Hydra is the fastest network logon cracker which supports numerous attack protocols. It is very fast and flexible, and new modules are easy to add. This tool Hydra is a fast and flexible login cracker which can be used on both Linux and Windows, and supports protocols like AFP, HTTP-FORM-GET, HTTP-GET,Hydra is a parallelized login cracker which supports numerous protocols to attack. It is very fast and flexible, and new modules are easy to add. This tool Hydra Description. A very fast network logon cracker which support many different services. Currently this tool supports the following protocols: Asterisk, Hydra is a pre-installed tool in Kali Linux used to brute-force username and password to different services such as ftp, ssh, telnet, MS-SQL, etc.