Useful Forums
Security and Cryptography Forum: Sponsered by DevShed. Discusses issues related to coding, server applications, network protection, data protection, firewalls, ciphers and the like. 
Cryptography Forum: On Topix. Fairly good focus on technical issues.
Security Forums: On WindowsSecurity.com. Broad range of forums, including cryptographic theory, cryptographic software, firewalls, and malware.
Cryptography Stack Exchange: Question and answer site for software developers, mathematicians and others interested in cryptography. Excellent resource. 
Useful Links
Computer Science Student Resource Site: Help and advice for the long-suffering, overworked student.
Errata sheet: Latest list of errors, updated at most monthly. File name is Errata-CompSec2e-mmyy. If you spot any errors, please contact me at 
. Chapter 1 - Overview
IETF Security Area: Provides up-to-date information on Internet security standardization efforts.
Computer and Network Security Reference Index: A good index to vendor and commercial products, FAQs, newsgroup archives, papers, and other Web sites.
IEEE Technical Committee on Security and Privacy: Home of the electronic newsletter Cipher, which provides book reviews, new crypto and security links, and links to reports and papers available online.
Computer Security Resource Center: Maintained by NIST; contains a broad range of information on security threats, technology, and standards.
European Network and Information Security Agency A source of expertise on security issues for the EU. Includes an excellent set of technical reports, plus numerous other documents and links.
Security Focus: A wide variety of security information, with an emphasis on vendor products and end-user concerns. Maintains the Bugtraq, a mailing list for the detailed discussion and announcement of computer security vulnerabilities.
SANS Institute: Similar to Security Focus. Extensive collection of white papers. Maintains Internet Storm Center, which provides a warning service to Internet users and organizations concerning security threats.
Risks Digest: Forum on risks to the public in computers and related systems.
United States Computer Emergency Readiness Team: US-CERT is a partnership between the Department of Homeland Security and the public and private sectors, intended to coordinate the response to security threats from the Internet. The site has a good collection of technical papers, and information and alerts on current security issues, vulnerabilities and exploits.
CERT Coordination Center: The organization that grew from the computer emergency response team formed by the Defense Advanced Research Projects Agency. Site provides good information on Internet security threats, vulnerabilities, and attack statistics.
Packet Storm: Resource of up-to-date and historical security tools, exploits, and advisories.
Institute for Security and Open Methodologies: An open, collaborative security research community. Lots of interesting information.
Security Cartoon: A cartoon-based approach aimed at improving the understanding of security risk among typical Internet users.
Center for Internet Security: Provides freeware benchmark and scoring tools for evaluating security of operating systems, network devices, and applications. Includes case studies and technical papers.
Chapter 2 - Cryptographic Tools
The Cryptography FAQ: Lengthy and worthwhile FAQ covering all aspects of cryptography.
Bouncy Castle Crypto Package: Java implementation of cryptographic algorithms. The package is organized so that it contains a light-weight API suitable for use in any environment. The package is distributed at no charge for commercial or non-commercial use.
Cryptography Code: Another useful collection of software.
American Cryptogram Association: An association of amateur cryptographers. The Web site includes information and links to sites concerned with classical cryptography.
Crypto Corner: Simon Singh's Website. Lots of good information, plus interactive tools for learning about cryptography.
Chapter 3 - User Authentication
NIST E-Authentication Page: Documents related to user authentication and password usage.
Biometrics Consortium: Government-sponsored site for the research, testing, and evaluation of biometric technology
Chapter 4 - Access Control
NIST RBAC site: Includes numerous documents, standards, and software on RBAC
Chapter 5 - Database Security
Cloud Security Alliance: Organization promoting best practices for cloud security implementation. Site contains useful documents and links.
Chapter 6 - Malicious Software
Vmyths: Dedicated to exposing virus hoaxes and dispelling misconceptions about real viruses.
SecureList: Information about viruses, hackers, and spam.
Symantec Internet Threat Security Report: Annual report on the Internet threat landscape by commercial antivirus software provider Symantec.
Symantec Security Response: Site maintained by commercial antivirus software provider Symantec, with much useful information on current malware risks.
Chapter 7 - Denial-of-Service Attacks
David Dittrich’s Distributed Denial Of Service Site: Contains lists of books, papers, and other information on DDoS attacks and tools.
Chapter 8 - Intrusion Detection
Open Security Foundation: Runs the DataLossDB project, which compiles a wide variety of statistics, charts, graphs, and incident report.
Honeynet Project: A research project studying the techniques of predatory hackers and developing honeypot products
Honeypots: A good collection of research papers and technical articles.
Snort: Web site for Snort, an open source network intrusion prevention and detection system.
Chapter 9 - Firewalls
Firewall.com: Numerous links to firewall references and software resources.
Chapter 10 - Buffer Overflow
Metasploit: The Metasploit Project provides useful information on shellcode exploits to people who perform penetration testing, IDS signature development, and exploit research
OpenBSD Security: The OpenBSD project produces a free, multiplatform 4.4BSD-based UNIX-like operating system.
Chapter 11 - Software Security
CERT Secure Coding: Resource on CERT site of links to information on common coding vulnerabilities and secure programming practices.
CWE/SANS Top 25 Most Dangerous Software Errors: A list of the most common types of programming errors that were exploited in many major cyber attacks, with details on how they occur and how to avoid them.
David Wheeler - Secure Programming: Provides links to his book and other articles on secure programming.
