This whitepaper discusses rooting windows server using the PHP Meterpreter Webshell in Metasploit.
You can download it from the following link: https://packetstormsecurity.com/files/download/125061/root3.pdf
Source: https://packetstormsecurity.com/files/125061/Rooting-Windows-Server-Using-PHP-Meterpreter-Webshell.html