CVE-2024-3874
📋 TL;DR
This critical vulnerability in Tenda W20E routers allows remote attackers to execute arbitrary code via a stack-based buffer overflow in the remote web management function. Attackers can exploit this without authentication to potentially take full control of affected devices. All users running vulnerable firmware versions are at risk.
💻 Affected Systems
- Tenda W20E
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise leading to persistent backdoor installation, network traffic interception, lateral movement to other devices, and botnet recruitment.
Likely Case
Remote code execution allowing attackers to modify router settings, intercept traffic, or use the device as a pivot point for further attacks.
If Mitigated
Limited impact if device is behind firewall with restricted WAN access, though internal network attacks remain possible.
🎯 Exploit Status
Public exploit code available on GitHub. Attack requires sending specially crafted HTTP request to vulnerable endpoint.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: None available
Restart Required: Yes
Instructions:
1. Check Tenda website for firmware updates
2. If update available, download and flash via web interface
3. Factory reset after update
4. Reconfigure with secure settings
🔧 Temporary Workarounds
Disable Remote Web Management
allTurn off the vulnerable remote management feature entirely
Access router admin interface > Advanced Settings > Remote Management > Disable
Restrict WAN Access
linuxBlock external access to router management interface using firewall rules
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
🧯 If You Can't Patch
- Isolate vulnerable devices in separate network segment with strict firewall rules
- Implement network monitoring for exploit attempts and anomalous traffic patterns
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router web interface: System Status > Firmware Version. If version is 15.11.0.6 or earlier, assume vulnerable.Check Version:
curl -s http://router-ip/goform/getStatus | grep versionVerify Fix Applied:
Verify firmware version has been updated beyond 15.11.0.6 and remote management is disabled.📡 Detection & Monitoring
Log Indicators:
- HTTP POST requests to /goform/SetRemoteWebManage with long remoteIP parameter
- Unusual process execution in router logs
- Configuration changes without admin login
Network Indicators:
- HTTP traffic to router on unusual ports
- Outbound connections from router to suspicious IPs
- DNS queries to known C2 domains
SIEM Query:
source="router_logs" AND (uri="/goform/SetRemoteWebManage" AND remoteIP.length>100) OR (process="sh" OR process="wget" OR process="curl")🔗 References
- https://github.com/abcdefg-png/IoT-vulnerable/blob/main/Tenda/W20E/formSetRemoteWebManage.md
- https://vuldb.com/?ctiid.260908
- https://vuldb.com/?id.260908
- https://vuldb.com/?submit.312816
- https://github.com/abcdefg-png/IoT-vulnerable/blob/main/Tenda/W20E/formSetRemoteWebManage.md
- https://vuldb.com/?ctiid.260908
- https://vuldb.com/?id.260908
- https://vuldb.com/?submit.312816
