Pitbull is an example of a system that takes advantage of a process address space in order to execute ELF binaries. It is primarily useful for building post-exploitation frameworks and rootkits.
You can download it from the following link: https://packetstormsecurity.com/files/download/45017/7a69-PUP.txt
Source: https://packetstormsecurity.com/files/45017/7a69-PUP.txt.html