CVE-2024-42976
📋 TL;DR
Tenda FH1206 routers running firmware v02.03.01.35 contain a stack overflow vulnerability in the fromSafeClientFilter function's page parameter. Attackers can exploit this via crafted POST requests to cause Denial of Service (DoS), potentially crashing the device. This affects all users of vulnerable Tenda FH1206 routers with the affected firmware.
💻 Affected Systems
- Tenda FH1206
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device crash requiring physical reboot, potential remote code execution if stack overflow can be controlled to execute arbitrary code (though not confirmed in this CVE).
Likely Case
Router becomes unresponsive, requiring reboot to restore functionality, disrupting network connectivity for all connected devices.
If Mitigated
If network filtering blocks malicious POST requests, impact is limited to potential service disruption from attack attempts.
🎯 Exploit Status
Public GitHub repository contains proof-of-concept. Crafted POST requests to vulnerable endpoint can trigger overflow without authentication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: Yes
Instructions:
1. Check Tenda website for firmware updates. 2. If update available, download and install via router admin interface. 3. Reboot router after update.
🔧 Temporary Workarounds
Network Filtering
allBlock POST requests to vulnerable endpoint using firewall or WAF
Disable Remote Management
allTurn off remote administration features to reduce attack surface
🧯 If You Can't Patch
- Isolate router on separate network segment with strict firewall rules
- Implement network monitoring for abnormal POST request patterns to vulnerable endpoints
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface. If version is v02.03.01.35, device is vulnerable.Check Version:
Login to router admin interface (typically 192.168.0.1 or 192.168.1.1) and check System Status or Firmware Update section.Verify Fix Applied:
After updating firmware, verify version is no longer v02.03.01.35. Test with controlled exploit attempt if possible.📡 Detection & Monitoring
Log Indicators:
- Multiple POST requests to fromSafeClientFilter endpoint
- Router crash/reboot logs
- Abnormal memory usage patterns
Network Indicators:
- Unusual POST requests with malformed page parameter
- Traffic spikes to router management interface
SIEM Query:
source="router_logs" AND (uri="/fromSafeClientFilter" OR message="stack overflow" OR message="crash")