Network Security Architectures

Book description

Expert guidance on designing secure networks

  • Understand security best practices and how to take advantage of the networking gear you already have

  • Review designs for campus, edge, and teleworker networks of varying sizes

  • Learn design considerations for device hardening, Layer 2 and Layer 3 security issues, denial of service, IPsec VPNs, and network identity

  • Understand security design considerations for common applications such as DNS, mail, and web

  • Identify the key security roles and placement issues for network security elements such as firewalls, intrusion detection systems, VPN gateways, content filtering, as well as for traditional network infrastructure devices such as routers and switches

  • Learn 10 critical steps to designing a security system for your network

  • Examine secure network management designs that allow your management communications to be secure while still maintaining maximum utility

  • Try your hand at security design with three included case studies

  • Benefit from the experience of the principal architect of the original Cisco Systems SAFE Security Blueprint

  • Written by the principal architect of the original Cisco Systems SAFE Security Blueprint, Network Security Architectures is your comprehensive how-to guide to designing and implementing a secure network. Whether your background is security or networking, you can use this book to learn how to bridge the gap between a highly available, efficient network and one that strives to maximize security. The included secure network design techniques focus on making network and security technologies work together as a unified system rather than as isolated systems deployed in an ad-hoc way.

    Beginning where other security books leave off, Network Security Architectures shows you how the various technologies that make up a security system can be used together to improve your network's security. The technologies and best practices you'll find within are not restricted to a single vendor but broadly apply to virtually any network system. This book discusses the whys and hows of security, from threats and counter measures to how to set up your security policy to mesh with your network architecture. After learning detailed security best practices covering everything from Layer 2 security to e-commerce design, you'll see how to apply the best practices to your network and learn to design your own security system to incorporate the requirements of your security policy. You'll review detailed designs that deal with today's threats through applying defense-in-depth techniques and work through case studies to find out how to modify the designs to address the unique considerations found in your network.

    Whether you are a network or security engineer, Network Security Architectures will become your primary reference for designing and building a secure network.

    This book is part of the Networking Technology Series from Cisco Press, which offers networking professionals valuable information for constructing efficient networks, understanding new technologies, and building successful careers.

