CVE-2025-61871
📋 TL;DR
NAS Navigator2 Windows service has an unquoted file path vulnerability that allows local users with write permissions on the system drive root directory to escalate privileges to SYSTEM level. This affects Windows installations of BUFFALO's NAS Navigator2 software. Attackers can execute arbitrary code with the highest system privileges.
💻 Affected Systems
- BUFFALO NAS Navigator2 for Windows
⚠️ 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 leading to complete host takeover, data theft, lateral movement, and persistence establishment.
Likely Case
Local privilege escalation from a standard user account to SYSTEM, enabling installation of malware, credential harvesting, and disabling security controls.
If Mitigated
Limited impact if proper file system permissions restrict write access to system drive root directory and least privilege principles are enforced.
🎯 Exploit Status
Requires local access and write permissions on system drive root. Exploitation involves creating malicious executables in the unquoted path location.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Update to latest version as specified in vendor advisory
Vendor Advisory: https://www.buffalo.jp/news/detail/20251009-01.html
Restart Required: No
Instructions:
1. Download latest version from BUFFALO website. 2. Install the update. 3. Verify service path is now properly quoted in Windows Services.
🔧 Temporary Workarounds
Add quotes to service path
WindowsManually add quotes around the service executable path in Windows Services configuration
sc config "NAS Navigator2 Service" binPath= "\"C:\Program Files\BUFFALO\NAS Navigator2\nasnavi.exe\""
Restrict root directory permissions
WindowsRemove write permissions for standard users on the system drive root directory
icacls C:\ /deny Users:(OI)(CI)W
🧯 If You Can't Patch
- Remove NAS Navigator2 from production systems if not essential
- Implement strict file system permissions to deny write access to system drive root for standard users
🔍 How to Verify
Check if Vulnerable:
Check if NAS Navigator2 service path is unquoted: sc qc "NAS Navigator2 Service" | findstr BINARY_PATH_NAMECheck Version:
Check program version in Control Panel > Programs and Features or run nasnavi.exe --version if supportedVerify Fix Applied:
Verify service path now has quotes: sc qc "NAS Navigator2 Service" | findstr BINARY_PATH_NAME should show quoted path📡 Detection & Monitoring
Log Indicators:
- Windows Event ID 4688 showing unexpected process execution from system drive root
- Service Control Manager logs showing service path modification
Network Indicators:
- Unusual outbound connections from SYSTEM-level processes
SIEM Query:
EventID=4688 AND (NewProcessName contains "C:\\" AND NewProcessName not contains "Program Files") AND SubjectUserName="SYSTEM"