CVE-2020-28212
📋 TL;DR
This vulnerability allows attackers to perform brute force attacks against the PLC Simulator in EcoStruxure Control Expert (Unity Pro) via Modbus protocol, potentially leading to unauthorized command execution. All versions of the software are affected, primarily impacting industrial control systems using Schneider Electric's PLC programming environment.
💻 Affected Systems
- EcoStruxure Control Expert
- Unity Pro
📦 What is this software?
Ecostruxure Control Expert by Schneider Electric
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of PLC simulator allowing unauthorized command execution, potential manipulation of simulated industrial processes, and foothold for attacking connected systems.
Likely Case
Unauthorized access to PLC simulator functions, manipulation of simulation parameters, and potential data exfiltration from the simulation environment.
If Mitigated
Limited impact with proper network segmentation and authentication controls, though simulation integrity could still be compromised.
🎯 Exploit Status
Brute force attacks via Modbus protocol are well-understood and tools exist for Modbus enumeration/attacks.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not version-specific - requires configuration changes
Vendor Advisory: https://www.se.com/ww/en/download/document/SEVD-2020-315-07
Restart Required: No
Instructions:
1. Download and review SEVD-2020-315-07 advisory. 2. Implement authentication rate limiting on Modbus interface. 3. Configure network access controls. 4. Apply principle of least privilege to simulator access.
🔧 Temporary Workarounds
Network Segmentation
allIsolate PLC Simulator from untrusted networks and implement strict firewall rules for Modbus traffic.
Authentication Hardening
windowsImplement account lockout policies and strong authentication mechanisms for simulator access.
🧯 If You Can't Patch
- Implement network-level rate limiting for Modbus traffic using firewalls or network security devices.
- Deploy intrusion detection systems monitoring for Modbus brute force patterns and anomalous command sequences.
🔍 How to Verify
Check if Vulnerable:
Test if Modbus interface accepts unlimited authentication attempts without lockout mechanisms.Check Version:
Check Control Expert/Unity Pro version in Help > About menu.Verify Fix Applied:
Verify authentication rate limiting is enforced and Modbus access is properly restricted.📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts from single source
- Unusual Modbus command sequences
- Authentication bypass events
Network Indicators:
- High volume of Modbus authentication packets
- Brute force patterns on TCP port 502
- Unauthorized Modbus function codes
SIEM Query:
source_port:502 AND (event_type:auth_failure OR event_type:modbus_command) | stats count by src_ip dest_ip