CVE-2024-39802
📋 TL;DR
This vulnerability allows authenticated attackers to execute arbitrary code on Wavlink AC3000 routers by sending specially crafted HTTP requests that trigger buffer overflows in the QoS settings functionality. Attackers could gain full control of affected devices. Only users of specific Wavlink router models with vulnerable firmware are affected.
💻 Affected Systems
- Wavlink AC3000
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, persistence, network pivoting, and data exfiltration
Likely Case
Router takeover allowing traffic interception, DNS manipulation, and credential theft
If Mitigated
Limited impact if proper network segmentation and authentication controls prevent access to management interface
🎯 Exploit Status
Requires authentication but buffer overflow exploitation is well-understood
🛠️ 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 3. Upload via web interface 4. Reboot router
🔧 Temporary Workarounds
Disable remote management
allPrevent external access to web management interface
Network segmentation
allIsolate router management interface to trusted network
🧯 If You Can't Patch
- Disable QoS functionality if not required
- Implement strict firewall rules to limit access to router management interface
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router web interface under System StatusCheck Version:
Not applicable - check via web interfaceVerify Fix Applied:
Verify firmware version is newer than M33A8.V5030.210505📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to /cgi-bin/qos.cgi with long qos_dat parameters
- Multiple failed authentication attempts followed by successful login
Network Indicators:
- HTTP traffic to router management port with unusually long POST data
- Outbound connections from router to unexpected destinations
SIEM Query:
http.method:POST AND http.uri:"/cgi-bin/qos.cgi" AND http.request_body_length > 1000