CVE-2022-3746 in LCFC BIOS
Summary
by MITRE • 08/23/2023
A potential vulnerability was discovered in LCFC BIOS for some Lenovo consumer notebook models that could allow a local attacker with elevated privileges to cause some peripherals to work abnormally due to an exposed Embedded Controller (EC) interface.
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Analysis
by VulDB Data Team • 08/24/2023
The vulnerability identified as CVE-2022-3746 resides within the LCFC BIOS implementation of specific Lenovo consumer notebook models, presenting a significant security concern for system integrity and peripheral management. This issue stems from improper access controls within the Embedded Controller interface, which serves as a critical communication pathway between the system's hardware components and the operating system. The exposed EC interface represents a fundamental flaw in the BIOS architecture that could be exploited by malicious actors with local elevated privileges to manipulate peripheral functionality in ways that were not intended by the system designers.
The technical flaw manifests through the lack of proper authorization checks when accessing the Embedded Controller interface, which is typically protected by hardware-level security mechanisms. When an attacker with elevated privileges can access this interface, they gain the ability to directly manipulate the EC's operational parameters and peripheral configurations. This vulnerability directly maps to CWE-284, which addresses inadequate access control mechanisms, and specifically relates to improper privilege management within firmware components. The EC interface typically handles critical system functions including keyboard input processing, fan control, power management, and other peripheral device interactions, making its exposure particularly dangerous for system stability and security.
The operational impact of this vulnerability extends beyond simple peripheral malfunction to potentially compromise system security and reliability. An attacker could exploit this weakness to disable critical system components, manipulate power management features, or interfere with input devices in ways that could disrupt normal system operation or provide covert channels for further attacks. The vulnerability's local nature means that it requires an attacker to already have elevated system privileges, but this access is often obtained through other exploitation techniques that leverage additional vulnerabilities or social engineering tactics. The potential for privilege escalation through this interface means that once an attacker gains elevated access, they could leverage this vulnerability to maintain persistence or escalate their privileges further.
Mitigation strategies for CVE-2022-3746 should focus on firmware updates provided by Lenovo, which typically address the exposed EC interface through proper access control implementation and privilege validation mechanisms. System administrators should ensure that all affected Lenovo notebook models receive the latest BIOS updates, as these patches typically implement proper access controls for the EC interface. Additionally, monitoring for unusual peripheral behavior or system instability could serve as an early warning indicator of exploitation attempts. The vulnerability aligns with ATT&CK technique T1068, which covers local privilege escalation, and represents a critical weakness in firmware security that could enable more sophisticated attacks. Organizations should also implement proper system hardening practices including disabling unnecessary peripheral interfaces, enforcing strict access controls, and maintaining current firmware versions to prevent exploitation of this and similar vulnerabilities.