CVE-2020-12336 in NUC
Summary
by MITRE • 11/13/2020
Insecure default variable initialization in firmware for some Intel(R) NUCs may allow an authenticated user to potentially enable escalation of privilege via local access.
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Analysis
by VulDB Data Team • 12/06/2020
The vulnerability identified as CVE-2020-12336 resides within the firmware of certain Intel NUC (Next Unit of Computing) devices, representing a critical security flaw that exploits insecure default variable initialization patterns. This issue affects the foundational firmware components that govern system behavior and security policies, specifically targeting the initialization of critical variables during the boot process. The flaw manifests when default variable values are not properly secured or validated, creating potential attack vectors that can be exploited by authenticated local users who possess legitimate access to the system.
The technical implementation of this vulnerability stems from improper handling of firmware variables that are intended to control system security parameters and access controls. During the device initialization phase, certain variables that should be explicitly set with secure default values are instead initialized with insecure configurations that may be predictable or easily manipulable. This insecure initialization creates a persistent weakness that allows an authenticated user to manipulate these variables and potentially gain elevated privileges within the system. The flaw specifically impacts the firmware's ability to properly enforce access controls and security boundaries, effectively undermining the system's integrity protection mechanisms.
From an operational perspective, this vulnerability presents a significant risk to Intel NUC deployments where local authentication is possible, as it enables privilege escalation without requiring external network access or sophisticated attack techniques. The impact extends beyond simple local access manipulation, as successful exploitation could allow attackers to bypass firmware security controls, modify system configurations, or potentially gain access to sensitive data stored within the device. The vulnerability is particularly concerning because it operates at the firmware level, making it difficult to detect through traditional operating system security measures and requiring specialized firmware-level monitoring and protection mechanisms.
The security implications of this vulnerability align with CWE-665 and CWE-707, which address improper initialization and insecure default configurations in software and firmware components. This flaw also corresponds to ATT&CK technique T1068, which involves the exploitation of local privilege escalation vulnerabilities, and T1059, which covers the use of system services and firmware for persistence and privilege escalation. Organizations deploying affected Intel NUC devices must consider this vulnerability as part of their broader security posture assessment, particularly in environments where physical access controls may be insufficient or where insider threats are a concern.
Mitigation strategies for CVE-2020-12336 should prioritize firmware updates from Intel as the primary remediation approach, ensuring that all affected devices receive the latest security patches addressing the insecure variable initialization issue. Additionally, system administrators should implement comprehensive access control policies that minimize the number of authenticated users with local access to affected devices, while maintaining strict physical security measures. Network segmentation and monitoring should be enhanced to detect anomalous behavior that might indicate exploitation attempts, and regular security audits should verify that firmware variables maintain their intended secure configurations. The vulnerability underscores the importance of firmware security hygiene and proper initialization practices in embedded systems, emphasizing that security must be considered throughout the entire system lifecycle from design through deployment and maintenance.