The Complete Metasploit Guide

What is an encoder?

The msfvenom utility would generate a payload for us. However, the possibility of our payload getting detected by antivirus on the target system is quite high. Almost all industry leading antivirus and security software programs have signatures to detect Metasploit payloads. If our payload gets detected, it would render useless and our exploit would fail. This is exactly where the encoder comes to rescue. The job of the encoder is to obfuscate the generated payload in such a way that it doesn't get detected by antivirus or similar security software programs.