Venom is a tool to run dictionary password attacks against Windows accounts by using the Windows Management Instrumentation (WMI) service. This can be useful in those cases where the server service has been disabled. The tool is written in VB6 and might require some additional runtime libraries to run.
Guessing speeds vary, but tend to be around 45-50 guesses/sec.
The password file supports the formats %username% and lc %username% with the result of the username being used as the password. The prefix lc converts the username to lowercase.