CVE-2024-39774
📋 TL;DR
This vulnerability allows authenticated attackers to execute arbitrary code on Wavlink AC3000 routers by sending a specially crafted HTTP request that triggers a stack-based buffer overflow. Attackers with administrative credentials can exploit this to gain full control of affected devices. Only Wavlink AC3000 M33A8.V5030.210505 routers are affected.
💻 Affected Systems
- Wavlink AC3000
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise leading to persistent backdoor installation, network traffic interception, lateral movement to other devices, and botnet recruitment.
Likely Case
Remote code execution allowing attackers to modify router settings, intercept traffic, or use the device as a pivot point for further attacks.
If Mitigated
Limited impact if strong authentication controls prevent unauthorized access to administrative interface.
🎯 Exploit Status
Exploitation requires authenticated access but is straightforward once credentials are obtained.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: Not available
Restart Required: No
Instructions:
1. Check Wavlink support for firmware updates
2. If update available, download from official source
3. Upload firmware via admin interface
4. Reboot router after update
🔧 Temporary Workarounds
Restrict Admin Interface Access
linuxLimit administrative interface access to trusted IP addresses only
iptables -A INPUT -p tcp --dport 80 -s TRUSTED_IP -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s TRUSTED_IP -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
Change Default Credentials
allReplace default admin credentials with strong, unique passwords
🧯 If You Can't Patch
- Isolate affected routers in separate VLAN with strict firewall rules
- Implement network monitoring for suspicious HTTP requests to admin interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface under System Status or About pageCheck Version:
curl -s http://router-ip/cgi-bin/adm.cgi | grep versionVerify Fix Applied:
Verify firmware version has been updated beyond M33A8.V5030.210505📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to /cgi-bin/adm.cgi
- Multiple failed authentication attempts followed by successful login
Network Indicators:
- HTTP requests with unusually long parameters to admin interface
- Traffic from router to unexpected external IPs
SIEM Query:
source="router-logs" AND (uri="/cgi-bin/adm.cgi" AND method="POST" AND size>1000)