CVE-2022-34417

Vulnerability

The vulnerability (CVE-2022-34417) resides in the System Management Mode (SMM) communication buffer verification of Dell PowerEdge BIOS and Dell Precision BIOS. Improper verification of the communication buffer allows a local attacker with high privileges to trigger arbitrary code execution or a denial of service. The affected versions are not explicitly listed in the available references, but the advisory [1] covers a range of related CVEs impacting these BIOS products.

Exploitation

Exploitation requires a local attacker with high privileges (e.g., administrative or kernel-level access) and the ability to interact with SMM through System Management Interrupts (SMIs). By sending specially crafted data to the SMM communication buffer, the attacker can bypass verification and cause the SMM handler to execute malicious code or enter an unrecoverable state. The CVSS vector string (CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:N/I:N/A:L) indicates high attack complexity and a scope change [1].

Impact

Successful exploitation allows the attacker to execute arbitrary code within SMM (ring -2) or trigger a denial of service. Arbitrary code execution in SMM gives the attacker full control over the system firmware and operating system, potentially bypassing all higher-level security controls. The denial of service can render the system unresponsive. The CVSS base score is 1.9 (low) due to the high required privileges and complexity, but the impact on confidentiality, integrity, and availability is limited to the local scope [1].

Mitigation

Dell has released BIOS updates to address this vulnerability. The advisory (DSA-2022-204) [1] provides a list of affected platforms and the corresponding fixed BIOS versions. Users should apply the relevant BIOS update from the Dell support site. No workaround is available; patching is required to eliminate the vulnerability.