Meterpreter is an advanced, dynamically extensible payload that uses in-memory DLL injection stagers and is extended over the network at runtime. It communicates over the stager socket and provides a comprehensive client-side Ruby API. It features command history, tab completion, channels, and more.
Metepreter was originally written by skape for Metasploit 2.x, common extensions were merged for 3.x and is currently undergoing an overhaul for Metasploit 3.3. The server portion is implemented in plain C and is now compiled with MSVC, making it somewhat portable. The client can be written in any language but Metasploit has a full-featured Ruby client API.
New features are added to Meterpreter by loading extensions.
This entire process is seamless and takes approximately 1 second to complete.
In the next Metasploit Unleashed tutorial we’ll discuss some of the various Meterpreter Commands available to us in this new environment.