinger protocol, 72\nICMP redirect messages, 73\nIDENT, 74\nIP Directed Broadcasts, 72\nIP source routing, 73\nIPv6, 75\nMOP, 72\nPAD, 73\nproxy ARP, 73\nTCP/UDP small servers, 74\nlocking unused network access device ports, 75\npolicy enforcement, 81\niACL, 82\nUnicast RPF, 83–84\nresource exhaustion control, 75\nCoPP, 80\nCPU packet generation, 78\nfiltering CPU traffic, 78\nprocessors versus interrupt time, 78\nrACL, 78–80\nrate limiting CPU traffic, 78\nresource threshold notifications, 76–77\nscheduler allocation command, 81\nscheduler interval command, 81\nrouter planes, 57–58\nrouting protocols, 67\nauthentication, 68–69\nroute filtering, 69\nstatic routing peers, 68\nTTL security checks, 70\nstrong device access control, 59\nauthentication banner configuration, 62\nCLI Views, 64–65\ninteractive access control, 62–64\nlocal password management, 61\nSNMP access control, 66\nSSH versus Telnet, 59–60\ntelemetry, 89\nIngress NetFlow, 111\ninstrumentation and management (SAVE \nframework), 193\nCisco IOS configuration logger logs, 195\nCisco IOS configuration rollback feature, 195\nCisco IOS CR XML interface, 196\nCSM, 195\nembedded device managers, 195\nRMON, 196\nSNMP, 196\nSyslog, 196\nintelligence (security), 50\nCisco Security Center, 50\nCVSS, 50\nbase metrics, 51\nenvironmental metrics, 52\ntemporal metrics, 51\nIMS (Internet Motion Sensor), 50\nresearch initiatives/organizations, 50\ninteractive access control (infrastructure \nsecurity), 62–64\nInternet edge routers\nmedium-sized business case studies, 391\nInternet usage policies\nlarge business case studies, 406\nIOS\nconfiguration logger\ninstrumentation and management (SAVE \nframework), 195\nconfiguration rollback feature\ninstrumentation and management (SAVE \nframework), 195\nCR XML interface\ninstrumentation and management (SAVE \nframework), 196\nrole-based CLI Access\nisolation and virtualization (SAVE \nframework), 197\nIOS routers\nsmall business case study, 360, 363, 366, 368, \n370–375\nSNMP logging, enabling, 119–121\nSYSLOG logging, enabling, 115–116\ninfrastructure devices\n"
        },
        {
            "page_number": 456,
            "text": " 433\nIOS switches\nSNMP logging, enabling, 119–121\nSYSLOG logging, enabling, 115–116\nIP\nsource routing\ninfrastructure security, disabling for, 73\nIP addresses\ndark IP addresses, 37\nIP addressing\nsmall business case study, 343\nIP Directed Broadcasts\ninfrastructure security, disabling for, 72\nip http access-class command\ninteractive access control (infrastructure \nsecurity), 63\nip http authentication command\nenabling HTTP authentication, 63\nip http max-connections command\ninteractive access control (infrastructure \nsecurity), 63\nIP routing\nsmall business case study, 343\nIP Source Guard\nidentity and trust (SAVE framework), 187–188\nIP telephony, 261–262, 265\naccess layer, 265, 272\nARP, 270–271\nBPDU, 268\nDAI, 270\nDHCP snooping, 269–270\nNAC, 271\nport security, 268–269\nroot guards, 268\nVLAN assignment, 267\nCisco Personal Assistant, 289\nhardening operating environment, \n289–290\nserver security policies, 291–293\nCisco Unified CallManager, 276–277\nCisco Unified CME, 277–281\nCisco Unity, 281–282, 286–287\nCisco Unity Express, 287–288\ncore layer, 265, 275\ndistribution layer, 265, 273\nGLBP, 274\nHSRP, 273–274\neavesdropping attacks, 293–294\nip verify source vlan dhcp-snooping interface \nsubcommand\nenabling IP Source Guard, 187\nIPFIX WG (IETF Internet Protocol Flow \nInformation Export Work Group), 110\nIPS\ndata center network intrusion detection/\nprevention systems\nsending selective traffic to, 322, 324\nIP telephony eavesdropping attacks, 294\nvisibility (SAVE framework), 190–191\nIPS (Intrusion Prevention Systems), 19, 22\ndata center security, 300\nidentifying/classifying security threats, 131\nanomaly detection, 137–138\nsignature updates, 131–132\ntuning, 133–134, 136\nIDM, 132\nwireless IPS, 239–240\nconfiguring