A Robot At DEFCON Cracked A Safe Within 30 Minutes

schwit1 shared an article from the BBC:
Using a cheap robot, a team of hackers has cracked open a leading-brand combination safe, live on stage in Las Vegas. The team from SparkFun Electronics was able to open a SentrySafe safe in around 30 minutes... After the robot discovered the combination was 51.36.93, the safe popped open -- to rapturous applause from the audience of several hundred... The robot, which cost around $200 to put together, makes use of 3D-printed parts that can be easily replaced to fit different brands of combination safe. It cannot crack a digital lock -- although vulnerabilities in those systems have been exposed by other hacking teams in the past.

Though the safe had a million possible combinations using three two-digit numbers, the last number had slightly larger indents on the dial -- reducing the possible combinations to just 10,000. And in addition, "the team also discovered that the safe's design allows for a margin of error to compensate for humans getting their combination slightly wrong" -- which meant that the robot only had to check every third number. "Using this method, they could cut down the number of possible combinations to around 1,000."

"Some SentrySafe models come with an additional lock and key, but the team was able to unlock it by using a Bic pen."