CVE-2024-7187
📋 TL;DR
This critical vulnerability in TOTOLINK A3600R routers allows remote attackers to execute arbitrary code via a buffer overflow in the UploadCustomModule function. Attackers can exploit this without authentication to potentially take 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
Complete device compromise leading to persistent backdoor installation, network traffic interception, lateral movement to other devices, and botnet recruitment.
Likely Case
Remote code execution allowing attackers to modify device configuration, steal credentials, or use the device as a pivot point for further attacks.
If Mitigated
Limited impact if devices are behind firewalls with strict inbound filtering, though internal network exposure remains a concern.
🎯 Exploit Status
Public exploit details are available on GitHub, making exploitation straightforward for attackers with basic skills.
🛠️ 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. Consider replacing affected devices or implementing strict network controls.
🔧 Temporary Workarounds
Block CGI endpoint access
linuxUse firewall rules to block external and internal access to the vulnerable /cgi-bin/cstecgi.cgi endpoint
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
Disable remote administration
allTurn off remote management features to prevent external exploitation
🧯 If You Can't Patch
- Isolate affected routers in a dedicated VLAN with strict access controls
- Implement network segmentation to limit potential lateral movement from compromised devices
🔍 How to Verify
Check if Vulnerable:
Check router web interface or SSH/Telnet for firmware version 4.1.2cu.5182_B20201102Check Version:
Check router web admin interface at System Status or via SSH: cat /proc/versionVerify Fix Applied:
Verify firmware 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 File parameter
- Large file uploads to the CGI endpoint
- System logs showing unexpected process execution
Network Indicators:
- HTTP requests with oversized File parameter values
- Traffic patterns suggesting buffer overflow exploitation
SIEM Query:
source="router_logs" AND (uri="/cgi-bin/cstecgi.cgi" AND (param="File" AND size>threshold))🔗 References
- https://github.com/abcdefg-png/IoT-vulnerable/blob/main/TOTOLINK/A3600R/UploadCustomModule.md
- https://vuldb.com/?ctiid.272608
- https://vuldb.com/?id.272608
- https://vuldb.com/?submit.378291
- https://github.com/abcdefg-png/IoT-vulnerable/blob/main/TOTOLINK/A3600R/UploadCustomModule.md
- https://vuldb.com/?ctiid.272608
- https://vuldb.com/?id.272608
- https://vuldb.com/?submit.378291
