CVE-2024-4491
📋 TL;DR
A critical stack-based buffer overflow vulnerability in Tenda i21 routers allows remote attackers to execute arbitrary code by sending specially crafted input to the formGetDiagnoseInfo function. This affects Tenda i21 router firmware version 1.0.0.14(4656). Attackers can potentially gain full control of affected devices without authentication.
💻 Affected Systems
- Tenda i21 router
📦 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
Remote code execution allowing attackers to modify router settings, intercept traffic, or use the device as part of a botnet.
If Mitigated
Denial of service if exploit fails or is detected by network monitoring.
🎯 Exploit Status
Exploit details are publicly available on GitHub. The vulnerability requires no authentication and has simple exploitation requirements.
🛠️ 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. Check Tenda website for firmware updates. If update exists, download from official source, upload via web interface, and reboot router.
🔧 Temporary Workarounds
Disable remote management
allDisable remote access to router web interface to prevent external exploitation
Access router web interface > Advanced Settings > Remote Management > Disable
Network segmentation
allIsolate affected routers in separate network segments
🧯 If You Can't Patch
- Replace affected routers with different models or brands
- Implement strict network access controls to limit exposure to router management interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface: Login > System Status > Firmware VersionCheck Version:
Check via web interface or attempt to access http://router-ip/goform/getDiagnoseInfo with test payloadVerify Fix Applied:
Verify firmware version is no longer 1.0.0.14(4656) and test with known exploit payloads📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /goform/getDiagnoseInfo
- Large or malformed cmdinput parameters
- Router reboot or crash logs
Network Indicators:
- Traffic to router port 80/443 with unusual payloads to getDiagnoseInfo endpoint
- Outbound connections from router to suspicious IPs
SIEM Query:
source="router_logs" AND (uri_path="/goform/getDiagnoseInfo" OR message="cmdinput")🔗 References
- https://github.com/abcdefg-png/IoT-vulnerable/blob/main/Tenda/i/i21/formGetDiagnoseInfo.md
- https://vuldb.com/?ctiid.263080
- https://vuldb.com/?id.263080
- https://vuldb.com/?submit.323600
- https://github.com/abcdefg-png/IoT-vulnerable/blob/main/Tenda/i/i21/formGetDiagnoseInfo.md
- https://vuldb.com/?ctiid.263080
- https://vuldb.com/?id.263080
- https://vuldb.com/?submit.323600
