CVE-2019-17354
📋 TL;DR
This vulnerability allows unauthenticated access to the wan.htm configuration page on Zyxel NBG-418N v2 routers. Attackers can view WAN configuration details and modify data fields without authentication. Only users with the affected router model and firmware version are impacted.
💻 Affected Systems
- Zyxel NBG-418N v2
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
An attacker could reconfigure WAN settings to redirect traffic, intercept communications, or disable internet connectivity entirely.
Likely Case
Information disclosure of WAN configuration details and potential modification of network settings by local network attackers.
If Mitigated
With proper network segmentation and firewall rules, impact is limited to information disclosure only.
🎯 Exploit Status
Direct HTTP access to /wan.htm without authentication is sufficient for exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Zyxel for updated firmware
Vendor Advisory: https://www.zyxel.com/us/en/
Restart Required: Yes
Instructions:
1. Visit Zyxel support website 2. Download latest firmware for NBG-418N v2 3. Log into router admin interface 4. Upload and apply firmware update 5. Reboot router
🔧 Temporary Workarounds
Network Segmentation
allIsolate the router from untrusted networks using firewall rules
Access Control Lists
allRestrict access to router management interface to trusted IPs only
🧯 If You Can't Patch
- Replace affected router with updated model
- Deploy router behind additional firewall with strict access controls
🔍 How to Verify
Check if Vulnerable:
Attempt to access http://[router-ip]/wan.htm without authentication. If page loads, system is vulnerable.Check Version:
Log into router admin interface and check firmware version in System StatusVerify Fix Applied:
After patching, attempt to access /wan.htm without authentication. Should receive authentication prompt or error.📡 Detection & Monitoring
Log Indicators:
- Unauthenticated access attempts to /wan.htm in router logs
- Unexpected WAN configuration changes
Network Indicators:
- HTTP requests to /wan.htm from unauthorized sources
- Unusual WAN configuration traffic
SIEM Query:
http.url:"/wan.htm" AND NOT user_agent:"ZyXEL"