May 30, 2008

Chris Tarnovsky demos smart card hacking

Filed under: Embedded,Hacking,Hardware,Security — Nate Lawson @ 3:21 pm

Chris Tarnovsky spoke to Wired and demonstrated his smart card hacking techniques. Chris became famous for hacking Echostar cards, which resulted in a multi-billion dollar lawsuit against News Corp. The trial ended in a pretty big win for DirecTV smart card supplier NDS, with the jury only finding them guilty of trying out a packaged attack that converted a DirecTV smart card to decrypt Dish Network video. The penalty for this? A whopping $46.95 (i.e., one month’s subscription fee) plus statutory damages.

In the video, Chris demonstrates some interesting techniques. It shows him decapsulating an ST16 CPU made by ST Micro from an IBM Java card. Then, he uses nail polish to mask the die and rust remover (i.e., hydrofluoric acid) to etch away the top metal layer of protective mesh to get at the CPU’s bus. He then uses a sewing needle to tap each line of the 8-bit bus in turn and then reassemble the data in software. He could just have easily driven the lines, allowing him to change instructions or data at will.

This attack is pretty amazing. It is simple in that it does not require an expensive FIB or other rework tools. Instead, a microscope and careful work with some household chemicals is all it takes. While the ST16 is a bit old, it was used in Echostar, hence the relevance of Chris’s demonstration. It will be interesting to see what happens next in the evolving capabilities for home-based silicon analysis.

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