CVE-2023-33831
📋 TL;DR
This is an unauthenticated remote command execution vulnerability in FUXA SCADA/HMI software that allows attackers to execute arbitrary commands on affected systems via a crafted POST request to the /api/runscript endpoint. Any organization running vulnerable versions of FUXA with the API exposed is affected, potentially allowing complete system compromise.
💻 Affected Systems
- FUXA
📦 What is this software?
Fuxa by Frangoteam
⚠️ Risk & Real-World Impact
Worst Case
Complete system takeover, data exfiltration, ransomware deployment, lateral movement to other systems, and disruption of industrial operations.
Likely Case
Initial foothold leading to data theft, installation of backdoors, and potential ransomware deployment on affected systems.
If Mitigated
Limited impact due to network segmentation, proper authentication controls, and monitoring that detects exploitation attempts.
🎯 Exploit Status
Multiple public proof-of-concept exploits and demonstration videos are available, making this trivial to exploit.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Unknown
Restart Required: No
Instructions:
No official patch available. Consider upgrading to latest version if available, or implement workarounds.
🔧 Temporary Workarounds
Block /api/runscript endpoint
allUse web application firewall or reverse proxy to block access to the vulnerable endpoint
# Example nginx location block
location /api/runscript { deny all; }
# Example Apache .htaccess
<Location "/api/runscript">
Order deny,allow
Deny from all
</Location>
Implement authentication
allAdd authentication requirement before accessing the API endpoint
# Implement authentication middleware or reverse proxy authentication
🧯 If You Can't Patch
- Network segmentation: Isolate FUXA systems from internet and restrict internal access
- Implement strict network monitoring and alerting for exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check if FUXA version is 1.1.13 or earlier and if /api/runscript endpoint is accessible without authenticationCheck Version:
Check FUXA web interface or configuration files for version informationVerify Fix Applied:
Verify that /api/runscript endpoint is either blocked, requires authentication, or returns appropriate error responses📡 Detection & Monitoring
Log Indicators:
- POST requests to /api/runscript endpoint
- Unusual command execution patterns in system logs
- Failed authentication attempts if authentication is implemented
Network Indicators:
- HTTP POST requests to /api/runscript with command execution payloads
- Unusual outbound connections from FUXA systems
SIEM Query:
http.method:POST AND http.uri:"/api/runscript" AND (process.executable:* OR cmd.exe OR bash OR sh)