CVE-2024-4250
📋 TL;DR
A critical stack-based buffer overflow vulnerability in Tenda i21 routers allows remote attackers to execute arbitrary code by manipulating the ssidIndex parameter in the formwrlSSIDset function. This affects Tenda i21 router users running vulnerable firmware version 1.0.0.14(4656). Successful exploitation could lead to complete device compromise.
💻 Affected Systems
- Tenda i21 router
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to full router compromise, credential theft, network traffic interception, and lateral movement into connected networks.
Likely Case
Router takeover enabling attackers to modify DNS settings, intercept traffic, or deploy malware to connected devices.
If Mitigated
Limited impact if routers are behind firewalls with strict inbound filtering and network segmentation.
🎯 Exploit Status
Public exploit details available on GitHub, making exploitation straightforward for attackers.
🛠️ 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 or consider replacing the device.
🔧 Temporary Workarounds
Network Segmentation
allIsolate Tenda i21 routers in a separate VLAN with strict firewall rules.
Access Control
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
- Replace vulnerable routers with supported models from different vendors
- Implement strict network monitoring for unusual router traffic patterns
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface at http://router_ip or using telnet/ssh if enabled.Check Version:
curl -s http://router_ip/goform/getStatus | grep versionVerify Fix Applied:
Verify firmware version has been updated beyond 1.0.0.14(4656) or device has been replaced.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /goform/wifiSSIDset
- Multiple failed authentication attempts to router interface
- Unexpected router reboots or configuration changes
Network Indicators:
- Unusual outbound connections from router IP
- DNS queries to suspicious domains from router
- Traffic redirection patterns
SIEM Query:
source="router_logs" AND (uri="/goform/wifiSSIDset" OR method="POST" AND uri CONTAINS "wifiSSIDset")🔗 References
- https://github.com/abcdefg-png/IoT-vulnerable/blob/main/Tenda/i/i21/formwrlSSIDset.md
- https://vuldb.com/?ctiid.262141
- https://vuldb.com/?id.262141
- https://vuldb.com/?submit.319835
- https://github.com/abcdefg-png/IoT-vulnerable/blob/main/Tenda/i/i21/formwrlSSIDset.md
- https://vuldb.com/?ctiid.262141
- https://vuldb.com/?id.262141
- https://vuldb.com/?submit.319835
