CVE-2024-0996
📋 TL;DR
A critical stack-based buffer overflow vulnerability in Tenda i9 routers allows remote attackers to execute arbitrary code by sending specially crafted requests to the /goform/setcfm endpoint. This affects Tenda i9 router firmware version 1.0.0.9(4122). Attackers can exploit this without authentication to potentially take full control of affected devices.
💻 Affected Systems
- Tenda i9
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, creation of persistent backdoors, lateral movement to internal networks, and botnet recruitment.
Likely Case
Remote code execution allowing attackers to modify router settings, intercept traffic, or use the device as a pivot point into internal networks.
If Mitigated
Limited impact if devices are behind firewalls with strict inbound filtering, though internal threats remain possible.
🎯 Exploit Status
Public exploit details are available in the disclosed references. The vulnerability is straightforward to exploit due to the stack buffer overflow in a web-accessible endpoint.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: None available - vendor did not respond to disclosure
Restart Required: Yes
Instructions:
No official patch available. Consider replacing affected devices or implementing strict network controls.
🔧 Temporary Workarounds
Network Access Control
linuxBlock external access to router management interface and restrict internal access to trusted IPs only.
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
Disable Remote Management
allEnsure router remote management is disabled and only accessible from LAN.
🧯 If You Can't Patch
- Isolate affected routers in separate VLANs with strict firewall rules preventing access to critical internal resources.
- Implement network monitoring for unusual traffic patterns or exploitation attempts targeting the /goform/setcfm endpoint.
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface at 192.168.0.1 or 192.168.1.1, or via SSH/telnet if enabled. Version 1.0.0.9(4122) is vulnerable.Check Version:
curl -s http://192.168.0.1/ | grep -i 'firmware version' or check web interface System Status pageVerify Fix Applied:
No fix available to verify. Monitor for firmware updates from Tenda and check version after any update.📡 Detection & Monitoring
Log Indicators:
- HTTP requests to /goform/setcfm with unusually long funcpara1 parameters
- Router crash/restart logs
- Unusual process execution in router logs
Network Indicators:
- HTTP POST requests to /goform/setcfm with large payloads
- Unusual outbound connections from router IP
SIEM Query:
source="router_logs" AND (url="/goform/setcfm" AND (param_length>1000 OR status_code=500))🔗 References
- https://jylsec.notion.site/Tenda-i9-has-stack-buffer-overflow-vulnerability-in-formSetCfm-c1bd9745c81e4207aceeaa1ba5e10563?pvs=4
- https://vuldb.com/?ctiid.252261
- https://vuldb.com/?id.252261
- https://jylsec.notion.site/Tenda-i9-has-stack-buffer-overflow-vulnerability-in-formSetCfm-c1bd9745c81e4207aceeaa1ba5e10563?pvs=4
- https://vuldb.com/?ctiid.252261
- https://vuldb.com/?id.252261
