Hydra was a software project developed by "The Hacker's Choice" (THC) that uses a dictionary attack to test for weak or simple passwords on one or many remote hosts running a variety of different services. It was designed as a proof-of-concept utility to demonstrate the ease of cracking poorly chosen passwords. It is licensed under version 2.0 of the GNU General Public License with the additional terms that the software may not be used for illegal purposes, and any commercial service or program that uses Hydra must give credit to THC. Hydra is now mainly used for Teamspeak password recovery.
The list of supported services includes: TELNET, FTP, HTTP, HTTPS, HTTP-PROXY, SMB, SMBNT, MS-SQL, MYSQL, REXEC, RSH, RLOGIN, CVS, SNMP, SMTP-AUTH, SOCKS5, VNC, POP3, IMAP, NNTP, PCNFS, ICQ, SAP/R3, LDAP, PostgreSQL, Teamspeak, Cisco auth, Cisco enable, and Cisco AAA.
More information on THC-Hydra @ http://freeworld.thc.org/thc-hydra/