Tool to check for trojans, CERT advisories, and system file permission correctness.

Practical measures for critical infrastructure protection, intrusion prevention and threat assessment.

Make your system seem to have network security bugs, and log attack attempts.

Fakes trojan servers (Back Orifice, NetBus) and logs every attempt from client.

Examines source code looking for security weaknesses.

The GMM library can be used to prevent and study buffer overflows exploits

Free software (GNU license) from Bell Labs for protecting internet servers from buffer overflow attacks, one of the most commonly exploited security vulnerabilities.

A tool for file integrity checking that optionally can be used as a client/server application for centralized monitoring of networked hosts.

This is the main FTP site for security tools and papers from Wietse Venema.

Tripwire, file integrity assessment tool for UNIX.