ISO 27001 Risk Register Template Walkthrough (SME Guide)

A Risk Register is a commonly used document in an ISO/IEC 27001:2022 implementation, especially useful for SMEs. It may serve as a reference for identifying threats, assessing likelihood and impact, supporting documentation of security control selection, and linking risks to a Statement of Applicability (SoA).

This guide describes each part of a practical ISO 27001 Risk Register and provides examples of how SMEs can structure risk entries, apply L / M / H scoring, assign ownership, and link risks to relevant Annex A controls – all aimed at illustrating how a lean and practical ISMS may be documented. This overview highlights considerations that SMEs may take into account for risk assessment, treatment, and traceability in small and medium-sized organisations.

Why the ISO 27001 Risk Register Matters for SMEs 

In an ISO 27001-aligned ISMS, a Risk Register is commonly used by SMEs to support structured identification, assessment, and documentation of information security risks. A well-structured Risk Register may:

• Identify potential threats and vulnerabilities in processes, systems, and assets
• Apply consistent L / M / H scoring to assess likelihood and impact
• Link risks to relevant Annex A controls and document the rationale
• Provide a framework for recording evidence of implemented controls
• Capture management-approved Risk Acceptance decisions
• Support documentation that could be referenced for internal or external review
• Enable consistent risk management while minimising unnecessary complexity
  

These functions describe a practical, repeatable approach commonly referenced in ISO 27001-aligned risk documentation.

ISO 27001 Risk Register Structure for SMEs 

A practical ISO 27001 Risk Register for SMEs may include, at minimum, the following fields to support consistent risk tracking, control mapping, and alignment with a Statement of Applicability (SoA): 

1. Risk ID – Unique identifier for traceability 
2. Risk Description – Clear explanation of the threat and potential impact 
3. Assets / Processes Affected – Systems or operations exposed to risk 
4. Threat and Vulnerability – Specific risk scenario 
5. Likelihood (L / M / H) – Probability of occurrence 
6. Impact (L / M / H) – Consequence severity 
7. Inherent Risk Rating – Pre-treatment risk level 
8. Treatment Option (Avoid / Mitigate / Transfer / Accept) – Risk management decision 
9. Annex A Control Mapping – Links risks to relevant ISO 27001 controls 
10. Treatment Actions – Steps taken to reduce risk 
11. Residual Likelihood and Impact – Post-treatment assessment 
12. Residual Risk Rating – Remaining exposure 
13. Risk Owner – Responsible role for mitigation 
14. Residual Risk Acceptance Approval (where required) – Formal sign-off for accepted risks 

This structure reflects practical ISO 27001 risk management practices for SMEs and may support traceable risk assessment, control mapping, and alignment with the ISMS.

Step-by-Step Walkthrough: Building an ISO 27001 Risk Register for SMEs 

This structured walkthrough can assist SMEs in populating a practical, well-documented Risk Register. Each step includes examples, L / M / H scoring guidance, control mapping tips, and considerations for maintaining traceability and alignment with ISO/IEC 27001:2022 practices.

Step 1 – Identify the Risk Clearly (Cause → Effect Format) 

In this context, a risk generally refers to an event or scenario that could negatively affect business objectives. Describe each risk using a precise cause-to-effect statement. 

Illustrative Example: “Phishing attack leads to unauthorised access to customer data.” 

Key Insight: Vague entries like “cybersecurity breach” may reduce clarity. Clear, actionable descriptions can support traceable risk documentation and alignment with Annex A controls.

Step 2 – Identify Affected Assets and Processes (Scope for Control Mapping) 

List assets, processes, or systems impacted by the risk. This defines the scope for treatment, control selection, and SoA mapping. 

Illustrative Examples: 

• CRM database 
• Cloud infrastructure 
• HR onboarding process 
• Production environment 

Tip: Using precise, unambiguous names may help maintain traceability in the Risk Register.

Step 3 – Identify Threats and Vulnerabilities (Supporting Evidence for Controls) 

Specify the threat and associated vulnerability to guide control selection. This demonstrates a logical connection between risks and Annex A controls. 

Illustrative Examples: 

• Threat: phishing email → Vulnerability: lack of employee training 
• Threat: misconfiguration → Vulnerability: no change control process 

Tip: Documenting threats and vulnerabilities thoroughly may support ISO 27001 documentation and SoA mapping.

Step 4 – Choose the Likelihood and Impact Scales 

SMEs can consider a simple 3×3 scale (Low / Medium / High) for rating likelihood and impact. This approach may help reduce confusion and support consistent scoring. 

Key Insight: Clearly defining what L, M, and H mean in your Risk Assessment Methodology may improve scoring consistency and traceability.

Step 5 – Score Likelihood and Impact (Using Defined Scales) 

SMEs may apply the L / M / H definitions consistently across risks, where appropriate to their context. Consistent scoring may assist in prioritising risks and supporting SoA alignment.

See the next section for suggested L / M / H definitions. 

Defining L / M / H Scales for Consistent ISO 27001 Risk Scoring 

To support consistency in an ISO/IEC 27001:2022 Risk Register, SMEs may find it helpful to clearly define what Low, Medium, and High mean for both likelihood and impact. Clear definitions can reduce scoring ambiguity, support Annex A control selection, and support traceable risk documentation.

Likelihood Scale (Probability of Occurrence)

Tip: Documenting how these likelihood scores are defined in your Risk Assessment Methodology may support consistent risk assessment and traceability.

Impact Scale (Consequence to the Business)

These scales are example definitions suitable for many SMEs. It may be helpful to define and document the scales that best reflect your organisation’s risk tolerance in your Risk Assessment Methodology.

Key Insight: Using consistent scales can support structured risk scoring. Each scored risk may then be mapped to relevant Annex A controls and referenced in the Statement of Applicability (SoA).

Step 6 – Estimate the Inherent Risk Rating (ISO 27001 Risk Matrix)

To estimate the inherent risk of each identified threat before any treatment, a commonly used approach is a simple 3×3 risk matrix based on Likelihood and Impact scores. This approach may help prioritise risks and support structured documentation.

A common SME approach is:

• High: Either Impact or Likelihood is High
• Medium: Both Impact and Likelihood are Medium, or one is Medium and one is Low
• Low: Both Impact and Likelihood are Low

Tip: Keeping the matrix simple can support clear, consistent scoring. Estimated inherent risk ratings can guide the choice of risk treatment and support Annex A control mapping.

Step 7 – Select the Risk Treatment Option (Avoid, Mitigate, Transfer, Accept)

ISO 27001 commonly references four risk treatment options:

• Avoid – Stop the activity causing the risk. Example: discontinue a high-risk legacy system.
• Mitigate – Apply controls to reduce the likelihood or impact. Example: deploy MFA or endpoint protection (many SME risks fall under this category).
• Transfer – Shift the risk to a third party, e.g. via insurance or outsourcing.
• Accept – Acknowledge the risk and document it as part of a Risk Acceptance process.

Tip: Documenting the rationale for each treatment option may help support traceable risk records and SoA mapping.