CVE-2022-30773 is a vulnerability involving a Time-of-Check to Time-of-Use (TOCTOU) race condition in the parameter buffer handling of the IhisiSmm driver. Specifically, this vulnerability arises from the ability of Direct Memory Access (DMA) attacks to alter the contents of the parameter buffer after the parameters have been validated but before they are actually used by the driver. The IhisiSmm driver operates at a low level within the system, likely within the System Management Mode (SMM) context, which is a highly privileged execution mode in modern CPUs. The vulnerability is classified under CWE-367 (TOCTOU Race Condition), indicating that the integrity of the parameter data can be compromised between the validation and usage phases. This can lead to unauthorized modification of critical parameters, potentially allowing an attacker with DMA capabilities to influence system behavior in unintended ways. The issue was discovered by Insyde engineering and has been addressed in specific kernel versions: Kernel 5.4 version 05.44.23 and Kernel 5.5 version 05.52.23. The CVSS v3.1 base score is 6.4, reflecting a medium severity level, with the vector indicating that the attack requires local access (AV:L), high attack complexity (AC:H), high privileges (PR:H), no user interaction (UI:N), unchanged scope (S:U), and impacts confidentiality, integrity, and availability all at a high level (C:H/I:H/A:H). No known exploits are currently reported in the wild. The vulnerability is particularly concerning because DMA attacks can be executed by an attacker with physical or logical access to the system's memory bus, such as through Thunderbolt interfaces or malicious peripherals, enabling them to bypass traditional software security controls and manipulate memory directly. This can lead to privilege escalation, data corruption, or system instability.

For European organizations, the impact of CVE-2022-30773 can be significant, especially in environments where systems with vulnerable IhisiSmm drivers are deployed. Since the vulnerability allows an attacker with local high privileges and DMA access to alter critical parameters post-validation, it can lead to unauthorized code execution, privilege escalation, or system compromise. This is particularly critical for sectors relying on high-assurance computing environments such as finance, healthcare, critical infrastructure, and government agencies. The compromise of confidentiality, integrity, and availability simultaneously can result in data breaches, operational disruptions, and loss of trust. Organizations using hardware or firmware components incorporating the affected IhisiSmm driver, especially those running the vulnerable kernel versions prior to the fixed releases, are at risk. The requirement for high privileges and local access somewhat limits remote exploitation but does not eliminate risk, especially in scenarios involving insider threats or physical access attacks. Additionally, the use of DMA-capable interfaces (e.g., Thunderbolt, PCIe) in enterprise laptops and servers increases the attack surface. Given the lack of known exploits in the wild, immediate widespread impact is limited, but the vulnerability remains a critical concern for secure environments.

1. Apply Patches: Ensure that all systems running kernels 5.4 and 5.5 are updated to at least versions 05.44.23 and 05.52.23 respectively, where the vulnerability is fixed. 2. Restrict DMA Access: Implement Input-Output Memory Management Unit (IOMMU) protections to restrict unauthorized DMA access. Configure IOMMU to isolate devices and prevent malicious peripherals from accessing sensitive memory regions. 3. Disable Unused DMA Interfaces: Where possible, disable or restrict interfaces that allow DMA, such as Thunderbolt ports, especially on systems in high-security environments. 4. Enforce Physical Security: Limit physical access to critical systems to prevent attackers from connecting malicious DMA-capable devices. 5. Monitor for Anomalies: Deploy monitoring solutions that can detect unusual memory access patterns or driver behavior indicative of exploitation attempts. 6. Firmware and Driver Updates: Coordinate with hardware vendors to ensure that firmware and drivers related to the IhisiSmm component are updated and hardened against TOCTOU and DMA attacks. 7. Harden System Management Mode: Apply best practices for securing SMM, including minimizing code running in SMM and validating parameters robustly. 8. User Privilege Management: Limit the number of users with high privileges to reduce the risk of insider threats exploiting this vulnerability. These mitigations go beyond generic advice by focusing on DMA-specific protections and system-level hardening relevant to the nature of the vulnerability.