CVE-2019-6526
📋 TL;DR
This vulnerability allows attackers to intercept administrative passwords and other sensitive data transmitted in plaintext across affected Moxa industrial network devices. Organizations using Moxa IKS-G6824A, EDS-405A, EDS-408A, or EDS-510A series devices with vulnerable firmware versions are affected.
💻 Affected Systems
- Moxa IKS-G6824A series
- Moxa EDS-405A series
- Moxa EDS-408A series
- Moxa EDS-510A series
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of industrial network devices leading to unauthorized configuration changes, network disruption, or lateral movement to critical systems.
Likely Case
Administrative credential theft enabling unauthorized access to network devices for reconnaissance or configuration manipulation.
If Mitigated
Limited impact if devices are isolated in protected networks with strict access controls and monitoring.
🎯 Exploit Status
Exploitation requires only network access to intercept plaintext traffic; no authentication or special tools needed beyond packet capture.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: IKS-G6824A: 4.6 or later; EDS-405A/408A/510A: 3.9 or later
Vendor Advisory: https://www.moxa.com/en/support/product-support/security-advisory/moxa-iks-g6824a-eds-405a-408a-510a-series-plaintext-transmission-vulnerability
Restart Required: Yes
Instructions:
1. Download latest firmware from Moxa support portal. 2. Backup device configuration. 3. Upload firmware via web interface or CLI. 4. Reboot device. 5. Verify firmware version and restore configuration if needed.
🔧 Temporary Workarounds
Network Segmentation
allIsolate affected devices in separate VLANs with strict firewall rules limiting management access.
VPN Tunnel for Management
allRequire VPN connection for all device management to encrypt traffic end-to-end.
🧯 If You Can't Patch
- Implement network monitoring for unauthorized access attempts to device management interfaces.
- Change administrative passwords regularly and use complex credentials unique to these devices.
🔍 How to Verify
Check if Vulnerable:
Check device firmware version via web interface (System > System Info) or CLI (show version). Compare against affected versions.Check Version:
show version (CLI) or check System Info in web interfaceVerify Fix Applied:
Confirm firmware version is 4.6+ for IKS-G6824A or 3.9+ for EDS series. Test management interface with packet capture to verify encrypted transmission.📡 Detection & Monitoring
Log Indicators:
- Multiple failed login attempts from new IPs
- Configuration changes from unexpected sources
- Unusual management session times
Network Indicators:
- Plaintext HTTP traffic to device management ports (80, 443)
- Unencrypted Telnet/SSH sessions to devices
- ARP spoofing or MITM activity near affected devices
SIEM Query:
source_ip IN (device_management_ips) AND (protocol="HTTP" OR protocol="TELNET") AND NOT is_encrypted=true