CVE-2024-26519
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on Casa Systems NTC-221 industrial IoT routers by sending a crafted payload to the /www/cgi-bin/nas.cgi component. It affects NTC-221 routers running version 2.0.99.0 and earlier. Organizations using these devices for industrial IoT/M2M connectivity are at risk.
💻 Affected Systems
- Casa Systems NTC-221
⚠️ 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 the router allowing attackers to pivot to internal networks, intercept/modify traffic, deploy persistent malware, or disable critical industrial connectivity.
Likely Case
Router takeover leading to network surveillance, credential theft, and potential lateral movement to connected industrial control systems.
If Mitigated
Limited impact if devices are behind firewalls with strict inbound filtering and network segmentation prevents lateral movement.
🎯 Exploit Status
The vulnerability requires no authentication and has a publicly available proof-of-concept, making exploitation straightforward for attackers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Unknown
Restart Required: Yes
Instructions:
1. Check vendor website for firmware updates. 2. Download latest firmware. 3. Upload via web interface. 4. Apply and reboot router.
🔧 Temporary Workarounds
Block CGI Access
linuxUse firewall rules to block external access to the vulnerable /www/cgi-bin/nas.cgi endpoint
iptables -A INPUT -p tcp --dport 80 -m string --string "/www/cgi-bin/nas.cgi" --algo bm -j DROP
iptables -A INPUT -p tcp --dport 443 -m string --string "/www/cgi-bin/nas.cgi" --algo bm -j DROP
Disable Web Interface
allDisable the router's web management interface if not required for operations
🧯 If You Can't Patch
- Segment NTC-221 routers on isolated VLANs with strict firewall rules preventing outbound traffic except required industrial protocols
- Implement network monitoring with IDS/IPS rules detecting exploitation attempts against the nas.cgi endpoint
🔍 How to Verify
Check if Vulnerable:
Check firmware version via web interface at System > Status > Firmware Version. If version is 2.0.99.0 or earlier, device is vulnerable.Check Version:
curl -s http://router-ip/status.cgi | grep -i firmwareVerify Fix Applied:
Verify firmware version is newer than 2.0.99.0. Test by attempting to access /www/cgi-bin/nas.cgi with monitoring for successful connections.📡 Detection & Monitoring
Log Indicators:
- HTTP requests to /www/cgi-bin/nas.cgi with unusual parameters or payloads
- Unusual process execution or file creation in router logs
Network Indicators:
- HTTP POST requests to /www/cgi-bin/nas.cgi from external IPs
- Unusual outbound connections from router after exploitation
SIEM Query:
source="router_logs" AND (url="/www/cgi-bin/nas.cgi" OR process="nas.cgi")