CVE-2023-44220
📋 TL;DR
This CVE describes a DLL search order hijacking vulnerability in SonicWall NetExtender Windows client versions 10.2.336 and earlier. A local attacker could exploit this to execute arbitrary commands on the target system with the privileges of the NetExtender process. Only Windows users running vulnerable NetExtender client versions are affected.
💻 Affected Systems
- SonicWall NetExtender Windows Client
📦 What is this software?
Netextender by Sonicwall
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise via arbitrary command execution with elevated privileges, potentially leading to complete system takeover, data exfiltration, or lateral movement.
Likely Case
Local privilege escalation leading to installation of malware, credential theft, or persistence mechanisms on the compromised system.
If Mitigated
Limited impact with proper application whitelisting, restricted user privileges, and security monitoring in place.
🎯 Exploit Status
Exploitation requires local access to place malicious DLL in a directory that will be searched before the legitimate DLL during application startup.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 10.2.337 or later
Vendor Advisory: https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2023-0017
Restart Required: Yes
Instructions:
1. Download the latest NetExtender client from the SonicWall support portal. 2. Uninstall the current vulnerable version. 3. Install the updated version (10.2.337 or later). 4. Restart the system to ensure all components are properly loaded.
🔧 Temporary Workarounds
Restrict DLL search paths
windowsConfigure Windows to use safe DLL search order by modifying the SafeDllSearchMode registry setting
reg add "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager" /v SafeDllSearchMode /t REG_DWORD /d 1 /f
Application whitelisting
windowsImplement application control policies to prevent execution of unauthorized DLLs
🧯 If You Can't Patch
- Remove local administrative privileges from users to limit impact of successful exploitation
- Implement strict file system permissions to prevent users from writing to directories in the DLL search path
🔍 How to Verify
Check if Vulnerable:
Check NetExtender client version in Control Panel > Programs and Features or by running the NetExtender application and viewing the About dialogCheck Version:
wmic product where name="SonicWall NetExtender" get versionVerify Fix Applied:
Verify installed version is 10.2.337 or later and check that the application loads without errors📡 Detection & Monitoring
Log Indicators:
- Windows Event Log entries showing DLL loading from unexpected locations
- Process Monitor logs showing NetExtender loading DLLs from user-writable directories
Network Indicators:
- Unusual outbound connections from NetExtender process after startup
SIEM Query:
EventID=7 AND ProcessName="NetExtender.exe" AND ImageLoaded CONTAINS "user\" OR ImageLoaded CONTAINS "temp\"