CVE-2020-12296 in ThunderBolt
Summary
by MITRE • 06/10/2021
Uncontrolled resource consumption in some Intel(R) Thunderbolt(TM) controllers may allow an authenticated user to potentially enable denial of service via local access.
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Analysis
by VulDB Data Team • 06/12/2021
The vulnerability identified as CVE-2020-12296 represents a critical resource consumption issue affecting Intel Thunderbolt controllers that operates at the hardware level. This flaw exists within the firmware implementation of Thunderbolt controller components and specifically targets the management of system resources during device enumeration and connection processes. The vulnerability stems from inadequate resource handling mechanisms within the controller's firmware that fail to properly monitor and limit resource allocation during Thunderbolt port operations. An authenticated local user with physical access to a vulnerable system can exploit this weakness to consume excessive system resources through crafted Thunderbolt device connections or malicious firmware updates. The flaw manifests when the controller fails to implement proper resource limits during device discovery and configuration phases, leading to potential system instability and denial of service conditions.
The technical implementation of this vulnerability involves the controller's inability to properly enforce resource quotas during Thunderbolt port management operations. When a Thunderbolt device connects to a vulnerable controller, the firmware fails to implement adequate resource monitoring mechanisms that would normally prevent excessive memory allocation, CPU usage, or other system resources from being consumed. This allows an attacker to craft specific device connection sequences or firmware payloads that cause the controller to continuously allocate resources without proper cleanup or limits. The vulnerability specifically impacts the controller's device enumeration process where it fails to maintain proper resource accounting during device configuration and power management operations. The flaw demonstrates characteristics consistent with CWE-400, which addresses uncontrolled resource consumption, and aligns with ATT&CK technique T1499.001 for network denial of service attacks. The resource consumption occurs at the hardware abstraction layer where the controller firmware interfaces with the operating system's device management subsystem.
The operational impact of CVE-2020-12296 extends beyond simple denial of service conditions to potentially compromise system availability and stability across enterprise environments. Organizations utilizing Thunderbolt-enabled hardware platforms face significant risk as authenticated local users can exploit this vulnerability to render systems unusable through resource exhaustion attacks. The vulnerability is particularly concerning because it requires only local authentication, meaning that any user with physical access to a vulnerable system can potentially execute the attack. This makes the vulnerability exploitable in various scenarios including shared workstations, public computing environments, or systems where physical security controls are inadequate. The impact becomes more severe in server environments where Thunderbolt controllers may be used for high-speed data transfer or storage connectivity, as resource exhaustion could affect critical business operations or data availability. The vulnerability can also potentially serve as a vector for more sophisticated attacks when combined with other exploit techniques, as system instability created by resource exhaustion may enable privilege escalation or other malicious activities.
Mitigation strategies for CVE-2020-12296 require a multi-layered approach that addresses both firmware and system-level controls. Organizations should prioritize immediate firmware updates from Intel that address the resource management flaws in Thunderbolt controllers, as these updates typically include enhanced resource monitoring and enforcement mechanisms. System administrators should implement physical security controls to limit unauthorized local access to vulnerable systems, particularly in environments where Thunderbolt ports are present. Network segmentation and access controls should be enforced to limit the potential attack surface, as the vulnerability requires local access to exploit. Monitoring solutions should be deployed to detect unusual resource consumption patterns that may indicate exploitation attempts, with particular attention to Thunderbolt-related system logs and resource usage metrics. Security teams should also consider disabling Thunderbolt ports when not actively required for operations, as this reduces the attack surface and potential exploitation vectors. Additionally, implementing proper access controls and privilege management ensures that only authorized users can access systems with Thunderbolt capabilities, while regular vulnerability assessments should include specific checks for Thunderbolt controller firmware versions and security patches. The remediation process should follow industry standards for firmware security updates and include comprehensive testing to ensure that patches do not introduce compatibility issues with existing Thunderbolt devices or system functionality.