Allows usernames to be loaded as a file (wordlist), that way the
it's much easier to manage. It defaults to unix_users.txt,
because these usernames are common in any SSH hosts out there.
If the user only wants to try a specific user (which is better,
because you reduce traffic noise that way), then he/she can set
the USERNAME option, and that should be the only one tried --
similar to how AuthBrute behaves.
I also fixed the regex in check().
This module works against FreeSSHD <= 1.2.6. Tested against
password and public key authentication methods. It will generate
a random key and password.
To use it you need to know a valid username. The module contains
a basic bruteforce methods, so you can specify more than one to try.