The technique involves cars equipped with keyless entry transmitter keys. Normally the key, which uses a radio signal, must be just a few feet away from the vehicle. The ADAC researchers figured out that with some inexpensive equipment, they could pick up the radio signal from a nearby keyless entry fob and extend it several hundred feet. The equipment cost ADAC roughly $225.
Once inside, the researchers (or thieves) would be able to start and drive the car away, as most automakers allow the engine to keep running and the car to drive even after the keyless entry fob goes out of range. ADAC used the technique on several cars in Europe, including Audis, BMWs, GM products, Fords, Kias, and Toyotas.
This hacking technique isn't new, but the ADAC release shows that it's still a threat to contemporary cars. The only effective deterrent is to keep a keyless fob inside a signal-blocking device, like a bag or a Faraday cage, when the key isn't in use. Even your freezer may be an effective signal blocker, if you don't have a Faraday cage handy, according to The New York Times.
So this is simply another demonstration that there's a simple, effective, inexpensive exploit that thieves can use to steal cars, and that automakers still haven't come up with an effective solutions. That's the point of ADAC's recent demonstration – and why we're reminding you that it's still a threat.