CVE-2021-3633
📋 TL;DR
This CVE describes a DLL preloading vulnerability in Lenovo Driver Management software that could allow local attackers to escalate privileges by placing a malicious DLL in a directory searched before the legitimate one. It affects users running vulnerable versions of Lenovo Driver Management on Windows systems.
💻 Affected Systems
- Lenovo Driver Management
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Local attacker gains SYSTEM/administrator privileges, enabling complete system compromise, data theft, persistence installation, and lateral movement.
Likely Case
Local user with limited privileges escalates to administrator to install software, modify system settings, or access protected data.
If Mitigated
Attack fails due to proper file permissions, application whitelisting, or the attacker lacking local access.
🎯 Exploit Status
DLL preloading attacks are well-understood and typically have low exploitation complexity when conditions are met.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.9.0719.1104 or later
Vendor Advisory: https://iknow.lenovo.com.cn/detail/dc_198418.html
Restart Required: Yes
Instructions:
1. Download Lenovo Driver Management version 2.9.0719.1104 or later from Lenovo's official website. 2. Run the installer to update the software. 3. Restart the system to ensure changes take effect.
🔧 Temporary Workarounds
Restrict DLL search path
windowsConfigure Windows to use Safe DLL Search Mode to prevent DLL preloading from current directory.
reg add "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager" /v SafeDllSearchMode /t REG_DWORD /d 1 /f
Remove vulnerable software
windowsUninstall Lenovo Driver Management if not required for system functionality.
appwiz.cpl
🧯 If You Can't Patch
- Implement strict file permissions to prevent users from writing to directories where Lenovo Driver Management executes.
- Use application whitelisting to prevent execution of unauthorized DLLs and restrict where Lenovo Driver Management can load DLLs from.
🔍 How to Verify
Check if Vulnerable:
Check Lenovo Driver Management version in Control Panel > Programs and Features or via command: wmic product where "name like 'Lenovo Driver Management%'" get versionCheck Version:
wmic product where "name like 'Lenovo Driver Management%'" get versionVerify Fix Applied:
Verify installed version is 2.9.0719.1104 or higher using the same version check command.📡 Detection & Monitoring
Log Indicators:
- Windows Event Logs showing DLL loading from unusual locations (Event ID 7 in Microsoft-Windows-Diagnostics-Performance)
- Process Monitor logs showing DLL search order manipulation
Network Indicators:
- No network indicators - this is a local attack
SIEM Query:
EventID=7 AND (ImagePath="*Lenovo Driver Management*" OR ProcessName="*Lenovo*") AND (FileName="*.dll" AND FilePath!="*System32*" AND FilePath!="*SysWOW64*")