It is a simple brute force attack, dumb as a rock that just tries keys. If it gets one, you manually have to check it and try activation. Is is ugly, takes hours, is far from point and click, but it is said to work. I don't have any Vista installs because of the anti-user licensing so I have not tested it personally.
The method of attack has got to be quite troubling for MS on many grounds. The crack is a glorified guesser, and with the speed of modern PCs and the number of outstanding keys, the 25-digit serials are within range. The biggest problem for MS? If this gets widespread, and I hope it will, people will start activating legit keys that are owned by other people
It won't take long for boxes bought at retail to be activated before they are bought, and the people who plunk down money for the mal^h^h^hsoftware for real get 'you are a filthy pirate' messages. Won't that be a laugh riot at the MS phone banks in Bangalore.