Windows Password Kracker is a free software to recover the lost or forgotten Windows password. It can quickly recover the original windows password from either LM (LAN Manager) or NTLM (NT LAN Manager) Hash.
Windows encrypts the login password using LM or NTLM hash algorithm. Since these are one way hash algorithms we cannot directly decrypt the hash to get back the original password. In such cases 'Windows Password Kracker' can help in recovering the windows password using the simple dictionary crack method.
Before that you need to dump the password hashes from live or remote windows system using pwdump tool (more details below). Then feed the hash (LM/NTLM) for the corresponding user into 'Windows Password Kracker' to recover the password for that user.
In forensic scenarios, investigator can dump the hashes from the live/offline system and then crack it using 'Windows Password Kracker' to recover the original password. This is very crucial as such a password can then be used to decrypt stored credentials as well as encrypted volumes on that system.
'Windows Password Kracker' uses simple & quicker Dictionary based password recovery technique. By default it comes with sample password file. However you can find good collection of password dictionaries (also called wordlist) here & here.
Though it supports only Dictionary Crack method, you can easily use tools like Crunch, Cupp to generate brute-force based or any custom password list file and then use it with 'Windows Password Kracker'.
It works on both 32 bit & 64 bit windows systems starting from Windows XP to Windows 8.