CVE-2022-32473 in InsydeH2O
Summary
by MITRE • 02/15/2023
An issue was discovered in Insyde InsydeH2O with kernel 5.0 through 5.5. DMA attacks on the HddPassword shared buffer used by SMM and non-SMM code could cause TOCTOU race-condition issues that could lead to corruption of SMRAM and escalation of privileges. This attack can be mitigated using IOMMU protection for the ACPI runtime memory used for the command buffer. This attack can be mitigated by copying the firmware block services data to SMRAM before checking it.
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Analysis
by VulDB Data Team • 05/29/2026
The vulnerability identified as CVE-2022-32473 represents a critical security flaw within Insyde InsydeH2O firmware implementations running kernel versions 5.0 through 5.5. This issue manifests through a sophisticated race condition involving DMA attacks against the HddPassword shared buffer that operates between System Management Mode and non-SMM code contexts. The fundamental problem arises from the improper handling of shared memory segments that are simultaneously accessible by both privileged SMM components and unprivileged user-mode applications, creating an exploitable window where malicious actors can manipulate memory contents during critical operations.
The technical implementation of this vulnerability leverages time-of-check to time-of-use race conditions that occur when the system validates data within the shared buffer. Specifically, the HddPassword shared buffer serves as a communication channel between SMM and non-SMM execution contexts, where the firmware performs validation checks on data before processing. During this validation phase, DMA attacks can intercept and modify the buffer contents, causing the system to operate on corrupted data that leads to SMRAM corruption. This corruption represents a severe compromise of the system's security architecture since SMRAM contains sensitive firmware code and data that should remain isolated from normal operating system execution contexts.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass complete system compromise through SMRAM corruption. Attackers can leverage this flaw to gain unauthorized access to the most privileged execution mode within the system, potentially enabling them to modify firmware code, bypass security features, or extract sensitive information from memory. The attack vector specifically targets the ACPI runtime memory used for command buffers, making it particularly dangerous as it operates at a level below the operating system's normal security boundaries. This vulnerability directly relates to CWE-367 Time-of-Check to Time-of-Use Race Condition and aligns with ATT&CK technique T1068, which covers local privilege escalation through kernel exploits.
The mitigation strategies for this vulnerability focus on implementing hardware-level protections through IOMMU (Input-Output Memory Management Unit) mechanisms that can prevent unauthorized DMA access to the ACPI runtime memory segments used for command buffers. Additionally, firmware developers can address this issue by implementing proper data copying procedures that move firmware block services data into SMRAM before performing any validation checks, thereby eliminating the shared buffer attack surface. These approaches align with industry best practices for firmware security and represent defensive measures that can be implemented at both the hardware and software levels to prevent exploitation of similar race condition vulnerabilities in firmware implementations.