Group dedicated to bringing you the latest news and utilities in computer security. Latest exploits with a focus on both Windows and Unix. http://www.securiteam.com/
Help Net Security is a security portal offering various information on security issues - news, vulnerabilities, press releases, software, viruses and a popular weekly newsletter. http://www.net-security.org
Information on the latest security vulnerablilities, free SecurityTracker Alerts, and customized vulnerability notification services. http://securitytracker.com/