ISO 27001:2022 Annex A 5.3 – Segregation of Duties Explained

Many security incidents don’t happen because controls don’t exist.
They happen because too much power sits with one person or one role.

Annex A 5.3 exists to reduce that risk.

This control focuses on separating conflicting duties and responsibilities so that no single individual is able to initiate, approve, and conceal actions that could compromise information security.

It’s a governance control with very practical consequences.

ISO 27001

Quick Guide: Annex A 5.3 at a Glance

Annex A 5.3 of ISO 27001:2022 addresses the segregation of duties to reduce the risk of error, misuse, or fraud.

At a practical level, this means:

  • Identifying duties that should not sit with the same individual
  • Separating critical tasks where risk justifies it
  • Reducing reliance on implicit trust
  • Applying compensating controls where full separation isn’t practical
  • Aligning segregation decisions with risk, not theory

The control does not require rigid role separation or large teams. It recognises that smaller organisations may not be able to fully segregate duties and allows for alternative controls where necessary.

The intent is not to slow the business down, but to introduce checks and balances where a lack of oversight would increase risk.

In-Depth Guide to Annex A 5.3

What Is Annex A 5.3 and Why Does It Matter?

Annex A 5.3 is designed to prevent situations where a single individual can:

  • Perform an action
  • Approve that action
  • Conceal the outcome

When this happens, errors and malicious activity become harder to detect.

From an information security perspective, this increases the likelihood of:

  • Fraud
  • Unauthorised changes
  • Abuse of privileged access
  • Bypassing or disabling controls

A common example is one person being able to request access, approve it, and implement it. Another is someone developing changes and deploying them directly into production without independent review.

Segregation of duties introduces independent oversight, which reduces both intentional and unintentional security failures.

How to Implement Annex A 5.3 Effectively

A risk-based approach to segregation of duties usually includes the following steps.

1. Identify Conflicting Duties

Start by identifying activities that, if combined, would create unacceptable risk.

Common examples include:

  • Requesting and approving access rights
  • Designing and approving system changes
  • Developing and deploying code
  • Using and administering the same system
  • Designing and reviewing security controls

The focus should be on risk exposure, not organisational convenience.

2. Apply Segregation Where It Matters Most

Not all duties need to be segregated equally.

Higher-risk systems, data, and processes usually justify stronger separation, while lower-risk areas may rely on lighter controls.

This prioritisation keeps segregation proportionate and practical.

3. Use Compensating Controls Where Full Segregation Isn’t Possible

Smaller organisations often lack the resources for full role separation.

Where this is the case, alternative controls may be applied, such as:

  • Management review and oversight
  • Activity logging and monitoring
  • Independent audits or peer review
  • Formal approval workflows

These controls do not replace segregation, but they help manage risk where segregation is limited.

4. Document and Communicate the Approach

Decisions around segregation should be documented clearly.

This helps ensure:

  • Consistent application
  • Transparency during reviews or incidents
  • Alignment between teams

It also avoids assumptions about who is allowed to do what.

5. Review as Risk Changes

Segregation decisions should be revisited when:

  • Systems change
  • Access levels increase
  • Responsibilities shift
  • Incidents highlight weaknesses

Segregation that made sense last year may no longer be appropriate.

In-Depth Guide to Annex A 5.1

What is Annex A 5.1 and Why Does It Matter?

  • What the organisation values
  • How security decisions are approached
  • Where accountability sits
  • Aligns security with business objectives
  • Supports proportionate, risk-based decisions
  • Provides a reference point during incidents and disputes
  • Creates consistency without bureaucracy

