Weevely is a stealth PHP web shell that simulates a telnet-like connection. It is an essential tool for web application testing post exploitation, and can be used as a stealth backdoor web shell to manage legit web accounts, even free hosted ones. Is currently included in Backtrack and Backbox and other Linux distributions for penetration testing.
You can download it from the following link: https://packetstormsecurity.com/files/download/114636/weevely-0.7.tar.gz
Source: https://packetstormsecurity.com/files/114636/Weevely-PHP-Backdoor-0.7.html