Easy tool to generate backdoor

This is not a novel tool. It is literally just running msfvenom with shikata, and setting up a listener. I'd recommend reading some tutorials on using msfvenom/msfconsole rather than relying on a tool to do what should be trivially understood. If you'd like to dig deeper into what metasploit can help you do, check out the Metasploit Unleashed material published by Offensive Security (a brief venom tutorial is at [0]).

[0] https://www.offensive-security.com/metasploit-unleashed/msfv...