    Table of contents

    1. About This eBook
    2. Title Page
    3. Copyright Page
    4. About the Author
      1. About the Technical Reviewers
    5. Acknowledgments
      1. A Note from Cisco Systems on the SAFE Blueprint and Network Security Architectures
    6. Dedication Page
    7. Contents at a Glance
    8. Table of Contents
    9. Icons Used in This Book
    10. Command Syntax Conventions
    11. Foreword
    12. Preface
      1. This Book’s Relationship to the SAFE White Papers
      2. Why Network Security?
      3. New Technologies, New Vulnerabilities
      4. How This Book Is Organized
      5. Who Should Read This Book?
        1. Network/Security Architect
        2. Network/Security Operations Engineer
        3. IT Manager
        4. CIO and Others with Passing Interest
      6. Caveats
      7. Summary
    13. Part I: Network Security Foundations
      1. Chapter 1. Network Security Axioms
        1. Network Security Is a System
        2. Business Priorities Must Come First
        3. Network Security Promotes Good Network Design
        4. Everything Is a Target
        5. Everything Is a Weapon
        6. Strive for Operational Simplicity
        7. Good Network Security Is Predictable
        8. Avoid Security Through Obscurity
        9. Confidentiality and Security Are Not the Same
        10. Summary
        11. Reference
        12. Applied Knowledge Questions
      2. Chapter 2. Security Policy and Operations Life Cycle
        1. You Can’t Buy Network Security
        2. What Is a Security Policy?
          1. Security Policy Enforcement Considerations
        3. Security System Development and Operations Overview
          1. Security System Development
          2. Security System Operations Life Cycle
        4. Summary
        5. References
        6. Applied Knowledge Questions
      3. Chapter 3. Secure Networking Threats
        1. The Attack Process
        2. Attacker Types
          1. Script Kiddie
          2. Cracker
          3. Elite
        3. Vulnerability Types
          1. Software Vulnerabilities
          2. Hardware Vulnerabilities
          3. Configuration Vulnerabilities
          4. Policy Vulnerabilities
          5. Usage Vulnerabilities
        4. Attack Results
          1. Disclosure of Information
          2. Corruption of Information
          3. Denial of Service
          4. Theft of Service
          5. Increased Access
        5. Attack Taxonomy
          1. Read
          2. Manipulate
          3. Spoof
          4. Flood
          5. Redirect
          6. Composite
        6. Summary
        7. References
        8. Applied Knowledge Questions
      4. Chapter 4. Network Security Technologies
        1. The Difficulties of Secure Networking
        2. Security Technologies
          1. Identity Technologies
          2. Host and Application Security
          3. Network Firewalls
          4. Content Filtering
          5. Network Intrusion Detection Systems
          6. Cryptography
        3. Emerging Security Technologies
          1. Hybrid Host Solutions
          2. Inline NIDS
          3. Application Firewalls
        4. Summary
        5. References
        6. Applied Knowledge Questions
    14. Part II: Designing Secure Networks
      1. Chapter 5. Device Hardening
        1. Components of a Hardening Strategy
          1. Security Policy
          2. Device Location
          3. Threat Profile
          4. Functional Requirements
          5. Management Requirements
        2. Network Devices
          1. Router
          2. Switches
          3. Firewalls
        3. NIDS
        4. Host Operating Systems
          1. Partitioning Disk Space
          2. Turning Off Unneeded Services
          3. Patching the Services Needed
          4. Logging Critical Events
        5. Applications
        6. Appliance-Based Network Services
        7. Rogue Device Detection
        8. Summary
        9. References
        10. Applied Knowledge Questions
      2. Chapter 6. General Design Considerations
        1. Physical Security Issues
          1. Control Physical Access to Facilities
          2. Control Physical Access to Data Centers
          3. Separate Identity Mechanisms for Insecure Locations
          4. Prevent Password Recovery Mechanisms in Insecure Locations
          5. Be Aware of Cable Plant Issues
          6. Be Aware of Electromagnetic Radiation
          7. Be Aware of Physical PC Security Threats
        2. Layer 2 Security Considerations
          1. L2 Control Protocols
          2. MAC Flooding Considerations
          3. VLAN Hopping Considerations
          4. ARP Considerations
          5. DHCP Considerations
          6. Private VLANs
          7. L2 Best Practices Recommendations
        3. IP Addressing Design Considerations
          1. General Best Practices and Route Summarization
          2. Ingress/Egress Filtering
          3. NAT
        4. ICMP Design Considerations
          1. ICMP Message Type Filtering
        5. Routing Considerations
          1. Routing Protocol Security
          2. Asymmetric Routing and State-Aware Security Technology
        6. Transport Protocol Design Considerations
        7. DoS Design Considerations
          1. Network Flooding Design Considerations
          2. TCP SYN Flooding Design Considerations
          3. ICMP Unreachable DoS Considerations
        8. Summary
        9. References
        10. Applied Knowledge Questions
      3. Chapter 7. Network Security Platform Options and Best Deployment Practices
        1. Network Security Platform Options
          1. General-Purpose Operating System Security Devices
          2. Appliance-Based Security Devices
          3. Network-Integrated Security Functions
          4. Network Security Platform Option Recommendations
        2. Network Security Device Best Practices
          1. Firewalls
          2. Proxy Servers/Content Filtering
          3. NIDS
        3. Summary
        4. Reference
        5. Applied Knowledge Questions
      4. Chapter 8. Common Application Design Considerations
        1. E-Mail
          1. Basic Two-Tier E-Mail Design
