“Volkswagen left not only its ignition vulnerable but the keyless entry system that unlocks the vehicle’s doors, too. And this time, they say, the flaw applies to practically every car Volkswagen has sold since 1995. One of the attacks would allow resourceful thieves to wirelessly unlock practically every vehicle the Volkswagen group has sold for the last two decades, including makes like Audi and Škoda. The second attack affects millions more vehicles, including Alfa Romeo, Citroen, Fiat, Ford, Mitsubishi, Nissan, Opel, and Peugeot. Both attacks use a cheap, easily available piece of radio hardware to intercept signals from a victim’s key fob, then employ those signals to clone the key.”
https://www.wired.com/2016/08/oh-good-new-hack-can-unlock-100-million-volkswagens/