CVE-2022-33907 in insyde
Summary
by MITRE • 11/15/2022
DMA transactions which are targeted at input buffers used for the software SMI handler used by the IdeBusDxe driver could cause SMRAM corruption through a TOCTOU attack... DMA transactions which are targeted at input buffers used for the software SMI handler used by the IdeBusDxe driver could cause SMRAM corruption through a TOCTOU attack. This issue was discovered by Insyde engineering based on the general description provided by Intel's iSTARE group. Fixed in kernel 5.2: 05.27.25, kernel 5.3: 05.36.25, kernel 5.4: 05.44.25 https://www.insyde.com/security-pledge/SA-2022049
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 06/12/2026
The vulnerability described in CVE-2022-33907 represents a critical security flaw within the Intel-based system management mode (SMM) architecture, specifically affecting the IdeBusDxe driver component. This issue stems from a fundamental design weakness in how the system handles DMA transactions targeting input buffers used by the software SMI handler, creating a window of opportunity for sophisticated attackers to compromise the most sensitive memory regions of a system. The vulnerability operates through a time-of-check to time-of-use (TOCTOU) attack pattern, where an attacker can manipulate data between the moment when a system checks the validity of a buffer and when it actually uses that buffer, leading to unauthorized modifications of SMRAM contents.
The technical implementation of this vulnerability involves the manipulation of Direct Memory Access operations that target input buffers utilized by the IdeBusDxe driver, which is responsible for handling IDE bus transactions within the UEFI environment. When DMA transactions are directed toward these specific input buffers, the system's SMM handler can be tricked into processing corrupted or malicious data, ultimately resulting in SMRAM corruption. This corruption occurs because the system fails to properly validate buffer contents between the initial check and the subsequent use, allowing attackers to inject malicious data that gets processed by the SMM handler. The flaw is particularly dangerous because it operates at the SMM level, where privilege escalation is already complete and the attacker gains access to the most protected memory regions of the system.
The operational impact of CVE-2022-33907 extends beyond traditional software vulnerabilities, as it fundamentally compromises the security model of modern x86 systems that rely on SMM for critical system functions. The vulnerability allows attackers to potentially execute arbitrary code within the SMM context, which operates at the highest privilege level and can bypass standard operating system protections. This capability enables attackers to establish persistent backdoors, modify system firmware, or exfiltrate sensitive data without detection. The attack vector through DMA transactions makes this vulnerability particularly concerning because DMA operations are commonly used by legitimate hardware components and can be initiated by malicious devices, making detection and prevention extremely challenging. According to industry standards such as CWE-367, this vulnerability demonstrates a classic time-of-check to time-of-use flaw that can lead to privilege escalation and system compromise.
The mitigation approach for this vulnerability requires both firmware and kernel-level updates, as indicated by the fixed versions provided in the advisory. System administrators must ensure that all affected systems receive the appropriate kernel updates, with specific version requirements for kernel 5.2, 5.3, and 5.4 releases. The fix addresses the underlying TOCTOU condition by implementing proper buffer validation mechanisms that prevent the SMM handler from processing potentially corrupted input data. Organizations should also consider implementing DMA protection measures, including disabling unused DMA capabilities, implementing IOMMU (Input-Output Memory Management Unit) controls, and monitoring for suspicious DMA activity. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation through SMM manipulation and system firmware attacks, making it a critical concern for enterprise security teams who must assess their systems against both software and hardware-based attack vectors. The vulnerability underscores the importance of maintaining up-to-date firmware and kernel components as part of comprehensive security strategies, particularly in environments where physical security cannot be guaranteed.