CVE-2022-49643 is a vulnerability identified in the Linux kernel, specifically affecting the Integrity Measurement Architecture (IMA) subsystem when the 'ima-modsig' feature is enabled. The vulnerability arises from a potential integer overflow in the function ima_appraise_measurement. This occurs because the return code (rc) passed to the evm_verifyxattr() function can be negative, which is not properly handled, leading to an integer overflow condition. The IMA subsystem is responsible for verifying the integrity of files and measurements to ensure system trustworthiness. The 'ima-modsig' module extends this by appraising digital signatures on files. An integer overflow in this context could cause incorrect appraisal results, potentially allowing maliciously modified files to be incorrectly verified as trusted. This could undermine the security guarantees provided by IMA, leading to integrity violations. The vulnerability does not have a CVSS score assigned yet, and there are no known exploits in the wild at the time of publication. The affected versions are identified by specific commit hashes, indicating that this is a recent and specific kernel patch-level issue. The vulnerability was published on February 26, 2025.

For European organizations, the impact of CVE-2022-49643 could be significant, especially for those relying on Linux systems with IMA and ima-modsig enabled for security-critical environments such as government, finance, healthcare, and critical infrastructure. The vulnerability could allow attackers to bypass file integrity checks, potentially enabling the execution of unauthorized or malicious code under the guise of trusted files. This undermines system integrity and could lead to data corruption, unauthorized access, or persistence of advanced threats. Organizations that enforce strict integrity verification policies may find their security posture weakened, increasing the risk of insider threats or external attackers exploiting this flaw to maintain footholds or escalate privileges. However, exploitation complexity is moderate since it requires the ima-modsig feature to be enabled and the attacker to influence the appraisal process. The absence of known exploits suggests limited immediate risk but does not preclude future exploitation attempts.

European organizations should prioritize updating their Linux kernels to versions that include the patch for CVE-2022-49643 as soon as it becomes available. Specifically, system administrators should: 1) Verify if the IMA subsystem with ima-modsig is enabled on their Linux systems, especially on servers and endpoints in sensitive environments. 2) Apply kernel updates from trusted sources or vendors that address this integer overflow vulnerability. 3) Review and tighten access controls to prevent unauthorized modification of files subject to IMA appraisal. 4) Monitor system logs for anomalies related to IMA appraisal failures or unexpected behavior in evm_verifyxattr calls. 5) Consider temporarily disabling ima-modsig if patching is delayed and the risk assessment justifies it, understanding this reduces integrity verification capabilities. 6) Employ defense-in-depth strategies such as mandatory access controls (e.g., SELinux, AppArmor) and endpoint detection to detect potential misuse. 7) Engage with Linux distribution vendors for timely security advisories and patches. These steps go beyond generic advice by focusing on the specific subsystem and feature implicated in the vulnerability.