A security flaw in keycard door locks from Onity could trouble the sleep of more than 4 million hotel guests around the world. According to a demonstration by 24-year old security researcher Cody Brocious in a BlackHat pre-briefing, the electronic part of the Onity locking system can be easily tricked into opening the door for unauthorized users through the 5-volt DC port it exposes.
Even though the keycard system uses advanced encryption for the password, the specific model exposes a DC port that can access the deviceâ€™s memory where the chunk of data (the master key) responsible for unlocking is stored. This DC port allows an electronic programmer to read and write the door lockâ€™s memory space, which is exactly what Brocious did with his device.
In order to unlock the door, he plugged into the DC port a home-made electronic key programmer – similar to what hotel staff use to program doors – that was built from parts one can buy at the local Radio Shack for less than $50.
“With how stupidly simple this is, it wouldn’t surprise me if a thousand other people have found this same vulnerability and sold it to other governments,” Brocious said, as quoted by Forbes. “An intern at the NSA could find this in five minutes.“
Although the system does not work every time in real-life scenarios because of alleged timing issues in communication between his device and the Onity locks, there is still a great chance of having a door open without an authorized key, making it easier for other hotel guests to break into othersâ€™ rooms, among others.
What Onity should learn from the hack is that advanced encryption is useless if you donâ€™t regulate which ports can read what. And thereâ€™s no need to re-think the entire system or change four million locks overnight â€“ one just needs a good old piece of thick brass shield over the exposed port to make things right again.