Digital license plates, already legal to buy in a growing number of states and to drive with nationwide, offer a few perks over their sheet metal predecessors. You can change their display on the fly to frame your plate number with novelty messages, for instance, or to flag that your car has been stolen. Now one security researcher has shown how they can also be hacked to enable a less benign feature: changing a car’s license plate number at will to avoid traffic tickets and tolls—or even pin them on someone else.
Josep Rodriguez, a researcher at security firm IOActive, has revealed a technique to “jailbreak” digital license plates sold by Reviver, the leading vendor of those plates in the US. By removing a sticker on the back of the plate and attaching a cable to its internal connectors, he’s able to rewrite a Reviver plate’s firmware in a matter of minutes. Then, with that custom firmware installed, the jailbroken license plate can receive commands via Bluetooth from a smartphone app to instantly change its display to show any characters or image.
That susceptibility to jailbreaking, Rodriguez points out, could let drivers with the license plates evade any system that depends on license plate numbers for enforcement or surveillance, from tolls to speeding and parking tickets to automatic license plate readers that police use to track criminal suspects. “You can put whatever you want on the screen, which users are not supposed to be able to do,” says Rodriguez. “Imagine you are going through a speed camera or if you are a criminal and you don’t want to get caught.”
Worse still, Rodriguez points out that a jailbroken license plate can be changed not just to an arbitrary number but also to the number of another vehicle—whose driver would then receive the malicious user’s tickets and toll bills. “If you can change the license plate number whenever you want, you can cause some real problems,” Rodriguez says.
All traffic-related mischief aside, Rodriguez also notes that jailbreaking the plates could also allow drivers to use the plates’ features, including its built-in GPS tracking, without paying Reviver’s $29.99 monthly subscription fee.
Because the vulnerability that allowed him to rewrite the plates’ firmware exists at the hardware level—in Reviver’s chips themselves—Rodriguez says there’s no way for Reviver to patch the issue with a mere software update. Instead, it would have to replace those chips in each display. That means the company’s license plates are very likely to remain vulnerable despite Rodriguez’s warning—a fact, Rodriguez says, that transport policymakers and law enforcement should be aware of as digital license plates roll out across the country. “It’s a big problem because now you have thousands of licensed plates with this issue, and you would need to change the hardware to fix it,” he says.
