CVE-2022-40135 in Lenovo
Summary
by MITRE • 01/31/2023
An information leak vulnerability in the Smart USB Protection 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
The vulnerability identified as CVE-2022-40135 represents a critical information disclosure flaw within the Smart USB Protection SMI Handler component of certain Lenovo computer models. This vulnerability exists within the System Management Mode (SMM) context, which operates at the highest privilege level in modern computing architectures and is responsible for handling critical system functions including hardware initialization and power management. The SMI Handler serves as an interface between the system management firmware and the operating system, making it a prime target for attackers seeking to escalate privileges and access sensitive system information.
The technical flaw stems from improper memory access controls within the SMM environment where the Smart USB Protection component fails to adequately validate memory read operations. This allows an attacker with local access and elevated privileges to potentially traverse SMM memory boundaries and extract sensitive data that should remain protected from unauthorized access. The vulnerability specifically affects systems where the SMM handler lacks proper input validation mechanisms and memory protection schemes that would normally prevent such unauthorized memory reads. The flaw operates at the firmware level, making it particularly dangerous as it bypasses traditional operating system security controls and memory protection mechanisms.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with potential access to sensitive system data that could include cryptographic keys, system configuration details, and other confidential information stored in SMM memory. Attackers could leverage this access to gain deeper insights into system architecture, potentially enabling more sophisticated attacks such as rootkit installation, privilege escalation to system administrator level, or even complete system compromise. The vulnerability's exploitation requires local access and elevated privileges, suggesting that while it may not be directly exploitable from remote locations, it presents a significant risk in environments where attackers have already achieved a foothold on the system through other means.
Mitigation strategies for CVE-2022-40135 should prioritize firmware updates from Lenovo as the primary remediation approach, as these patches would address the underlying memory access control issues within the SMM handler. Organizations should also implement strict access controls and privilege management policies to minimize the risk of local privilege escalation that would be necessary for exploitation. The vulnerability aligns with CWE-200, which addresses information exposure, and represents a specific implementation weakness in firmware security controls that could be addressed through proper memory protection mechanisms. From an attack surface perspective, this vulnerability maps to ATT&CK technique T1068, which involves local privilege escalation, and T1547, concerning registry run keys and startup folder modifications, as attackers might attempt to establish persistence following successful exploitation of SMM memory access. Security teams should also consider implementing runtime monitoring of SMM activities and memory access patterns to detect potential exploitation attempts, given that traditional endpoint protection solutions may not adequately monitor firmware-level operations.