Need a quick way to generate a PHP backdoor for a compromised server you want to come back to later, then weevely is your application. I was pleasantly surprised when I started playing around with weevely in more detail as it provides a ton of built in functionality and does a lot more than I initially though that weevely did. The weevely application is built using Python and its current version on Backtrack 5 R3 is weevely v0.7. The weevley.py Python script is located in the /pentest/backdoors/web/weevely directory and some of its uses are described in more detail below.
The sbd command is a netcat clone that offers decent encryption, allows for command execution, and will install on Linux or Windows. You are likely aware of netcat and all of the different ways you can use it including reverse shells, port scanning, etc. The sbd command is a great tool for opening up protected listeners or as noted in the Backtrack Linux menu for maintaining access to servers on compromised networks. Since it is likely you are familiar with nc or netcat below I go into setting up a reverse shell using a secret key between the listener and the connecting client.