Thieves Break Into Cars by Amplifying Signals from Wireless Keys Inside Homes

Storing your wireless car keys in the freezer might be the best way to defeat crooks with door-hack gadgets.

A series of break-ins in in the Los Feliz neighborhood of Los Angeles impacted only cars that use remote keyless systems, which replace traditional keys with wireless fobs.

“The most recent incident took place on a Monday morning 10 days ago,” according to New York Times writer Nick Bilton, a victim of the car crime spree.  He spotted two teen mischief-makers near his Prius on the street in front of his house. “I watched as the girl, who was dressed in a baggy T-shirt and jeans, hopped off her bike and pulled out a small black device from her backpack. … I rushed after them, partly with the hope of catching the attempted thieves, but more because I was fascinated by their little black device. How were they able to unlock my car door so easily?”

Most likely, according to security expert Boris Danev, who specializes in wireless devices, including key fobs, the teenagers used a relatively simple gizmo called a “power amplifier.”

In a normal situation, when a car owner walks up to a vehicle with a keyless lock and tries the door handle, the car wirelessly calls out for the key so the owner doesn’t have to press any buttons to get inside. When the key calls back, the door unlocks.

The keyless system is capable of searching for a key only within a couple of feet.

Probably, the girl’s device amplified the distance that the car could search, which then allowed Bilton’s car to talk to his key, which happened to be sitting about 50 feet away, on the kitchen counter.  And, then, open sesame.

“It’s a bit like a loudspeaker, so when you say hello over it, people who are 100 meters away can hear the word, ‘hello,’ ” Danev said. “You can buy these devices anywhere for under $100.”

He advised that, to protect a car, “put your keys in the freezer, which acts as a Faraday Cage, and won’t allow a signal to get in or out.”