In one case, a pair of hackers manipulated two cars by plugging a laptop into a port beneath the dashboard where mechanics connect their computers to search for problems. Scarier yet, another group took control of a car's computers through cellular telephone and Bluetooth connections, the compact disc player and even the tire pressure monitoring system.
To be sure, the "hackers" involved were well-intentioned computer security experts, and it took both groups months to break into the computers. And there have been no real-world cases of a hacker remotely taking over a car.
But experts say high-tech hijackings will get easier as automakers give cars full internet access and add computer-controlled safety devices that take over driving duties, such as braking or steering, in emergencies.
Another possibility: A tech-savvy thief could unlock the doors and drive off with your vehicle.
"The more technology they add to the vehicle, the more opportunities there are for that to be abused for nefarious purposes," says Rich Mogull, CEO of Phoenix-based Securosis, a security research firm. "Anything with a computer chip in it is vulnerable, history keeps showing us."
Computers take over
In the last 25 years, automakers have gradually computerized functions such as steering, braking, accelerating and shifting. Electronic gas pedal position sensors, for instance, are more reliable than the old throttle cables. Electronic parts also reduce weight and help cars use less gasoline.
The networks of little computers inside today's cars are fertile ground for hackers.