CVE-2021-47726
📋 TL;DR
This vulnerability allows non-privileged users on NuCom 11N Wireless Router to retrieve administrative credentials by accessing the configuration backup endpoint. Attackers can send a crafted HTTP GET request with a specific cookie to decode the admin password in Base64 format. This affects users of NuCom 11N Wireless Router version 5.07.90.
💻 Affected Systems
- NuCom 11N Wireless Router
⚠️ 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 administrative control of the router, allowing attackers to modify network settings, intercept traffic, install malicious firmware, or use the router as a pivot point into the internal network.
Likely Case
Attackers gain administrative access to the router, enabling them to change DNS settings, redirect traffic, or disable security features.
If Mitigated
Limited impact if proper network segmentation and access controls prevent unauthorized users from reaching the router's web interface.
🎯 Exploit Status
Exploitation requires network access to the router's web interface and a valid non-privileged user session. The exploit is publicly available and relatively simple to execute.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.nucom.es
Restart Required: No
Instructions:
No official patch is available. Check the vendor website for firmware updates or security advisories.
🔧 Temporary Workarounds
Disable Remote Management
allDisable remote management/administration features to prevent external access to the router's web interface.
Restrict Access to Web Interface
allUse firewall rules to restrict access to the router's web interface to trusted IP addresses only.
🧯 If You Can't Patch
- Replace affected routers with models from vendors that provide security updates
- Implement network segmentation to isolate the router from untrusted networks
🔍 How to Verify
Check if Vulnerable:
Access the router's web interface, attempt to retrieve configuration backup with a non-admin session, and check if admin credentials are exposed.Check Version:
Check router web interface admin panel for firmware version informationVerify Fix Applied:
Verify that configuration backup endpoint no longer exposes admin credentials when accessed with non-privileged credentials.📡 Detection & Monitoring
Log Indicators:
- Unusual access to configuration backup endpoint from non-admin users
- Multiple failed login attempts followed by configuration backup access
Network Indicators:
- HTTP GET requests to /backupcfg.cgi or similar backup endpoints with specific cookie parameters
SIEM Query:
source="router_logs" AND (uri="/backupcfg.cgi" OR uri="/backupcfg") AND user!="admin"