PCRsec

PCRsec is a security vulnerability that affects certain implementations of the Trusted Platform Module (TPM). The TPM is a hardware chip designed to provide security-related functions, such as secure storage of cryptographic keys and attestation of a platform's integrity. PCRsec specifically targets the Platform Configuration Registers (PCRs) within the TPM. PCRs are used to record measurements of the system's boot process and software environment. These measurements are critical for attestation, allowing a remote party to verify that the system has booted in a known, trusted state.

The PCRsec vulnerability arises from a flaw in how some TPMs handle updates to PCR values. In certain scenarios, an attacker could potentially manipulate the order in which PCR values are extended or reset. This manipulation could allow an attacker to trick the TPM into recording a measurement that does not accurately reflect the actual state of the system. Consequently, an attestation process relying on these compromised PCR values might incorrectly conclude that the system is secure when it is not. The impact of PCRsec can vary depending on the specific implementation and its usage, but it can undermine the trust established through TPM-based attestation mechanisms. Mitigations typically involve updating TPM firmware and ensuring that software properly sequences PCR operations.