This is a whitepaper tutorial that walks through creating a proof of concept exploit for a remote command execution vulnerability in NagiosXI version 5.6.
You can download it from the following link: https://packetstormsecurity.com/files/download/157156/nagiosxi-exec.pdf
Source: https://packetstormsecurity.com/files/157156/NagiosXI-5.6-Remote-Command-Execution.html