CVE-2025-40576
📋 TL;DR
A vulnerability in Siemens SCALANCE LPE9403 industrial switches allows unauthenticated remote attackers to crash the dcpd process by sending specially crafted Profinet packets. This affects all versions before V4.0 HF0 and could lead to denial of service in industrial networks.
💻 Affected Systems
- Siemens SCALANCE LPE9403 (6GK5998-3GS00-2AC2)
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Persistent denial of service affecting industrial control system availability, potentially disrupting manufacturing or critical processes.
Likely Case
Temporary service interruption requiring device reboot, causing minor operational disruption.
If Mitigated
Limited impact with proper network segmentation and monitoring to detect and block malicious packets.
🎯 Exploit Status
Exploitation requires sending specially crafted Profinet packets to vulnerable devices.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: V4.0 HF0
Vendor Advisory: https://cert-portal.siemens.com/productcert/html/ssa-327438.html
Restart Required: Yes
Instructions:
1. Download firmware V4.0 HF0 from Siemens support portal. 2. Backup current configuration. 3. Upload and install new firmware via web interface or CLI. 4. Reboot device. 5. Verify firmware version.
🔧 Temporary Workarounds
Network segmentation
allIsolate SCALANCE devices in separate VLANs with strict firewall rules limiting Profinet traffic to trusted sources only.
Access control lists
allImplement ACLs on upstream devices to restrict access to SCALANCE management interfaces and Profinet ports.
🧯 If You Can't Patch
- Implement strict network segmentation to isolate vulnerable devices from untrusted networks.
- Deploy intrusion detection systems to monitor for anomalous Profinet traffic patterns.
🔍 How to Verify
Check if Vulnerable:
Check firmware version via web interface (System > Device Information) or CLI command 'show version'.Check Version:
show versionVerify Fix Applied:
Confirm firmware version is V4.0 HF0 or later using same methods.📡 Detection & Monitoring
Log Indicators:
- dcpd process crashes
- unexpected device reboots
- Profinet protocol errors
Network Indicators:
- Malformed Profinet packets to port 34964
- Unusual traffic patterns to industrial devices
SIEM Query:
source="industrial_switch" AND (event="process_crash" OR event="unexpected_reboot")