CVE-2021-31892
📋 TL;DR
This vulnerability in multiple Siemens SINUMERIK industrial software products allows man-in-the-middle attacks due to improper SSL/TLS certificate validation. Attackers could intercept and manipulate encrypted communications between affected software and servers. All listed SINUMERIK products with specified versions are affected.
💻 Affected Systems
- SINUMERIK Analyse MyCondition
- SINUMERIK Analyze MyPerformance
- SINUMERIK Analyze MyPerformance /OEE-Monitor
- SINUMERIK Analyze MyPerformance /OEE-Tuning
- SINUMERIK Integrate Client 02
- SINUMERIK Integrate Client 03
- SINUMERIK Integrate Client 04
- SINUMERIK Integrate for Production 4.1
- SINUMERIK Integrate for Production 5.1
- SINUMERIK Manage MyMachines
- SINUMERIK Manage MyMachines /Remote
- SINUMERIK Manage MyMachines /Spindel Monitor
- SINUMERIK Manage MyPrograms
- SINUMERIK Manage MyResources /Programs
- SINUMERIK Manage MyResources /Tools
- SINUMERIK Manage MyTools
- SINUMERIK Operate V4.8
- SINUMERIK Operate V4.93
- SINUMERIK Operate V4.94
- SINUMERIK Optimize MyProgramming /NX-Cam Editor
📦 What is this software?
Sinumerik Analyse Mycondition Firmware by Siemens
View all CVEs affecting Sinumerik Analyse Mycondition Firmware →
Sinumerik Analyze Myperformance Firmware by Siemens
View all CVEs affecting Sinumerik Analyze Myperformance Firmware →
Sinumerik Integrate Client Firmware by Siemens
View all CVEs affecting Sinumerik Integrate Client Firmware →
Sinumerik Integrate Client Firmware by Siemens
View all CVEs affecting Sinumerik Integrate Client Firmware →
Sinumerik Integrate Client Firmware by Siemens
View all CVEs affecting Sinumerik Integrate Client Firmware →
Sinumerik Integrate For Production Firmware by Siemens
View all CVEs affecting Sinumerik Integrate For Production Firmware →
Sinumerik Integrate For Production Firmware by Siemens
View all CVEs affecting Sinumerik Integrate For Production Firmware →
Sinumerik Manage Mymachines Firmware by Siemens
View all CVEs affecting Sinumerik Manage Mymachines Firmware →
Sinumerik Manage Myprograms Firmware by Siemens
View all CVEs affecting Sinumerik Manage Myprograms Firmware →
Sinumerik Manage Myresources Firmware by Siemens
View all CVEs affecting Sinumerik Manage Myresources Firmware →
Sinumerik Manage Mytools Firmware by Siemens
⚠️ Risk & Real-World Impact
Worst Case
Attackers could intercept sensitive industrial control data, manipulate machine commands, steal credentials, or inject malicious code into manufacturing systems.
Likely Case
Data interception leading to intellectual property theft, operational data exposure, or credential harvesting for further attacks.
If Mitigated
Limited to internal network attacks only, with proper network segmentation preventing external exploitation.
🎯 Exploit Status
Exploitation requires network access to intercept TLS traffic. No authentication needed as this is a protocol-level vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Various - see Siemens advisory for specific product updates
Vendor Advisory: https://cert-portal.siemens.com/productcert/pdf/ssa-729965.pdf
Restart Required: Yes
Instructions:
1. Review Siemens advisory SSA-729965. 2. Identify affected products in your environment. 3. Apply vendor-provided updates for each affected product. 4. Restart systems as required. 5. Verify TLS certificate validation is functioning correctly.
🔧 Temporary Workarounds
Network Segmentation
allIsolate affected systems from untrusted networks to prevent MITM attacks
VPN/Encrypted Tunnel
allUse VPN or encrypted tunnels for all communications between affected systems and servers
🧯 If You Can't Patch
- Implement strict network segmentation to isolate affected systems
- Monitor network traffic for unusual TLS handshake patterns or certificate validation failures
🔍 How to Verify
Check if Vulnerable:
Check installed SINUMERIK product versions against affected versions list in Siemens advisoryCheck Version:
Check version through SINUMERIK software interface or Windows installed programs listVerify Fix Applied:
Test TLS connections to verify server certificates are properly validated after patching📡 Detection & Monitoring
Log Indicators:
- TLS handshake failures
- Certificate validation errors
- Unexpected certificate authorities
Network Indicators:
- Unencrypted fallback attempts
- TLS version downgrades
- Suspicious MITM patterns in network traffic
SIEM Query:
tls.handshake.type:1 AND (NOT tls.handshake.extensions_server_name OR tls.handshake.certificate_verify:0)