sensors in WLC, 241–242\nconfiguring signatures, 242–243\nIPsec\nIPv6, 335–337\nremote access VPN\nlarge business case studies, 406, 408, \n411–412, 415–417\nIPsec (IP Security)\ntechnical overview of, 14\nmain mode negotiation, 15–16\nphase 1 negotiation, 14, 16\nphase 2 negotiation, 16–17\nTransport mode, 17\nTunnel mode, 17\nWEP, 218\nIPv4 (Internet Protocol version 4)\nIPv6 versus, 329\nIPv6 (Internet Protocol version 6), 329\nfiltering, 331\nACL, 331–332\nextension headers, 332\nICMP filtering, 332\nfragmentation, 333\nheader manipulation attacks, 333\nIPsec, 335–337\nIPv4 versus, 329\nlocal identifiers, 331\nreconnaissance, 330\nsecurity through obscurity, 330\nIPv6 (Internet Protocol version 6)\n"
        },
        {
            "page_number": 457,
            "text": "434\nrouting security, 334\nsmurf attacks, 334\nspoofing, 333\nsubnet prefixes, 331\nIPv6 (IP Version 6)\ninfrastructure security, disabling for, 75\nipv6 access-list command, 331\nISAC (Information Sharing and Analysis \nCenters), 54\nisolation and virtualization (SAVE framework), \n196\nanomaly detection zones, 198\nCisco IOS role-based CLI Access, 197\nCLI Views, 197\nfirewall segmentation, 200\nnetwork device virtualization, 198–199\nVLAN segmentation, 199\nVRF segmentation, 200\nVRF-Lite segmentation, 200\nITU-T X.805\nSAVE versus, 178, 180–181\nL\nlarge business case studies, 401, 403\nCSIRT, 403\nincident response, 419–420\nIPsec remote access VPN, deploying, 406, 408, \n411–412, 415–417\nload-balancing, 415–417\nsecurity policy creation, 404\nchange management policies, 406\ndevice security policies, 405\nInternet usage policies, 406\npatch management policies, 406\nperimeter security policies, 404\nphysical security policies, 404\nremote access VPN policies, 405\nlaw enforcement, 155\nComputer Fraud and Abuse Act, 156\nHIPAA, 156\nIC3, 156\nInfragard, 156\nU.S. Department of Justice website, 156\nLawful intercept view (CLI Views), 64\nlayer 2 routing\nvisibility (SAVE framework), 191\nlayer 3 routing\nvisibility (SAVE framework), 191\nlayered diagrams, 106\nLEAP, 222\nLessons Learned section (Incident Response \nReports), 171\nlink state protocols (IGP), 67\nLinux\nforensics tools\nAutopsy, 162–163\nnetstat command, 163\npstree command, 163\nSleuth Kit, 162\nload balancers\ndata center security\nSYN cookies, 297–299\nload-balancing\nlarge business case studies, 415–417\nlocal identifiers\nIPv6, 331\nlog files (forensics), 161\nlogging on host command\nenabling SYSLOG logging on ASA/PIX \nsecurity appliances, 117\nlogging on command\nenabling SYSLOG logging on ASA/PIX \nsecurity appliances, 117\nlogging trap command\nenabling SYSLOG logging on ASA/PIX \nsecurity appliances, 117\nSYSLOG logging, 116\nlogic attacks\ndefining, 99\nexamples of, 99\nlogin block-for command\ninteractive access control (infrastructure \nsecurity), 64\nlogin delay command\ninteractive access control (infrastructure \nsecurity), 63\nlogin quiet-mode access-class global command\nconfiguring exception ACL, 64\nlooped feedback\npostmortems, 167\nm/p, 271\nIPv6 (Internet Protocol version 6)\n"
        },
        {
            "page_number": 458,
            "text": " 435\nLWAPP (Lightweight Access Point Protocol), 215\nLWAPP (Lightweight Acess Point Protocol), \n236–239\nM\nmain mode negotiation (IPsec), 15–16\nmedium-sized business case studies, 389\nAAA, configuring on infrastructure devices, \n400–401\nactive-standby failovers, configuring on ASA, \n394–396, 398–399\nAIP-SSM, configuring on ASA, 391–394\nInternet edge routers, 391\nmemory\nthreshold notifications, 77\nmemory free low-watermark io threshold \ncommand\nmemory threshold notifications, configuring for \ninfrastructure security, 77\nmemory free low-watermark processor threshold \nglobal command\nmemory threshold notifications, configuring\nfor infrastructure security, 77\nmemory reserve critical kilobytes command\nmemory threshold