          2. Distributed Two-Tier E-Mail Design
          3. Access Control Example
          4. Mail Application Design Recommendations
        2. DNS
          1. Don’t Put All Your DNS Servers in One Place
          2. Have More Than One Authoritative DNS Server
          3. Make Your External DNS Servers Nonrecursive Responders Only
          4. Provide Protected Internal DNS Servers
          5. Separate the Information Provided by External and Internal DNS Servers
          6. Limit Zone Transfers to Authorized Servers
          7. DNS Filtering Case Studies
        3. HTTP/HTTPS
          1. Simple Web Design
          2. Two-Tier Web Design
          3. Three-Tier Web Design
        4. FTP
          1. Active Mode
          2. Passive Mode
        5. Instant Messaging
        6. Application Evaluation
        7. Summary
        8. References
        9. Applied Knowledge Questions
      5. Chapter 9. Identity Design Considerations
        1. Basic Foundation Identity Concepts
          1. Device Versus User Identity
          2. Network Versus Application Identity
          3. Whom Do You Trust?
          4. Identity and Authentication, Authorization, and Accounting
          5. Shared Identity
          6. Cryptographic Identity Considerations
        2. Types of Identity
          1. Physical Access
          2. MAC Addresses
          3. IP Addresses
          4. Layer 4 Information
          5. Usernames
          6. Digital Certificates
          7. Biometrics
        3. Factors in Identity
        4. Role of Identity in Secure Networking
        5. Identity Technology Guidelines
          1. AAA Server Design Guidelines
          2. 802.1x/EAP Identity Design Guidelines
          3. Gateway-Based Network Authentication
          4. PKI Usage Basics
        6. Identity Deployment Recommendations
          1. Device to Network
          2. User to Network
          3. User to Application
        7. Summary
        8. References
        9. Applied Knowledge Questions
      6. Chapter 10. IPsec VPN Design Considerations
        1. VPN Basics
        2. Types of IPsec VPNs
          1. Site-to-Site VPNs
          2. Remote User VPNs
        3. IPsec Modes of Operation and Security Options
          1. The Three Elements of IPsec
          2. Transport Mode and Tunnel Mode
          3. IPsec SA Establishment
          4. Other Security Options
        4. Topology Considerations
          1. Split Tunneling
          2. Topology Choices
        5. Design Considerations
          1. Platform Options
          2. Identity and IPsec Access Control
          3. Layer 3 IPsec Considerations
          4. Fragmentation and Path Maximum Transmission Unit Discovery
          5. Firewall and NIDS Placement for VPNs
          6. High Availability
          7. QoS
          8. IPsec Vendor Interoperability
        6. Site-to-Site Deployment Examples
          1. Basic IPsec
          2. GRE + IPsec
          3. Dynamic Multipoint VPN
        7. IPsec Outsourcing
          1. Network-Based Managed IPsec
          2. CPE Managed IPsec
        8. Summary
        9. References
        10. Applied Knowledge Questions
      7. Chapter 11. Supporting-Technology Design Considerations
        1. Content
          1. Caching
          2. Content Distribution and Routing
        2. Load Balancing
          1. Security Considerations
          2. Server Load Balancing
          3. Security Device Load Balancing
        3. Wireless LANs
          1. General Considerations
          2. Technology Options
          3. Unique Deployment Options
          4. WLAN Conclusion
        4. IP Telephony
          1. Security Considerations
          2. Deployment Options
          3. IP Telephony Recommendations
        5. Summary
        6. References
        7. Applied Knowledge Questions
      8. Chapter 12. Designing Your Security System
        1. Network Design Refresher
          1. Core, Distribution, Access/Edge
          2. Management
        2. Security System Concepts
          1. Domains of Trust
          2. Choke Points
          3. Security Roles: Access/Edge, Distribution, Core
        3. Impact of Network Security on the Entire Design
          1. Routing and IP Addressing
          2. Manageability
          3. Scalability and Performance
        4. Ten Steps to Designing Your Security System
          1. Step 1: Review Completed Security Policy Documents
          2. Step 2: Analyze the Current Network Against the Security Policy
          3. Step 3: Select Technologies and Evaluate Product Capabilities
          4. Step 4: Design an Ideal Rough Draft of the Security System
          5. Step 5: Test Key Components in a Lab
          6. Step 6: Evaluate and Revise Design/Policy
          7. Step 7: Finalize Design
          8. Step 8: Implement the Security System in One Critical Area
          9. Step 9: Roll Out to Other Areas
          10. Step 10: Design/Policy Validation
          11. Two-Step Evaluation Checklist
        5. Summary
        6. Applied Knowledge Questions
    15. Part III: Secure Network Designs
      1. Chapter 13. Edge Security Design
        1. What Is the Edge?
        2. Expected Threats
        3. Threat Mitigation
        4. Identity Considerations
        5. Network Design Considerations
          1. ISP Router
          2. Number of Public Servers
          3. Branch Versus Head-End Design Considerations
          4. Remote Access Alternatives
        6. Small Network Edge Security Design
          1. Design Requirements
          2. Design Overview
          3. Edge Devices and Security Roles
          4. VPN
          5. Design Evaluation
          6. Design Alternatives
        7. Medium Network Edge Security Design
          1. Design Requirements
          2. Design Overview
          3. Internet Edge
          4. Remote Access Edge
          5. Design Evaluation
          6. Design Alternatives
        8. High-End Resilient Edge Security Design
          1. Design Requirements
          2. Design Overview
          3. Internet Edge
          4. Remote Access Edge
          5. Design Evaluation
          6. Design Alternatives
