ISO 27001 Annex A 5.35 Independent review of information security requires organisations to assess security management independently. Impartial reviews ensure controls remain effective, identify blind spots, and keep leadership informed of actual security posture.
Table of contents
Key Takeaways
- Ensure objective evaluation: Carry out planned, independent reviews of security approaches and control implementation.
- Store review records centrally: Keep audit schedules, independent reports, and remediation plans in a central document repository.
- Maintain auditor independence: Ensure reviewers have no direct operational responsibility for the systems or areas they inspect.
- Review on planned intervals: Run independent assessments at set intervals or whenever major infrastructure changes happen.
- Use qualified assessors: Engage competent internal staff from other units or trusted external specialists to conduct reviews.
- Report results to leadership: Present independent findings, risks, and corrective actions directly to executive management.
- Track corrective actions: Log all identified weaknesses and resolve non-conformities within agreed remediation windows.
- Support continuous improvement: Use independent insights to improve policies, enhance technical defences, and build client trust.
How to Implement ISO 27001 Annex A 5.35
- Draft an independent review policy: Write a documented procedure for independent assessments and store it in your central repository.
- Set an annual review schedule: Establish a calendar mapping out independent reviews across all operational and technical scopes.
- Select impartial reviewers: Appoint internal auditors separate from operations or hire independent external review specialists.
- Define clear review scopes: Agree formal terms of reference and scopes before each assessment begins.
- Assess policies and controls: Evaluate how well policies, processes, and security controls function against ISO standards.
- Log gaps in an action tracker: Record every flagged finding and vulnerability in a central corrective action system.
- Assign remediation owners: Designate clear owners and set target closure dates for each independent finding.
- Brief senior leadership: Share full audit results and remediation progress with executive managers during formal reviews.
- Trigger reviews on major changes: Schedule extra independent checks when expanding into new business markets or rebuilding core systems.
When you’re ready to bring compliance into one place
How to Audit ISO 27001 Annex A 5.35
- Review the independent review schedule: Inspect written audit programmes to verify regular independent reviews take place.
- Verify reviewer independence: Check auditor reporting lines to ensure reviewers do not assess their own work or direct operational tasks.
- Inspect independent audit reports: Sample past review reports to verify thorough evaluations of security controls and management practices.
- Verify assessor qualifications: Check records to confirm internal or external reviewers possess suitable skills and certifications.
- Track corrective action closure: Inspect action registers to confirm teams resolved findings from past independent reviews on time.
- Check executive reporting records: Confirm leadership received independent assessment summaries and approved remediation plans.
- Assess change-triggered reviews: Check if major technical or organizational changes prompted additional independent evaluations.
- Evaluate review completeness: Confirm that independent assessments covered all relevant business departments and technical environments.
Audit Evidence Checklist
- Independent review policy: Maintain a documented audit procedure with complete version history in your central repository.
- Annual review schedule: Supply a formal audit plan showing past and scheduled independent assessments across all scopes.
- Independent audit reports: Provide signed reports from internal or external assessors detailing review findings and recommendations.
- Auditor competence records: Maintain training certificates, CVs, or provider contracts proving assessor competence and independence.
- Corrective action logs: Supply an active tracking register showing remediated audit findings, assigned owners, and closure dates.
- Management review meeting minutes: Provide executive records proving leadership reviewed independent findings and approved actions.
- Scope and engagement agreements: Maintain terms of reference documents defining the boundaries for each completed independent review.
What to Teach Employees
- Understand the value of audits: Teach workers that independent reviews identify improvement opportunities rather than assigning personal blame.
- Provide open assistance: Instruct staff to share accurate records and answer questions honestly during independent reviews.
- Never hide known gaps: Encourage workers to discuss known challenges openly so assessors can help solve operational issues.
- Act on audit feedback: Remind teams to complete assigned remediation actions promptly after audit reports are finalized.
- Respect auditor independence: Teach managers not to influence or restrict the objective findings of internal or external reviewers.
- Understand compliance goals: Educate staff on how independent reviews protect customer information and support official certification.
Common Implementation Challenges
- Compromised auditor independence: Teams audit their own operational systems due to small staff size. Use cross-departmental peer reviews or external consultants.
- Ignoring audit findings: Reports sit unread without remediation progress. Require leadership oversight on corrective action closure rates.
- Incomplete audit scopes: Reviews exclude critical cloud systems or remote teams. Define comprehensive review scopes covering the full organisation.
- Irregular review cadence: Fast-growing teams postpone reviews indefinitely. Lock in annual assessment dates well in advance.
- Defensive staff culture: Workers fear audit findings and conceal operational weaknesses. Foster a blameless culture that rewards finding and fixing risks.
- Inadequate assessor skills: Reviewers lack technical depth to evaluate modern environments. Ensure assessors have proven domain expertise.
How to Measure Effectiveness (KPIs)
- Review schedule completion rate: Track the percentage of scheduled independent reviews carried out on time.
- Remediation closure speed: Measure the average number of days taken to resolve findings from independent reviews.
- High-risk finding resolution rate: Track the proportion of critical audit observations closed within target deadlines.
- Repeat finding rate: Measure the percentage of independent audit findings that recur in subsequent reviews.
- Audit scope coverage: Track the proportion of company departments and business systems covered by independent reviews each year.
- External certification success: Measure outcomes and non-conformities raised during official third-party ISO 27001 certification audits.
Related ISO 27001 Controls
ISO 27001 Control A 5.35 connects to several other ISO 27001 requirements:
- Clause 9.2: Internal audit requirements.
- Clause 9.3: Management review obligations.
- Annex A 5.36: Compliance with security policies.
