CVE-2023-45075 in Lenovo
Summary
by MITRE • 11/09/2023
A memory leakage vulnerability was reported in the SWSMI_Shadow DXE driver that may allow a local attacker with elevated privileges to write to NVRAM variables.
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Analysis
by VulDB Data Team • 11/09/2023
The vulnerability identified as CVE-2023-45075 resides within the SWSMI_Shadow DXE driver component of certain firmware implementations, representing a critical memory management flaw that could be exploited by adversaries with elevated system privileges. This issue manifests as a memory leakage condition that enables unauthorized modification of Non-Volatile RAM (NVRAM) variables through the SWSMI (Software System Management Interrupt) mechanism. The SWSMI_Shadow DXE driver operates within the UEFI firmware environment, where it handles system management interrupts and manages the shadowing of system memory regions during boot processes. The memory leakage vulnerability specifically affects how the driver manages memory allocation and deallocation during SWSMI processing, creating opportunities for memory corruption that could be leveraged to manipulate system variables stored in NVRAM.
The technical exploitation of this vulnerability requires an attacker to possess elevated privileges within the system, typically corresponding to kernel-level or firmware-level access. This prerequisite aligns with the ATT&CK framework's concept of privilege escalation, where adversaries must first establish a foothold with sufficient permissions before attempting to leverage firmware-level vulnerabilities. The CWE classification for this issue would likely fall under CWE-129, representing an insufficient input validation, or potentially CWE-787, representing an out-of-bounds write condition, given the memory management implications. The vulnerability stems from improper handling of memory references within the SWSMI_Shadow DXE driver, where memory addresses may not be properly validated or sanitized before being used to modify NVRAM contents. This flaw allows for arbitrary writes to NVRAM variables, which could include critical system parameters such as boot configurations, secure boot settings, or other firmware-relevant data structures.
The operational impact of this vulnerability extends beyond simple data corruption, as it enables persistent modifications to system firmware settings that could compromise system integrity and security posture. An attacker could potentially alter boot parameters to redirect system execution paths, modify secure boot configurations to disable critical security checks, or manipulate system variables to create backdoors for future access. The implications are particularly severe because NVRAM variables often store configuration data that persists across system reboots, meaning that any modifications made through this vulnerability would remain effective until manually corrected or the system is rebuilt with clean firmware. This characteristic makes the vulnerability particularly dangerous in environments where firmware integrity is paramount, such as enterprise server deployments, industrial control systems, or security-sensitive government installations. The attack surface is further expanded by the fact that the SWSMI mechanism is designed to operate with high privileges, making the exploitation chain more straightforward for attackers who have already achieved kernel-level access.
Mitigation strategies for CVE-2023-45075 should focus on both immediate firmware updates and broader system hardening measures. System administrators should prioritize applying vendor-provided firmware updates that address the memory leakage condition in the SWSMI_Shadow DXE driver, as these patches typically implement proper memory validation and sanitization procedures. The mitigation approach aligns with industry best practices outlined in NIST Special Publication 800-144 and the Common Vulnerability Scoring System, which emphasize the importance of timely patch management for firmware-level vulnerabilities. Additional protective measures include implementing robust firmware integrity monitoring systems that can detect unauthorized modifications to NVRAM variables, enabling secure boot configurations that validate firmware signatures, and establishing strict access controls to prevent unauthorized privilege escalation. Organizations should also consider implementing runtime protection mechanisms that monitor for suspicious SWSMI activity patterns and establish baseline configurations for NVRAM variables to quickly identify any unauthorized modifications. The ATT&CK framework's perspective on firmware attacks suggests that layered defense strategies combining patch management, integrity monitoring, and access controls provide the most effective protection against such vulnerabilities, as they address both the exploitation vector and potential post-exploitation activities that could leverage the compromised NVRAM access.