How to Implement Annex A 5.1 Effectively

1. Define a Comprehensive Information Security Policy
  • Scope: What the policy applies to (systems, data, people).
  • Objectives: Why security is important for the business.
  • Roles & Responsibilities: Who is accountable for security.
  • Key Principles: Risk management, access control, and data protection.
2. Secure Senior Management Approval
  • Review and approve policies.
  • Ensure resources are allocated for implementation.
  • Lead by example in enforcing security policies.
3. Communicate and Train Employees
  • Include security policies in onboarding and ongoing training.
  • Ensure policies are easily accessible to all employees.
  • Encourage acknowledgment and acceptance of security responsibilities.
4. Regular Review & Continuous Improvement
  • Set a schedule for periodic policy reviews (at least annually).
  • Update policies based on business changes, new threats, or regulatory updates.
  • Conduct audits to ensure compliance and effectiveness.
5. Integrate Policies into the ISMS
  • Use it to develop more detailed security procedures.
  • Ensure policies align with other Annex A controls and broader risk management practices.
Key Differences: ISO 27001:2013 vs ISO 27001:2022
AspectISO 27001:2013ISO 27001:2022
Control StructureTwo separate controls: 5.1.1 & 5.1.2Merged into one control (5.1)
Implementation GuidanceLess prescriptiveMore detailed guidance for policy creation and alignment
Awareness & TrainingNot explicitly mentionedExplicitly requires policies to be part of training programmes
Attributes TableNot includedew attributes table for mapping policies to industry terms
Common Challenges & How to Overcome Them
  • Challenge: Employees don’t follow security policies.
  • Solution: Make policies practical and relevant to daily work. Use real-world examples in training.
  • Challenge: Policies are outdated or too generic.
  • Solution: Schedule annual reviews and update policies based on real threats and business changes.
  • Challenge: Policies are written in technical jargon.
  • Solution: Use plain language that all employees can understand.
  • Challenge: Lack of leadership buy-in.
  • Solution: Show how weak security affects business objectives—costs of breaches, loss of client trust, and legal penalties.
Final Recommendations
  • Make security policies living documents—review, refine, and update regularly.
  • Use policy training and awareness to create a security-conscious workforce.
  • Ensure policies are accessible, relevant, and easy to understand.
  • Keep policies aligned with business strategy and regulatory requirements.
  • Engage leadership in driving security culture from the top down.

Common Challenges and How to Overcome Them

  • Assuming segregation isn’t possible in small organisations
  • Apply risk-based separation and compensating controls
  • Over-separating low-risk activities
  • ocus segregation where impact and likelihood justify it
  • Relying solely on trust
  • Use oversight and transparency to support trust
  • Unclear boundaries between roles
  • Define responsibilities and access clearly

Segregation works best when it is deliberate, not accidental.

In-Depth Guide to Annex A 5.1

What is Annex A 5.1 and Why Does It Matter?

  • What the organisation values
  • How security decisions are approached
  • Where accountability sits
  • Aligns security with business objectives
  • Supports proportionate, risk-based decisions
  • Provides a reference point during incidents and disputes
  • Creates consistency without bureaucracy

How to Implement Annex A 5.1 Effectively

1. Define a Comprehensive Information Security Policy
  • Scope: What the policy applies to (systems, data, people).
  • Objectives: Why security is important for the business.
  • Roles & Responsibilities: Who is accountable for security.
  • Key Principles: Risk management, access control, and data protection.
2. Secure Senior Management Approval
  • Review and approve policies.
  • Ensure resources are allocated for implementation.
  • Lead by example in enforcing security policies.
3. Communicate and Train Employees
  • Include security policies in onboarding and ongoing training.
  • Ensure policies are easily accessible to all employees.
  • Encourage acknowledgment and acceptance of security responsibilities.
4. Regular Review & Continuous Improvement
  • Set a schedule for periodic policy reviews (at least annually).
  • Update policies based on business changes, new threats, or regulatory updates.
  • Conduct audits to ensure compliance and effectiveness.
5. Integrate Policies into the ISMS
  • Use it to develop more detailed security procedures.
  • Ensure policies align with other Annex A controls and broader risk management practices.
Key Differences: ISO 27001:2013 vs ISO 27001:2022
AspectISO 27001:2013ISO 27001:2022
Control StructureTwo separate controls: 5.1.1 & 5.1.2Merged into one control (5.1)
Implementation GuidanceLess prescriptiveMore detailed guidance for policy creation and alignment
Awareness & TrainingNot explicitly mentionedExplicitly requires policies to be part of training programmes
Attributes TableNot includedew attributes table for mapping policies to industry terms
Common Challenges & How to Overcome Them
  • Challenge: Employees don’t follow security policies.
  • Solution: Make policies practical and relevant to daily work. Use real-world examples in training.
  • Challenge: Policies are outdated or too generic.
  • Solution: Schedule annual reviews and update policies based on real threats and business changes.
  • Challenge: Policies are written in technical jargon.
  • Solution: Use plain language that all employees can understand.
  • Challenge: Lack of leadership buy-in.
  • Solution: Show how weak security affects business objectives—costs of breaches, loss of client trust, and legal penalties.
Final Recommendations
  • Make security policies living documents—review, refine, and update regularly.
  • Use policy training and awareness to create a security-conscious workforce.
  • Ensure policies are accessible, relevant, and easy to understand.
  • Keep policies aligned with business strategy and regulatory requirements.
  • Engage leadership in driving security culture from the top down.

