What is a Risk Assessment?
A risk assessment is the systematic identification, analysis and evaluation of risks that could affect the safety, availability, integrity or confidentiality of systems, processes and people. In an OT context, it helps protect industrial installations from both technical and human threats.
Risk assessment is a core activity within Risk Management and forms the basis for taking targeted security measures.
🧠 How does a risk assessment work?
- Identification of risks
- What threats exist to systems, networks, processes and personnel?
- Examples: cyber attacks, faults, human error, fire, power outage, sabotage
- Identifying vulnerabilities
- Which weak spots make the system vulnerable?
- Examples: legacy PLCs, insufficient Access Control, outdated firmware
- Determining impact
- What is the possible damage if the risk is exploited?
- Factors: financial loss, environmental damage, production downtime, danger to life
- Estimating likelihood
- How likely is it that the risk will materialise?
- Based on historical data, threat information, Threat Intelligence
- Calculating the risk score
- Impact × Likelihood = Risk score
- Plotted on a risk matrix
- Defining controls
- Prevention (e.g. Firewall, Security Awareness)
- Detection (e.g. anomaly detection, SIEM)
- Response (e.g. Incident Response Plan)
- Recovery (e.g. Backup, Disaster Recovery)
🏭 Risk assessment in OT
| Aspect | Explanation |
|---|---|
| Industrial processes | High impact when disrupted: safety, production, environment |
| Legacy systems | Not always patchable or possible to monitor |
| Physical components | Risks are not just digital, but also mechanical/electrical |
| Compliance requirements | IEC 62443, ISO 27001, BIO and NIS2 all require risk assessment |
Common methods:
- HAZOP (Hazard and Operability Study)
- LOPA (Layer of Protection Analysis)
- FMEA (Failure Mode and Effects Analysis)
- BOW-TIE analysis
🔐 Relationship to cybersecurity
- In an OT context, often part of a broader Cybersecurity Risk Assessment
- Provides input for:
- The Security Level (under IEC 62443)
- The Business Impact Analysis
- Mitigating measures such as network segmentation or Access Control
📌 In summary
A risk assessment is essential to understand vulnerabilities and put the right security measures in place, especially in environments where safety, availability and continuity are crucial.