Building an ISO 27001 Risk Register: A Practical Exercise in Seeing Risk Clearly

Understanding risk is one of the core skills in cybersecurity.

ISO/IEC 27001 provides a formal framework for assessing, prioritizing, and treating risks - but the real value comes from practicing how these concepts work in context.

After passing the JLPT N2 earlier this year, I began my cybersecurity journey with a focus on foundations. One of the most meaningful exercises from my ISO 27001 studies was building a Risk Register from scratch.

🌐 What Is a Risk Register?

A Risk Register is a structured document used to:

Identify assets and threats
Estimate likelihood and impact
Map risks to existing or needed controls
Prioritize treatment actions
Track progress over time

It turns abstract standards into an actionable view of what actually matters to an organization.

🛠️ How I Built My Example Register

To internalize the concepts, I created a simplified scenario and applied the ISO 27001 methodology:

Defined Assets - endpoints, credentials, cloud services, and internal data
Identified Threats & Vulnerabilities - unauthorized access, misconfiguration, weak passwords, data exposure
Evaluated Risk Levels - using a simple 1-5 likelihood/impact scale
Mapped Applicable Controls - referencing Annex A (e.g., A.5.1, A.8.3, A.8.16)
Assigned Treatment Options - mitigate, transfer, avoid, or accept
Noted Residual Risk - what remains after controls are applied

This helped me practice “thinking like a risk analyst” - understanding how security decisions flow from visibility, context, and prioritization.

📊 Example Risk Register Table

Below is a shortened example of how the data is structured. The example is based on a fictional school environment.

Download the full version below. ⬇️

📥 Download the Full Register

You can download the example file here:

👉 Download ISO 27001 Risk Register (Excel)

👉 Download ISO 27001 Risk Register (PDF)

🎯 Key Takeaways

Working through this exercise deepened my understanding of:

How risks interact with business context
Why control selection must be purposeful
The balance between likelihood and impact
The importance of clear communication in security management

Security, much like photography, relies on perspective.

The more sharply we see details - and the more clearly we frame them - the better we can understand the whole picture.

If you're studying ISO 27001 or building foundational risk skills, I hope this example is helpful.

Feel free to reach out with questions or thoughts.