Meterpreter is a Metasploit attack payload that provides an interactive shell from which an attacker can explore the target machine and execute code. Meterpreter is deployed using in-memory DLL injection. As a result, Meterpreter resides entirely in memory and writes nothing to disk. No new processes are created as Meterpreter injects itself into the compromised process, from which it can migrate to other running processes. As a result, the forensic footprint of an attack is very limited.
Meterpreter was designed to circumvent the drawbacks of using specific payloads, while enabling the writing of commands and ensuring encrypted communication. The disadvantage of using specific payloads is that alarms may be triggered when a new process starts in the target system.
Metepreter was originally written for Metasploit 2.x by Skape, a hacker moniker used by Matt Miller. Common extensions were merged for 3.x and is currently undergoing an overhaul for Metasploit 3.3.