CVE-2023-38861
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on Wavlink WL_WNJ575A3 routers by exploiting improper input validation in the username parameter of the set_sys_adm function. Attackers can gain full control of affected devices without authentication. This affects users of specific Wavlink router models running vulnerable firmware.
💻 Affected Systems
- Wavlink WL_WNJ575A3
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the router allowing attackers to install persistent malware, intercept all network traffic, pivot to internal networks, and use the device for botnet activities.
Likely Case
Router takeover leading to network traffic interception, DNS hijacking, credential theft, and use as a proxy for malicious activities.
If Mitigated
Limited impact if device is behind strict firewall rules, not internet-facing, and network segmentation prevents lateral movement.
🎯 Exploit Status
Public GitHub repository contains proof-of-concept code. Exploitation requires sending crafted HTTP requests to the vulnerable endpoint.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: No
Instructions:
No official patch available. Check Wavlink website for firmware updates. If update exists, download from official source and flash via web interface.
🔧 Temporary Workarounds
Disable Remote Administration
allDisable remote access to the router's web interface
Network Segmentation
allIsolate vulnerable routers from critical network segments
🧯 If You Can't Patch
- Place device behind firewall blocking all inbound access to port 80/443
- Replace vulnerable device with supported hardware
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router web interface. If version is R75A3_V1410_220513, device is vulnerable.Check Version:
curl -s http://router-ip/status.cgi | grep firmwareVerify Fix Applied:
Verify firmware version has been updated to a newer release than R75A3_V1410_220513📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to /cgi-bin/adm.cgi
- Multiple failed authentication attempts followed by successful access
Network Indicators:
- Unexpected outbound connections from router
- DNS queries to suspicious domains
- Traffic spikes on router management interface
SIEM Query:
source="router_logs" AND (uri="/cgi-bin/adm.cgi" OR method="POST" AND user_agent="*curl*")