CVE-2022-3500 is a medium-severity vulnerability affecting version 6.5.2 of Keylime, an open-source remote attestation framework designed to verify the integrity of hosts in distributed environments. The vulnerability arises from improper exception handling within the verifier component of Keylime. Specifically, under certain conditions, a rogue agent can trigger errors on the verifier that cause it to cease attestation attempts for the affected host. Consequently, the host remains in an attested state, but the verifier no longer actively verifies its integrity. This creates a state where the system falsely assumes the host is secure, while in reality, no ongoing attestation is performed. The vulnerability is categorized under CWE-248 (Uncaught Exception), indicating that the software fails to properly handle unexpected exceptions, leading to a security impact. The CVSS v3.1 base score is 5.1, reflecting a medium severity level. The vector indicates that exploitation requires local access (AV:L), high attack complexity (AC:H), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), no impact on confidentiality or integrity (C:N, I:N), but a high impact on availability (A:H). No known exploits are reported in the wild, and no patches are currently linked, suggesting that mitigation may require manual intervention or updates from maintainers. The vulnerability could allow an attacker with local access to disrupt the attestation process, potentially enabling persistent compromise or evasion of security monitoring in environments relying on Keylime for host integrity verification.

For European organizations utilizing Keylime for host attestation, this vulnerability poses a risk primarily to the availability and reliability of their security monitoring infrastructure. Since Keylime is used to ensure that hosts remain in a trusted state by continuously verifying their integrity, a failure in the verifier due to this vulnerability could lead to hosts being incorrectly marked as attested without ongoing verification. This undermines trust in the attestation process, potentially allowing compromised hosts to operate undetected. Organizations in sectors with high security requirements—such as finance, critical infrastructure, government, and cloud service providers—may face increased risk of undetected breaches or insider threats. The impact is particularly significant in environments where Keylime is integrated into automated security workflows or compliance frameworks. However, the vulnerability requires local access and has high attack complexity, limiting the ease of exploitation. The absence of confidentiality and integrity impact reduces the risk of data leakage or unauthorized modification directly from this flaw, but the availability impact could disrupt security operations and incident response capabilities.

Implement strict access controls to limit local access to systems running Keylime, reducing the risk of rogue agents triggering the vulnerability. Monitor Keylime verifier logs and alert on any unexpected errors or cessation of attestation attempts to detect exploitation attempts early. Develop or apply patches from Keylime maintainers that address the improper exception handling once available; in the meantime, consider contributing or reviewing the source code to implement exception handling improvements. Use defense-in-depth strategies by complementing Keylime attestation with other host integrity monitoring tools to avoid single points of failure. Regularly audit and update Keylime deployments to the latest stable versions to benefit from security fixes and improvements. Establish incident response procedures specifically for attestation failures or anomalies in Keylime to quickly investigate and remediate potential compromises.