shackspace member [@dop3j0e] found himself in a real bind when trying to recover some data after his ThinkPad’s fingerprint scanner died. You see, he stored his hard drive password in the scanner, and over time completely forgot what it was. Once the scanner stopped working, he had no way to get at his data.
He brainstormed, trying to figure out the best way to recover his data. He considered reverse engineering the BIOS, which was an interesting exercise, but it did not yield any password data. He also thought about swapping the hard drive’s logic board with that of a similar drive, but it turns out that the password is stored on the platters, not the PCB.
With his options quickly running out, he turned to a piece of open-source hardware we’ve covered here in the past, the OpenBench Logic Sniffer. The IDE bus contains 16 data pins, and lucky for [@dop3j0e] the OpenBench has 16 5v pins as well – a perfect match. He wired the sniffer up to the laptop and booted the computer, watching SUMP for the unlock command to be issued. Sure enough he captured the password with ease, after which he unlocked and permanently removed it using hdparm.
Be sure to check out [@dop3j0e's] presentation on the subject if you are interested in learning more about how the recovery was done.