CVE-2024-4115
📋 TL;DR
This critical vulnerability in Tenda W15E routers allows remote attackers to execute arbitrary code via a stack-based buffer overflow in the DNS forwarding configuration function. Attackers can exploit this without authentication to potentially take full control of affected devices. All users running the vulnerable firmware version are at risk.
💻 Affected Systems
- Tenda W15E
📦 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 strict inbound rules, though internal network exposure remains possible.
🎯 Exploit Status
Public exploit details are available on GitHub, making exploitation straightforward for attackers. The vendor has not responded to disclosure attempts.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: None available
Restart Required: No
Instructions:
No official patch is available. Monitor Tenda's website for firmware updates and apply immediately when released.
🔧 Temporary Workarounds
Disable remote management
allPrevent external access to the router's web interface
Access router admin panel → Advanced Settings → Remote Management → Disable
Block access to vulnerable endpoint
linuxUse firewall rules to block access to /goform/AddDnsForward
iptables -A INPUT -p tcp --dport 80 -m string --string "/goform/AddDnsForward" --algo bm -j DROP
iptables -A INPUT -p tcp --dport 443 -m string --string "/goform/AddDnsForward" --algo bm -j DROP
🧯 If You Can't Patch
- Replace affected devices with non-vulnerable models from different vendors
- Isolate vulnerable routers in separate network segments with strict firewall rules
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via admin panel: System Status → Firmware Version. If version is 15.11.0.14, device is vulnerable.Check Version:
curl -s http://router-ip/ | grep -i firmware || Check web interface manuallyVerify Fix Applied:
After applying any firmware update, verify version has changed from 15.11.0.14. Test if /goform/AddDnsForward endpoint still accepts malformed input.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /goform/AddDnsForward with long parameter values
- Router crash/restart logs
- Unusual outbound connections from router
Network Indicators:
- HTTP requests with oversized DnsForwardRule parameter
- Traffic patterns suggesting router compromise (beaconing, scanning)
SIEM Query:
source="router_logs" AND (url="/goform/AddDnsForward" AND content_length>1000) OR (event="crash" AND process="httpd")🔗 References
- https://github.com/abcdefg-png/IoT-vulnerable/blob/main/Tenda/W15Ev1.0/formAddDnsForward.md
- https://vuldb.com/?ctiid.261858
- https://vuldb.com/?id.261858
- https://vuldb.com/?submit.317818
- https://github.com/abcdefg-png/IoT-vulnerable/blob/main/Tenda/W15Ev1.0/formAddDnsForward.md
- https://vuldb.com/?ctiid.261858
- https://vuldb.com/?id.261858
- https://vuldb.com/?submit.317818
