CVE-2021-44222
📋 TL;DR
This vulnerability allows unauthenticated remote attackers to send arbitrary messages to the MQTT service in SIMATIC eaSie Core Package systems. Attackers can issue arbitrary requests to affected systems, potentially leading to unauthorized control or data manipulation. All users of SIMATIC eaSie Core Package versions before V22.00 are affected.
💻 Affected Systems
- SIMATIC eaSie Core Package
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing remote code execution, data theft, or disruption of industrial processes
Likely Case
Unauthorized message injection leading to system manipulation, data corruption, or denial of service
If Mitigated
Limited impact if proper network segmentation and authentication controls are implemented
🎯 Exploit Status
Direct exploitation via MQTT protocol without authentication
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: V22.00 or later
Vendor Advisory: https://cert-portal.siemens.com/productcert/pdf/ssa-580125.pdf
Restart Required: Yes
Instructions:
1. Download V22.00 or later from Siemens support portal
2. Backup current configuration
3. Install update following Siemens documentation
4. Restart affected systems
5. Verify MQTT authentication is enabled
🔧 Temporary Workarounds
Enable MQTT Authentication
allConfigure MQTT service to require authentication before accepting messages
Refer to Siemens documentation for specific MQTT authentication configuration
Network Segmentation
allRestrict network access to MQTT service ports
firewall rules to block external access to MQTT ports (typically 1883/8883)
🧯 If You Can't Patch
- Implement strict network segmentation and firewall rules to block all external access to MQTT ports
- Enable MQTT authentication and use strong credentials if supported by current version
🔍 How to Verify
Check if Vulnerable:
Check if SIMATIC eaSie Core Package version is below V22.00 and MQTT authentication is disabledCheck Version:
Check via Siemens management interface or product documentationVerify Fix Applied:
Verify version is V22.00 or later and MQTT service requires authentication📡 Detection & Monitoring
Log Indicators:
- Unauthenticated MQTT connection attempts
- MQTT messages from unexpected sources
Network Indicators:
- MQTT traffic on ports 1883/8883 without authentication
- Unusual MQTT message patterns
SIEM Query:
mqtt AND (port:1883 OR port:8883) AND NOT auth_success