Webhandler is a ‘Linux bash prompt like’ to handle and process:

PHP program execution functions e.g. system, passthru, exec, etc
Bind shell connections
Reverse shell connections

Webhandler contains a lot of post exploitation modules that help during penetration testing and security assessments.

It also has many features like:

1- Works with GET and POST requests.
2- Command Injection through cookies (https://github.com/lnxg33k/webhandler/issues/12)
3- Spoof the "User-Agent" field in the HTTP header.
4- Supports HTTP proxies (--proxy http://<ip>:<port>)
5- Works with Tor anonymity network (--tor)
6- Alternative for netcat.

Also it is easy to write your own module and get it working within webhandler as a post exploitation module.

Here is a demonstration for pushing a module into webhanlder: http://ruinedsec.wordpress.com/2013/03/30/webhandler-write-your-own-module/

We regularly updates webhandler and add some new features and enhancements.

Project: https://github.com/lnxg33k/webhandler/

Developers:
Ahmed Shawky ~ @lnxg33k (http://lnxg33k.wordpress.com)
g0tmi1k ~ @g0tmi1k (http://www.g0tmi1k.com)