Researchers at the Technische Universität Berlin say they’ve found a way to enable free access to software that Tesla makes buyers pay for. The exploit isn’t one that a nefarious ne’er-do-well would use but instead, something an owner could use to enable features their car is already capable of. As automakers aim to squeeze more cash from subscriptions this kind of exploit could slow that move.

Hacking a Tesla or cars, in general, isn’t anything new. We’ve seen situations where outsiders could unlock or even start a Tesla, and hacks where remote parties could track a car or others that enabled secret features. In this case, the hack simply enables features, like heated seats, that are already a part of the car.

“We are not the evil outsider, but we’re actually the insider, we own the car,” Christian Werling, one of the researchers, told TechCrunch. “And we don’t want to pay these $300 for the rear heated seats.” He also took the time to explain, in layman’s terms, exactly how they do it.

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 Researchers Hack Tesla To Enable Features Previously Behind A Paywall

It all comes down to changing the voltage at the AMD processing unit of the infotainment system. “If we do it at the right moment, we can trick the CPU into doing something else. It has a hiccup, skips an instruction, and accepts our manipulated code. That’s basically what we do in a nutshell,” he said.

Once the researchers have access they can make lasting changes to the system like enabling heated seats, improving performance, or unlocking full self-driving. Currently, these are features that the average customer can only get if they’re willing to fork out cash despite the fact that the car they own is already equipped to use them.

According to the researchers, this particular type of hack isn’t patchable unless Tesla upgrades the processor in the infotainment system. That means that it should work for every model already made for the foreseeable future. In fact, if these sorts of hacks become commonplace they could take a bite out of long-term subscription models.

For decades, tech-savvy customers have managed to work around similar paywalls and blockades to enable similar features. Tuners have developed piggyback systems that enable more horsepower, torque, or fuel-efficiency on internal combustion engines too. The hackers will share all of their findings next week at the Black Hat USA conference.

 Researchers Hack Tesla To Enable Features Previously Behind A Paywall