CVE-2024-7172
📋 TL;DR
A critical buffer overflow vulnerability in TOTOLINK A3600R routers allows remote attackers to execute arbitrary code by manipulating the http_host parameter in the getSaveConfig function. This affects TOTOLINK A3600R firmware version 4.1.2cu.5182_B20201102. Attackers can exploit this without authentication to potentially take full control of affected devices.
💻 Affected Systems
- TOTOLINK A3600R
📦 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
Remote code execution allowing attackers to modify router settings, intercept traffic, or use the device as a foothold into internal networks.
If Mitigated
Limited impact if devices are behind firewalls with strict inbound filtering, though internal threats remain possible.
🎯 Exploit Status
Public exploit code is available on GitHub. The vulnerability requires no authentication and has straightforward exploitation.
🛠️ 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 TOTOLINK website for firmware updates. If update exists: 1. Download firmware from official source 2. Log into router admin interface 3. Navigate to firmware update section 4. Upload and apply new firmware 5. Reboot router
🔧 Temporary Workarounds
Block CGI endpoint access
linuxUse firewall rules to block access to the vulnerable 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 separate network segments with strict firewall rules
- Implement network monitoring for exploitation attempts and anomalous traffic patterns
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface. If version is exactly 4.1.2cu.5182_B20201102, device is vulnerable.Check Version:
curl -s http://router-ip/ | grep -i firmware || ssh admin@router-ip 'cat /etc/version'Verify Fix Applied:
Verify firmware version has changed from vulnerable version. Test if /cgi-bin/cstecgi.cgi endpoint still responds to buffer overflow attempts.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /cgi-bin/cstecgi.cgi with long http_host parameters
- Router crash/restart logs
- Unusual process execution in router logs
Network Indicators:
- HTTP requests with abnormally long http_host parameters
- Traffic patterns suggesting reverse shell connections from router
- Unexpected outbound connections from router
SIEM Query:
source="router_logs" AND (uri="/cgi-bin/cstecgi.cgi" AND http_host LENGTH > 100) OR (event="buffer_overflow" OR event="crash")🔗 References
- https://github.com/abcdefg-png/IoT-vulnerable/blob/main/TOTOLINK/A3600R/getSaveConfig.md
- https://vuldb.com/?ctiid.272593
- https://vuldb.com/?id.272593
- https://vuldb.com/?submit.378039
- https://github.com/abcdefg-png/IoT-vulnerable/blob/main/TOTOLINK/A3600R/getSaveConfig.md
- https://vuldb.com/?ctiid.272593
- https://vuldb.com/?id.272593
- https://vuldb.com/?submit.378039
