CVE-2018-12147 in CSME
Summary
by MITRE
Insufficient input validation in HECI subsystem in Intel(R) CSME before version 11.21.55, Intel? Server Platform Services before version 4.0 and Intel? Trusted Execution Engine Firmware before version 3.1.55 may allow a privileged user to potentially enable escalation of privileges via local access.
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Analysis
by VulDB Data Team • 06/23/2020
The vulnerability identified as CVE-2018-12147 resides within the Hardware Enablement Component Interface (HECI) subsystem of Intel's management engines, specifically affecting Intel Client Side Management Engine (CSME) versions prior to 11.21.55, Intel Server Platform Services before version 4.0, and Intel Trusted Execution Engine Firmware before version 3.1.55. This issue represents a critical security flaw that stems from inadequate input validation mechanisms within the HECI communication interface, which serves as a bridge between the operating system and Intel's embedded management subsystems. The HECI interface is designed to facilitate communication between the host system and various Intel management engines including the CSME, which operates with elevated privileges and maintains control over critical system functions such as firmware updates, hardware configuration, and security policy enforcement. The vulnerability creates a pathway for privilege escalation attacks where authenticated users with local access can exploit the insufficient validation to gain elevated privileges within the management engine environment.
The technical flaw manifests as a failure in validating input parameters received through the HECI interface, allowing maliciously crafted requests to bypass normal access controls and authentication mechanisms. This weakness specifically affects the HECI message processing functions that handle communication between the host operating system and the embedded management engine components. When the management engine receives requests through HECI, it should validate the integrity and authorization of each message before processing. However, the vulnerability allows attackers to submit malformed or unauthorized requests that can be processed without proper validation, potentially enabling them to execute arbitrary code or access restricted functionality within the management engine's operational context. The flaw operates at the firmware level where the management engine operates with the highest privilege levels, making successful exploitation particularly dangerous as it could allow attackers to manipulate system security policies, modify firmware components, or gain persistent access to the system.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and persistent access capabilities. Attackers with local access can leverage this vulnerability to gain elevated privileges within the management engine environment, which operates independently of the main operating system and maintains its own security boundaries. This creates a significant risk for enterprise environments where the management engine controls critical security functions and firmware integrity checks. The vulnerability's impact is particularly severe in server environments where Intel Server Platform Services are deployed, as these systems often require elevated privileges for management operations and may be targeted by sophisticated attackers seeking persistent access. The management engine's ability to perform firmware updates and system configuration changes means that successful exploitation could lead to complete system compromise, potentially allowing attackers to install backdoors, modify security policies, or disable critical protective mechanisms.
Mitigation strategies for CVE-2018-12147 should prioritize immediate firmware updates from Intel to the latest versions that contain patches addressing the input validation issues within the HECI subsystem. Organizations must ensure that all affected Intel CSME, Server Platform Services, and Trusted Execution Engine firmware components are updated to versions 11.21.55 or later for CSME, version 4.0 or later for Server Platform Services, and version 3.1.55 or later for Trusted Execution Engine Firmware. System administrators should also implement network segmentation and access controls to limit local access to systems running affected firmware versions, as the vulnerability requires local privileged access for exploitation. Additionally, monitoring and logging of HECI communications should be enhanced to detect anomalous behavior that might indicate exploitation attempts. The vulnerability aligns with CWE-20, which addresses "Improper Input Validation," and represents a significant concern from an ATT&CK perspective under T1068, "Exploitation for Privilege Escalation," and T1059, "Command and Scripting Interpreter," as successful exploitation could enable attackers to execute commands with elevated privileges within the management engine environment. Organizations should also consider implementing additional security controls such as firmware integrity monitoring and privileged access management to reduce the risk of successful exploitation.
This vulnerability demonstrates the critical importance of firmware security in modern computing environments, where embedded management engines operate with elevated privileges and control fundamental system functions. The issue highlights the need for comprehensive security testing of firmware components and regular update management processes to address vulnerabilities that may not be immediately apparent through traditional software security measures. The HECI subsystem's role in system management and security enforcement makes it a prime target for attackers seeking persistent access, emphasizing the necessity of protecting these critical firmware components through proper access controls, regular updates, and continuous monitoring of management engine activities.