For Chrysler, the fix was embarrassing and costly. But now those two researchers have returned with work that asks Chrysler and the automotive industry to imagine an alternate reality, one where instead of reporting their research to the automaker so it could be fixed, they had kept working on it in secret—the way malicious hackers would have. In doing so, they've developed a new hack that offers a sobering lesson: It could have been—and still could be—much worse.

At the Black Hat security conference later this week, automotive cybersecurity researchers Charlie Miller and Chris Valasek will present a new arsenal of attacks against the same 2014 Jeep Cherokee they hacked in 2015. Last year, they remotely hacked into the car and paralyzed it on highway I-64—while I was driving in traffic. They were even able disable the car's brakes at low speeds. By sending carefully crafted messages on the vehicle's internal network known as a CAN bus, they're now able to pull off even more dangerous, unprecedented tricks like causing unintended acceleration and slamming on the car's brakes or turning the vehicle's steering wheel at any speed.