CVE-2022-29642
📋 TL;DR
This vulnerability is a stack overflow in TOTOLINK A3100R routers that allows attackers to cause Denial of Service (DoS) by sending specially crafted POST requests to the setUrlFilterRules function. It affects users of TOTOLINK A3100R routers running vulnerable firmware versions. Attackers can crash the router's web interface or potentially execute arbitrary code.
💻 Affected Systems
- TOTOLINK A3100R
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete router compromise, persistent backdoor installation, and network infiltration.
Likely Case
Denial of Service causing router web interface crash and potential device reboot, disrupting network connectivity.
If Mitigated
Limited to DoS with quick recovery if proper network segmentation and monitoring are in place.
🎯 Exploit Status
Exploit details are publicly available in GitHub repositories. The vulnerability requires sending a crafted POST request to the vulnerable endpoint.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: Yes
Instructions:
1. Check TOTOLINK website for firmware updates. 2. Download latest firmware for A3100R. 3. Access router web interface. 4. Navigate to firmware upgrade section. 5. Upload new firmware file. 6. Wait for reboot.
🔧 Temporary Workarounds
Disable remote management
allPrevent external access to router web interface
Network segmentation
allIsolate router management interface to trusted network
🧯 If You Can't Patch
- Implement strict firewall rules to block external access to router management interface (typically port 80/443)
- Monitor network traffic for unusual POST requests to router management endpoints
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in web interface under System Status or similar sectionCheck Version:
Login to router web interface and check firmware version in system informationVerify Fix Applied:
Verify firmware version is newer than affected versions and test with known exploit payloads📡 Detection & Monitoring
Log Indicators:
- Multiple POST requests to /cgi-bin/setUrlFilterRules with large url parameters
- Router crash/reboot logs
Network Indicators:
- Unusual POST requests to router management interface from external IPs
- Traffic patterns indicating DoS attempts
SIEM Query:
source="router_logs" AND (uri="/cgi-bin/setUrlFilterRules" AND method="POST" AND size>1000)