'Car Whisperer' puts hackers in the driver's seat

If you happen to hear a disembodied computer voice tell you to "drive carefully" next time you're behind the wheel, you've probably met the Car Whisperer.

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Released late last week at the What the Hack computer security conference in Liempde, Netherlands, Car Whisperer is software that tricks the hands-free Bluetooth systems installed in some cars into connecting with a Linux computer.

Car Whisperer was developed by a group of European wireless security experts, called the Trifinite Group, as a way of illustrating the shortcomings of some Bluetooth systems, said Martin Herfurt, an independent security consultant based in Salzburg, Austria, and a founder of Trifinite.

The software takes advantage of the fact that many of these hands-free systems require only a very simple four-digit security key -- often a number such as 1234 or 0000 -- in order to grant a device access to the system. Many car manufacturers use the same code for all their Bluetooth systems, making it easy for Car Whisperer to send and receive audio from the car.

Using a special directional antenna that allowed him to extend the normally short range of his Bluetooth connections to about a mile, Herfurt was able to listen and send audio to about 10 cars over a one-hour period recently.

"I could hear voices from cars passing by," he said. "If I had been following the car, I would have been able to eavesdrop for a longer time."

Though some Bluetooth users may be shocked to learn that everything they say during their next car ride could be overheard, blame for the problem lies squarely with the Bluetooth system manufacturers, not with Bluetooth itself, Herfut said. "Manufacturers are doing something wrong with this. Bluetooth is a very good thing, once everything is correct."

The solution is for makers of the Bluetooth in-car systems to stop using only one security key for all their units, but that would probably cost them money, he said.

Trifinite is currently studying whether unauthorized Bluetooth intruders could do anything more serious than listen in or offer driving tips. Herfut said it's not possible for an attacker to do something really serious such as disabling airbags or brakes, but he believes there may be other implications to his group's hack.

It's possible, for example, that an attacker could access a telephone address book once he has connected with the Bluetooth system, but Trifinite will have to conduct more research before it can say for sure whether this could happen, he said.

The best way to avoid being "Car Whispered" is to simply connect the in-car system to a Bluetooth phone, because only one such device can be connected at a time, Herfurt said.

The Car Whisperer software, which includes an audio clip that says, "Hello there. This is the Trifinite Car Whisperer. Drive carefully," can be found here: http://trifinite.org/trifinite_downloads.html.