CVE-2024-4495
📋 TL;DR
A critical stack-based buffer overflow vulnerability in Tenda i21 routers allows remote attackers to execute arbitrary code by manipulating the index parameter in the formWifiMacFilterGet function. This affects Tenda i21 firmware version 1.0.0.14(4656). Attackers can exploit this without authentication to potentially take complete 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, network pivoting, and data exfiltration.
Likely Case
Device takeover enabling network traffic interception, credential theft, and botnet recruitment.
If Mitigated
Limited impact if devices are behind firewalls with strict inbound filtering and network segmentation.
🎯 Exploit Status
Public exploit code exists in GitHub repositories, 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 replace affected devices.
🔧 Temporary Workarounds
Network Isolation
allIsolate affected routers from critical networks and internet exposure
Access Control
linuxImplement strict firewall rules to block external access to router management interfaces
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
🧯 If You Can't Patch
- Replace affected Tenda i21 routers with different models or brands
- Deploy network segmentation to limit potential lateral movement
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface at 192.168.0.1 or 192.168.1.1, login and navigate to System StatusCheck Version:
curl -s http://192.168.0.1/goform/getStatus | grep versionVerify Fix Applied:
Verify firmware version is no longer 1.0.0.14(4656)📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /goform/formWifiMacFilterGet
- Multiple failed buffer overflow attempts in system logs
- Unexpected process crashes or restarts
Network Indicators:
- Unusual traffic patterns to router management ports (80, 443, 8080)
- Suspicious payloads in HTTP POST requests
SIEM Query:
source="router.log" AND "formWifiMacFilterGet" AND ("index" OR "overflow")🔗 References
- https://github.com/abcdefg-png/IoT-vulnerable/blob/main/Tenda/i/i21/formWifiMacFilterGet.md
- https://vuldb.com/?ctiid.263084
- https://vuldb.com/?id.263084
- https://vuldb.com/?submit.323605
- https://github.com/abcdefg-png/IoT-vulnerable/blob/main/Tenda/i/i21/formWifiMacFilterGet.md
- https://vuldb.com/?ctiid.263084
- https://vuldb.com/?id.263084
- https://vuldb.com/?submit.323605