notifications, configuring \nfor infrastructure security, 77\nMFP (Management Frame Protection), 243\nmls flow ip interface-full command\ncollecting CLI NetFlow statistics, 114\nmode multiple command\nFWSM configuration for data center \nsegmentation, 311\nmonitoring tools (open source)\nidentifying/classifying security threats, \n126–127\nMOP (Maintenance Operations Protocol)\ninfrastructure security, disabling for, 72\nN\nNAC (Network Admission Control), 27, 94, 245\naccess layer (IP telephony), 271\nadministrative tasks, 96\nappliance configuration, \n246–248, 251, 253–254\nescalation procedures, 97\nidentity and trust (SAVE framework), 188\nNAC Appliance, 27, 33\nCAM, 27, 31\nCAS, 27–31\nClean Access Agents, 27\nHigh Availability, 31\nIB mode, 29\nOOB mode, 29–30\nNAC Framework, 33–34, 36\nNAD, 34\nNAH, 35\nphased deployments, 94–95\nstaff and support, 96–97\nWLC configuration, 255, 257, 259\nNAC Appliance, 27, 33\nCAM, 27, 31\nCAS, 27–28\nCentralized Deployment mode, 31\nEdge Deployment mode, 30\nReal IP mode, 29\nVirtual Gateway mode, 28\nClean Access Agents, 27\nHigh Availability, 31\nIB mode, 29\nOOB mode, 29–30\nNAC Framework, 33–34, 36\nNAD, 34\nNAH, 35\nNAD (NAC Framework), 34\nNAH (NAC Agentless Hosts), 35\nNAM (Network Analysis Module), 125–126\nvisibility (SAVE framework), 191\nNANOG (North American Network Operators \nGroup)\ntracebacks, 142\nNAS (network access servers). See also RADIUS, \n23\nNAT\nconfiguring\nsmall business case study, 376\nNAT (Network Address Translation)\nFWSM configuration for data center \nsegmentation, 313–314, 316\nnetwork firewalls, 7–8\nNAT (Network Address Translation)\n"
        },
        {
            "page_number": 459,
            "text": "436\nNDE packet templates (NetFlow), 110\nNetFlow, 108\nas anomaly detection systems, 22\nCisco platform support, 108\nCLI statistics, collecting, 112–114\ndata center security, 301\ndistribution layer switches\nconfiguring at, 103\nEgress NetFlow, 111\nenabling, 111–112\nFlexible NetFlow, 301\nflows\nelements of, 109\nexporting data from, 110\nIPFIX WG, 110\nobtaining additional information from, \n109–110\nIngress NetFlow, 111\nNDE packet templates, 110\nnetstat command\nLinux forensics, 163\nnetwork access devices\nlocking down unused ports (infrastructure \nsecurity), 75\nNetwork Authentication screen (CSSC), 234\nnetwork devices\nisolation and virtualization (SAVE framework), \n198–199\nnetwork firewalls, 6\ndeep packet inspection, 10\nDMZ, 10\nNAT, 7–8\npacket filters, 7\nrouter configurations, 6\nstateful firewalls, 9\nnetwork intrusion detection/prevention systems\ndata centers, deploying for, 322\nmonitoring, 325\nsending selectiv traffic to IDS/IPS devices, \n322, 324\ntuning, 325\nNetwork Profile screen (CSSC), 233\nnetworks\ndiagrams\nhigh-level enterprise diagrams, 101, 103\nlayered diagrams, 106\nvisibility, 101, 103, 106–107\nthreat modeling (risk analysis), 45\nno ip bootp server global command\nBOOTP servers, disabling for infrastructure \nsecurity, 73\nno ip identd global command\nIDENT, disabling for infrastructure security, 74\nno ip redirects interface subcommand\nICMP redirect messages, disabling for \ninfrastructure security, 73\nno ipv6 address interface subcommand\ndisabling IPv6 for infrastructure security, 75\nno ipv6 enable interface subcommand\ndisabling IPv6 for infrastructure security, 75\nno service pad global command\nPAD, disabling for infrastructure security, 73\nO\nOOB (out-of-band) mode (NAC appliance), 29–30\nopen source\nmonitoring tools\nidentifying/classifying security threats, \n126–127\nP\npacket filters, 7\npacket registration\nCPU traffic\ninfrastructure security, 78\nPAD (Packet Assembler/Disassembler)\ninfrastructure security, disabling for, 73\nparser view command, 65\npasswords\nlocal password management\ninfrastructure security, 61\nPAT\nsmall business case study, 347\npatch management\nendpoint security, 90–91\nsecurity policies, building, 56\npatch management policies\nlarge business case studies, 406\nNDE packet templates (NetFlow)\n"
