CVE-2023-38584
📋 TL;DR
This vulnerability in Weintek's cMT3000 HMI Web CGI device allows anonymous attackers to exploit a stack-based buffer overflow in the command_wb.cgi component. This could lead to control flow hijacking and login 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, unauthorized access to industrial control systems, and potential physical process manipulation.
Likely Case
Authentication bypass leading to unauthorized access to HMI interface and potential data exfiltration or configuration changes.
If Mitigated
Limited impact if devices are isolated behind firewalls with strict network segmentation and access controls.
🎯 Exploit Status
Stack-based buffer overflow with authentication bypass suggests relatively straightforward exploitation.
🛠️ 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 firmware update following vendor instructions. 3. Restart device. 4. Verify web interface functionality.
🔧 Temporary Workarounds
Network Isolation
allDisable external web access and isolate device on internal network
Configure firewall to block external access to port 80/443
Implement VLAN segmentation
CGI Disable
allDisable CGI functionality if not required
Modify web server configuration to disable cgi-bin access
🧯 If You Can't Patch
- Implement strict network segmentation and firewall rules to limit access to HMI devices
- Deploy intrusion detection systems to monitor for buffer overflow attempts and authentication bypass patterns
🔍 How to Verify
Check if Vulnerable:
Check device firmware version against vendor advisory; test web CGI interface for command_wb.cgi endpointCheck Version:
Check device web interface or serial console for firmware version informationVerify Fix Applied:
Verify firmware version matches patched version; test that authentication bypass is no longer possible📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts followed by successful access
- Unusual CGI command execution patterns
- Buffer overflow error messages in web logs
Network Indicators:
- HTTP requests to /cgi-bin/command_wb.cgi with oversized parameters
- Unusual traffic patterns to HMI web interface
SIEM Query:
source="web_logs" AND (uri="/cgi-bin/command_wb.cgi" AND (param_size>threshold OR status=200 AFTER auth_failures))