‘War Texting’ Lets Hackers Unlock Car Doors via SMS

Software that lets drivers unlock car doors and even start their vehicles using a mobile phone could let car thieves do the very same things, according to computer security researchers at iSec Partners.

Don Bailey and fellow iSec researcher Mathew Solnik say they’ve figured out the protocols that some of these software makers use to remote control the cars, and they’ve produced a video showing how they can unlock a car and turn the engine on via a laptop. According to Bailey, it took them about two hours to figure out how to intercept wireless messages between the car and the network and then recreate them from his laptop.

Bailey will discuss the research at next week’s Black Hat conference in Las Vegas, but he isn’t going to name the products they’ve hacked — they’ve looked at two so far — or provide full technical details of their work until the software makers can patch them.

Probably the best known of this type of product is the OnStar RemoteLink app, which can be used to start up and unlock many late-model General Motors vehicles, but similar software is available for other makes of cars, including Mercedes and BMW.

Bailey calls his technique “war texting,” a reference to another hacking technique called “war driving,” which involves driving around cities looking for data on wireless networks.

War texting is technically complex. First of all, the researchers have to identify cars that are using these mobile applications. Then they have to find a way to connect with them. With these mobile car apps, the phone connects to a server that then sends secret numerical keys to the car in order to authenticate itself, but the iSec researchers figured out ways to get around this by looking at the messages sent between the server and the car over the mobile network, Bailey said in an interview. “We reverse-engineer the protocol and then we build our own tools to use that protocol to contact that system,” he said.

The iSec researchers believe that they are uncovering symptoms of a much more widespread problem. In recent years, mobile networking has been built into an astonishing range of devices — everything from picture frames to cars to smart meters — giving them a cheap and easy way to communicate. According to Bailey, however, security has often been an afterthought, and many of these products can be hacked and misused.

Research in this area has taken off in recent years as open-source tools have given hackers an inexpensive way of setting up their own mobile-phone test networks.

In April, Bailey used similar techniques to hack Zoombak’s personal locator devices, and there are hundreds of other similar products that have not been examined. “This architectural flaw expands to so many engineering industries,” he said.

Robert McMillan covers computer security and general technology breaking news for The IDG News Service. Follow Robert on Twitter at @bobmcmillan. Robert’s e-mail address is robert_mcmillan@idg.com