MODSECURITY

ModSecurity is an open source, cross-platform web application firewall (WAF) module. Known as the "Swiss Army Knife" of WAFs, it enables web application defenders to gain visibility into HTTP(S) traffic and provides a power rules language and API to implement advanced protections.

A list of the most important usage scenarios:

-Real-time application security monitoring and access control
-Virtual patching
-Full HTTP traffic logging
-Continuous passive security assessment
-Web application hardening