CVE-2024-4236
📋 TL;DR
This critical vulnerability in Tenda AX1803 routers allows remote attackers to execute arbitrary code via a stack-based buffer overflow in the DDNS configuration function. Attackers can exploit this by sending specially crafted requests to the vulnerable endpoint, potentially taking full control of affected devices. All users of Tenda AX1803 routers with firmware version 1.0.0.1 are affected.
💻 Affected Systems
- Tenda AX1803
📦 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
Exploit details are publicly available on GitHub, making weaponization likely. The vulnerability requires no authentication to exploit.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: None available
Restart Required: Yes
Instructions:
No official patch available. Contact Tenda support for firmware updates. If an update becomes available, download from official Tenda website, upload via router admin interface, and reboot.
🔧 Temporary Workarounds
Disable Remote Management
allDisable WAN access to router management interface
Login to router admin > Advanced Settings > System Tools > Remote Management > Disable
Block Vulnerable Endpoint
linuxUse firewall rules to block access to /goform/SetDDNSCfg
iptables -A INPUT -p tcp --dport 80 -m string --string "/goform/SetDDNSCfg" --algo bm -j DROP
🧯 If You Can't Patch
- Replace affected routers with different models from vendors with better security track records
- Segment affected routers into isolated network zones with strict firewall rules
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface (typically under System Status or About). If version is 1.0.0.1, device is vulnerable.Check Version:
curl -s http://router-ip/ | grep -i firmware || Check web interface manuallyVerify Fix Applied:
Verify firmware version has changed from 1.0.0.1 to a newer version after update.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /goform/SetDDNSCfg
- Large payloads in requests to DDNS configuration endpoint
- Multiple failed buffer overflow attempts
Network Indicators:
- Unusual traffic patterns from router to external IPs
- Exploit kit signatures targeting CVE-2024-4236
- HTTP requests with oversized serverName/ddnsUser/ddnsPwd/ddnsDomain parameters
SIEM Query:
source="router_logs" AND (uri="/goform/SetDDNSCfg" AND (param_length>100 OR contains(param,"\x90\x90\x90")))🔗 References
- https://github.com/abcdefg-png/IoT-vulnerable/blob/main/Tenda/AX/AX1803/formSetSysToolDDNS.md
- https://vuldb.com/?ctiid.262127
- https://vuldb.com/?id.262127
- https://vuldb.com/?submit.319230
- https://github.com/abcdefg-png/IoT-vulnerable/blob/main/Tenda/AX/AX1803/formSetSysToolDDNS.md
- https://vuldb.com/?ctiid.262127
- https://vuldb.com/?id.262127
- https://vuldb.com/?submit.319230
