CVE-2024-7157
📋 TL;DR
A critical buffer overflow vulnerability in TOTOLINK A3100R routers allows remote attackers to execute arbitrary code by manipulating the http_host parameter in the getSaveConfig function. This affects devices running firmware version 4.1.2cu.5050_B20200504. Attackers can exploit this without authentication to potentially take full control of affected routers.
💻 Affected Systems
- TOTOLINK A3100R
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, creation of persistent backdoors, lateral movement to internal networks, and botnet recruitment.
Likely Case
Remote code execution allowing attackers to modify router settings, intercept network traffic, or use the device as a pivot point for further attacks.
If Mitigated
Limited impact with proper network segmentation and firewall rules preventing external access to router management interfaces.
🎯 Exploit Status
Public exploit code is available on GitHub, making exploitation straightforward for attackers with basic skills. The vendor has not responded to disclosure attempts.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: None available
Restart Required: No
Instructions:
No official patch is available. Monitor TOTOLINK's website for firmware updates. Consider replacing affected devices if no patch becomes available.
🔧 Temporary Workarounds
Disable WAN access to management interface
allPrevent external access to the router's web management interface by disabling remote administration features.
Access router web interface → Advanced Settings → Remote Management → Disable
Implement network segmentation
allIsolate the router management interface to a dedicated VLAN or network segment with strict access controls.
🧯 If You Can't Patch
- Replace affected TOTOLINK A3100R routers with devices from vendors that provide security updates
- Implement strict firewall rules to block all external access to port 80/443 on the router's WAN interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface: Login → System Tools → Firmware Upgrade. If version is 4.1.2cu.5050_B20200504, device is vulnerable.Check Version:
curl -s http://router-ip/cgi-bin/cstecgi.cgi | grep version or check web interface manuallyVerify Fix Applied:
Verify firmware version has been updated to a version later than 4.1.2cu.5050_B20200504. No official fix exists as of this analysis.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /cgi-bin/cstecgi.cgi with long http_host parameters
- Multiple failed buffer overflow attempts in router logs
- Unexpected configuration changes
Network Indicators:
- Unusual outbound connections from router to unknown IPs
- Spike in traffic to router's management port from external sources
- DNS queries to suspicious domains from router
SIEM Query:
source="router_logs" AND (uri="/cgi-bin/cstecgi.cgi" AND method="POST" AND param="http_host" AND length(param_value)>100)🔗 References
- https://github.com/abcdefg-png/IoT-vulnerable/blob/main/TOTOLINK/A3100R/getSaveConfig.md
- https://vuldb.com/?ctiid.272571
- https://vuldb.com/?id.272571
- https://vuldb.com/?submit.377542
- https://github.com/abcdefg-png/IoT-vulnerable/blob/main/TOTOLINK/A3100R/getSaveConfig.md
- https://vuldb.com/?ctiid.272571
- https://vuldb.com/?id.272571
- https://vuldb.com/?submit.377542
