CVE-2022-0317 is a medium-severity vulnerability affecting the go-attestation library developed by Google LLC, specifically versions prior to 0.3.3. The vulnerability arises from improper input validation (CWE-20) in the handling of TPM (Trusted Platform Module) attestation quotes and event logs. In TPM attestation, a Quote is a cryptographic proof generated by the TPM that binds platform configuration registers (PCRs) to a signature, allowing remote verification of system integrity during measured boot. The go-attestation library's AKPublic.Verify function is responsible for verifying these Quotes. However, due to improper input validation, local attackers can provide maliciously-formed Quotes over no or some PCRs, causing AKPublic.Verify to incorrectly succeed despite inconsistencies in the PCR values. Subsequently, the Eventlog.Verify function uses the same PCR values but lacks the authentication step performed during quote verification. This flaw allows an attacker to couple the malformed Quote with a maliciously-crafted TCG (Trusted Computing Group) event log, effectively spoofing events in the event log. This undermines the integrity of remotely-attested measured boot processes, potentially allowing attackers to hide unauthorized changes or malicious activity on the system. The vulnerability requires local access to the system, as the attacker must provide the malicious Quote and event log. No known exploits in the wild have been reported. The recommended remediation is to upgrade to go-attestation version 0.4.0 or later, where proper input validation and verification steps have been implemented to prevent this attack vector.

For European organizations relying on TPM-based measured boot attestation using the go-attestation library, this vulnerability could allow local attackers to bypass remote attestation integrity checks. This undermines trust in platform integrity verification, potentially allowing sophisticated attackers to conceal unauthorized firmware or software modifications. Critical infrastructure sectors, financial institutions, and government agencies that depend on TPM attestation for secure boot and platform integrity verification could face increased risk of persistent local compromise. Although exploitation requires local access, the ability to spoof event logs can facilitate stealthy attacks, complicate forensic investigations, and weaken security assurances in supply chain and endpoint security scenarios. This could lead to unauthorized access, data breaches, or disruption of services if attackers leverage the spoofed attestation to deploy further attacks or evade detection. The impact is particularly significant in environments where remote attestation is used as a trust anchor for security policies or compliance verification.

1. Upgrade the go-attestation library to version 0.4.0 or later immediately to ensure that proper input validation and verification mechanisms are in place. 2. Implement strict local access controls and monitoring to limit the ability of unprivileged users to interact with TPM attestation components and submit Quotes or event logs. 3. Employ additional integrity verification layers beyond TPM attestation, such as endpoint detection and response (EDR) tools, to detect anomalous behavior that might indicate tampering. 4. Regularly audit and verify TPM attestation logs and configurations to detect inconsistencies or suspicious modifications. 5. For organizations developing or deploying software that relies on go-attestation, incorporate fuzz testing and input validation checks to detect malformed TPM data inputs proactively. 6. Educate system administrators and security teams about the limitations of TPM attestation and the importance of layered security controls to mitigate risks from local attackers. 7. Where possible, restrict the ability to load or modify event logs to trusted processes and users only, reducing the attack surface for spoofing attempts.