CVE-2022-32267 is a vulnerability involving a Time-Of-Check to Time-Of-Use (TOCTOU) race condition in the System Management Mode (SMM) of certain systems, specifically related to the SmmResourceCheckDxe software System Management Interrupt (SMI) handler. The vulnerability arises when Direct Memory Access (DMA) transactions target input buffers used by this SMI handler. Because the SMI handler operates within the System Management RAM (SMRAM), which is a highly privileged and isolated memory region, any corruption here can lead to severe security implications. The TOCTOU flaw allows an attacker to manipulate the timing of DMA transactions to cause SMRAM corruption by altering the input buffers between the time they are checked and the time they are used by the handler. This can potentially lead to arbitrary code execution within SMM, privilege escalation, or system instability. The issue was discovered by Insyde engineering and affects kernel versions 5.2 through 5.5, with fixes released in May 2023. The vulnerability has a CVSS v3.1 score of 6.4, indicating a medium severity level, with high impact on confidentiality, integrity, and availability but requiring local access with high privileges and no user interaction. No known exploits are reported in the wild. The vulnerability is categorized under CWE-367 (Time-of-check Time-of-use Race Condition). Given the involvement of SMM and DMA, exploitation requires sophisticated local access and hardware capabilities, making it a complex attack vector primarily targeting firmware-level security.

For European organizations, the impact of CVE-2022-32267 can be significant, especially for those relying on affected kernel versions and hardware platforms utilizing the vulnerable SmmResourceCheckDxe driver. Successful exploitation could allow attackers with local privileged access to corrupt SMRAM, potentially leading to full system compromise, bypassing OS-level security controls, and persistent firmware-level malware implantation. This could affect critical infrastructure, enterprise servers, and sensitive computing environments by undermining confidentiality, integrity, and availability of systems. The risk is heightened in sectors with high-value targets such as finance, government, telecommunications, and industrial control systems. However, the requirement for local privileged access and the complexity of the attack reduce the likelihood of widespread exploitation. Still, targeted attacks by advanced threat actors against high-value European organizations could leverage this vulnerability to gain stealthy, persistent control over systems.

1. Apply Firmware and Kernel Updates: Ensure all systems running affected kernel versions (5.2 to 5.5) are updated with the patches released in May 2023 or later. Coordinate with hardware vendors to verify firmware updates addressing the SmmResourceCheckDxe driver are applied. 2. Restrict DMA Access: Implement Input-Output Memory Management Unit (IOMMU) protections to restrict and monitor DMA transactions, preventing unauthorized devices or processes from accessing sensitive memory regions like SMRAM. 3. Harden Local Access Controls: Enforce strict access controls and monitoring on systems to prevent unauthorized local privileged access, including limiting administrative privileges and using multi-factor authentication. 4. Monitor for Anomalous SMI Activity: Deploy advanced endpoint detection solutions capable of monitoring System Management Interrupt behavior and detecting unusual SMRAM access patterns indicative of exploitation attempts. 5. Conduct Firmware Integrity Checks: Regularly verify firmware integrity using secure boot and trusted platform modules (TPM) to detect unauthorized modifications potentially caused by exploitation of this vulnerability. 6. Isolate High-Value Systems: Physically and logically isolate critical systems to reduce the risk of local access by untrusted users or malware that could exploit this vulnerability.