CVE-2023-49713
📋 TL;DR
This vulnerability allows remote unauthenticated attackers to cause a denial-of-service condition in HMI GC-A2 series devices by sending specially crafted packets to NetBIOS service ports. The affected systems are industrial human-machine interface devices used in automation and control systems. Attackers can disrupt device functionality without requiring authentication.
💻 Affected Systems
- HMI GC-A2 series
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device unavailability requiring physical reset or reboot, potentially disrupting industrial processes or production lines.
Likely Case
Temporary service disruption requiring manual intervention to restore functionality.
If Mitigated
Minimal impact if devices are properly segmented and protected by network controls.
🎯 Exploit Status
Attack requires sending crafted packets to specific NetBIOS ports, which is relatively simple for attackers with network access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firmware update as specified in vendor advisory
Vendor Advisory: https://www.electronics.jtekt.co.jp/en/topics/202312116562/
Restart Required: Yes
Instructions:
1. Download latest firmware from vendor website. 2. Follow vendor's firmware update procedure. 3. Verify successful update. 4. Restart device as required.
🔧 Temporary Workarounds
Network Segmentation
allIsolate HMI devices from untrusted networks using firewalls or VLANs
Port Blocking
linuxBlock NetBIOS ports (137-139) at network perimeter and between zones
iptables -A INPUT -p tcp --dport 137:139 -j DROP
iptables -A INPUT -p udp --dport 137:139 -j DROP
🧯 If You Can't Patch
- Implement strict network segmentation to isolate HMI devices
- Deploy intrusion prevention systems to detect and block malicious NetBIOS traffic
🔍 How to Verify
Check if Vulnerable:
Check if device is running vulnerable firmware version and has NetBIOS ports openCheck Version:
Check device firmware version through HMI interface or vendor-specific toolsVerify Fix Applied:
Verify firmware version has been updated and test device functionality under normal load📡 Detection & Monitoring
Log Indicators:
- Unusual NetBIOS traffic patterns
- Device restart logs
- Service disruption alerts
Network Indicators:
- High volume of NetBIOS packets to HMI devices
- Malformed NetBIOS packets
SIEM Query:
source_ip=* AND dest_port IN (137,138,139) AND packet_size>normal AND dest_ip=HMI_subnet