CVE-2016-9366
📋 TL;DR
This vulnerability allows attackers to bypass authentication on affected Moxa NPort serial device servers through brute force attacks. Attackers can determine parameters needed to gain unauthorized access to device management interfaces. Organizations using vulnerable Moxa NPort serial device servers in industrial control systems are affected.
💻 Affected Systems
- Moxa NPort 5110
- NPort 5130/5150 Series
- NPort 5200 Series
- NPort 5400 Series
- NPort 5600 Series
- NPort 5100A Series
- NPort P5150A
- NPort 5200A Series
- NPort 5150AI-M12 Series
- NPort 5250AI-M12 Series
- NPort 5450AI-M12 Series
- NPort 5600-8-DT Series
- NPort 5600-8-DTL Series
- NPort 6x50 Series
- NPort IA5450A
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of industrial control systems, allowing attackers to manipulate serial communications, disrupt operations, or gain foothold in OT networks for further attacks.
Likely Case
Unauthorized access to device configuration, potential for network reconnaissance, and possible disruption of serial communications to connected industrial equipment.
If Mitigated
Limited impact if devices are properly segmented, authentication is strengthened, and network monitoring detects brute force attempts.
🎯 Exploit Status
Brute force attacks are simple to implement. No authentication required to attempt exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: See CVE description for specific version requirements per product line
Vendor Advisory: https://ics-cert.us-cert.gov/advisories/ICSA-16-336-02
Restart Required: Yes
Instructions:
1. Identify affected Moxa NPort devices. 2. Download appropriate firmware updates from Moxa website. 3. Backup device configuration. 4. Apply firmware update following Moxa documentation. 5. Verify update successful and restore configuration if needed.
🔧 Temporary Workarounds
Network Segmentation
allIsolate Moxa NPort devices in separate VLANs with strict firewall rules limiting access to management interfaces.
Access Control Lists
allImplement IP-based access control to restrict management interface access to authorized administrative hosts only.
🧯 If You Can't Patch
- Implement network segmentation to isolate devices from untrusted networks
- Deploy intrusion detection systems to monitor for brute force attempts
🔍 How to Verify
Check if Vulnerable:
Check device firmware version via web interface or serial console and compare against patched versions listed in CVE description.Check Version:
Check via web interface at http://[device-ip]/ or via serial console connectionVerify Fix Applied:
Verify firmware version matches or exceeds patched versions specified for each product line.📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts from single source
- Successful logins from unusual IP addresses
- Configuration changes from unauthorized users
Network Indicators:
- High volume of HTTP/HTTPS requests to device management ports (typically 80/443)
- Traffic patterns consistent with brute force tools
SIEM Query:
source_ip=[device_ip] AND (event_type="authentication_failure" COUNT > 10 WITHIN 5min) OR (event_type="configuration_change" AND user NOT IN [authorized_users])