SecurityFocus is designed to facilitate discussion on computer security related topics, create computer security awareness, and to provide the Internet's largest and most comprehensive database of computer security knowledge and resources to the public. It also hosts the BUGTRAQ mailing list.

Antiy Ghostbusters is an advanced anti-hacker utility that finds and disinfects backdoor, trojans and worms .and include many powerful security tools.

MakeSecure.com is designed to facilitate discussion on security related topics, create network security awareness, and provide secure solutions.

Elefire is an information security company based in the UK. Our services include Risk Assessment, Remote Management, Security Audits, Business Continuity, and Systems Penetration

Help Net Security is a daily updated security related site. We offer information on the latest advisories, viruses, press releases, papers, etc. The site also has a large download section that helps you get protected, a well-stocked bookstore, and the largest Security Database of security products.

The Ethical Hacker Network - Your educational authority on penetration testing and incident response.

Developers of ZoneAlarm, a free, dynamic, application-level personal firewall, and of TrueVector technology for real-time Internet traffic information and online security

Independent comparatives of Anti-Virus software

Windows Security Software - restriction options for internet explorer, network settings and windows operating system 95, 98, Me, NT, 2000 and XP

The STAT® family of network security products includes STAT® Analyzer, a vulnerability and risk assessment tool, STAT® Neutralizer, an intrusion prevention tool, and STAT® Scanner, the most accurate and comprehensive vulnerability assessment tool for Windows NT® and Windows 2000® available today.