CVE-2020-24516 in CSME
Summary
by MITRE • 06/10/2021
Modification of assumed-immutable data in subsystem in Intel(R) CSME versions before 13.0.47, 13.30.17, 14.1.53, 14.5.32, 15.0.22 may allow an unauthenticated user to potentially enable escalation of privilege via physical access.
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Analysis
by VulDB Data Team • 06/12/2021
The vulnerability identified as CVE-2020-24516 resides within Intel's Converged Security and Management Engine (CSME) subsystem, a critical component embedded in numerous Intel processors and chipsets. This flaw represents a significant security weakness that affects multiple versions of the CSME firmware across different generations, specifically targeting versions prior to 13.0.47, 13.30.17, 14.1.53, 14.5.32, and 15.0.22. The CSME operates as a separate computing environment within the processor that handles security functions including firmware updates, hardware configuration, and system management. This vulnerability falls under the CWE-284 access control weakness category, specifically involving improper privilege management where data that should remain immutable is susceptible to modification by unauthorized parties. The issue is particularly concerning because it requires only physical access to exploit, making it a serious concern for devices that may be compromised in physical possession scenarios.
The technical nature of this vulnerability stems from the CSME's handling of assumed-immutable data structures within its subsystem. When the CSME processes firmware updates or manages system security functions, it relies on certain data elements that are expected to remain unchanged during normal operation. However, the flaw allows an attacker with physical access to manipulate these data structures, potentially enabling privilege escalation attacks. This modification capability can be leveraged to alter security policies, bypass authentication mechanisms, or modify system configurations that should remain protected. The vulnerability demonstrates a fundamental breakdown in the integrity protection mechanisms that are supposed to safeguard critical system components, particularly those that operate outside the normal operating system execution context and maintain their own privileged execution environment.
The operational impact of CVE-2020-24516 extends beyond simple privilege escalation, as it represents a potential gateway for more sophisticated attacks within the system. An attacker who gains physical access to a vulnerable device can potentially establish persistent backdoors, modify system security parameters, or even compromise the integrity of the entire platform. The attack vector requires physical access, which means that while it may be more difficult to exploit remotely, it remains a serious concern for mobile devices, servers, and other systems that might be physically compromised. This vulnerability particularly affects enterprise environments where physical security controls may be inadequate, and it also poses risks to consumer devices that could be accessed by adversaries with physical possession. The potential for privilege escalation means that once exploited, attackers could gain administrative access to the system management functions that are designed to be protected from unauthorized modification.
Mitigation strategies for CVE-2020-24516 primarily focus on firmware updates and physical security measures. Organizations should prioritize updating their systems to the latest CSME versions that contain patches for this vulnerability, specifically versions 13.0.47, 13.30.17, 14.1.53, 14.5.32, and 15.0.22 or later. The update process should be carefully managed to ensure that all affected systems receive the necessary patches without disrupting critical operations. Additionally, physical security controls should be strengthened, including secure storage of devices, proper access controls for system maintenance, and monitoring for unauthorized physical access to sensitive equipment. This vulnerability aligns with ATT&CK technique T1068, which involves local privilege escalation through exploitation of system vulnerabilities, and T1543, which covers persistence mechanisms that can be established through system management interface manipulation. Organizations should also consider implementing hardware-based security features such as Intel's Platform Trust Technology and secure boot mechanisms to provide additional protection layers against such attacks.