CVE-2024-4247
📋 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 formQosManage_auto function. This affects Tenda i21 router firmware version 1.0.0.14(4656). Attackers can exploit this without authentication to potentially take full control of affected devices.
💻 Affected Systems
- Tenda i21
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, persistence installation, lateral movement to internal networks, and botnet recruitment.
Likely Case
Router takeover allowing traffic interception, DNS hijacking, credential theft, and denial of service.
If Mitigated
Limited impact if devices are behind firewalls with strict inbound filtering and network segmentation.
🎯 Exploit Status
Public proof-of-concept available on GitHub. Exploitation requires sending crafted HTTP requests to the vulnerable endpoint.
🛠️ 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. Consider replacing affected devices if no patch is forthcoming.
🔧 Temporary Workarounds
Network Isolation
allPlace affected routers behind firewalls with strict inbound filtering to block external exploitation attempts.
Access Restriction
allDisable remote administration and restrict web interface access to trusted internal IP addresses only.
🧯 If You Can't Patch
- Replace affected Tenda i21 routers with patched or alternative devices
- Implement strict network segmentation to isolate vulnerable devices from critical assets
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface at http://router_ip/status.asp or http://router_ip/goform/getStatusCheck Version:
curl -s http://router_ip/status.asp | grep -i 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 HTTP POST requests to /goform/formQosManage_auto
- Multiple failed exploitation attempts with malformed ssidIndex parameters
- Sudden router configuration changes
Network Indicators:
- External IP addresses accessing router web interface on port 80/443
- Unusual outbound connections from router to unknown destinations
- DNS or routing table modifications
SIEM Query:
source="router_logs" AND (uri="/goform/formQosManage_auto" OR method="POST" AND uri CONTAINS "QosManage")🔗 References
- https://github.com/abcdefg-png/IoT-vulnerable/blob/main/Tenda/i/i21/formQosManage_auto.md
- https://vuldb.com/?ctiid.262138
- https://vuldb.com/?id.262138
- https://vuldb.com/?submit.319832
- https://github.com/abcdefg-png/IoT-vulnerable/blob/main/Tenda/i/i21/formQosManage_auto.md
- https://vuldb.com/?ctiid.262138
- https://vuldb.com/?id.262138
- https://vuldb.com/?submit.319832
