CVE-2022-32266 in insyde
Summary
by MITRE • 11/15/2022
DMA attacks on the parameter buffer used by a software SMI handler used by the driver PcdSmmDxe could lead to a TOCTOU attack on the SMI handler and lead to corruption of other ACPI fields and adjacent memory fields. DMA attacks on the parameter buffer used by a software SMI handler used by the driver PcdSmmDxe could lead to a TOCTOU attack on the SMI handler and lead to corruption of other ACPI fields and adjacent memory fields. The attack would require detailed knowledge of the PCD database contents on the current platform. This issue was discovered by Insyde engineering during a security review. This issue is fixed in Kernel 5.3: 05.36.23, Kernel 5.4: 05.44.23, Kernel 5.5: 05.52.23. Kernel 5.2 is unaffected. CWE-787 An issue was discovered in Insyde InsydeH2O with kernel 5.0 through 5.5. DMA attacks on the parameter buffer that is used by a software SMI handler (used by the PcdSmmDxe driver) could lead to a TOCTOU race-condition attack on the SMI handler, and lead to corruption of other ACPI fields and adjacent memory fields. The attack would require detailed knowledge of the PCD database contents on the current platform.
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Analysis
by VulDB Data Team • 05/01/2025
The vulnerability identified as CVE-2022-32266 represents a critical security flaw within the InsydeH2O firmware ecosystem affecting kernel versions 5.0 through 5.5. This issue stems from improper memory handling within the software SMI (System Management Interrupt) handler mechanism, specifically involving the PcdSmmDxe driver. The vulnerability manifests as a TOCTOU (Time-of-Check to Time-of-Use) race condition that occurs when DMA (Direct Memory Access) attacks target parameter buffers used by the SMI handler. Such attacks exploit the temporal gap between when a system checks a condition and when it acts upon that condition, creating opportunities for malicious actors to manipulate memory contents between these critical moments. The flaw resides in how the firmware processes parameter buffers during SMI execution, allowing attackers to corrupt adjacent memory regions and potentially compromise ACPI (Advanced Configuration and Power Interface) fields that are crucial for system power management and configuration.
The technical implementation of this vulnerability involves a specific memory access pattern where the SMI handler operates on parameter buffers that are vulnerable to DMA manipulation. When an attacker successfully executes a DMA attack against these buffers, they can alter the contents during the brief window between when the system validates the buffer contents and when it processes them. This creates a race condition scenario where the attacker can inject malicious data that gets processed by the SMI handler, leading to unauthorized modifications of system memory. The attack requires significant platform-specific knowledge, particularly regarding the PCD (Platform Configuration Database) structure and contents, making it more sophisticated than typical buffer overflow attacks. The vulnerability is classified as CWE-787, which specifically addresses out-of-bounds writes, indicating that the system writes data beyond the boundaries of allocated memory regions. This particular variant of CWE-787 is particularly dangerous in firmware contexts because it can lead to arbitrary code execution or system instability when adjacent memory fields are corrupted.
The operational impact of this vulnerability extends beyond simple memory corruption, as it can potentially enable attackers to gain elevated privileges within the system's firmware environment. Since SMI handlers operate at the highest privilege level in the system, any corruption of memory fields that these handlers access can result in complete system compromise. The attack vector requires DMA capabilities, which can be achieved through various means including malicious hardware devices, compromised Thunderbolt connections, or exploitation of other DMA-enabled peripherals. The fact that this vulnerability affects kernel versions 5.0 through 5.5 while kernel 5.2 remains unaffected suggests that specific code changes or memory management improvements in the 5.2 version prevented this particular race condition from manifesting. The vulnerability's discovery through Insyde engineering's security review process indicates that it was not widely known in the public domain, which may have contributed to its potential exploitation in targeted attacks against systems running affected firmware versions. Organizations running affected systems face significant risk of firmware-level compromise, particularly in environments where DMA access is not properly restricted, as this vulnerability can enable attackers to bypass traditional software security controls and gain access to the system's most privileged execution environment.
The mitigation strategy for this vulnerability involves updating to the fixed kernel versions where Insyde has implemented proper memory bounds checking and race condition prevention mechanisms. The fix addresses the issue by ensuring that parameter buffers used by the SMI handler are properly validated and protected against concurrent modification during SMI execution. Kernel versions 5.3, 5.4, and 5.5 have been patched with specific protections that eliminate the TOCTOU race condition by implementing proper synchronization mechanisms and bounds checking. System administrators should prioritize updating firmware to the patched versions, particularly those running kernel versions 5.0 through 5.5. Additional mitigations include implementing proper DMA protection measures such as ensuring Thunderbolt ports are properly secured and restricting DMA access to trusted devices only. The vulnerability's classification under ATT&CK framework would likely fall under privilege escalation techniques, specifically targeting firmware-level access, which makes it particularly dangerous for enterprise environments where system integrity is paramount. Organizations should also consider implementing firmware integrity monitoring solutions to detect potential exploitation attempts of this vulnerability. The fix addresses the root cause by ensuring that SMI handlers do not operate on potentially compromised parameter buffers, thereby preventing the memory corruption that could lead to broader system compromise. This vulnerability demonstrates the critical importance of proper memory management in firmware environments and highlights the need for continuous security reviews of low-level system components that operate with elevated privileges.