CVE-2024-7176
📋 TL;DR
This critical vulnerability in TOTOLINK A3600R routers allows remote attackers to execute arbitrary code via a buffer overflow in the setIpQosRules function. Attackers can exploit this by sending specially crafted requests to the vulnerable CGI endpoint, potentially gaining full control of affected devices. All users running the vulnerable firmware version are at risk.
💻 Affected Systems
- TOTOLINK A3600R
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, allowing attackers to install malware, pivot to internal networks, or create persistent backdoors.
Likely Case
Remote code execution enabling attackers to take control of the router, intercept network traffic, or use the device as part of a botnet.
If Mitigated
Limited impact if devices are behind firewalls with strict inbound filtering, though internal exploitation remains possible.
🎯 Exploit Status
Exploit details are publicly available on GitHub, making weaponization straightforward for attackers with basic skills.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: None available
Restart Required: Yes
Instructions:
No official patch available. Contact TOTOLINK for firmware updates or consider replacing affected devices.
🔧 Temporary Workarounds
Disable CGI endpoint access
linuxBlock external access to the vulnerable /cgi-bin/cstecgi.cgi endpoint using firewall rules.
iptables -A INPUT -p tcp --dport 80 -m string --string "/cgi-bin/cstecgi.cgi" --algo bm -j DROP
iptables -A INPUT -p tcp --dport 443 -m string --string "/cgi-bin/cstecgi.cgi" --algo bm -j DROP
Network segmentation
allIsolate affected routers in a separate network segment with strict access controls.
🧯 If You Can't Patch
- Replace affected TOTOLINK A3600R routers with devices from vendors that provide security updates
- Implement strict network monitoring and intrusion detection for traffic to/from affected devices
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface at System Status > Firmware Version or via SSH with 'cat /proc/version'Check Version:
ssh admin@router-ip 'cat /proc/version' or check web interfaceVerify Fix Applied:
Verify firmware version has been updated to a version newer than 4.1.2cu.5182_B20201102📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /cgi-bin/cstecgi.cgi with long comment parameters
- Router crash logs or unexpected reboots
Network Indicators:
- HTTP POST requests to /cgi-bin/cstecgi.cgi with unusually large payloads in comment field
- Traffic patterns suggesting buffer overflow attempts
SIEM Query:
source="router-logs" AND uri="/cgi-bin/cstecgi.cgi" AND (method="POST" AND size>1024)🔗 References
- https://github.com/abcdefg-png/IoT-vulnerable/blob/main/TOTOLINK/A3600R/setIpQosRules.md
- https://vuldb.com/?ctiid.272597
- https://vuldb.com/?id.272597
- https://vuldb.com/?submit.378043
- https://github.com/abcdefg-png/IoT-vulnerable/blob/main/TOTOLINK/A3600R/setIpQosRules.md
- https://vuldb.com/?ctiid.272597
- https://vuldb.com/?id.272597
- https://vuldb.com/?submit.378043