        9. Provisions for E-Commerce and Extranet Design
          1. E-Commerce
          2. Extranet
        10. Summary
        11. References
        12. Applied Knowledge Questions
      2. Chapter 14. Campus Security Design
        1. What Is the Campus?
        2. Campus Trust Model
        3. Expected Threats
        4. Threat Mitigation
        5. Identity Considerations
        6. Network Design Considerations
          1. Layer 2 Considerations
          2. Stateful Versus Stateless ACLs and L3 Versus L4 Filtering
          3. Intrusion Detection Systems
          4. WLAN Considerations
          5. Network Management
          6. Rogue Devices
        7. Small Network Campus Security Design
          1. Design Requirements
          2. Design Overview
          3. Campus Devices and Security Roles
          4. Design Evaluation
          5. Design Alternatives
          6. Increased Security Alternative
          7. Decreased Security Alternative
        8. Medium Network Campus Security Design
          1. Design Requirements
          2. Design Overview
          3. Campus Devices and Security Roles
          4. Design Evaluation
          5. Design Alternatives
          6. Increased Security Alternative
          7. Decreased Security Alternative
        9. High-End Resilient Campus Security Design
          1. Design Requirements
          2. Design Overview
          3. Campus Devices and Security Roles
          4. Design Evaluation
          5. Design Alternatives
        10. Summary
        11. References
        12. Applied Knowledge Questions
      3. Chapter 15. Teleworker Security Design
        1. Defining the Teleworker Environment
        2. Expected Threats
        3. Threat Mitigation
        4. Identity Considerations
        5. Network Design Considerations
          1. Host Protections
          2. Network-Transit Protections
        6. Software-Based Teleworker Design
          1. Design Requirements
          2. Design Overview
        7. Hardware-Based Teleworker Design
          1. Design Requirements
          2. Design Overview
          3. Physical Security Considerations
        8. Design Evaluations
        9. Summary
        10. Reference
        11. Applied Knowledge Questions
    16. Part IV: Network Management, Case Studies, and Conclusions
      1. Chapter 16. Secure Network Management and Network Security Management
        1. Utopian Management Goals
        2. Organizational Realities
        3. Protocol Capabilities
          1. Telnet/Secure Shell
          2. HTTP/HTTPS
          3. Simple Network Management Protocol
          4. TFTP/FTP/SFTP/SCP
          5. Syslog
          6. NetFlow
          7. Others
        4. Tool Capabilities
          1. Network Security Management Tools
          2. Secure Network Management Tools
        5. Secure Management Design Options
          1. Cleartext In-Band
          2. Cryptographically Secure In-Band (Session and Application Layer)
          3. Cryptographically Secure In-Band (Network Layer)
          4. Hybrid Management Design
          5. Secure Network Management Optional Components
        6. Network Security Management Best Practices
          1. Monitor Critical Security Events 24*7*365
          2. Separate Historical Event Data from Critical Notifications
          3. Choose Sensible Logging Levels
          4. Separate Network Management and Network Security Management
          5. Focus on Operational Requirements
          6. Consider Outsourcing
        7. Summary
        8. References
        9. Applied Knowledge Questions
      2. Chapter 17. Case Studies
        1. Introduction
        2. Real-World Applicability
        3. Organization
          1. Organization Overview
          2. Current Design
          3. Security Requirements
          4. Design Choices
          5. Migration Strategy
          6. Attack Example
        4. NetGamesRUs.com
          1. Organization Overview
          2. Current Design
          3. Security Requirements
          4. Design Choices
          5. Migration Strategy
          6. Attack Example
        5. University of Insecurity
          1. Organization Overview
          2. Current Design
          3. Security Requirements
          4. Design Choices
          5. Migration Strategy
          6. Attack Example
        6. Black Helicopter Research Limited
          1. Organization Overview
          2. Current Design
          3. Security Requirements
          4. Design Choices
          5. Migration Strategy
          6. Attack Example
        7. Summary
        8. Reference
        9. Applied Knowledge Questions
      3. Chapter 18. Conclusions
        1. Introduction
        2. Management Problems Will Continue
        3. Security Will Become Computationally Less Expensive
        4. Homogeneous and Heterogeneous Networks
        5. Legislation Should Garner Serious Consideration
        6. IP Version 6 Changes Things
        7. Network Security Is a System
        8. Summary
        9. References
    17. Appendix A. Glossary of Terms
    18. Appendix B. Answers to Applied Knowledge Questions
      1. Chapter 1
      2. Chapter 2
      3. Chapter 3
      4. Chapter 4
      5. Chapter 5
      6. Chapter 6
      7. Chapter 7
      8. Chapter 8
      9. Chapter 9
      10. Chapter 10
      11. Chapter 11
      12. Chapter 12
      13. Chapter 13
      14. Chapter 14
      15. Chapter 15
      16. Chapter 16
    19. Appendix C. Sample Security Policies
      1. INFOSEC Acceptable Use Policy
        1. 1.0 Overview
        2. 2.0 Purpose
        3. 3.0 Scope
        4. 4.0 Policy
        5. 5.0 Enforcement
        6. 6.0 Definitions
        7. 7.0 Revision History
      2. Password Policy
        1. 1.0 Overview
        2. 2.0 Purpose
        3. 4.0 Policy
        4. 5.0 Enforcement
        5. 6.0 Definitions
        6. 7.0 Revision History
      3. Guidelines on Antivirus Process
    20. Index
    21. Code Snippets

    Product information

    • Title: Network Security Architectures
    • Author(s): Sean Convery
    • Release date: April 2004
    • Publisher(s): Cisco Press
    • ISBN: 158705115X