The Antivirus Information Exchange Network - AVIEN and AVI-EWS are international on-line communities dedicated to a cooperative, grassroots information sharing effort to reduce the impact of malicious code (viruses, worms, Trojan Horses, Spyware) and other related vulnerabilities.

N-Stealth Security Scanner - Vulnerability-assessment product that scans web servers to identify security problems and weaknesses on local and remote web servers. Commercial and free editions are available

Wilson Consulting - Provides network security auditing and analysis, vulnerability assessment, penetration testing, remediation, information security policy and procedures development, and business continuity planning for small to medium sized businesses.

Secure20 - Provides consulting and solutions specializing in network and application vulnerability testing and risk assessment services.

Open Source Vulnerability Database - Searchable database of vulnerabilities. Offers data for download in XML format as well as via website. Details of how to submit new vulnerabilities, database schema and FAQ.

VulnWatch - Computer security vulnerability disclosure mailing list