CVE-2011-20002
📋 TL;DR
This vulnerability allows an on-path attacker between engineering software and SIMATIC S7-1200 controllers to replay previously captured commands, potentially executing unauthorized actions like stopping the controller. It affects SIMATIC S7-1200 CPU V1 and V2 families (including SIPLUS variants) in versions before V2.0.2. The attack works even when controllers have passwords configured.
💻 Affected Systems
- SIMATIC S7-1200 CPU V1 family
- SIMATIC S7-1200 CPU V2 family
- SIPLUS variants of both families
⚠️ 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
Attacker replays STOP commands to halt industrial processes, causing production downtime, safety incidents, or equipment damage in critical infrastructure.
Likely Case
Unauthorized command execution leading to process disruption, operational interference, or unauthorized configuration changes in industrial environments.
If Mitigated
Limited impact if network segmentation isolates engineering traffic and monitoring detects anomalous command patterns.
🎯 Exploit Status
Exploitation requires on-path position between engineering station and PLC, plus ability to capture legitimate command traffic. No authentication bypass needed as attack replays legitimate commands.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: V2.0.2 or later
Vendor Advisory: https://cert-portal.siemens.com/productcert/html/ssa-625789.html
Restart Required: Yes
Instructions:
1. Download firmware V2.0.2 or later from Siemens Industry Online Support. 2. Use TIA Portal engineering software to upload new firmware to affected S7-1200 controllers. 3. Restart controllers after firmware update.
🔧 Temporary Workarounds
Network Segmentation
allIsolate engineering network from production network using firewalls to prevent on-path attacks
Encrypted Communication
allUse secure communication protocols (like VPN tunnels) between engineering stations and PLCs
🧯 If You Can't Patch
- Implement strict network segmentation to isolate engineering traffic from potential attackers
- Monitor network traffic for command replay patterns and unauthorized engineering access
🔍 How to Verify
Check if Vulnerable:
Check controller firmware version via TIA Portal: Online & Diagnostics > Functions > Firmware updateCheck Version:
Not applicable (requires TIA Portal engineering software interface)Verify Fix Applied:
Confirm firmware version is V2.0.2 or higher in TIA Portal diagnostics📡 Detection & Monitoring
Log Indicators:
- Repeated identical commands in short timeframes
- Engineering commands from unexpected source IPs
- Controller state changes without corresponding engineering station activity
Network Indicators:
- Duplicate command packets with identical timestamps/content
- Engineering protocol traffic from non-engineering network segments
SIEM Query:
source_ip NOT IN (engineering_station_ips) AND protocol="s7comm" AND command_type IN ("STOP","WRITE")