Here is link to Backtrack’s wiki which list ways of intrusion testing.
BackTrack is the most highly-rated Linux live distribution focused on penetration testing. With no installation whatsoever, the analysis platform is launched directly the external media and is fully accessible within moments. BackTrack functions and performs operations without touching a single file on the system’s internal storage.
It’s evolved from the merger of the two distributions Whax and Auditor Security Collection in 2006. By combining both communities into one, BackTrack has since gained wide-spread popularity and recognition. Security professionals and newcomers alike from all over the globe are using BackTrack as their favourite tool-set for penetration testing.