CVE-2024-35400
📋 TL;DR
This vulnerability allows remote attackers to cause a stack overflow in TOTOLINK CP900L routers by sending specially crafted requests to the SetPortForwardRules function. Attackers could potentially execute arbitrary code or crash the device. Only users of TOTOLINK CP900L routers with the vulnerable firmware version are affected.
💻 Affected Systems
- TOTOLINK CP900L
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, allowing attackers to install malware, pivot to internal networks, or create persistent backdoors.
Likely Case
Denial of service causing router crashes and network disruption, requiring physical reset or manual intervention to restore functionality.
If Mitigated
Limited impact with proper network segmentation and firewall rules preventing external access to the vulnerable interface.
🎯 Exploit Status
Exploitation requires authentication to the router's web interface. Public proof-of-concept code is available in GitHub repositories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: http://totolink.com
Restart Required: Yes
Instructions:
1. Check TOTOLINK website for firmware updates. 2. Download latest firmware. 3. Access router web interface. 4. Navigate to firmware upgrade section. 5. Upload and apply new firmware. 6. Reboot router.
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to router web interface
Restrict Access with Firewall
linuxBlock external access to router management ports
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
🧯 If You Can't Patch
- Segment affected routers in isolated network zones
- Implement strict access controls allowing only trusted IPs to access management interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in web interface under System Status or About pageCheck Version:
curl -s http://router-ip/status.cgi | grep firmwareVerify Fix Applied:
Verify firmware version has been updated beyond v4.1.5cu.798_B20221228📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts
- Unusual POST requests to /cgi-bin/SetPortForwardRules
- Router crash/reboot events
Network Indicators:
- Unusual traffic patterns to router management interface
- Large payloads sent to port 80/443 of router
SIEM Query:
source="router-logs" AND (uri="/cgi-bin/SetPortForwardRules" OR desc="stack overflow")