CVE-2022-32477 is a high-severity vulnerability affecting InsydeH2O firmware versions with kernel 5.0 through 5.5. The issue arises from a time-of-check to time-of-use (TOCTOU) race condition in the handling of the FvbServicesRuntimeDxe shared buffer, which is accessed by both System Management Mode (SMM) and non-SMM code. Specifically, the vulnerability involves Direct Memory Access (DMA) attacks targeting the shared buffer used for firmware block services runtime data. Because SMM operates at a highly privileged level with access to System Management RAM (SMRAM), corruption of SMRAM through this race condition can lead to privilege escalation, allowing an attacker to execute arbitrary code at the highest privilege level on the system. The vulnerability is rooted in improper synchronization and validation of the shared buffer, enabling an attacker with limited privileges (local access) to exploit the race condition. Mitigation strategies include enabling Input-Output Memory Management Unit (IOMMU) protections to restrict DMA access to the ACPI runtime memory used by the command buffer, and architectural changes such as copying firmware block services data into SMRAM before validation to prevent TOCTOU issues. The CVSS v3.1 score is 7.0 (high), reflecting the vulnerability's potential to compromise confidentiality, integrity, and availability, though exploitation requires local access and elevated privileges. No public exploits are currently known in the wild, but the vulnerability poses a significant risk due to the critical nature of SMM and firmware security in modern computing platforms.

For European organizations, the impact of CVE-2022-32477 can be substantial, especially for sectors relying heavily on secure firmware environments such as finance, government, critical infrastructure, and manufacturing. Successful exploitation could allow attackers to gain kernel-level or firmware-level privileges, bypassing operating system security controls and potentially implanting persistent malware or rootkits that are difficult to detect or remove. This could lead to data breaches, intellectual property theft, disruption of critical services, and compromise of system integrity. Given that firmware vulnerabilities affect the foundational trust of computing devices, the attack could undermine endpoint security across enterprise networks. Organizations using devices with vulnerable InsydeH2O firmware may face challenges in incident response and recovery, as firmware-level compromises require specialized remediation. The requirement for local access and elevated privileges limits remote exploitation but does not eliminate risk, as insider threats or attackers with initial footholds could leverage this vulnerability to escalate privileges and move laterally within networks.

European organizations should implement the following specific mitigations: 1) Verify and apply firmware updates from device manufacturers that address this vulnerability, prioritizing devices known to use InsydeH2O firmware with kernel versions 5.0 to 5.5. 2) Enable and enforce IOMMU protections on all systems to restrict unauthorized DMA access, particularly for ACPI runtime memory regions. This may require BIOS/UEFI configuration changes or platform firmware updates. 3) Employ endpoint detection and response (EDR) solutions capable of monitoring for anomalous SMM or firmware-level activity, although detection is challenging at this layer. 4) Limit local administrative access and enforce strict privilege management to reduce the risk of attackers gaining the necessary privileges to exploit the vulnerability. 5) Conduct regular firmware integrity checks and audits to detect unauthorized modifications. 6) Collaborate with hardware vendors to ensure secure firmware supply chains and timely patch deployment. 7) For critical systems, consider hardware-based security features such as Trusted Platform Module (TPM) and secure boot to provide additional layers of defense.