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Researchers at the Technical University of Berlin have published a paper called "faulTPM: Exposing AMD fTPMs' Deepest Secrets," highlighting AMD's firmware-based Trusted Platform Module (TPM) is susceptible to the new exploit targeting Zen 2 and Zen 3 processors. The faulTPM attack against AMD fTPMs involves utilizing the AMD secure processor's (SP) vulnerability to voltage fault injection attacks. This allows the attacker to extract a chip-unique secret from the targeted CPU, which is then used to derive the storage and integrity keys protecting the fTPM's non-volatile data stored on the BIOS flash chip. The attack consists of a manual parameter determination phase and a brute-force search for a final delay parameter. The first step requires around 30 minutes of manual attention, but it can potentially be automated. The second phase consists of repeated attack attempts to search for the last-to-be-determined parameter and execute the attack's payload.
Once these steps are completed, the attacker can extract any cryptographic material stored or sealed by the fTPM regardless of authentication mechanisms, such as Platform Configuration Register (PCR) validation or passphrases with anti-hammering protection. Interestingly, BitLocker uses TPM as a security measure, and faulTPM compromises the system. Researchers suggested that Zen 2 and Zen 3 CPUs are vulnerable, while Zen 4 wasn't mentioned. The attack requires several hours of physical access, so remote vulnerabilities are not a problem. Below, you can see the $200 system used for this attack and an illustration of the physical connections necessary.
AMD has issued a statement for Tom's Hardware:
The attack is also public with code available on GitHub.
View at TechPowerUp Main Site | Source
Once these steps are completed, the attacker can extract any cryptographic material stored or sealed by the fTPM regardless of authentication mechanisms, such as Platform Configuration Register (PCR) validation or passphrases with anti-hammering protection. Interestingly, BitLocker uses TPM as a security measure, and faulTPM compromises the system. Researchers suggested that Zen 2 and Zen 3 CPUs are vulnerable, while Zen 4 wasn't mentioned. The attack requires several hours of physical access, so remote vulnerabilities are not a problem. Below, you can see the $200 system used for this attack and an illustration of the physical connections necessary.
AMD has issued a statement for Tom's Hardware:
AMD Spokesperson said:
The attack is also public with code available on GitHub.
View at TechPowerUp Main Site | Source
