SecurityRatty: Magnetic Ring Attack on Electronic Locks

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Magnetic Ring Attack on Electronic Locks

2008-06-18 06:35:16 by schneier in Schneier on Security

Impressive:

The 'ring of the devil' is capable of attacking this kind of electronic motor lock on two ways.
Scenario 1: An electronic motor is nothing more then a metal part on an axe that turns because of a changing magnetic field. Turning electro magnets on and off will generate a pulling force on the metal part, making it rotate. The ring does the same thing. By turning the ring, the metal part in the electro motor starts turning, opening the lock. As Rop suggested in the comments of the previous posting, a bunch of bigger magnets and maybe a high-speed drill can amplify this effect some more.

Scenario 2: A dynamo is nothing more then a coil charged by a changing magnetic field. So any coil in the lock will start generating current when a magnetic field is rotating around it. If the coil is in the path of the electro motor, it might generate enough current for the motor to start turning.