Brutus is a free,  flexible remote password cracker.  it was written originally to help check routers etc for default and common passwords.

Features: Brutus version AET2 is the current release and includes the following authentication types :

• HTTP (Basic Authentication)
• HTTP (HTML Form/CGI)
• POP3
• FTP
• SMB
• Telnet

The current password release includes the following functionality :

• Multi-stage authentication engine
• 60 simultaneous target connections
• No username, single username and multiple username modes
• Password list, combo (user/password) list and configurable brute force modes
• Highly customisable authentication sequences
• Load and resume position
• Import and Export custom authentication types as BAD files seamlessly
• SOCKS proxy support for all authentication types
• User and password list generation and manipulation functionality
• HTML Form interpretation for HTML Form/CGI authentication types
• Error handling and recovery capability inc. resume after crash/failure.