CVE-2025-66264
📋 TL;DR
This vulnerability allows local attackers with filesystem write access to escalate privileges to SYSTEM level by exploiting an unquoted service path in CMService.exe. It affects systems running the vulnerable service with default configurations. Attackers can plant malicious executables that get executed with elevated privileges.
💻 Affected Systems
- CMService.exe (likely from Megatec software)
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Full SYSTEM privilege compromise allowing complete control over the affected system, installation of persistent backdoors, credential theft, and lateral movement.
Likely Case
Local privilege escalation from a lower-privileged user account to SYSTEM, enabling installation of malware, disabling security controls, and accessing sensitive data.
If Mitigated
Limited impact if proper access controls prevent unauthorized filesystem writes and service path manipulation.
🎯 Exploit Status
Unquoted service path vulnerabilities are well-known and easily exploitable with standard techniques. Requires local access and filesystem write permissions.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.megatec.com.tw/software-download/
Restart Required: Yes
Instructions:
1. Check vendor website for updated version. 2. Install updated software. 3. Restart service or system. 4. Verify service path is properly quoted.
🔧 Temporary Workarounds
Quote Service Path
windowsModify the service configuration to use quoted paths in the service executable path
sc config "ServiceName" binPath= "\"C:\Path\To\CMService.exe\""
sc stop "ServiceName"
sc start "ServiceName"
Restrict Filesystem Permissions
windowsRemove write permissions from directories in the service path for non-administrative users
icacls "C:\Path\To\Service" /deny Users:(OI)(CI)W
icacls "C:\Path" /deny Users:(OI)(CI)W
🧯 If You Can't Patch
- Implement strict access controls to prevent unauthorized users from writing to filesystem locations in service path
- Monitor for suspicious file creation in service path directories and unexpected service restarts
🔍 How to Verify
Check if Vulnerable:
Run: sc qc "ServiceName" and check if binPath value has spaces and is not quoted. Also verify service runs as SYSTEM.Check Version:
Check vendor documentation or file properties of CMService.exeVerify Fix Applied:
Verify service path is quoted in sc qc output and test that non-admin users cannot write to path directories.📡 Detection & Monitoring
Log Indicators:
- Unexpected service restarts
- File creation in service path directories by non-admin users
- Process creation from unusual locations
Network Indicators:
- None - local exploitation only
SIEM Query:
EventID=4688 AND NewProcessName contains spaces AND (ParentProcessName contains 'services.exe' OR CommandLine contains 'CMService')