Final Recommendations

Annex A 5.3 is about reducing unchecked power, not creating bureaucracy.

When segregation of duties is applied thoughtfully:

  • Errors are caught earlier
  • Abuse is harder to conceal
  • Accountability is clearer
  • Security controls are more resilient

Where full segregation isn’t possible, recognising the risk and applying compensating controls is far better than ignoring the issue entirely.

Segregation should always be driven by risk and impact, not organisational diagrams.

In-Depth Guide to Annex A 5.1

What is Annex A 5.1 and Why Does It Matter?

  • What the organisation values
  • How security decisions are approached
  • Where accountability sits
  • Aligns security with business objectives
  • Supports proportionate, risk-based decisions
  • Provides a reference point during incidents and disputes
  • Creates consistency without bureaucracy

How to Implement Annex A 5.1 Effectively

1. Define a Comprehensive Information Security Policy
  • Scope: What the policy applies to (systems, data, people).
  • Objectives: Why security is important for the business.
  • Roles & Responsibilities: Who is accountable for security.
  • Key Principles: Risk management, access control, and data protection.
2. Secure Senior Management Approval
  • Review and approve policies.
  • Ensure resources are allocated for implementation.
  • Lead by example in enforcing security policies.
3. Communicate and Train Employees
  • Include security policies in onboarding and ongoing training.
  • Ensure policies are easily accessible to all employees.
  • Encourage acknowledgment and acceptance of security responsibilities.
4. Regular Review & Continuous Improvement
  • Set a schedule for periodic policy reviews (at least annually).
  • Update policies based on business changes, new threats, or regulatory updates.
  • Conduct audits to ensure compliance and effectiveness.
5. Integrate Policies into the ISMS
  • Use it to develop more detailed security procedures.
  • Ensure policies align with other Annex A controls and broader risk management practices.
Key Differences: ISO 27001:2013 vs ISO 27001:2022
AspectISO 27001:2013ISO 27001:2022
Control StructureTwo separate controls: 5.1.1 & 5.1.2Merged into one control (5.1)
Implementation GuidanceLess prescriptiveMore detailed guidance for policy creation and alignment
Awareness & TrainingNot explicitly mentionedExplicitly requires policies to be part of training programmes
Attributes TableNot includedew attributes table for mapping policies to industry terms
Common Challenges & How to Overcome Them
  • Challenge: Employees don’t follow security policies.
  • Solution: Make policies practical and relevant to daily work. Use real-world examples in training.
  • Challenge: Policies are outdated or too generic.
  • Solution: Schedule annual reviews and update policies based on real threats and business changes.
  • Challenge: Policies are written in technical jargon.
  • Solution: Use plain language that all employees can understand.
  • Challenge: Lack of leadership buy-in.
  • Solution: Show how weak security affects business objectives—costs of breaches, loss of client trust, and legal penalties.
Final Recommendations
  • Make security policies living documents—review, refine, and update regularly.
  • Use policy training and awareness to create a security-conscious workforce.
  • Ensure policies are accessible, relevant, and easy to understand.
  • Keep policies aligned with business strategy and regulatory requirements.
  • Engage leadership in driving security culture from the top down.

The Annex Control Table

ISO 27001:2022 Organisational Controls
ISO 27001:2022 Technological Controls