BackTrack is a Linux distro which is derived from slackware which is the merger of whax and auditor security collection. Backtrack two was released on 6 March 2007 which include more than 300 security tools while the beta 3 version of backtrack released on 14 december 2007 on the third release is more focused on hardware support. While the version of backtrack 3 was released on 19 June 2008 on backtrack version 3 of this insert saint and maltego while Nessus is not included. But still using kernel version 2.6.21.5., On BackTrack 4 Final today offers the latest Linux kernel 2.6.30.4 kernel. Equipped also with a patch for the wireless drivers to cope with wireless attacks injection (wireless injection attacks).
