CVE-2019-13925
📋 TL;DR
A vulnerability in Siemens SCALANCE S industrial switches allows remote attackers to cause a denial-of-service condition by sending specially crafted packets to port 443/tcp. This affects the web server component, potentially disrupting management access. Organizations using affected SCALANCE S602, S612, S623, or S627-2M switches with vulnerable firmware versions are impacted.
💻 Affected Systems
- SCALANCE S602
- SCALANCE S612
- SCALANCE S623
- SCALANCE S627-2M
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete loss of web management interface functionality, requiring physical access to restore service, potentially disrupting network operations and maintenance.
Likely Case
Temporary unavailability of the web management interface, forcing administrators to use alternative management methods until service is restored.
If Mitigated
Minimal operational impact if alternative management methods (CLI, other interfaces) are available and network segmentation limits attack surface.
🎯 Exploit Status
No authentication required. Attackers need network access to port 443/tcp of affected devices.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: V4.1 or later
Vendor Advisory: https://cert-portal.siemens.com/productcert/pdf/ssa-591405.pdf
Restart Required: Yes
Instructions:
1. Download firmware V4.1 or later from Siemens Industrial Network. 2. Backup current configuration. 3. Upload new firmware via web interface or TFTP. 4. Reboot device. 5. Restore configuration if needed.
🔧 Temporary Workarounds
Block port 443 access
allRestrict access to port 443/tcp using firewall rules to only trusted management networks.
Use alternative management
allDisable web interface and use CLI or other management interfaces if available.
🧯 If You Can't Patch
- Implement strict network segmentation to isolate SCALANCE devices from untrusted networks.
- Monitor port 443 traffic for anomalous patterns and implement rate limiting where possible.
🔍 How to Verify
Check if Vulnerable:
Check firmware version via web interface (System > Device Information) or CLI (show version). Compare against affected range (V3.0 to V4.1).Check Version:
CLI: show version | Web: Navigate to System > Device InformationVerify Fix Applied:
Confirm firmware version is V4.1 or later. Test web interface functionality after applying patch.📡 Detection & Monitoring
Log Indicators:
- Web server crash logs
- Repeated connection attempts to port 443
- Unusual traffic patterns to management interface
Network Indicators:
- High volume of malformed packets to port 443/tcp
- Sudden drop in web interface responsiveness
SIEM Query:
source_ip:* dest_port:443 AND (packet_size:anomalous OR protocol_violation:true)