CVE-2022-26858 in Dell
Summary
by MITRE • 09/07/2022
Dell BIOS versions contain an Improper Authentication vulnerability. A locally authenticated malicious user could potentially exploit this vulnerability by sending malicious input to an SMI in order to bypass security controls.
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Analysis
by VulDB Data Team • 10/14/2022
The vulnerability identified as CVE-2022-26858 represents a critical weakness in Dell BIOS implementations that fundamentally undermines system security through improper authentication mechanisms. This flaw resides within the System Management Interrupt (SMI) handler architecture, where insufficient validation of input parameters allows for unauthorized privilege escalation. The vulnerability manifests when a locally authenticated user can craft and inject malicious SMI calls that bypass normal authentication checks, effectively creating a backdoor into the system's most privileged execution environment. Such a weakness directly violates the principle of least privilege and creates an attack surface that can be exploited without requiring network connectivity or sophisticated external attack vectors.
The technical implementation of this vulnerability stems from inadequate input sanitization within the SMI handler code that processes system management interrupts. When the BIOS receives an SMI call, it should perform rigorous validation of all parameters before executing any privileged operations. However, in affected Dell BIOS versions, this validation process fails to properly authenticate the source of SMI requests, allowing malicious payloads to be processed as legitimate system management operations. The SMI mechanism operates at the highest privilege level in the system, typically running with full administrative rights and direct hardware access, making this authentication bypass particularly dangerous. This weakness aligns with CWE-287, which addresses improper authentication issues in system management interfaces, and represents a classic example of how insufficient input validation can lead to privilege escalation in firmware environments.
The operational impact of CVE-2022-26858 extends beyond simple privilege escalation, creating potential for complete system compromise and persistent malware installation. Once exploited, the malicious user gains access to the system's firmware layer where traditional operating system security controls become ineffective. Attackers can leverage this vulnerability to install rootkits, modify system firmware, or establish persistent backdoors that survive operating system reinstallation or disk formatting. The attack vector requires local authentication access, which means the vulnerability can be exploited by users with physical access to the system or those who have already compromised a user account. This makes the vulnerability particularly concerning in enterprise environments where physical security controls may be insufficient, and the attack surface includes not just external threats but also insider risks. The exploitation aligns with ATT&CK technique T1068, which covers local privilege escalation through system management mechanisms, and demonstrates how firmware-level vulnerabilities can be leveraged to achieve persistent access.
Mitigation strategies for CVE-2022-26858 primarily focus on firmware updates from Dell, which address the authentication flaw in the SMI handler implementation. Organizations should prioritize immediate deployment of BIOS updates provided by Dell, as these patches specifically target the input validation weaknesses that allow malicious SMI calls to bypass authentication. System administrators should also implement additional security controls including physical security measures to prevent unauthorized local access, enhanced monitoring for unusual SMI activity, and regular firmware integrity checks. The vulnerability highlights the importance of maintaining up-to-date firmware across all system components, as firmware-level vulnerabilities often remain undetected by traditional security tools and can persist across operating system updates. Network segmentation and access control policies should be strengthened to limit local access privileges, while security awareness training should emphasize the risks associated with unauthorized physical access to computing systems. Organizations should also consider implementing firmware-based security solutions such as Trusted Platform Modules that can detect and prevent unauthorized firmware modifications, providing an additional layer of protection against this class of vulnerability.