ISO 27001 Requirements List | Key ISMS Compliance Essentials

Introduction

ISO 27001 is an international standard that specifies the requirements for establishing, implementing, and maintaining an Information Security Management System (ISMS) to protect information assets. ISO 27001 certification offers benefits such as enhanced information security, improved customer trust, and a competitive advantage. The PDCA (Plan-Do-Check-Act) methodology is a cyclical approach used in ISO 27001 for the continuous improvement of an Information Security Management System (ISMS).

ISO 27001 Structure

The provided list accurately outlines the main structure of ISO 27001, which includes 10 mandatory clauses (4-10) that form the core of the Information Security Management System (ISMS) and Annex A which provides a reference list of controls.

The Mandatory ISMS Core Clauses (4-10)

• Clause 4: Context of the Organization: Understand the internal and external environment to define the ISMS scope including stakeholders and their requirements.

• Clause 5: Leadership: Ensure commitment from top management, define roles, and allocate resources for information security.

• Clause 6: Planning: Plan for risks and opportunities, set objectives, and manage changes to the ISMS.
  
  
• Clause 7: Support: Provide necessary resources, competence, awareness, and communication to support the ISMS.
  
  
• Clause 8: Operation: Implement the processes and controls to meet requirements and manage risks including risk assessment and treatment.

• Clause 9: Performance Evaluation: Monitor, measure, analyze, and evaluate the performance and effectiveness of the ISMS, including internal audits and management reviews.
  
  
• Clause 10: Improvement: Address nonconformities, take corrective actions, and make continual improvements to the ISMS
  
  
  

Annex A: Controls

This annex is a normative part of ISO 27001, meaning it is required for compliance. It provides a list of control objectives and a reference set of controls that an organization can select from to treat identified risks. The current version, ISO 27001:2022, aligns with ISO 27002:2022 and lists 93 controls organized into four thematic areas:

• Organizational Controls: Focused on policies, roles, threat intelligence, and managing assets and suppliers.
  
  
• People Controls: Related to human resource security, such as screening, awareness, and remote working.
  
  
• Physical Controls: Covering physical security, including secure areas, entry controls, and equipment protection.
  
  
• Technological Controls: Addressing technological security, including access controls, cryptography, and network security.
  

An organization must create a Statement of Applicability (SoA) to document which controls from Annex A (and any additional controls) have been selected and implemented, and to justify the exclusion of any controls.

Key Documents Required For ISO 27001

The key documents for ISO 27001 include the ISMS Policy, Risk Assessment Report, Statement of Applicability (SoA), Internal Audit Reports, Corrective Action Reports, Management Review Meeting Minutes, and Training Records. Other essential documents are the ISMS scope, risk treatment plan, and various operational and procedural documents, with the SoA being particularly important as it outlines the organization's control choices based on its risk assessment.

Core documents

• ISMS Policy: Documents the organization's commitment to information security and its specific, measurable security goals. 

• Risk Assessment Report: Summarizes the findings of the risk assessment, including identified risks and their evaluation.

• Statement of Applicability (SoA): Lists all Annex A controls, indicating which are applicable, and how they are implemented or justified.

• Internal Audit Reports: Provides evidence of the effectiveness of the ISMS through internal reviews.

• Corrective Action Reports: Documents the actions taken to address issues found during audits and other processes.

• Management Review Meeting Minutes: Records the outcomes of management reviews, which are critical for the continuous improvement of the ISMS.

• Training Records: Evidence of employee training, skills, experience, and qualifications related to information security.

The Mandatory ISMS Core Clauses (4-10)

• Clause 4: Context of the Organization: Understand the internal and external environment to define the ISMS scope, including stakeholders and their requirements.
  
  
• Clause 5: Leadership: Ensure commitment from top management, define roles, and allocate resources for information security.
  
  
• Clause 6: Planning: Plan for risks and opportunities, set objectives, and manage changes to the ISMS.
  
  
• Clause 7: Support: Provide necessary resources, competence, awareness, and communication to support the ISMS.
  
  
• Clause 8: Operation: Implement the processes and controls to meet requirements and manage risks, including risk assessment and treatment.
  
  
• Clause 9: Performance Evaluation: Monitor, measure, analyze, and evaluate the performance and effectiveness of the ISMS, including internal audits and management reviews.
  
  
• Clause 10: Improvement: Address nonconformities, take corrective actions, and make continual improvements to the ISMS.     
  
  

Steps to Achieve ISO 27001 Certification

Implementing ISO 27001 is a structured process that requires planning, documentation, and continual improvement. Below are the seven essential steps to help your organization achieve certification effectively.

