CVE-2021-47707
📋 TL;DR
COMMAX CVD-Axx DVR 5.1.4 uses weak default administrative credentials ('1234') that allow attackers to bypass authentication via a simple POST request. This vulnerability enables unauthorized access to the web control panel and disclosure of RTSP video streams. Organizations using these DVR systems with default settings are affected.
💻 Affected Systems
- COMMAX CVD-Axx DVR
⚠️ 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 compromise of surveillance system allowing attackers to view/record all camera feeds, disable security monitoring, and potentially pivot to internal networks.
Likely Case
Unauthorized access to live video streams and DVR configuration, potentially leading to privacy violations and security monitoring disruption.
If Mitigated
Limited impact if strong unique passwords are configured and network segmentation is implemented.
🎯 Exploit Status
Exploit requires sending POST request with passkey=1234 to web interface. Public exploit code available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.commax.com
Restart Required: No
Instructions:
1. Access DVR web interface
2. Navigate to password settings
3. Change default password to strong unique password
4. Apply changes
🔧 Temporary Workarounds
Change Default Password
allImmediately change the default administrative password from '1234' to a strong, unique password.
Network Segmentation
allIsolate DVR systems on separate VLAN or network segment with strict firewall rules.
🧯 If You Can't Patch
- Implement network access controls to restrict DVR access to authorized IPs only
- Monitor for authentication attempts and failed logins to detect exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Send POST request to DVR web interface with passkey=1234 parameter. If access granted, system is vulnerable.Check Version:
Check web interface login page or system information page for version detailsVerify Fix Applied:
Attempt same POST request with old password. Should be denied. Verify new strong password works.📡 Detection & Monitoring
Log Indicators:
- Multiple failed login attempts followed by successful login with default credentials
- Unauthorized access to RTSP streams
Network Indicators:
- POST requests to DVR web interface with passkey parameter
- Unusual RTSP stream access from external IPs
SIEM Query:
source_ip=external AND dest_ip=DVR_IP AND (http_method=POST AND uri_contains='passkey=1234')