CVE-2024-38896
📋 TL;DR
This CVE describes a command injection vulnerability in WAVLINK WN551K1 routers through the start_hour parameter of the nightled.cgi script. Attackers can execute arbitrary commands on the device with the privileges of the web server process. This affects all users of vulnerable WAVLINK WN551K1 routers.
💻 Affected Systems
- WAVLINK WN551K1
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise allowing attacker to install persistent backdoors, pivot to internal networks, or use device as part of botnet.
Likely Case
Local network compromise, device takeover for credential theft or network reconnaissance, and potential lateral movement.
If Mitigated
Limited impact if device is isolated from critical networks and proper network segmentation is in place.
🎯 Exploit Status
Exploit requires authentication to the web interface. Command injection is straightforward once authenticated.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: Yes
Instructions:
1. Check WAVLINK website for firmware updates
2. Download latest firmware for WN551K1
3. Upload via web interface
4. Reboot device
5. Verify fix by testing parameter injection
🔧 Temporary Workarounds
Disable web management interface
allPrevent access to vulnerable CGI script by disabling web interface
Use device CLI or alternative management method to disable web interface
Network isolation
linuxPlace device on isolated VLAN with strict firewall rules
iptables -A INPUT -s [device_ip] -j DROP
vlan configuration commands vary by switch
🧯 If You Can't Patch
- Isolate device on separate network segment with strict firewall rules
- Implement network monitoring for suspicious outbound connections from device
🔍 How to Verify
Check if Vulnerable:
Test by sending crafted payload to /cgi-bin/nightled.cgi?start_hour=`command` (requires authentication)Check Version:
Check web interface footer or use curl to query device info endpointsVerify Fix Applied:
Test same payload after patch - should return error or sanitized output📡 Detection & Monitoring
Log Indicators:
- Unusual command execution in system logs
- Web server logs showing shell metacharacters in parameters
Network Indicators:
- Unexpected outbound connections from device
- Traffic to known C2 servers
SIEM Query:
source="router_logs" AND ("nightled.cgi" AND ("`" OR ";" OR "|" OR "$"))