There is an AMD-based infotainment system vulnerability that can be exploited by researchers from the Technical University of Berlin to unlock restricted vehicle features, according to research. As a result, it has become particularly noticeable in vehicles that provide premium features behind a paywall, including Tesla. 

Tesla has arguably one of the most comprehensive systems (if not the most extensive) of its kind in the automotive industry. BMW is not the only automaker that charges for optional extras, with subscription models for commodities such as heated seats also making headlines in recent months. 

Using hacking techniques on the embedded computer in the car, you can unlock these features without paying an additional fee, the team claims. Security researchers from the University of Massachusetts have reportedly discovered a way to exploit Tesla's modern AMD-based cars to create a persistent Tesla jailbreak that might be the first of its kind in the world. It is the work of three German Ph.D. students. 

As part of the preparation for their presentation at next week's Blackhat 2023 conference, the team published a briefing. A working command and control attack against Tesla's next-generation AMD-based media control unit (MCU) will be demonstrated. In the opinion of the researchers, the jailbreak used a hardware exploit against a component in the MCU that has already been known to exist – an exploit that the researchers say has enabled access to one of the most important cars purchase-making systems – and perhaps even tricks the car into thinking it has already paid for them. 

Since Teslas are among the most popular electric vehicles on the market, they are an easy target for hackers, for sensitive data they contain. Researchers from the Technical University of Berlin have now discovered a way to exploit the Multi-Channel Units found in modern Tesla vehicles to unlock paid features and unlock many more in the future. They exploited a vulnerability known to be present in AMD's processor that controls Tesla's motor control unit to execute the attack. The Media Control Unit, or MCU, is a Tesla term used to describe the system that controls all the facets of the car, including the touch screen, navigation system, and entertainment system. Among the first few generations there is the NVIDIA Tegra-powered MCU0/1, and the second generation is the Intel Atom-based MCU2. 

There is a new generation of MCU-Z implemented based on a custom AMD Ryzen SoC that comes with a custom processor. The researchers are focusing their attention on the MCU-Z because of its interesting features. Apparently, according to the researchers, they were able to exploit the MCU-Z by using voltage fault injection attacks (an attack type usually found in certain types of malware). 

Tesla's MCU-Z processor is designed to be resilient to such attacks, and it is known that voltage glitching can also be used to exploit Zen 2- and Zen 3-based processors; this attack vector also affects the Ryzen SoC found inside Tesla's MCU-Z. The researchers performed a voltage fault injection attack on the MCU-Z's Platform Security Processor using multiple connections to the power supply, BIOS SPI chip, and SVI2 bus by using the various connections to the power supply, SPI chip, and SVI2 bus. 

It was discovered by using a voltage fault injection attack against the AMD Security Processor, which serves as the heart of the platform's security. This attack allowed researchers to bypass software locks on certain features intended to prevent the exploitation of the vulnerability. It is also important to note that bypassing built-in security does not require expensive hardware or gadgets—the researchers reported that they used inexpensive hardware to subvert the ASP's initial boot code, and then reverse engineer the boot flow to gain deep access that was normally out of reach of humans.

For those users who wish to bypass Tesla's security locks to bypass Tesla's network, this amounts to a jailbreak. This is one of the greatest security concerns, as it makes private information vulnerable to hackers. However, that is probably not a problem if the vehicle is physically accessible. 

As a result of this method, researchers claim that certain features that are normally paid for can be unlocked for free. In addition, it is unclear whether or not that includes those more expensive features that add to the overall cost, such as Enhanced Autopilot and/or Full Self-Driving functionality. Those features cost $6,000 and $15,000, respectively. With this exploit, it is possible to gain access to hundreds of dollars worth of paid features that are otherwise unavailable. 

In addition, Tesla cannot address the issue with a software update since it is supposedly unpatched and cannot be patched in the future. This attack is not yet clear in terms of the specifics, researchers say they can accomplish this by using inexpensive, off-the-shelf hardware to accomplish this task. 

Despite the complexity of this attack, it is possible to deduce how the researchers plan to carry out the attack. This is done using a previous presentation at Black Hat 2022 given in part by Niklas Jacob (one of the students who worked on this project). Assuming that the attack is similar, it is possible to deduce how they might plan on performing it. Typically, voltage-based faults can cause problems during the boot process, where a fault can cause a failure. In the first step, the researchers replaced AMD's public cryptographic key with their own. 

At the same time, they injected their custom bootloader image into the processor. This error would typically fail to verify the key because it would not be a trusted key expected to be used while booting the system. Despite this, the attackers can fool the ASP and its components by making them think that a valid key is present, causing the ASP and its components to believe that the key is valid, using the magic of voltage faulting, that is, applying a specific voltage to the integrated circuit to simulate a particular fault condition.