Weevely is a stealth PHP web shell that provides a telnet-like console. It is an essential tool for web application post exploitation, and can be used as stealth backdoor or as a web shell to manage legit web accounts, even free hosted ones.

Weevely is currently included in Backtrack and Backbox and all the major Linux distributions oriented for penetration testing.

Start with a quick Tutorial, read about Modules and Generators.