        },
        {
            "page_number": 460,
            "text": " 437\npatches\nmanaging (incident-handling policies), 154\npattern matching\nstateful pattern-matching recognition, 20\npattern matching (IDS), 20\nPeakflow SP\ncorrelation (SAVE framework), 193\nPeakflow X\ncorrelation (SAVE framework), 193\nPEAP, 223, 225\npenetration testing, 46\nblack-box testing, 46\nconfidentiality requirements, 48\ncrystal-box (grey box) testing, 46\ninfrastructure device configuration audits, 47\nopen-source tools, 46–48\nscheduling, 48\nwhite-box testing, 46\nperimeter security policies\nlarge business case studies, 404\npersonal firewalls, 11\nCSA, 11\nphase 1 negotiation (IPsec), 14, 16\nphase 2 negotiation (IPsec), 16–17\nphishing attacks, 49\nphone tapping attacks\nIP telephony, 293–294\nphysical security policies\nlarge business case studies, 404\nping-of-death attacks, 99\nPIX security appliances\nenabling SNMP logging on, 121\nenabling SYSLOG logging on, 117–118\nPKI\ndigital certificates\nidentity and trust (SAVE framework), 188\npolicies (security), building, 54–55\nflexibility, 56\npatch management, 56\nsecurity changes, 56\nSME (subject matter experts), 56\nupdates, 56\npolicy enforcement (SAVE framework), 202–203\nport-control auto command, 271\nports\nsecurity\naccess layer (IP telephony), 268–269\nTCP ports\nCisco Unity, 282–285\nUDP ports\nCisco Unity, 282–285\nunused network access device ports\nlocking for infrastructure security, 75\npostmortems, 167\naction plans, building, 173–174\ndata analysis, 169\ndata collection, 169\nIncident Response Reports, 169\nLessons Learned section, 171\nratings systems, 173\nlarge business case studies, 419–420\nlooped feedback, 167\ntypical questions answered in, 168\nprosecuting attacks, 155\nComputer Fraud and Abuse Act, 156\nHIPAA, 156\nIC3, 156\nInfragard, 156\nU.S. Department of Justice website, 156\nprotocol analysis, 21\nproxy ARP (Address Resolution Protocol)\ninfrastructure security, disabling for, 73\npstree command\nLinux forensics, 163\nQ\nquarantining, 157\nR\nrACL (receive Access Control Lists)\nCPU traffic\ninfrastructure security, 78–80\nRADIUS (Remote Authentication Dial-In User \nService), 23, 25\nRADIUS (Remote Authentication Dial-In User \nService).\nRADIUS servers\nWLC\nadding to, 226, 228\nRADIUS servers\n"
        },
        {
            "page_number": 461,
            "text": "438\nRaleigh Office Cisco ASA configuration (small \nbusiness case studies), 343\nconfiguring\naccess control, 352\nantispoofing configuration, 353\nIdentity NAT, 351\nIM, 354–355, 357–359\nIP addressing/routing, 343\nPAT, 347\nStatic NAT, 349\nrate limits\nCPU traffic\ninfrastructure security, 78\nratings systems (Incident Response Reports), 173\nReal IP mode (CAS), 29\nreconnaissance\nIPv6, 330\nsecurity through obscurity, 330\nredirect messages (ICMP)\ninfrastructure security, disabling for, 73\nremote access VPN\nlarge business case studies, \n406, 408, 411–412, 415–417\nremote access VPN policies\nlarge business case studies, 405\nremote-access VPN (Virtual Private Networks), \n13\nresource attacks\ndefining, 99\nexamples of, 99\nresource exhaustion, controlling (infrastructure \nsecurity), 75\nCoPP, 80\nCPU packet generation, 78\nfiltering CPU traffic, 78\nprocessors versus interrupt time, 78\nrACL, 78–80\nrate limiting CPU traffic, 78\nresource threshold notifications, 76–77\nscheduler allocate command, 81\nscheduler interval command, 81\nRF (radio frequencies)\nWLC, 238\nrisk analysis, 43\npenetration testing, 46\nblack-box testing, 46\nconfidentiality requirements, 48\ncrystal-box (grey-box) testing, 46\ninfrastructure device configuration audits, \n47\nopen-source tools, 46–48\nscheduling, 48\nwhite-box testing, 46\nthreat modeling, 44\nCOPM, 45\nDREAD model, 44–45\nnetwork visibility, 45\nvulnerabilities, defining, 