CVE-2021-3922: Lenovo System Interface Race Condition

CVE-2021-3922 Overview

A race condition vulnerability was identified in IMController, a software component of Lenovo System Interface Foundation, prior to version 1.1.20.3. This vulnerability allows a local attacker to exploit a timing flaw to connect and interact with the IMController child process' named pipe. Successful exploitation could lead to unauthorized access and manipulation of system functions managed by the IMController component.

Critical Impact

Local attackers can exploit the race condition to gain unauthorized access to IMController named pipes, potentially leading to confidentiality, integrity, and availability impacts on affected Lenovo systems.

Affected Products

• Lenovo System Interface Foundation (versions prior to 1.1.20.3)

Discovery Timeline

• 2022-05-18 - CVE CVE-2021-3922 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2021-3922

Vulnerability Analysis

This vulnerability is classified as a Time-of-Check Time-of-Use (TOCTOU) race condition (CWE-367) and general race condition (CWE-362). The flaw exists in the IMController component, which is part of Lenovo System Interface Foundation—a software suite that provides system management capabilities on Lenovo devices.

The vulnerability allows a local attacker with low privileges to exploit a timing window during the creation or access of the IMController child process' named pipe. By winning this race condition, an attacker can establish an unauthorized connection to the named pipe before legitimate security checks are completed or before the intended process connects.

Root Cause

The root cause stems from improper synchronization during the named pipe creation and access sequence in the IMController child process. When the IMController spawns child processes that communicate via named pipes, there exists a window of opportunity between the pipe creation and the establishment of a secure connection. This TOCTOU vulnerability occurs because the security validation and the actual pipe connection are not atomic operations, allowing an attacker to insert themselves into the communication channel.

Attack Vector

The attack requires local access to a system running a vulnerable version of Lenovo System Interface Foundation. An attacker must:

1. Monitor for the creation of IMController child processes
2. Quickly connect to the named pipe during the race window
3. Interact with the named pipe before the legitimate process establishes its connection

Due to the local attack vector and the requirement for precise timing, exploitation requires both physical or local access and the ability to execute code with at least low-level privileges. The high complexity nature of this attack stems from the need to win the race condition consistently.

The vulnerability allows attackers to potentially intercept or inject data through the named pipe, which could result in unauthorized command execution, information disclosure, or manipulation of system management functions depending on the capabilities exposed through the IMController interface.

Detection Methods for CVE-2021-3922

Indicators of Compromise

• Unusual processes attempting to connect to IMController named pipes
• Multiple rapid connection attempts to named pipes associated with Lenovo System Interface Foundation
• Unexpected child processes spawned by IMController with anomalous behavior
• Logs showing failed or unauthorized named pipe access attempts

Detection Strategies

• Monitor for suspicious named pipe connections using Windows Event Logs and Sysmon
• Implement endpoint detection rules that flag multiple rapid connection attempts to Lenovo service named pipes
• Use behavioral analysis to identify processes that exhibit race condition exploitation patterns
• Deploy file integrity monitoring on Lenovo System Interface Foundation components

Monitoring Recommendations

• Enable Windows Security Event logging for named pipe access events
• Configure Sysmon to capture PipeEvent (Event IDs 17 and 18) for pipe creation and connection monitoring
• Establish baseline behavior for IMController processes and alert on deviations
• Review process creation logs for unusual timing patterns around IMController activity

How to Mitigate CVE-2021-3922

Immediate Actions Required

• Update Lenovo System Interface Foundation to version 1.1.20.3 or later immediately
• Review systems for any signs of compromise or unauthorized named pipe access
• Restrict local access to systems running vulnerable versions until patching is complete
• Implement application whitelisting to prevent unauthorized processes from connecting to system named pipes

Patch Information

Lenovo has released a security update addressing this vulnerability. Users should update Lenovo System Interface Foundation to version 1.1.20.3 or later. The patch can be obtained through the Lenovo Security Advisory LEN-75210. Organizations using Lenovo Vantage or System Update can apply the update through those management tools.

Workarounds

• If immediate patching is not possible, consider temporarily disabling Lenovo System Interface Foundation services where not critically needed
• Implement strict access controls to limit which users can execute code on affected systems
• Use endpoint protection solutions to monitor and block suspicious named pipe activity
• Apply the principle of least privilege to reduce the attack surface for local exploitation

# Check installed version of Lenovo System Interface Foundation
# Navigate to Control Panel > Programs and Features
# Locate "Lenovo System Interface Foundation" and verify version is 1.1.20.3 or higher

# Alternative: Check via PowerShell
Get-WmiObject -Class Win32_Product | Where-Object {$_.Name -like "*Lenovo System Interface*"} | Select-Object Name, Version