CVE-2024-35397
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary commands on TOTOLINK CP900L routers by injecting malicious commands into the hostTime parameter of the NTPSyncWithHost function. Attackers can gain full control of affected devices without authentication. All users running vulnerable firmware versions are affected.
💻 Affected Systems
- TOTOLINK CP900L
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device takeover leading to persistent backdoor installation, network pivoting to internal systems, data exfiltration, and participation in botnets.
Likely Case
Router compromise allowing traffic interception, DNS hijacking, credential theft, and use as a foothold for further attacks.
If Mitigated
Limited impact if device is behind firewall with restricted inbound access and proper network segmentation.
🎯 Exploit Status
Public exploit code available in GitHub repository. Simple HTTP request with command injection payload required.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: http://totolink.com
Restart Required: No
Instructions:
1. Check vendor website for firmware updates
2. If update available, download and install via web interface
3. Verify installation and restart device if required
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to web management interface
Network Segmentation
allIsolate router on separate VLAN with restricted access
🧯 If You Can't Patch
- Block inbound access to router web interface (port 80/443) at network perimeter
- Implement strict egress filtering to prevent compromised device from communicating externally
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router web interface under System Status or AdministrationCheck Version:
curl -s http://router-ip/cgi-bin/cstecgi.cgi -d '{"topicurl":"setting/getSysStatus"}' | grep versionVerify Fix Applied:
Verify firmware version is newer than v4.1.5cu.798_B20221228📡 Detection & Monitoring
Log Indicators:
- Unusual command execution in system logs
- Multiple failed NTP sync attempts with unusual hostnames
Network Indicators:
- HTTP POST requests to /cgi-bin/cstecgi.cgi with shell metacharacters in parameters
- Outbound connections from router to unexpected destinations
SIEM Query:
source="router_logs" AND ("NTPSyncWithHost" OR "hostTime") AND ("|" OR ";" OR "$" OR "`")