CVE-2025-15387
📋 TL;DR
QNO Technology VPN Firewall devices have an insufficient entropy vulnerability that allows unauthenticated remote attackers to brute-force logged-in user sessions. Attackers can hijack active sessions and gain unauthorized access to the firewall system. This affects all organizations using vulnerable QNO VPN Firewall devices.
💻 Affected Systems
- QNO Technology VPN Firewall
⚠️ 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
Complete system compromise where attackers gain administrative access, reconfigure firewall rules, intercept network traffic, and use the device as a pivot point to attack internal networks.
Likely Case
Unauthorized access to firewall management interface leading to configuration changes, network monitoring, credential theft, and potential lateral movement into protected networks.
If Mitigated
Limited impact if proper network segmentation, strong authentication, and monitoring are in place, though session hijacking remains possible.
🎯 Exploit Status
Brute-force attacks against session IDs are straightforward. No authentication required makes exploitation simple.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified in references; check vendor advisory
Vendor Advisory: https://www.twcert.org.tw/en/cp-139-10614-dee41-2.html
Restart Required: Yes
Instructions:
1. Check QNO Technology website for security updates. 2. Download latest firmware. 3. Backup configuration. 4. Apply firmware update. 5. Verify update successful. 6. Restart device.
🔧 Temporary Workarounds
Network Segmentation
allRestrict access to firewall management interface to trusted IP addresses only
Configure firewall rules to allow management access only from specific source IPs/networks
Session Timeout Reduction
allReduce session timeout values to limit window for brute-force attacks
Set shorter session timeout in firewall management settings
🧯 If You Can't Patch
- Isolate firewall management interface on separate VLAN with strict access controls
- Implement network-based intrusion detection to monitor for session brute-force attempts
🔍 How to Verify
Check if Vulnerable:
Check device model and firmware version against vendor advisory. Test if session IDs appear predictable or enumerable.Check Version:
Login to firewall web interface and check System Status or About page for firmware versionVerify Fix Applied:
Verify firmware version matches patched version from vendor. Test session generation for sufficient randomness.📡 Detection & Monitoring
Log Indicators:
- Multiple failed login attempts from same source
- Successful logins from unusual IP addresses
- Session ID enumeration patterns
Network Indicators:
- High volume of requests to session-related endpoints
- Traffic patterns suggesting brute-force attacks
SIEM Query:
source_ip=* AND (url_path CONTAINS "/session" OR url_path CONTAINS "/login") AND status_code=200|401 GROUP BY source_ip COUNT > 100 WITHIN 5m