CVE-2022-30774 in insyde
Summary
by MITRE • 11/15/2022
DMA attacks on the parameter buffer used by the PnpSmm driver could change the contents after parameter values have been checked but before they are used (a TOCTOU attack) DMA attacks on the parameter buffer used by the PnpSmm driver could change the contents after parameter values have been checked but before they are used (a TOCTOU attack) . This issue was discovered by Insyde engineering during a security review. This iss was fixed in Kernel 5.2: 05.27.29, Kernel 5.3: 05.36.25, Kernel 5.4: 05.44.25, Kernel 5.5: 05.52.25. CWE-367 https://www.insyde.com/security-pledge/SA-2022043
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Analysis
by VulDB Data Team • 05/01/2025
The vulnerability identified as CVE-2022-30774 represents a critical timing-of-check to timing-of-use (TOCTOU) flaw within the PnpSmm driver component of certain firmware implementations. This issue specifically affects systems utilizing the Insyde H2O firmware platform where the PnpSmm driver handles parameter buffers during system management mode operations. The vulnerability arises from the lack of proper synchronization mechanisms between the validation phase and the execution phase of parameter processing, creating a window where malicious actors can manipulate memory contents between verification and utilization. The flaw exists in the parameter buffer handling logic where input validation occurs before parameter processing but does not prevent subsequent modifications to the same memory regions.
This vulnerability operates at the intersection of firmware security and system management mode operations, specifically targeting the System Management Mode (SMM) environment where the PnpSmm driver executes with elevated privileges. The TOCTOU condition allows an attacker to modify parameter values after they have been validated but before they are consumed by the driver, effectively bypassing security checks that were designed to prevent malicious input. The vulnerability is particularly concerning because it occurs within the SMM context, which operates with the highest privilege level on the system, enabling potential escalation to full system compromise. The issue was discovered through systematic security review processes conducted by Insyde engineering, demonstrating the importance of thorough firmware security assessments.
The operational impact of this vulnerability extends beyond simple parameter manipulation, as it provides a potential pathway for attackers to escalate privileges and gain unauthorized access to system resources. An attacker with DMA (Direct Memory Access) capabilities can exploit this vulnerability by modifying the parameter buffer contents during the brief window between validation and execution. This attack vector is particularly dangerous because it can be executed through various DMA-enabled interfaces such as PCIe, USB, or Thunderbolt connections. The vulnerability affects multiple kernel versions including 5.2 through 5.5, indicating a widespread impact across different firmware implementations. This widespread exposure increases the potential attack surface and makes the vulnerability particularly attractive to threat actors seeking persistent system compromise.
The fix implemented by Insyde addresses this vulnerability through enhanced synchronization mechanisms that prevent parameter buffer modifications between validation and execution phases. The mitigation strategy involves implementing proper memory protection and validation techniques that ensure parameter integrity throughout the entire processing lifecycle. This approach aligns with established security principles and follows the CWE-367 guideline for preventing time-of-check to time-of-use vulnerabilities. The patch updates across kernel versions 5.2 through 5.5 demonstrate the vendor's commitment to addressing the issue promptly. From an ATT&CK perspective, this vulnerability maps to techniques involving privilege escalation and persistence through firmware manipulation, making it particularly relevant to threat actors seeking long-term system access.
Security practitioners should prioritize patching affected systems as soon as possible, given the severity of the vulnerability and the potential for exploitation through DMA interfaces. The vulnerability highlights the importance of firmware security reviews and the need for robust protection mechanisms in system management mode environments. Organizations should also implement monitoring for suspicious DMA activity and ensure proper system integrity verification processes are in place. The fix demonstrates the critical nature of proper synchronization in security-critical code paths, particularly within firmware components that operate with elevated privileges and have direct access to system memory. This vulnerability serves as a reminder of the increasing sophistication of attacks targeting firmware-level components and the necessity for comprehensive security approaches that consider all layers of system architecture.