CVE-2023-43492
📋 TL;DR
This vulnerability in Weintek's cMT3000 HMI Web CGI device allows anonymous attackers to exploit a stack-based buffer overflow in the codesys.cgi component. This could lead to control flow hijacking and authentication bypass, affecting industrial control systems using these vulnerable HMI devices.
💻 Affected Systems
- Weintek cMT3000 HMI
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing remote code execution, manipulation of industrial processes, and lateral movement to other systems in the OT network.
Likely Case
Authentication bypass leading to unauthorized access to HMI interface, potential manipulation of industrial processes, and data exfiltration.
If Mitigated
Limited impact if device is behind firewalls with strict network segmentation and access controls.
🎯 Exploit Status
Buffer overflow in web CGI component suggests relatively straightforward exploitation for attackers with appropriate skills.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Security update referenced in TEC23005E document
Vendor Advisory: https://dl.weintek.com/public/Document/TEC/TEC23005E_cMT_Web_Security_Update.pdf
Restart Required: Yes
Instructions:
1. Download security update from Weintek website. 2. Apply update following vendor instructions. 3. Restart device. 4. Verify web interface functionality.
🔧 Temporary Workarounds
Disable Web Interface
allDisable the web CGI interface if not required for operations
Device-specific configuration commands to disable web interface
Network Segmentation
allIsolate HMI devices in separate network segments with strict firewall rules
🧯 If You Can't Patch
- Implement strict network access controls to limit access to HMI web interface
- Deploy intrusion detection systems monitoring for buffer overflow attempts on port 80/443
🔍 How to Verify
Check if Vulnerable:
Check device version and compare against patched versions in vendor advisoryCheck Version:
Device-specific command via HMI interface or web consoleVerify Fix Applied:
Verify applied security update version matches vendor recommendation📡 Detection & Monitoring
Log Indicators:
- Unusual web CGI requests
- Buffer overflow patterns in web logs
- Failed authentication attempts followed by successful access
Network Indicators:
- Unusual HTTP POST requests to /cgi-bin/codesys.cgi
- Traffic patterns indicating buffer overflow attempts
SIEM Query:
source="web_logs" AND (uri="/cgi-bin/codesys.cgi" AND (content_length>threshold OR contains(buffer_overflow_patterns)))