CVE-2022-40134 in Lenovo
Summary
by MITRE • 01/31/2023
An information leak vulnerability in the SMI Set BIOS Password SMI Handler in some Lenovo models may allow an attacker with local access and elevated privileges to read SMM memory.
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Analysis
by VulDB Data Team • 01/31/2023
This vulnerability resides within the System Management Mode SMI handler responsible for setting BIOS passwords in certain Lenovo computer models. The flaw represents a critical information disclosure issue that stems from improper memory access controls within the System Management Mode environment. The vulnerability specifically affects the SMI handler that manages BIOS password operations, creating an unintended pathway for memory exposure that can be exploited by malicious actors with local access and elevated privileges.
The technical implementation of this vulnerability demonstrates a failure in proper privilege validation and memory protection mechanisms within the SMM context. When the SMI handler processes BIOS password operations, it fails to adequately verify memory access permissions, allowing unauthorized reading of SMM memory regions. This represents a classic case of insufficient access control enforcement that violates fundamental security principles governing privileged execution environments. The vulnerability manifests as a direct memory read operation that bypasses normal memory protection boundaries, potentially exposing sensitive system information including cryptographic keys, firmware configurations, and other confidential data stored within the SMM memory space.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates potential pathways for further exploitation within the system's security architecture. Attackers who gain local access and can elevate privileges can leverage this flaw to extract sensitive information from the SMM memory, which may include encryption keys, system configuration data, or other confidential parameters. This information leak can facilitate more sophisticated attacks such as firmware modification, privilege escalation, or the development of additional exploits targeting other system components. The vulnerability affects the integrity of the system's security model by undermining the isolation guarantees typically provided by the SMM environment.
From a cybersecurity perspective, this vulnerability aligns with CWE-284, which addresses improper access control in software systems, and represents a significant weakness in the privilege management model of the affected Lenovo systems. The ATT&CK framework categorizes this issue under privilege escalation and credential access techniques, as it enables attackers to gain unauthorized access to system memory that would normally be protected. The vulnerability also relates to firmware security concerns and represents a failure in the secure boot chain validation, as it allows information leakage that could compromise the overall system security posture. Organizations should consider this vulnerability as part of their broader firmware security assessment and implement appropriate monitoring and mitigation strategies.
Mitigation efforts should focus on firmware updates provided by Lenovo to address the specific SMI handler implementation flaw. System administrators should ensure that all affected systems receive the latest firmware patches and security updates from the vendor. Additionally, implementing runtime monitoring solutions that can detect anomalous SMI handler activity or unauthorized memory access patterns can provide additional detection capability. Access control measures should be strengthened to prevent unauthorized local access to systems, and privilege escalation controls should be reviewed and hardened. Organizations should also consider implementing memory protection mechanisms and regular security assessments of firmware components to identify similar vulnerabilities in other system components. The remediation process should include comprehensive testing of the firmware updates to ensure they do not introduce compatibility issues while effectively addressing the identified information leak vulnerability.