webApp.secure SE for Linux Description:

webApp.secure SE is a straightforward, easy-to-install/use application firewall that protects a Web site against defacement, known as well as unknown server worms (Code Red, Nimbda, etc.), and other application-level attacks.
Its minimal footprint, high-performance, and low cost make it the perfect addition to any Web security tool kit.

Event logging, 2 forms of notification, and support for most client-side scripting is also included.

webApp.secure SE is also available for Windows 2000/XP, FreeBSD, Solaris, and QNX.