CVE-2025-55740
📋 TL;DR
This CVE describes a configuration vulnerability in nginx-defender where default administrative credentials are present in example configuration files. Attackers with network access can use these default credentials to gain administrative control over the WAF, potentially bypassing security protections. Organizations using nginx-defender with default configurations are affected.
💻 Affected Systems
- nginx-defender
⚠️ 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
Attackers gain full administrative control over the WAF, disable security protections, and potentially compromise the entire web infrastructure behind it.
Likely Case
Attackers gain administrative access to the WAF management interface, allowing them to modify rules, disable protections, or exfiltrate configuration data.
If Mitigated
With proper credential management, the vulnerability is eliminated and the WAF functions as intended.
🎯 Exploit Status
Exploitation requires network access to the management interface and knowledge of default credentials, which are publicly documented in example configuration files.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v1.5.0 and later
Vendor Advisory: https://github.com/Anipaleja/nginx-defender/security/advisories/GHSA-pr72-8fxw-xx22
Restart Required: No
Instructions:
1. Upgrade nginx-defender to version 1.5.0 or later. 2. Review and update configuration files to ensure no default credentials remain. 3. Change all administrative passwords to strong, unique values.
🔧 Temporary Workarounds
Change Default Credentials
allManually change all default credentials in configuration files to strong, unique passwords.
Edit config.yaml and replace 'default_password: "change_me_please"' with a strong password
Edit docker-compose.yml and replace 'GF_SECURITY_ADMIN_PASSWORD=admin123' with a strong password
Restrict Network Access
allLimit network access to the nginx-defender management interface to trusted IP addresses only.
Configure firewall rules to restrict access to nginx-defender management ports
Use network segmentation to isolate the management interface
🧯 If You Can't Patch
- Immediately change all default credentials in configuration files to strong, unique passwords
- Restrict network access to the management interface using firewall rules or network segmentation
- Implement multi-factor authentication if supported by the WAF management interface
- Monitor authentication logs for suspicious login attempts
🔍 How to Verify
Check if Vulnerable:
Review config.yaml for 'default_password: "change_me_please"' and docker-compose.yml for 'GF_SECURITY_ADMIN_PASSWORD=admin123'. If present and unchanged, the system is vulnerable.Check Version:
Check the nginx-defender version in the management interface or deployment configurationVerify Fix Applied:
Confirm configuration files no longer contain default credentials and that nginx-defender version is 1.5.0 or higher.📡 Detection & Monitoring
Log Indicators:
- Failed authentication attempts followed by successful login with default credentials
- Configuration changes from unknown IP addresses
- Administrative actions from unexpected sources
Network Indicators:
- Unauthorized access attempts to the WAF management interface
- Traffic patterns suggesting credential brute-forcing
SIEM Query:
source="nginx-defender" AND (event_type="authentication" AND (username="admin" OR password="admin123" OR password="change_me_please"))