Wired | 21 July 2015

I was driving 70 mph on the edge of downtown St. Louis when the exploit began to take hold.

Though I hadn’t touched the dashboard, the vents in the Jeep Cherokee started blasting cold air at the maximum setting, chilling the sweat on my back through the in-seat climate control system. Next the radio switched to the local hip hop station and began blaring Skee-lo at full volume. I spun the control knob left and hit the power button, to no avail. Then the windshield wipers turned on, and wiper fluid blurred the glass.

As I tried to cope with all this, a picture of the two hackers performing these stunts appeared on the car’s digital display: Charlie Miller and Chris Valasek, wearing their trademark track suits. A nice touch, I thought.

The Jeep’s strange behavior wasn’t entirely unexpected. I’d come to St. Louis to be Miller and Valasek’s digital crash-test dummy, a willing subject on whom they could test the car-hacking research they’d been doing over the past year. The result of their work was a hacking technique—what the security industry calls a zero-day exploit—that can target Jeep Cherokees and give the attacker wireless control, via the Internet, to any of thousands of vehicles. Their code is an automaker’s nightmare: software that lets hackers send commands through the Jeep’s entertainment system to its dashboard functions, steering, brakes, and transmission, all from a laptop that may be across the country.

To better simulate the experience of driving a vehicle while it’s being hijacked by an invisible, virtual force, Miller and Valasek refused to tell me ahead of time what kinds of attacks they planned to launch from Miller’s laptop in his house 10 miles west. Instead, they merely assured me that they wouldn’t do anything life-threatening. Then they told me to drive the Jeep onto the highway. “Remember, Andy,” Miller had said through my iPhone’s speaker just before I pulled onto the Interstate 64 on-ramp, “no matter what happens, don’t panic.”¹

Click to Open Overlay Gallery

As the two hackers remotely toyed with the air-conditioning, radio, and windshield wipers, I mentally congratulated myself on my courage under pressure. That’s when they cut the transmission.

Immediately my accelerator stopped working. As I frantically pressed the pedal and watched the RPMs climb, the Jeep lost half its speed, then slowed to a crawl. This occurred just as I reached a long overpass, with no shoulder to offer an escape. The experiment had ceased to be fun.

At that point, the interstate began to slope upward, so the Jeep lost more momentum and barely crept forward. Cars lined up behind my bumper before passing me, honking. I could see an 18-wheeler approaching in my rearview mirror. I hoped its driver saw me, too, and could tell I was paralyzed on the highway.

“You’re doomed!” Valasek shouted, but I couldn’t make out his heckling over the blast of the radio, now pumping Kanye West. The semi loomed in the mirror, bearing down on my immobilized Jeep.

I followed Miller’s advice: I didn’t panic. I did, however, drop any semblance of bravery, grab my iPhone with a clammy fist, and beg the hackers to make it stop.

Wireless Carjackers

This wasn’t the first time Miller and Valasek had put me behind the wheel of a compromised car. In the summer of 2013, I drove a Ford Escape and a Toyota Prius around a South Bend, Indiana, parking lot while they sat in the backseat with their laptops, cackling as they disabled my brakes, honked the horn, jerked the seat belt, and commandeered the steering wheel. “When you lose faith that a car will do what you tell it to do,” Miller observed at the time, “it really changes your whole view of how the thing works.” Back then, however, their hacks had a comforting limitation: The attacker’s PC had been wired into the vehicles’ onboard diagnostic port, a feature that normally gives repair technicians access to information about the car’s electronically controlled systems.

A mere two years later, that carjacking has gone wireless. Miller and Valasek plan to publish a portion of their exploit on the Internet, timed to a talk they’re giving at the Black Hat security conference in Las Vegas next month. It’s the latest in a series of revelations from the two hackers that have spooked the automotive industry and even helped to inspire legislation; WIRED has learned that senators Ed Markey and Richard Blumenthal plan to introduce an automotive security bill today to set new digital security standards for cars and trucks, first sparked when Markey took note of Miller and Valasek’s work in 2013.

As an auto-hacking antidote, the bill couldn’t be timelier. The attack tools Miller and Valasek developed can remotely trigger more than the dashboard and transmission tricks they used against me on the highway. They demonstrated as much on the same day as my traumatic experience on I-64; After narrowly averting death by semi-trailer, I managed to roll the lame Jeep down an exit ramp, re-engaged the transmission by turning the ignition off and on, and found an empty lot where I could safely continue the experiment.

Miller and Valasek’s full arsenal includes functions that at lower speeds fully kill the engine, abruptly engage the brakes, or disable them altogether. The most disturbing maneuver came when they cut the Jeep’s brakes, leaving me frantically pumping the pedal as the 2-ton SUV slid uncontrollably into a ditch. The researchers say they’re working on perfecting their steering control—for now they can only hijack the wheel when the Jeep is in reverse. Their hack enables surveillance too: They can track a targeted Jeep’s GPS coordinates, measure its speed, and even drop pins on a map to trace its route.

Click to Open Overlay Gallery

All of this is possible only because Chrysler, like practically all carmakers, is doing its best to turn the modern automobile into a smartphone. Uconnect, an Internet-connected computer feature in hundreds of thousands of Fiat Chrysler cars, SUVs, and trucks, controls the vehicle’s entertainment and navigation, enables phone calls, and even offers a Wi-Fi hot spot. And thanks to one vulnerable element, which Miller and Valasek won’t identify until their Black Hat talk, Uconnect’s cellular connection also lets anyone who knows the car’s IP address gain access from anywhere in the country. “From an attacker’s perspective, it’s a super nice vulnerability,” Miller says.

From that entry point, Miller and Valasek’s attack pivots to an adjacent chip in the car’s head unit—the hardware for its entertainment system—silently rewriting the chip’s firmware to plant their code. That rewritten firmware is capable of sending commands through the car’s internal computer network, known as a CAN bus, to its physical components like the engine and wheels. Miller and Valasek say the attack on the entertainment system seems to work on any Chrysler vehicle with Uconnect from late 2013, all of 2014, and early 2015. They’ve only tested their full set of physical hacks, including ones targeting transmission and braking systems, on a Jeep Cherokee, though they believe that most of their attacks could be tweaked to work on any Chrysler vehicle with the vulnerable Uconnect head unit. They have yet to try remotely hacking into other makes and models of cars.

After the researchers reveal the details of their work in Vegas, only two things will prevent their tool from enabling a wave of attacks on Jeeps around the world. First, they plan to leave out the part of the attack that rewrites the chip’s firmware; hackers following in their footsteps will have to reverse-engineer that element, a process that took Miller and Valasek months. But the code they publish will enable many of the dashboard hijinks they demonstrated on me as well as GPS tracking.

Second, Miller and Valasek have been sharing their research with Chrysler for nearly nine months, enabling the company to quietly release a patch ahead of the Black Hat conference. On July 16, owners of vehicles with the Uconnect feature were notified of the patch in a post on Chrysler’s website that didn’t offer any details or acknowledge Miller and Valasek’s research. “[Fiat Chrysler Automobiles] has a program in place to continuously test vehicles systems to identify vulnerabilities and develop solutions,” reads a statement a Chrysler spokesperson sent to WIRED. “FCA is committed to providing customers with the latest software updates to secure vehicles against any potential vulnerability.”