Network Perimeter Defense Architecture: A Case Study

This paper, written as a case study in 2001, documents a comprehensive architecture for defending network resources of a fictitious company. It illustrates an approach to setting up a strong security perimeter. This document was submitted to SANS GIAC to fulfill GIAC Certified Firewall Analyst (GCFW) certification requirements. This paper is only available in Adobe Acrobat PDF format. You may download it here. The table of contents is listed below for your convenience:

Part 1: Security Architecture

1.1 Assigned Task
1.2 Application Architecture
1.3 Perimeter Defense
1.4 External Connectivity
1.5 Implementation

Part 2: Security Policy

2.1 Assigned Task
2.2 Guiding Principles
2.3 Border Router
2.4 Firewalls
2.5 VPN Configuration
2.6 Applying Policy
2.7 Compliance Monitoring

Part 3: Audit of the Security Architecture

3.1 Assigned Task
3.2 Planning the Assessment
3.3 Assessment of Security Design
3.4 Assessment of Defense Perimeter Implementation
3.5 Assessment of Defense Component Implementation
3.6 Defense Improvement Recommendations

Part 4: Design Under Fire

4.1 Assigned Task
4.2 Targeted Architecture
4.3 Attacking the Firewall
4.4 Denial of Service Attack
4.5 Compromising an Internal System

About the Author

Lenny Zeltser is a cybersecurity leader with deep technical roots and product management experience. He created REMnux, an open-source malware analysis toolkit, and the reverse-engineering course at SANS Institute. As CISO at Axonius, he leads the security and IT program, focusing on trust and growth. He writes this blog to think out loud and share resources with the community.

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