43\nRMON\ninstrumentation and management (SAVE \nframework), 196\nrole-based CLI. See CLI Views, 64\nroot guards\nIP telephony\naccess layer, 268\nRoot views (CLI Views), 64\nroute filtering\ninfrastructure security, 69\nRouted mode (FWSM), 306\nrouter planes\ninfrastructure security, 57–58\nrouters\nACL\nblocking unauthorized hosts/users, 6\nBGP routers\nhopy-by-hop tracebacks, 146\nIOS routers\nenabling SNMP logging, 119–121\nenabling SYSLOG logging, 115–116\nnetwork firewalls\nconfiguring, 6\nsinkhole routers, 37\nrouting protocols\nauthentication\nidentity and trust (SAVE framework), 189\nEGP, 67\nIGP\ndistance vector protocols, 67\nlink state protocols, 67\ninfrastructure security, 67\nauthentication, 68–69\nroute filtering, 69\nstatic routing peers, 68\nTTL security checks, 70\nRaleigh Office Cisco ASA configuration (small business case studies)\n"
        },
        {
            "page_number": 462,
            "text": " 439\nrouting security\nIPv6, 334\nrouting tables\nvisibility (SAVE framework), 191\nRTBH (Remotely Triggered Black Hole), 158, 160\nRTBH (Remotely Triggered Black Holes), 36\niBGP, 36\nsinkholes, 36–37\nS\nSAVE (Security Assessment, Validation, and \nExecution) framework, 177\ncorrelation, 192\nCSA-MC, 193\nCS-MARS, 193\nPeakflow SP, 193\nPeakflow X, 193\nidentity and trust, 183\nAAA, 183–184\nCisco Guard active verification, 185\nDHCP snooping, 186–187\ndigital certificates, 188\nIKE, 188\nIP Source Guard, 187–188\nNAC, 188\nrouting protocol authentication, 189\nstrict Unicast RPF, 189\ninstrumentation and management, 193\nCisco IOS configuration logger logs, 195\nCisco IOS configuration rollback feature, \n195\nCisco IOS XR XML interface, 196\nCSM, 195\nembedded device managers, 195\nRMON, 196\nSNMP, 196\nSyslog, 196\nisolation and virtualization, 196\nanomaly detection zones, 198\nCisco IOS role-based CLI Access, 197\nCLI Views, 197\nfirewalls segmentation, 200\nnetwork device virtualization, 198–199\nVLAN segmentation, 199\nVRF segmentation, 200\nVRF-Lite segmentation, 200\nITU-T X.805 versus, 178, 180–181\npolicy enforcement, 202–203\nvisibility, 189\nanomaly detection, 190\nCDP, 191\nCEF tables, 191\nIDS, 190–191\nIPS, 190–191\nlayer 2 routing information, 191\nlayer 3 routing information, 191\nNAM, 191\nrouting tables, 191\nvisualization techniques, 203–205, 207\nscheduler allocate command\ninfrastructure security, 81\nscheduler interval command\ninfrastructure security, 81\nscheduling\npenetration tests, 48\nSDM (Secure Device Manager)\ninfrastructure security, 88–89\nSecure ACS Servers\nconfiguring 802.1x with EAP-FAST, \n229, 232–233\nsecurity intelligence, 50\nCisco Security Center, 50\nCVSS, 50\nbase metrics, 51\nenvironmental metrics, 52\ntemporal metrics, 51\nIMS (Internet Motion Sensor), 50\nresearch initiatives/organizations, 50\nsecurity policies\nchange management policies\nlarge business case studies, 406\ndevice security policies\nlarge business case studies, 405\nInternet usage policies\nlarge business case studies, 406\nlarge business case studies, 404\nchange management policies, 406\ndevice security policies, 405\nInternet usage policies, 406\npatch management policies, 406\nperimeter security policies, 404\nphysical security policies, 404\nremote access VPN policies, 405\nsecurity policies\n"
        },
        {
            "page_number": 463,