1. Conduct A Gap Analysis

The first step in your ISO 27001 journey is to identify where your organization currently stands in relation to the requirements of the standard.

A gap analysis compares your existing information security practices with ISO 27001 requirements to highlight areas that need improvement.

Key actions:

• Review current policies, procedures, and controls.
  
  
•  Identify missing documentation or unimplemented clauses.
  
  
• Assess the maturity of your existing Information Security Management System (ISMS).
  
  
• Develop a roadmap to bridge the identified gaps.

Purpose: To establish a clear baseline and prioritize actions required to align your ISMS with ISO 27001 standards.

2. Perform A Risk Assessment

Once the gaps are identified, the next step is to assess risks to your organization’s information assets.

Risk assessment is the core of ISO 27001—it helps you identify, analyze, and evaluate security threats that could impact your business operations.

Key actions:

• Identify your information assets (data, systems, infrastructure, people).
  
  
• Determine potential threats and vulnerabilities (cyberattacks, data breaches, insider threats).
  
  
• Evaluate the likelihood and impact of each risk.
  
  
• Assign risk owners and document the findings in a Risk Assessment Report.

Purpose: To understand where your information security weaknesses lie and to decide how to mitigate or accept these risks.

3. Implement Information Security Controls

After assessing the risks, you need to apply controls to reduce or eliminate them.

ISO 27001 provides a comprehensive list of 114 controls in Annex A, covering areas like access management, cryptography, supplier relationships, and incident response.

Key actions:

• Select relevant controls from Annex A based on your risk treatment plan.
  
  
• Create a Statement of Applicability (SoA) listing chosen controls and their implementation status.
  
  
• Develop policies and procedures that define how each control will be applied.
  
  
• Implement technical, administrative, and physical security measures (e.g., encryption, firewalls, secure login policies).

Purpose: To establish robust safeguards that ensure information confidentiality, integrity, and availability across the organization.

4. Conduct Internal Audits

Before facing external auditors, organizations must verify the effectiveness of their ISMS through internal audits.

Internal audits help detect nonconformities, evaluate control performance, and ensure continuous compliance with ISO 27001 requirements.

Key actions:

• Schedule and plan regular internal audits.
  
  
•  Evaluate processes, documentation, and implemented controls.
  
  
•  Record findings and categorize them as conformities, nonconformities, or observations.
  
  
•  Communicate audit results to management for review and action.

Purpose: To ensure that your ISMS is effectively implemented and ready for external evaluation.

5. Correct Nonconformities

During audits or implementation, nonconformities may arise—these are gaps where your ISMS does not meet ISO 27001 requirements.

Addressing these issues promptly is crucial for achieving certification.

Key actions:

• Record nonconformities in a Corrective Action Report (CAR).
  
  
•  Analyze the root cause of each issue.
  
  
•  Implement corrective actions and preventive measures.

Purpose: To strengthen the ISMS by eliminating weaknesses and preventing recurrence

6. Conduct Management Review

Top management plays a key role in ensuring the effectiveness of the ISMS. The management review is a formal evaluation of the ISMS performance, audit results, and improvement opportunities.

Key actions:

• Review internal audit results, risk assessments, and corrective actions.
  
  
• Evaluate the adequacy of resources and staff competencies.
  
  
• Assess opportunities for continual improvement.
  
  
• Document meeting minutes and action points.
  

Purpose: To demonstrate leadership commitment, ensure alignment with business goals, and prepare the ISMS for external certification.

7. Undergo the Certification Audit

The final stage is the ISO 27001 certification audit, conducted by an accredited certification body (e.g., TUV, BSI, SGS).

The audit is typically carried out in two stages:

• Stage 1 Audit: Documentation review — auditors evaluate your ISMS documentation, policies, and readiness.
  
  
• Stage 2 Audit: Implementation review — auditors assess the effectiveness of your ISMS in operation.
  

If your organization meets all requirements, you will be awarded the ISO 27001 Certificate, valid for three years with annual surveillance audits.

Purpose: To achieve formal recognition that your organization complies with international information security standards.

Conclusion

ISO 27001 serves as a strategic framework for managing information security and safeguarding business data. It not only helps organizations reduce risks but also ensures compliance with global standards. Achieving certification builds customer trust, strengthens resilience against cyber threats, and enhances operational efficiency. More importantly, ISO 27001 promotes a culture of continual improvement, encouraging organizations to regularly assess and refine their security measures. In today’s digital age, it stands as a vital tool for sustaining long-term information security and business success.