Friday, August 15, 2008

Ophcrack

Windows stores user passwords in hashes. Hashing is a one way transformation of text and thus Windows passwords can be cracked by matching hashed passwords with rainbow tables.
Ophcrack is an open source program that cracks Windows passwords. Burn Ophcrack into a bootable CD and boot up your target system with the CD. Ophcrack will dump the Windows hashes and start matching the dumped hashes against its rainbow tables.
In this specific scenario, the caveat is that you need physical access. There are tools that perform offline cracking. Cracking passwords can be time consuming but it doesn't alert the admin or user as you do not change the original password. Did you know that all it takes to change the user password in Mac OS X is to boot up using the installation CD???
The high res version of this demo can be downloaded here.