            "text": "440\npatch management policies\nlarge business case studies, 406\nperimeter security policies\nlarge business case studies, 404\nphysical security policies\nlarge business case studies, 404\nremote access VPN policies\nlarge business case studies, 405\nsecurity policies, building, 54–55\nflexibility, 56\npatch management, 56\nsecurity changes, 56\nSME (subject matter experts), 56\nupdates, 56\nsecurity through obscurity, 330\nseeds, 216\nsegmentation\ndata center security, 303–304\nFWSM, 306–314, 316–322\nfirewalls\nisolation and virtualization (SAVE \nframework), 200\nVLAN\nisolation and virtualization (SAVE \nframework), 199\nVRF\nisolation and virtualization (SAVE \nframework), 200\nVRF-Lite\nisolation and virtualization (SAVE \nframework), 200\nservice password-encryption global command\nlocal password management (infrastructure \nsecurity), 61\nservice tcp-keepalives-in command\nenabling TCP keepalives on incoming sessions, \n63\nservice timestamps log datetime command\nenabling SYSLOG logging on IOS routers, 116\nset port disable command\nnetwork access device ports, locking for \ninfrastructure security, 75\nShadowserver.com website\nbotnet activity, 145\nshow ip cache flow command\ncollecting CLI NetFlow statistics, 112, 114\nEnterprise tracebacks, 147\nshow ip dhcp snooping command\nverifying DHCP snooping VLAN \nconfigurations, 187\nshow ip flow export command\ncollecting CLI NetFlow statistics, 114\nshow snmp group command\nviewing SNMP group information, 120\nsignature updates\nIPS/IDS devices, 131–132\nsignatures\nIDS, 20\nsinkholes, 36–37\nsite-to-site VPN\nsmall business case study, 377, 380–381, 383, \n385, 387, 389\nsite-to-site VPN (Virtual Private Networks), 12\nSleuth Kit (Linux forensics tool), 162\nsmall business case studies, 341–342\nAtlanta Office Cisco ISO configuration, 360\nlocking down IOS routers, 360, 363, 366, \n368, 370–375\nNAT configuration, 376\nsite-to-site VPN, 377, 380–381, 383, 385, \n387, 389\nRaleigh Office Cisco ASA configuration, 343\naccess control, 352\nantispoofing configuration, 353\nIdentity NAT, 351\nIM, 354–355, 357–359\nIP addressing/routing, 343\nPAT, 347\nStatic NAT, 349\nSME (subject matter experts)\nsecurity policies, building, 56\nsmurf attacks\nIPv6, 334\nSNMP, 118–119\naccess control\ninfrastructure security, 66\nASA security appliances, enabling logging on, \n121\ninstrumentation and management (SAVE \nframework), 196\nIOS router/switch logging, enabling, 119–121\nPIX security appliances, enabling logging on, \n121\nsnmp deny version command, 121\nsecurity policies\n"
        },
        {
            "page_number": 464,
            "text": " 441\nsnmp-server enable traps cpu threshold \ncommand\nCPU threshold violation notification, \nconfiguring for infrastructure security, 76\nsnooping (DHCP)\nidentity and trust (SAVE framework), 186–187\nsocial engineering, 49\nsource routing (IP)\ninfrastructure security, disabling for, 73\nspoofing\nIPv6, 333\nSRTP (Source Real-Time Transport Protocol)\nIP telephony eavesdropping attacks, 294\nSSH\nTelnet versus, 59–60\nssh timeout command\nmodifying idle timeouts, 63\nSSL (Secure Sockets Layer)\nVPN, 18\nstateful firewalls, 9\nstateful pattern-matching recognition, 20\nStatic NAT\nsmall business case study, 349\nstrong device access control (infrastructure \nsecurity), 59\nauthentication banner configuration, 62\nCLI Views, 64–65\ninteractive access control, 62–64\nlocal password management, 61\nSNMP access control, 66\nSSH versus Telnet, 59–60\nsubnet prefixes\nIPv6, 331\nSuperviews (CLI Views), 64\nsupplicants (802.1x), 26, 219\nswitches\ncatalyst switches\nenabling SYSLOG logging on CATOS \nrunning switches, 117\ndistribution layer switches\nconfiguring NetFlow at, 103\nIOS switches\nenabling SNMP logging, 119–121\nenabling SYSLOG logging, 115–116\nswitchport port-security violation restrict \ncommand\nIP telephony security, 269\nSYN cookies\ndata center security, 297–299\nSYN-flooding, 297\nSyslog\ninstrumentation and management (SAVE \nframework), 196\nSYSLOG (System Logs), 115\nASA security appliances, enabling logging on, \n117–118\nCATOS running catalyst switches, enabling \nlogging on, 117\nIOS router/switch logging, enabling, 115–116\nPIX security appliances, enabling logging on, \n117–118\nSystenals (Windows forensics tools), 164\nT\nTACACS+, 25\nTAD XT (Traffic Anomaly Detectors XT)\nidentifying/classifying security threats, \n127–128, 131\nTCP Client\nIDENT\ninfrastructure security, disabling for, 74\nTCP ports\nCisco Unity, 282–285\nTCP small servers\ninfrastructure security, disabling for, 74\nTEAP (Tunneled EAP). See EAP-FAST, 224\ntelemetry\ninfrastructure security, 89\ntelemetry/anomaly detection\nCS-MARS, 121–122, 125\nGuard XT, 127, 129–131\nIPS, 137–138\nNAM, 125–126\nNetFlow, 108\nCisco platform support, 108\ncollecting CLI statistics, 112–114\nEgress NetFlow, 111\nenabling, 111–112\nflows, elements of, 109\nflows, exporting data from, 110\nflows, obtaining additional information \nfrom, 109–110\ntelemetry/anomaly detection\n"
