NEW YORK (CBSNewYork) – Criminals have a new trick to exploit keyless doors, hijacking the signal from the real owner’s device to unlock locks, start cars and more.

Eric Ellis is like millions of Americans in using a key fob to unlock his car when in close range, but it’s far from secure from modern thieves, reports CBS2’s Ali Bauman.

In a surveillance video, Ellis watched two people walk into his driveway and unlock his vehicle without the fob.

One of them tries to open up other cars but it doesn’t work.

“Everything from the glove box is sitting in the passenger seat, so that’s when I knew somebody had been in there,” said Ellis.

It turns out the thieves only got away with some workout gear from the car, but police are seeing more cases where thieves open vehicles without a key.

“With all this new technology, the criminals are out there trying to defeat it,” Roger Morris of the National Insurance Crime Bureau.

Morris says in some cases criminals are using an amplifying device that grabs signal from a fob inside the house and amplifies it to another device and allows doors to be opened.

To prevent this trick, people can keep a fob inside a metal box, aluminum foil or a Faraday bag, a pouch designed to protect electronics from signal interference.

“If you can block the signal, the radio frequency of the device communicating to the vehicle, then you can block the effectiveness of these,” said Morris.

But crooks have also figured out how to steal a fob’s signal while you’re using it.

In a demonstration, a driver getting out of his car is using the fob to lock it. Morris uses a relay box to intercept the fob’s code which is immediately sent to a second man with a small box that now acts as the vehicle’s fob.
Together they unlock the car, open the door, start the car and drive away.

“Cars are basically computers on wheels and anything that can defeat the computer system on the car is a very popular item among car thieves and hackers,” said Morris.

He says auto makers are aware of this hacking technology and are working on improvements to thwart it.