pwnshell is a stripped down version of the c99 shell and the likes. The only difference is that it a single JSP file, embedded with jQuery with a xterm like interface. It can also show and alter session variables and help you dump JNDI entries. The best of all, it is open source and can run on any system that supports Java 1.5 upwards. It’s usage is also simple upload it to a vulnerable web directory, point your browser to the shell and pretend that you’re looking at the xterm interface.
Source: https://thehackernews.com/2011/01/pwnshell-better-jsp-shell-download.html