        },
        {
            "page_number": 465,
            "text": "442\nIngress NetFlow, 111\nIPFIX WG, 110\nNDE packet templates, 110\nopen source monitoring tools, 126–127\nSNMP, 118–119\nenabling IOS router/switch logging, \n119–121\nenabling logging on ASA security \nappliances, 121\nenabling logging on PIX security \nappliances, 121\nSYSLOG, 115\nenabling IOS router/switch logging, \n115–116\nenabling logging on ASA security \nappliances, 117–118\nenabling logging on CATOS running \ncatalyst switches, 117\nenabling logging on PIX security \nappliances, 117–118\nTAD XT, 127–128, 131\ntelephony (IP), 261–262, 265\naccess layer, 265, 272\n802.1x, 271\nARP, 270\nBPDU, 268\nDAI, 270\nDHCP snooping, 269–270\nNAC, 271\nport security, 268–269\nroot guards, 268\nVLAN assignment, 267\nCisco Personal Assistant, 289\nhardening operating environment,\n289–290\nserver security policies, 291–293\nCisco Unified CallManager, 276–277\nCisco Unified CME, 277–281\nCisco Unity, 281–282, 286–287\nCisco Unity Express, 287–288\ncore layer, 265, 275\ndistribution layer, 265, 273\nGLBP, 274\nHSRP, 273–274\neavesdropping attacks, 293–294\nTelnet\nSSH versus, 59–60\ntelnet timeout command\nmodifying idle timeouts, 63\ntemplates\nNDE packet templates (NetFlow), 110\ntemporal metrics (CVSS), 51\nthreat modeling, 44\nCOPM, 45\nDREAD model, 44–45\nnetwork visibility, 45\nthreats (security)\nidentifying/classifying\nCS-MARS, 121–122, 125\nGuard XT, 127, 129–131\nIDS, 131–134, 136\nIPS, 131–134, 136–138\nNAM, 125–126\nNetFlow, 108–114\nnetwork visibility, 101, 103, 106–107\nopen source monitoring tools, 126–127\nSNMP, 118–121\nSYSLOG, 115–118\nTAD XT, 127–128, 131\nthreshold notifications\ninfrastructure security, 76–77\ntiered access control\ndata centers, 303–304\ntimeouts\nidle timeouts\nmodifying, 63\nTKIP (Temporal Key Integrity Protocol)\nWEP, 218\nWPA, 218\ntopology maps\nSAVE framework, 203\ntracebacks, 141\nbackscatter, 146\nbotnets, 150\nEnterprise, 147\nCS-MARS, 148\ndot-dot attacks, 148\nhop-by-hop, 142\nbotnets, 145–146\nzombies, 145\nrequirements, 142\nservice provider environments, 142, 145–146\nzombies, 150\ntelemetry/anomaly detection\n"
        },
        {
            "page_number": 466,
            "text": " 443\ntraffic flows\nSAVE framework, 204–205\ntransmitting data\ntelemetry\ninfrastructure security, 89\nTransparent mode (FWSM), 306–307\ntransport input command\ninteractive access control (infrastructure \nsecurity), 62\nTransport mode (IPsec), 17\nTTL (Time-to-Live) security checks\nrouting protocols\ninfrastructure security, 70\ntuning\ndata center network intrusion detection/\nprevention systems, 325\nIPS/IDS devices, 133–134, 136\nTunnel mode (IPsec), 17\ntunneled authentication, 224\nU\nUDP ports\nCisco Unity, 282–285\nUDP small servers\ninfrastructure security, disabling for, 74\nunauthorized hosts/users\nblocking from routers via ACL, 6\nUnicast RPF\nidentity and trust (SAVE framework), 189\nUnicast RPF (Reverse Path Forwarding)\ninfrastructure security policy enforcement, \n83–84\nunified mode (AP), 215\nUnified Wireless Networks\nAP, 215\narchitecture of, 212, 214–215\nconfiguring 802.1x with EAP-FAST, 226\nLWAPP, 236–239\nMFP, 243\nNAC, 245\nappliance configuration, 246–248, 251, \n253–254\nWLC configuration, 255, 257, 259\nwireless IPS, 239–240\nconfiguring sensors in WLC, 241–242\nconfiguring signatures, 242–243\nWireless