The passive keyless entry and start systems supported by many modern cars are susceptible to attacks that allow thieves to relatively easily steal the vehicles, security researchers at Switzerland ETH Zurich University said. In demonstrations using 10 cars from 8 makers, the researchers showed how they were able to unlock, start and drive away the cars in each case, by outsmarting the smart key system. The break-ins were carried out using commercial, off-the-shelf electronic equipment available for as little as $100, the researchers said in a paper describing their exploits. Although the possibility of such attacks on keyless systems has been discussed previously, it has not been clear before if they would be feasible on modern cars, the researchers said. In this paper, we demonstrate that these attacks are both feasible and practical, they said.