What is Vulnerability Scanning?
Vulnerability Scanning is the automated scanning of systems, devices and software for known vulnerabilities, such as unpatched software, misconfigurations or outdated Firmware.
In OT environments, it helps to map vulnerabilities, but must be applied carefully because of the sensitivity of industrial systems.
🧠 Why is Vulnerability Scanning important in OT?
| Challenge | Solution through scanning |
|---|---|
| Legacy systems without patch management | Detection of known vulnerabilities |
| Unknown components or versions | Inventory of versions, firmware and software |
| Supply chain risks | Identifying vulnerable supplier components |
| Unintended exposure | Identifying open ports, services or remote access |
⚠️ Important: caution in OT
OT devices such as PLCs, HMIs and SCADA servers often cannot withstand aggressive scans. It is therefore crucial to:
- Use only passive scans or read-only methods
- Run scans outside production hours
- Involve engineering and operations in the execution
- Carry out trial scans in an OT test environment or digital twin
🔧 Types of Vulnerability Scans
| Type | Description |
|---|---|
| Network-based | Scans an IP range for open ports, services and banners |
| Credentialed | Logs into devices (where possible) to read versions/configs |
| Passive scanning | Observes network traffic to infer vulnerabilities |
| Firmware scanning | Analyses firmware version/signature against known CVEs |
| Web app scanning | Tests for vulnerabilities in web interfaces (e.g. on HMI, VPN, Historian) |
🛠️ Tools (examples)
| Tool | Application in OT |
|---|---|
| Tenable.ot | OT-aware scanner with safe profiles |
| Nozomi Guardian | Passive asset and vulnerability scanning |
| Claroty | ICS-specific vulnerability scanning at protocol level |
| OpenVAS | Use only in OT test networks or under strict control |
| Nessus | Use only on the IT side or for very controlled scans |
✅ Best practices
- Combine scanning with Asset Inventory and patch management
- Only scan at agreed times, coordinated through Change Management
- Document all findings in your risk register
- Link vulnerabilities to priority and likely impact (e.g. via CVSS)
- Use SIEM or dashboards to track vulnerability trends
- Integrate with Third Party Risk Management for supplier components
📌 In summary
Vulnerability Scanning provides insight into digital weaknesses within OT environments. The condition is that it is carried out safely, carefully and in collaboration with operations.