CVE-2021-40392
📋 TL;DR
CVE-2021-40392 is an information disclosure vulnerability in Moxa MXView network management software where unencrypted network traffic exposes sensitive information. Attackers can sniff network communications to obtain credentials, configuration data, or other sensitive information. This affects organizations using Moxa MXView Series 3.2.4 for industrial network management.
💻 Affected Systems
- Moxa MXView Series
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of industrial control systems through credential theft, unauthorized access to critical infrastructure, and potential operational disruption.
Likely Case
Theft of administrative credentials and sensitive network configuration data leading to unauthorized access to network devices.
If Mitigated
Limited exposure of non-critical information if proper network segmentation and encryption are implemented.
🎯 Exploit Status
Exploitation requires network access to sniff traffic but no authentication or special tools beyond standard network sniffing capabilities.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.2.4 or later (check Moxa advisory for specific fixed version)
Vendor Advisory: https://www.moxa.com/en/support/product-support/security-advisory/mxview-series-web-application-vulnerability
Restart Required: Yes
Instructions:
1. Download latest MXView version from Moxa website. 2. Backup current configuration. 3. Install update following vendor instructions. 4. Restart MXView service. 5. Verify encryption is enabled for all communications.
🔧 Temporary Workarounds
Enable TLS/SSL Encryption
allForce all web application traffic to use HTTPS/TLS encryption
Configure MXView to use HTTPS only in web server settings
Disable HTTP access completely
Network Segmentation
allIsolate MXView traffic to separate VLAN with strict access controls
Configure firewall rules to restrict MXView traffic to specific subnets
Implement VLAN segmentation for industrial control network
🧯 If You Can't Patch
- Implement network-level encryption using VPN or IPsec tunnels for all MXView communications
- Deploy network monitoring and intrusion detection to alert on suspicious sniffing activity
🔍 How to Verify
Check if Vulnerable:
Check MXView version in web interface or via command line: mxview --version. If version is 3.2.4, you are vulnerable.Check Version:
mxview --versionVerify Fix Applied:
Verify HTTPS is enforced by attempting HTTP access (should be redirected or blocked). Check version is updated beyond 3.2.4.📡 Detection & Monitoring
Log Indicators:
- Multiple failed HTTPS redirect attempts
- Unusual network traffic patterns to MXView server
Network Indicators:
- Unencrypted HTTP traffic to MXView web port
- Network sniffing tools detected on same segment
SIEM Query:
source="mxview" AND (protocol="HTTP" OR port=80) AND NOT protocol="HTTPS"