Jailbreaking an Electric Vehicle in 2023 or What It Means to Hotwire Tesla's x86-Based Seat Heater
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Presented at BlackHat USA 2023 by
Tesla has been known for their advanced and well-integrated car computers, from serving mundane entertainment purposes to fully autonomous driving capabilities. More recently, Tesla has started using this well-established platform to enable in-car purchases, not only for additional connectivity features but even for analog features like faster acceleration or rear heated seats. As a result, hacking the embedded car computer could allow users to unlock these features without paying.In this talk, we will present an attack against newer AMD-based infotainment systems (MCU-Z) used on all recent models. It gives us two distinct capabilities: First, it enables the first unpatchable AMD-based "Tesla Jailbreak", allowing us to run arbitrary software on the infotainment. Second, it will enable us to extract an otherwise vehicle-unique hardware-bound RSA key used to authenticate and authorize a car in Tesla's internal service network.For this, we are using a known voltage fault injection attack against the AMD Secure Processor (ASP), serving as the root of trust for the system. First, we present how we used low-cost, off-the-self hardware to mount the glitching attack to subvert the ASP's early boot code. We then show how we reverse-engineered the boot flow to gain a root shell on their recovery and production Linux distribution.Our gained root permissions enable arbitrary changes to Linux that survive reboots and updates. They allow an attacker to decrypt the encrypted NVMe storage and access private user data such as the phonebook, calendar entries, etc. On the other hand, it can also benefit car usage in unsupported regions. Furthermore, the ASP attack opens up the possibility of extracting a TPM-protected attestation key Tesla uses to authenticate the car. This enables migrating a car's identity to another car computer without Tesla's help whatsoever, easing certain repairing efforts.