CVE-2020-12499
📋 TL;DR
CVE-2020-12499 is an improper path sanitation vulnerability in PHOENIX CONTACT PLCnext Engineer that allows attackers to execute arbitrary code by importing malicious project files. This affects users of PLCnext Engineer version 2020.3.1 and earlier who import project files from untrusted sources.
💻 Affected Systems
- PHOENIX CONTACT PLCnext Engineer
📦 What is this software?
Plcnext Engineer by Phoenixcontact
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with system-level privileges leading to complete compromise of the engineering workstation and potential lateral movement to industrial control systems.
Likely Case
Local privilege escalation or arbitrary code execution when users import malicious project files, potentially compromising the engineering environment.
If Mitigated
Limited impact if proper file validation and user awareness controls prevent import of untrusted project files.
🎯 Exploit Status
Exploitation requires user interaction to import malicious project file, but the path traversal mechanism is straightforward once file is loaded.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2020.3.2 or later
Vendor Advisory: https://cert.vde.com/en-us/advisories/vde-2020-025
Restart Required: Yes
Instructions:
1. Download PLCnext Engineer version 2020.3.2 or later from official PHOENIX CONTACT portal. 2. Uninstall previous version. 3. Install updated version. 4. Restart system.
🔧 Temporary Workarounds
Restrict project file imports
allImplement policies to only import project files from trusted sources and validate file integrity before import.
User awareness training
allTrain engineers to only open project files from verified sources and to be cautious of unexpected project files.
🧯 If You Can't Patch
- Implement application whitelisting to prevent execution of unauthorized binaries
- Use network segmentation to isolate engineering workstations from critical control systems
🔍 How to Verify
Check if Vulnerable:
Check PLCnext Engineer version in Help > About. If version is 2020.3.1 or earlier, system is vulnerable.Check Version:
Check Help > About in PLCnext Engineer GUIVerify Fix Applied:
Verify version is 2020.3.2 or later in Help > About menu.📡 Detection & Monitoring
Log Indicators:
- Unusual project file import activity
- Process creation from PLCnext Engineer with unusual parameters
Network Indicators:
- Unexpected network connections from engineering workstation after project file import
SIEM Query:
Process creation where parent_process contains 'PLCnext' and command_line contains unusual paths or parameters