Hydra is a free brute force password cracking tool. You can attack either single or multiple user accounts and try single passwords or a list of passwords. Hydra provides IPv6 support, a graphical user interface, internationalized support (RFC 4013), HTTP proxy support, and SOCKS proxy support. Hydra knows how to interact with a huge range of target services, including AFP, FTP, HTTP, IMAP, LDAP, MySQL, Oracle, POP3, RDP, RSH, SMB, SMTP, VNC, and VMware.