CVE-2020-8751 in CSME
Summary
by MITRE • 11/12/2020
Insufficient control flow management in subsystem for Intel(R) CSME versions before 11.8.80, Intel(R) TXE versions before 3.1.80 may allow an unauthenticated user to potentially enable information disclosure via physical access.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 12/06/2020
The vulnerability identified as CVE-2020-8751 represents a critical weakness in the control flow management mechanisms of Intel's Converged Security Management Engine (CSME) and Trusted Execution Engine (TXE) subsystems. This flaw affects versions prior to 11.8.80 for CSME and 3.1.80 for TXE, creating a significant security gap that can be exploited by attackers with physical access to affected systems. The vulnerability stems from inadequate safeguards that govern the execution flow within these low-level security components, which are designed to provide hardware-level security functions and system integrity verification.
The technical root cause of this vulnerability lies in insufficient validation and control of execution paths within the firmware subsystems. When a system boots with vulnerable firmware, the control flow management mechanisms fail to properly validate the integrity of code execution paths, potentially allowing unauthorized code execution or information disclosure. This weakness specifically impacts the security boundaries that protect system firmware from tampering and unauthorized access, as outlined in the CWE taxonomy under control flow management weaknesses. The vulnerability manifests when an attacker can manipulate the execution flow to bypass normal security checks and access sensitive information that should remain protected within the secure execution environment.
From an operational standpoint, this vulnerability poses a severe risk to system security as it requires only physical access to exploit, making it particularly dangerous in environments where physical security controls may be insufficient. An attacker with physical access can potentially extract sensitive data such as cryptographic keys, system configuration information, or other confidential data that resides within the CSME and TXE memory spaces. The impact extends beyond simple information disclosure, as the compromised subsystems may be used to establish persistent backdoors or facilitate further attacks on the broader system. This aligns with ATT&CK framework techniques that involve privilege escalation and persistence mechanisms through firmware manipulation, particularly targeting the system firmware and boot processes.
The mitigation strategy for CVE-2020-8751 requires immediate firmware updates to versions 11.8.80 or later for CSME and 3.1.80 or later for TXE, which contain the necessary control flow management improvements. Organizations should also implement enhanced physical security measures to prevent unauthorized access to critical systems, particularly in high-risk environments. Additionally, continuous monitoring of system firmware integrity through hardware-based attestation mechanisms can help detect potential exploitation attempts. The vulnerability demonstrates the importance of robust control flow management in security-critical firmware components and underscores the need for comprehensive firmware security testing and validation processes. Regular security assessments of embedded systems and firmware components should include evaluation of control flow integrity mechanisms to prevent similar vulnerabilities from being introduced in future releases.