CVE-2018-4852
📋 TL;DR
This vulnerability allows attackers with network access to SICLOCK TC100 and TC400 time synchronization devices to bypass authentication by using device-specific knowledge. Affected organizations using these devices for time synchronization in industrial environments are at risk of unauthorized access.
💻 Affected Systems
- SICLOCK TC100
- SICLOCK TC400
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of time synchronization infrastructure, enabling attackers to manipulate time settings across industrial networks, potentially disrupting operations or enabling further attacks.
Likely Case
Unauthorized access to device configuration, allowing attackers to modify time settings or use the device as a foothold into industrial networks.
If Mitigated
Limited impact if devices are properly segmented and monitored, with attackers unable to reach vulnerable interfaces.
🎯 Exploit Status
Requires network access and device-specific knowledge, but no authentication needed once knowledge is obtained.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Siemens advisory for specific firmware updates
Vendor Advisory: https://cert-portal.siemens.com/productcert/pdf/ssa-197012.pdf
Restart Required: Yes
Instructions:
1. Download firmware update from Siemens support portal. 2. Apply update following Siemens documentation. 3. Restart device. 4. Verify authentication mechanisms are functioning.
🔧 Temporary Workarounds
Network Segmentation
allIsolate SICLOCK devices in separate VLANs with strict access controls
Access Control Lists
allImplement firewall rules to restrict access to SICLOCK management interfaces
🧯 If You Can't Patch
- Implement strict network segmentation to isolate SICLOCK devices from untrusted networks
- Monitor network traffic to SICLOCK devices for unauthorized access attempts
🔍 How to Verify
Check if Vulnerable:
Check device model and firmware version against Siemens advisory SSA-197012Check Version:
Check via web interface or SNMP query (device-specific)Verify Fix Applied:
Verify firmware version has been updated to patched version specified in Siemens advisory📡 Detection & Monitoring
Log Indicators:
- Failed authentication attempts followed by successful access
- Configuration changes from unexpected sources
Network Indicators:
- Unauthorized access to management ports (typically 80/443)
- Traffic patterns indicating authentication bypass
SIEM Query:
source_ip=* AND dest_port IN (80,443) AND dest_ip=SICLOCK_IP AND (event_type='auth_failure' OR event_type='config_change')