[SickPsycko]

They typically use combolists. Lists generated from already hacked websites. A lot of people reuse their passwords so when websites are hacked and databases are leaked those lists are generated in the implemented into a program in which then loads the list, a proxy list (typically, but some websites are vulnerable to the action of attempting more then enough logins without checking. ) This program will also handle all HTTP/S related headers and queries. Cookies, keys, etc. Some even have the option to handle captchas. It will then login , and check for a failure or success key. These are actually fairly easy to make. I haven't seen one for linux but am currently making one in C.