CVE-2023-28039 in Dell
Summary
by MITRE • 06/23/2023
Dell BIOS contains an improper input validation vulnerability. A local authenticated malicious user with administrator privileges may potentially exploit this vulnerability in order to modify a UEFI variable.
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Analysis
by VulDB Data Team • 07/17/2023
The vulnerability identified as CVE-2023-28039 affects Dell BIOS implementations and represents a critical weakness in input validation mechanisms that could enable privilege escalation and system compromise. This issue resides within the Unified Extensible Firmware Interface firmware layer, where inadequate validation of user inputs allows for potentially dangerous modifications to UEFI variables that control fundamental system operations. The vulnerability specifically targets the BIOS firmware interface, which operates at a low level within the system architecture and maintains direct control over hardware initialization and system security policies.
The technical flaw manifests as insufficient validation of UEFI variable modifications, enabling an authenticated user with administrator privileges to manipulate firmware settings that should remain protected from unauthorized modification. This improper input validation creates an attack surface where malicious actors can alter critical system parameters such as boot configurations, security policy settings, or firmware update mechanisms. The vulnerability falls under the CWE-20 category of "Improper Input Validation" and demonstrates how firmware-level security controls can be bypassed when proper sanitization and validation procedures are not implemented. UEFI variables typically control essential system functions including secure boot policies, system configuration parameters, and firmware integrity checks that maintain the overall security posture of the platform.
From an operational impact perspective, this vulnerability enables a local authenticated attacker with administrator privileges to potentially gain deeper system control and compromise the integrity of the boot process. The ability to modify UEFI variables creates opportunities for persistent backdoor installation, bootkit development, or complete system compromise through manipulation of firmware-level security controls. Attackers could exploit this weakness to disable secure boot mechanisms, modify system firmware, or establish persistent access points that survive operating system reinstallation. The attack vector requires local administrator access, which means that while the initial compromise may be limited to privileged users, the potential impact extends far beyond the immediate user context due to the fundamental nature of firmware-level operations. This vulnerability directly relates to ATT&CK technique T1542.003 for "Taint or Modify System Firmware" and represents a significant threat to endpoint security and system integrity.
Mitigation strategies for CVE-2023-28039 should focus on immediate firmware updates from Dell, which typically address the root cause by implementing proper input validation mechanisms for UEFI variable modifications. System administrators should also implement additional security controls including regular firmware integrity monitoring, restricted administrative access controls, and enhanced logging of UEFI variable modifications. Organizations should consider implementing firmware lockdown mechanisms that prevent unauthorized modifications to critical system parameters and establish baseline firmware configurations that can be monitored for unauthorized changes. The remediation process should include verification of firmware integrity using trusted platform module measurements and implementation of secure boot policies that validate firmware modifications before they are applied to the system. Additionally, network segmentation and privileged access management controls should be strengthened to limit potential exploitation opportunities while ensuring that only authorized personnel have access to systems with elevated privileges that could potentially exploit this vulnerability.