CVE-2022-32469 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 PnpSmm 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-2022-32469 represents a critical security flaw within Insyde InsydeH2O firmware implementations running kernel versions 5.0 through 5.5. This issue stems from improper handling of shared memory buffers between System Management Mode and non-SMM code contexts, creating exploitable conditions that can be leveraged by malicious actors to compromise system security. The vulnerability specifically affects the PnpSmm shared buffer mechanism, which serves as a communication channel between different firmware execution contexts. The fundamental problem manifests when DMA operations target this shared buffer, creating opportunities for timing-based attacks that exploit race conditions between different code execution paths. Such vulnerabilities are particularly dangerous because they operate at the firmware level, below the operating system's normal security boundaries and often undetected by traditional security mechanisms.
The technical exploitation of this vulnerability involves a Time-of-Check to Time-of-Use race condition that occurs when the system checks data in the PnpSmm shared buffer before and after DMA operations. This race condition creates a window where an attacker can manipulate the buffer contents between the initial check and the subsequent use, potentially corrupting System Management RAM or SMRAM. The flaw allows for privilege escalation because the shared buffer is used to communicate between SMM and non-SMM contexts, where SMM operates with the highest privilege level. The vulnerability can be classified under CWE-367 Time-of-Check to Time-of-Use (TOCTOU) Error, which is a well-documented weakness in software security that occurs when a system checks a condition and then uses the result without revalidating the condition. This type of vulnerability is particularly relevant in firmware security contexts where different execution modes must maintain data integrity across memory boundaries.
The operational impact of CVE-2022-32469 extends beyond simple privilege escalation to encompass potential complete system compromise and data corruption. When an attacker successfully exploits this vulnerability, they can gain access to SMRAM, which contains sensitive system information and firmware code that operates with the highest privilege level. This access enables attackers to execute arbitrary code with system-level privileges, potentially allowing them to modify firmware, extract cryptographic keys, or establish persistent backdoors. The attack surface is particularly concerning because it affects firmware implementations that are deeply embedded in the system architecture, making it difficult to patch or mitigate without complete system replacement or firmware updates. The vulnerability affects a wide range of devices including laptops, desktops, and servers that utilize InsydeH2O firmware, making it a significant concern for enterprise security and critical infrastructure protection.
Mitigation strategies for this vulnerability focus on implementing hardware-based protections and firmware-level code changes to prevent the race condition from being exploitable. The primary recommended approach involves enabling IOMMU (Input-Output Memory Management Unit) protection for the ACPI runtime memory used for command buffers, which prevents unauthorized DMA operations from accessing the vulnerable shared memory regions. This approach aligns with the broader security principle of defense in depth and represents a hardware-level solution that can effectively prevent the exploitation pathway. Additionally, firmware developers should implement code changes that copy firmware block services data to SMRAM before performing any validation checks, eliminating the race condition window. This mitigation technique follows the principle of least privilege and ensures that critical data remains protected during the validation process. The ATT&CK framework categorizes this type of vulnerability under T1068, Exploitation for Privilege Escalation, and T1211, Exploitation for Execution, as it enables attackers to gain elevated privileges and execute code within the system. Organizations should prioritize updating to firmware versions that address this vulnerability while implementing monitoring for suspicious DMA activity and memory access patterns that could indicate exploitation attempts.