CVE-2025-66835
📋 TL;DR
TrueConf Client 8.5.2 is vulnerable to DLL hijacking where attackers can place a malicious wfapi.dll file to execute arbitrary code. This affects local users who can write to directories where TrueConf searches for DLLs. The vulnerability allows privilege escalation within the user's context.
💻 Affected Systems
- TrueConf Client
📦 What is this software?
Trueconf by Trueconf
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise via arbitrary code execution with user privileges, potentially leading to data theft, persistence, or lateral movement.
Likely Case
Local privilege escalation allowing attackers to execute malicious code, install malware, or access sensitive user data.
If Mitigated
Limited impact with proper file permissions and application whitelisting preventing unauthorized DLL loading.
🎯 Exploit Status
Exploitation requires local access to place malicious DLL. Public references available with proof-of-concept details.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: http://trueconf.com
Restart Required: No
Instructions:
1. Check TrueConf website for security updates. 2. Update to latest version if patch available. 3. Monitor vendor communications for fix.
🔧 Temporary Workarounds
Restrict DLL Search Path
windowsUse Windows policies to restrict DLL search paths and prevent loading from untrusted directories.
Set SafeDllSearchMode registry key: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\SafeDllSearchMode = 1
File Permission Hardening
windowsSet strict file permissions on TrueConf installation directory to prevent unauthorized DLL placement.
icacls "C:\Program Files\TrueConf\" /deny Users:(OI)(CI)W
🧯 If You Can't Patch
- Implement application whitelisting to prevent unauthorized DLL execution
- Monitor for suspicious DLL creation in TrueConf directories using file integrity monitoring
🔍 How to Verify
Check if Vulnerable:
Check if TrueConf Client version is 8.5.2 and if wfapi.dll can be placed in writable directories within its search path.Check Version:
Check TrueConf Client About dialog or examine installed programs in Control PanelVerify Fix Applied:
Verify TrueConf version is updated beyond 8.5.2 or test DLL hijacking attempt fails.📡 Detection & Monitoring
Log Indicators:
- Windows Event Logs showing DLL loading from unusual paths
- Process Monitor logs showing wfapi.dll being loaded from non-standard locations
Network Indicators:
- Unusual outbound connections from TrueConf process after DLL load
SIEM Query:
Process Creation where Image contains 'TrueConf' and CommandLine contains 'wfapi.dll'