Navigating ISO 27001 Annex A: Control A.5.2

Welcome to our ISO 27001 Annex A Blog series:

Following our previous discussion on ISO 27001 Annex A Control A.5.1, we now turn to Control A.5.2, which is vital for defining and assigning information security roles and responsibilities. This control ensures clarity and accountability throughout the organisation, preventing conflicts and bolstering the Information Security Management System (ISMS). Explore how to effectively implement these requirements to maintain a strong and resilient security framework.

Control A.5.2 – Information security roles and responsibilities should be defined and allocated according to the organisation’s needs.

Purpose: To ensure information security responsibilities are clear, well-coordinated, and effectively implemented.

According to ISO/IEC 27002:2022, organisations must define and assign specific responsibilities for information security to ensure that all relevant tasks. From policy approval to incident response are carried out effectively.

• Documented roles and responsibilities for information security at all relevant levels.
• Clear allocation of authority and accountability, ensuring segregation of duties where appropriate.
• Avoidance of conflicts of interest, particularly between those who operate controls and those who monitor them.
• Integration into job descriptions, contracts, or governance documents, ensuring that everyone knows their role in maintaining information security.

• Regular review and adjustment of roles and responsibilities when organisational or technological changes occur.

  ISO/IEC 27002 further emphasises that information security is not just an IT function. It is a shared responsibility across departments, management, and employees.

Clear roles and responsibilities are at the heart of an effective ISMS. Without defined ownership, even the best controls can fail in practice.

When everyone assumes “someone else” is responsible, incidents are missed, gaps appear in risk management, and the ISMS loses credibility.

• Strengthen accountability – people understand what they own and can be measured against it.
• Ensure segregation of duties – no single individual has unchecked control over sensitive systems or processes.
• Enable consistency and continuity – staff changes or absences don’t lead to confusion over who’s responsible.

• Support compliance and auditability – auditors can trace who is accountable for each process and control.

  From my own auditing experience, I can often gauge an organisation’s maturity by how confidently staff describe their ISMS roles. When responsibilities are unclear or overlap, it’s a signal that implementation may exist only on paper.

According to ISO/IEC 27006-1:2024 Annex E, auditors expect to see that:

• Roles and responsibilities are formally documented and approved by management.
• Accountability is visible. There is evidence of who is responsible for which control, process, or asset.
• Segregation of duties is implemented where applicable (system administration vs monitoring).
• Staff interviews confirm understanding, employees and managers can describe their role in maintaining information security.
• Role definitions are up to date and align with the organisation’s structure, the ISMS scope, and risk treatment plans.

In practice, I often trace responsibility for a specific control (say, backup testing or access review) and follow it through. Who owns it, who approves it, and who verifies it. If I can’t find a clear line, that’s usually where the ISMS weakens.

• Use a RACI matrix to clarify who is Responsible, Accountable, Consulted, and Informed for each ISMS activity.
• Document everything from governance charts to committee terms of reference.
• Keep the balance between formal structure and agility. Avoid over-complicating the model with too many layers.
• Engage HR early. They play a key role in embedding security duties into roles and contracts.
• Communicate regularly. Security roles evolve with organisational change. Make sure updates are cascaded to all affected staff.
• Leverage management reviews to verify whether responsibilities remain appropriate and effective.

No formal documentation - roles are known informally but not recorded.
Overlap or conflict - two departments believe they share responsibility, leading to gaps.
One-person dependency - critical security functions rely on a single individual.
Outdated assignments - roles haven’t been updated since restructuring or outsourcing.
Poor awareness - staff unaware of their responsibilities during interviews.

I’ve seen many findings arise from simple confusion. For example, when no one can clearly say who reviews access rights or who approves the Statement of Applicability.

Control A.5.2 turns “policy intent” into real accountability. Once management defines who does what for information security, the ISMS becomes operational and auditable.

As auditors, we look less at titles and more at clarity. Does everyone know their role, and can they prove it?

Define, document, communicate, and review. When everyone knows their part, information security stops being a shared assumption and it becomes a shared responsibility.