BackTrack 5 R1 (Latest release)

 BackTrack is a Linux-based penetration testing arsenal that aids security professionals in the ability to  perform assessments in a purely native environment dedicated to hacking. BackTrack has been customized down to every package, kernel configuration, script and 
patch intended for the purpose of the penetration testing...

BackTrack provides a very easy access to a comprehensive and large collection of security-related tools ranging from port scanners to password crackers. BackTrack can be run on a Live DVD and Live USB without installing it as a primary Operating system on a hard disk. Permanent installation of backtrack on to a hard disk is also an option for the user.
 BackTrack tools are arranged into the follwing  categories;

•   Network Mapping
•    Web Application Analysis
•    Penetration 
•    Maintaining Access
•    Reverse Engineering
•    Information Gathering
•    Vulnerability Identification
•    Radio Network Analysis (802.11, Bluetooth, RFID)
•    Privilege Escalation
•    Digital Forensics
•    Voice Over IP 

Some of the tools found in backtrack include;

•  Metasploit integration
• RFMON Injection capable wireless drivers
• Kismet
• Nmap
• Ophcrack
• Ettercap
• Wireshark (formerly known as Ethereal)
• BeEF (Browser Exploitation Framework)
• Hydra
• Cisco OCS Mass Scanner (A very reliable and fast scanner for Cisco routers with telnet/enable default password)
• A huge collection of exploits as well as more commonplace software such as browsers.

DOWNLOAD

BackTrack 5 R1 http://www.backtrack-linux.org/downloads/