CVE-2022-1891 in Notebook
Summary
by MITRE • 01/26/2023
A buffer overflow in the SystemLoadDefaultDxe driver in some Lenovo Notebook products may allow an attacker with local privileges to execute arbitrary code.
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Analysis
by VulDB Data Team • 02/23/2023
The vulnerability identified as CVE-2022-1891 represents a critical buffer overflow flaw within the SystemLoadDefaultDxe driver component of specific Lenovo notebook models. This driver operates within the UEFI firmware environment, serving as a crucial bridge between hardware initialization and the operating system boot process. The buffer overflow condition occurs when the driver processes untrusted input data without proper bounds checking, creating an exploitable memory corruption vulnerability that can be leveraged by malicious actors.
This technical flaw manifests as a classic stack-based buffer overflow within the SystemLoadDefaultDxe driver, which operates at the highest privilege level within the UEFI ecosystem. The vulnerability stems from insufficient input validation mechanisms that fail to properly sanitize user-supplied data before copying it into fixed-size memory buffers. According to CWE-121, this represents a stack-based buffer overflow where attacker-controlled data can overwrite adjacent memory locations, potentially including return addresses and control flow information. The flaw exists in the driver's handling of configuration parameters or firmware update data, making it particularly dangerous as it operates during the critical early boot phase when system security controls are most vulnerable.
The operational impact of this vulnerability extends beyond typical local privilege escalation scenarios due to the driver's privileged execution context within the UEFI environment. An attacker with local access to a targeted system can exploit this vulnerability to execute arbitrary code with the highest system privileges, effectively bypassing traditional operating system security mechanisms. The attack vector requires local system access, which aligns with ATT&CK technique T1068, where adversaries leverage legitimate system access to escalate privileges. This vulnerability compromises the integrity of the boot process, potentially allowing for persistent backdoor installation or complete system compromise before the operating system has fully initialized.
The implications of this vulnerability are particularly severe given that UEFI drivers operate outside the normal operating system security boundaries, making them attractive targets for attackers seeking persistent access. The SystemLoadDefaultDxe driver's role in system initialization means that exploitation could result in complete system compromise or the installation of rootkits that persist across reboots. Organizations should consider this vulnerability as a potential entry point for advanced persistent threats, where attackers can establish footholds that survive operating system reinstalls or security updates. Mitigation efforts should focus on firmware updates provided by Lenovo, as well as implementing runtime protection measures such as kernel patch protection and memory integrity checks that can detect and prevent exploitation attempts.
The vulnerability demonstrates the critical importance of firmware security in modern computing environments, where traditional operating system security controls become ineffective once the system reaches the UEFI boot phase. This flaw exemplifies the growing concern around firmware-based attacks and highlights the need for comprehensive security assessments that include firmware components. Organizations should implement continuous monitoring for unauthorized firmware modifications and establish secure boot policies that can detect and prevent exploitation of such vulnerabilities. The security community should treat this as a high-priority issue requiring immediate attention from both vendors and end users to prevent potential exploitation in targeted attacks against vulnerable Lenovo notebook deployments.