Is your server running slowly? Clamav-sniffer could help - it scans for malware such as phishes and viruses and configures your firewall to block the cracker.
High interaction honeypot solution for Linux based systems
NOTICE:
The format of this project has been changed from ISO to using ansible and has been moved to GitHub.
Github link: https://github.com/Bifrozt/bifrozt-ansible
Copfilter is a easy to install addon for the opensource firewall IPCop. It filters POP3, SMTP, HTTP, and FTP traffic for viruses and spam using various open source programs.
Anoubis is a Security Suite which implements a secured environment for applications. The core of the suite is an Application Firewall alongside with a Sandbox. Mechanisms to assure the authenticity of files, directories and applications are provided.
A packet dissector driven by machine learning algorithms. You train it to recognize specific types of packets by showing it examples and counterexamples of some packet type, and it will figure out which bits in the packet define it as the type you seek.