Ophcrack is a free Windows password cracker based on rainbow tables. It is a very efficient implementation of rainbow tables done by the inventors of the method. It comes with a Graphical User Interface and runs on multiple platforms.
Ophcrack is a free open source (GPL licensed) program that cracks Windows passwords by using LM hashes through rainbow tables. The program includes the ability to import the hashes from a variety of formats, including dumping directly from the SAM files of Windows. On most computers, ophcrack can crack most passwords within a few minutes.
Rainbow tables for LM hashes are provided for free by the developers. By default, ophcrack is bundled with tables that allows it to crack passwords no longer than 14 characters using only alphanumeric characters. Available for free download are four Windows XP tables and four Windows Vista tables.
Objectif Sécurité has even larger tables for purchase, intended for professional use. Larger rainbow tables are NTLM hash for cracking Windows Vista/Windows 7.
Starting with version 2.3, Ophcrack also cracks NTLM hashes. This is necessary if the generation of the LM hash is disabled (this is default for Windows Vista), or if the password is longer than 14 characters (in which case the LM hash is not stored).
• Cracks LM and NTLM Windows hashes
• Free tables available for Windows XP, Vista and 7
• Brute-force module for simple passwords
• Audit mode and CSV export
• Real-time graphs to analyze the passwords
• LiveCD available to simplify the cracking
• Loads hashes from encrypted SAM recovered from a Windows partition