What is an Internal Audit in ISO 27001?
Overview
An Internal Audit is a systematic, independent evaluation of your ISMS to verify it conforms to ISO 27001:2022 requirements and is effectively implemented. It's a mandatory requirement under Clause 9.2 and a critical tool for identifying gaps before your certification audit.
Internal audits provide objective evidence that your ISMS is working as intended and help drive continual improvement.
Internal Audit in Practice
ISO 27001:2022 requires you to conduct internal audits at planned intervals to assess whether your ISMS:
Conforms to your own ISMS requirements and ISO 27001:2022 standards
Is effectively implemented and maintained
Achieves the intended outcomes defined in your information security objectives
You must establish an audit program that considers the importance of processes, changes affecting the organization, and results from previous audits.
Internal audits should be conducted by competent personnel who are independent of the area being audited to ensure objectivity.
Key Components of Internal Audits
Audit Planning
Your audit program must define:
Audit frequency (typically annually, but high-risk areas may need more frequent reviews)
Audit scope covering all ISMS clauses (4-10) and applicable Annex A controls
Audit criteria based on ISO 27001:2022 requirements and your documented procedures
Audit methods (document review, interviews, observation, sampling)
Conducting the Audit
During the audit, you should:
Review documented information (policies, procedures, records)
Interview process owners and staff
Observe implementation of controls
Sample evidence of control effectiveness
Document findings objectively with evidence
Audit Reporting
Clause 9.2 requires you to retain documented information as evidence of audit results. Your audit reports should include:
Conformities and non-conformities identified
Opportunities for improvement
Evidence supporting findings
Corrective action requirements for non-conformities
Non-conformities found during internal audits must be addressed through corrective action (Clause 10.2) before your certification audit.
Auditor Requirements
ISO 27001:2022 Clause 9.2 specifies that auditors must:
Be competent in auditing and information security
Be impartial and objective
Not audit their own work (independence requirement)
Example: An IT security manager can audit HR processes, but someone else must audit the IT security controls the manager is responsible for.
Audit Frequency and Timing
While ISO 27001:2022 doesn't mandate specific intervals, best practices include:
Complete ISMS audit at least annually
More frequent audits for critical or high-risk areas
Additional audits after significant changes
Timing that allows corrective action before external certification audits
Use ISMS Copilot to generate internal audit checklists tailored to specific Annex A controls or create audit questions for interviews with process owners.
Common Audit Areas
Your internal audit should cover:
Clause 4: Context, scope, and ISMS boundaries
Clause 5: Leadership commitment and policy
Clause 6: Risk assessment and treatment
Clause 7: Resources, competence, awareness, communication
Clause 8: Operational planning and control implementation
Clause 9: Monitoring, measurement, internal audit, management review
Clause 10: Nonconformity and corrective action, continual improvement
Annex A: Applicable controls from your SoA
Related Terms
ISMS – The system being audited
Management Review – Uses audit findings as input
Control – Individual security measures evaluated in audits
Statement of Applicability – Defines which controls to audit