SAN FRANCISCO — Texting and driving don't go well together — though not in the way you might think.
Computer hackers can force some cars to unlock their doors and start their engines without a key by sending specially crafted messages to a car's anti-theft system. They can also snoop at where you've been by tapping the car's GPS system.
That is possible because car alarms, GPS systems and other devices are increasingly connected to cellular telephone networks and thus can receive commands through text messaging. That capability allows owners to change settings on devices remotely, but it also gives hackers a way in.
Researchers from iSEC Partners recently demonstrated such an attack on a Subaru Outback equipped with a vulnerable alarm system, which wasn't identified. With a laptop perched on the hood, they sent the Subaru's alarm system commands to unlock the doors and start the engine.
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Their findings show that text messaging is no longer limited to short notes telling friends you're running late or asking if they're free for dinner.
Texts are a powerful means of attack because the devices that receive them generally cannot refuse texts and the commands encoded in them. Users can't block texts; only operators of the phone networks can.
These devices are assigned phone numbers just like fax machines. So if you can find the secret phone number attached to a particular device, you can throw it off by sending your own commands through text messaging.
Although these numbers are only supposed to be known by the devices' operators, they aren't impossible to find.
Hackers can use that information to craft attacks against devices they know are vulnerable. (In this case, the researchers bypassed these steps and simply took the alarm system out of the car to identify the secret phone number.)
Actually stealing a car wouldn't be so easy.
You'd have to ensure that the phone number you found is attached to the car you're standing in front of, for instance. There are hacking tools to do that — they listen for cellular traffic around a particular vehicle — but in many cases it's easier to take a car that doesn't have an alarm.
Researchers Don Bailey and Mathew Solnik are working with the manufacturer of the car alarm system to fix its vulnerabilities. Bailey said the unidentified manufacturer has fixed many of the security issues.