Mod_security is an Apache module whose purpose is to protect vulnerable applications and reject human or automated attacks. In addition to filtering requests, it also can create Web application audit logs. Understands regular expressions and POST payloads. Changes: Selective filtering has been introduced. You can now filter requests based on the contents of individual variables (HTTP headers, environment variables, and individual script arguments) coming either from GET or POST.
At the moment its main features are:
* Audit log; store full request details in a separate file, including POST payloads.
* Request filtering; incoming requests can be analyzed and offensive requests can be rejected (or simply logged, if that is what you want). This feature can be used to prevent many types of attacks (e.g. XSS attacks, SQL injection, ...) and even allow you to run insecure applications on your servers (if you have no other choice, of course).
