CVE-2020-5348 in Latitude 7202 Rugged Tablet BIOS
Summary
by MITRE
Dell Latitude 7202 Rugged Tablet BIOS versions prior to A28 contain a UAF vulnerability in EFI_BOOT_SERVICES in system management mode. A local unauthenticated attacker may exploit this vulnerability by overwriting the EFI_BOOT_SERVICES structure to execute arbitrary code in system management mode.
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Analysis
by VulDB Data Team • 05/13/2024
This vulnerability exists in Dell Latitude 7202 Rugged Tablet devices with BIOS versions prior to A28, representing a critical heap-based use-after-free condition within the EFI_BOOT_SERVICES interface. The flaw occurs in system management mode, which operates with elevated privileges and direct hardware access, making it particularly dangerous for attackers seeking persistent system compromise. The UAF vulnerability stems from improper memory management during EFI boot service operations, where freed memory locations are accessed after being reallocated, creating opportunities for code execution in the privileged system management mode context. This represents a direct violation of secure coding practices and exposes the system to arbitrary code execution capabilities that bypass normal operating system security controls.
The technical exploitation of this vulnerability requires an attacker to have local access to the device and leverage the UAF condition to overwrite the EFI_BOOT_SERVICES structure with malicious code. This attack vector operates entirely within the firmware layer, making it extremely difficult to detect and mitigate through traditional operating system security measures. The vulnerability's impact extends beyond simple code execution as it allows attackers to manipulate core boot services and potentially establish persistent backdoors within the system firmware. This aligns with CWE-416 which describes use-after-free vulnerabilities, and represents a sophisticated attack surface that can be leveraged for advanced persistent threats. The attack chain typically involves initial local access followed by exploitation of the memory corruption to gain control of the system management mode execution context.
The operational implications of this vulnerability are severe for enterprise environments where these rugged tablets may be deployed in sensitive locations or critical infrastructure. Attackers could potentially use this vulnerability to establish root-level persistence, modify boot processes, or extract sensitive data from devices that are often considered secure due to their ruggedized nature. The impact is particularly concerning because system management mode operates outside normal OS protections and can manipulate hardware directly, making it a prime target for advanced malware or nation-state actors. This vulnerability can be exploited to create stealthy attack vectors that persist across system reboots and are difficult to detect through conventional security monitoring approaches. The threat landscape for such firmware-level vulnerabilities aligns with ATT&CK technique T1068 which covers local privilege escalation and T1542 which covers exploitation for persistence in firmware contexts.
Mitigation strategies should focus on immediate BIOS firmware updates to version A28 or later, which address the specific memory management issues in EFI_BOOT_SERVICES. Organizations should also implement firmware integrity monitoring solutions that can detect unauthorized modifications to system firmware components. Network segmentation and access controls should be strengthened to limit local access to affected devices, while regular firmware inventory management should be established to track and remediate vulnerable systems. Security teams should consider implementing hardware security modules or trusted platform modules to provide additional firmware integrity verification. Additionally, regular penetration testing and firmware vulnerability assessments should be conducted to identify similar issues in other system components. The remediation process must include thorough validation that the update has been properly applied and that no malicious code has been injected into the firmware before considering systems as secure.