Fuzz Testing of Application Reliability: Provides details of the security analysis of applications using random input performed by the University of Wisconsin Madison.
Open Web Application Security Project (OWASP): Dedicated to finding and fighting the causes of insecure software and providing open source tools to assist this process. Includes the OWASP Secure Coding Practices Quick Reference Guide, which defines a set of general software security coding practices, in a checklist format, that can be integrated into the software development lifecycle. Implementation of these practices will mitigate most common software vulnerabilities.
Chapter 12 - OS Security
DSD Top35 Intrusion Mitigation Strategies: The Australian Defence Signals Directorate list of top intrusion mitigation strategies.
Linux Documentation Project: manuals on Linux systems administration.
Microsoft Security Tools & Checklists: tools and guidance to assess security on Microsoft Windows systems.
SANS - Top Cyber Security Risks: that organizations should address.
Chapter 13 - Trusted Computing
Trusted Computing Group: Vendor group involved in developing and promoting trusted computer standards. Site includes white papers, specifications, and vendor links.
Common Criteria Portal: Official Web site of the common criteria project.
Chapter 14 - IT Security Management and Risk Assessment
Information Security Guide: A compendium of information providing guidance on effective approaches to the application of information security at institutions of higher education. The information is useful for any organization.
ISO 27000 Directory: An overview of the ISO 27000 series of standards reserved by ISO for information security matters
Verizon Security Blog: and their Data Breach Investigations Report provide regular updates on security issues, and their annual summary report is compiled with the assistance of the US Secret Service.
Chapter 16 - Physical Security
InfraGuard: An FBI program to support infrastructure security efforts. Contains a number of useful documents and links
The Infrastructure Security Partnership: A public-private partnership dealing with infrastructure security issues. Contains a number of useful documents and links.
Federal Emergency Management Administration (FEMA): Contains a number of useful documents related to physical security for businesses and individuals.
NIST PIV program: Contains working documents, specifications, and links related to PIV.
Chapter 17 - Human Resources
Federal Agency Security Practices: A voluminous set of documents covering all aspects of organizational security policy
ISO 27002 Community Portal: Documents, links, and other resources related to ISO 27002
Computer Security Incident Response Team: Provide security professionals with the means to report, discuss, and disseminate computer security related information to others around the world. This site provides information for reporting security incidents and information on technical resources.
Chapter 18 - Security Auditing
Security Issues in Network Event Logging: This IETF working group is developing standards for system logging.
Chapter 19 - Legal and Ethical Aspects
International Cyber Threat Task Force: An online security community of cyber security professionals collaborating to deal with all related cyber threats including all aspects of cyber crime and cyber warfare. Useful documents and other information.
Criminal Justice Resources: CyberCrime: Excellent collection of links maintained by Michigan State University.
International High Technology Crime Investigation Association: A collaborative effort of law enforcement and the private sector. Contains useful set of links and other resources.
Computer Ethics Institute: Includes documents, case studies, and links.
The Rules: Maintained by the Ad Hoc Committee on Responsible Computing.
Chapter 20 - Symmetric Encryption and Message Confidentiality
AES Home Page: NIST's page on AES. Contains the standard plus a number of other relevant documents
AES Lounge: Contains a comprehensive bibliography of documents and papers on AES, with access to electronic copies.
Block Cipher Modes of Operation: NIST page with full information on NIST-approved modes of operation.
Chapter 21 - Public-Key Cryptography and Message Authentication
RSA Laboratories: The research center of RSA Security, Inc., it offers an extensive collection of technical material on RSA and other topics in cryptography.
NIST Secure Hashing Page: SHA FIPS and related documents.
Chapter 22 - Internet Security Protocols and Standards
S/MIME Charter: Latest RFCs and internet drafts for S/MIME.
DKIM Website hosted by Mutual Internet Practices Association, this site contains a wide range of documents and information related to DKIM.
DKIM Charter: Latest RFCs and internet drafts for DKIM.
TLS Charter: Latest RFCs and internet drafts for TLS.
OpenSSL Project: Project to develop open-source SSL and TLS software. Site includes documents and link.
NIST IPSec Project: Contains papers, presentations, and reference implementations.
IPsec Maintenance and Extensions Charter: Latest RFCs and internet drafts for IPsec.
Chapter 23 - Internet Authentication Applications
MIT Kerberos Site: Information about Kerberos, including the FAQ, papers and documents, and pointers to commercial product sites.
MIT Kerberos Consortium: Created to establish Kerberos as the universal authentication platform for the world's computer networks.
USC/ISI Kerberos Page: Another good source of Kerberos material.
Kerberos Working Group: IETF group developing standards for Kerberos.
Public-Key Infrastructure Working Group: IETF group developing standards based on X.509v3.
NIST PKI Program: Good source of information.
Chapter 24 - Wireless Network Security
IEEE 802.11 Wireless LAN Working Group: Contains working group documents plus discussion archives.
Wi-Fi Alliance: An industry group promoting the interoperabiltiy of 802.11 products with each other and with Ethernet.
Extensible Authentication Protocol (EAP) Working Group: IETF working group responsible for EAP and related issues.
Chapter 25 - Linux Security
NSA SELinux Web site: Contains useful documentation on SELinux.
Chapter 26 - Windows Security
Microsoft Security Central: Good collection of information about Windows and Windows Vista security
Appendix C - RFCs
RFCs: IETF RFC repository. Includes a complete list of all RFCs, constantly updated.
RFC Sourcebook: Provides the relevant information on RFCs in an easy to use, easy to access format.