Location Appliance, 244\nupdates\nsecurity policies, 56\nsignatures\nIPS/IDS devices, 131–132\nU.S. Department of Justice website, 156\nusername command\nassociating local users CLI Views, 65\nV\nVACL (VLAN ACL), 157\nVirtual Fragment Reassembly\nFWSM data center segmentation, 322\nVirtual Gateway mode (CAS), 28\nvisibility (networks), 101, 103, 106–107\nvisibility (SAVE framework), 189\nanomaly detection, 190\nCDP, 191\nCEF tables, 191\nIDS, 190–191\nIPS, 190–191\nlayer 2 routing information, 191\nlayer 3 routing information, 191\nNAM, 191\nrouting tables, 191\nVLAN\nDHCP snooping, 186–187\nIP telephony\naccess layer, 267\nprivate VLAN, 158\nsegmentation\nisolation and virtualization (SAVE \nframework), 199\nVPN (Virtual Private Networks), 12\nIPsec\ntechnical overview of, 14–17\nremote access VPN policies\nlarge business case studies, 405\nremote-access VPN, 13\nsite-to-site VPN, 12\nsmall business case study, \n377, 380–381, 383, 385, 387, 389\nSSL VPN, 18\nVPN (Virtual Private Networks)\n"
        },
        {
            "page_number": 467,
            "text": "444\nVPN (virtual private networks)\nremote access VPN\nlarge business case studies, 406, 408, \n411–412, 415–417\nVRF\nsegmentation\nisolation and virtualization (SAVE \nframework), 200\nVRF-Lite\nsegmentation\nisolation and virtualization (SAVE \nframework), 200\nvulnerabilities (risk analysis), defining, 43\nW\nwebsites\nsecurity intelligence, 50\nCisco Security Center, 50\nIMS (Internet Motion Sensor), 50\nWEP (Wired Equivalent Privacy), 216\nAES encryption protocol, 218\nICV, 216–217\nIPsec, 218\nlimitations of, 217\nseeds, 216\nTKIP, 218\nwhite-box penetration testing, 46\nWindows\nforensics tools\nEnCase, 165\nSysternals, 164\nwireless IPS (Intrusion Prevention Systems), \n239–240\nconfiguring\nsensors in WLC, 241–242\nsignatures, 242–243\nWireless Location Appliance, 244\nwireless networks, 211\nauthentication, 216\n802.1x, 219–221, 226, 229, 232–233\nconfiguring CSSC, 233–234, 236\nconfiguring WLC, 226, 228\nEAP-FAST, 224–226, 229, 232–233\nEAP-GTC, 225\nEAP-MD5, 221–222\nEAP-TLS, 223\nEAP-TTLS, 224\nLEAP, 222\nPEAP, 223, 225\nWEP, 216–218\nWPA, 218\nSecure ACS Servers\nconfiguring for 802.1x and EAP-FAST, \n229, 232–233\nUnified Wireless Networks\nAP, 215\narchitecture of, 212, 214–215\nconfiguring 802.1x with EAP-FAST, 226\nLWAPP, 236–239\nMFP, 243\nNAC, 245–248, 251, 253–255, 257, 259\nwireless IPS, 239–243\nWireless Location Appliance, 244\nWLC\nconfiguring via NAC, 255, 257, 259\nRF, 238\nWLC (wireless LAN context)\nadding RADIUS servers to, 226, 228\nconfiguring, 226, 228\nworms\ndata center security, 297\nCisco Guard, 302\nFlexible NetFlow, 301\nIDS, 300\ninfrastructure protection, 302–303\nIPS, 300\nNetFlow, 301\nWPA (Wi-Fi Protected Access), 218\nZ\nzombies, 99\nhop-by-hop tracebacks, 145\ntracebacks, 150\nVPN (virtual private networks)\n"
        },
        {
            "page_number": 468,
            "text": "3 STEPS TO LEARNING\nNETWORK BUSINESS SERIES\nThe Network Business series helps professionals tackle the \nbusiness issues surrounding the network. Whether you are a \nseasoned IT professional or a business manager with minimal\ntechnical expertise, this series will help you understand the \nbusiness case for technologies.\nJustify Your Network Investment.\nLook for Cisco Press titles at your favorite bookseller today.\nVisit www.ciscopress.com/series for details on each of these book series.\nNetworking \nTechnology Guides\nFirst-Step\nSTEP 1\nSTEP 3\nSTEP 2\nFundamentals\nSTEP 1\nFirst-Step—Benefit from easy-to-grasp explanations. \nNo experience required!\nSTEP 2\nFundamentals—Understand the purpose, application, \nand management of technology.\nSTEP 3\nNetworking Technology Guides—Gain the knowledge \nto master the challenge of the network.\nCisco Press\n"
        },
        {
            "page_number": 469,
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    ]
}