What is ISO 27001? A Guide to Information Security Certification

Understanding what is ISO 27001?

ISO 27001 is a globally recognised international standard for managing information security. It provides a framework for implementing and maintaining an effective Information Security Management System (ISMS) that is designed to protect the confidentiality, integrity, and availability of an organisation’s information assets.

The standard has been around since 2005. Before that was a British standard, BS7799, and ISO 27001 is now one of the world’s most widely adopted information security standards.

As a standard, it applies to all organizations of any size. The bar provides a systematic approach for identifying, assessing, and managing information security risks. It is designed to be flexible so that organisations can tailor it to their needs and requirements. The standard also ensures that organisations comply with legal, regulatory, and contractual requirements related to information security.

The ISO 27001 standard consists of ten sections, each outlining a set of requirements organisations must meet to achieve certification.

The ten sections of the standard are:

Scope: The scope outlines the boundaries of the ISMS, including the assets, processes, people, and technologies that the ISMS is designed to protect.
Normative references: This section lists the standards and other documents that are referenced in ISO 27001.
Terms and definitions: This section provides definitions for terms used in the standard to ensure a common understanding of the concepts and terminology used.
Context of the organisation: This section requires organisations to define the internal and external context of their operations and to identify the risks and opportunities associated with the context.
Leadership: This section outlines the responsibilities of top management in establishing and maintaining the ISMS.
Planning: This section requires organisations to develop a risk management strategy and plan to identify and address risks to the organisation’s information assets.
Support: This section outlines the resources and support required to implement and maintain the ISMS.
Operation: This section requires organisations to implement the ISMS and ensure that information assets are protected against threats.
Performance evaluation: This section requires organisations to monitor, measure, analyse, and evaluate the effectiveness of the ISMS.
Improvement: This section requires organisations to continuously improve the ISMS to ensure that it remains effective in protecting information assets.

Annex A refers to the list of information security controls an organisation can implement, as outlined in section 6.1.3 of the standard. The list is not exhaustive, and additional controls can be added as needed. However, any control added must be justified, and any control from Annex A that is not included must also be justified. It is important to note that excluding any requirement specified in Clauses 4 to 10 is not acceptable.

ISO 27001 Accreditation

Organisations seeking certification against ISO 27001 must show compliance with clauses 4 through 10 and an appropriate set of security controls. Accreditation is achieved through an external audit by an accredited certification body. In the United Kingdom, the accreditation body is UKAS (United Kingdom Accreditation Service).

The audit assesses the organisation’s ISMS and determines whether it meets the standard’s requirements.

The process usually follows the following steps.

Gap Analysis: Although not technically required, gap analysis against the standard is usually recommended. If outsourcing, gap analysis is completed as part of the implementation but can be done independently.
Stage 1 Audit: This audit focuses on clauses 4 through 10, ensuring the ISMS is in place and demonstrable as running. The audit will also be used to determine your readiness for Stage 2 by discussing your security control set.
Stage 2 Audit: A re-review of your ISMS for changes and a deep dive into your security control set to ensure you meet each control’s control objective.

During an audit, one of four outcomes will be marked against each control:

Compliant: the implemented control meets the expectations of the standard.
Opportunity for Improvement: Although compliant, the control could be improved.
Minor Non-Conformity: A minor lapse in a control; this could be a missed audit or missed review.
Major Non-Conformity: A breakdown of the control; this would be no audits completed, no reviews carried out or a high number of Minor NCs in one area.

Only a major NC will result in a failing audit, and corrective action plans may be needed for any minor NCs.

The Benefits of ISO 27001 Certification

Implementing ISO 27001 provides several benefits for organisations:

Enhanced Data Security – Protects sensitive information from unauthorised access, theft, or loss.
Regulatory Compliance – Helps organisations meet legal and industry-specific security requirements (e.g., GDPR, HIPAA).
Increased Customer Trust – Demonstrates a commitment to security, fostering confidence among clients and partners.
Improved Risk Management – Encourages proactive identification and mitigation of security threats.
Business Continuity Planning – Ensures critical systems and data remain available in case of incidents.
Competitive Advantage – Enhances credibility and strengthens positioning in tenders and contract bids.
Cost Savings – Reduces the likelihood of security incidents, preventing financial losses from data breaches, fines, and reputational damage.

Final Thoughts

ISO 27001 is not just about achieving certification—it’s about building a resilient security framework that adapts to evolving threats. Organisations that effectively integrate ISO 27001 into their operations gain long-term benefits in risk management, regulatory compliance, and customer trust.

If you're considering ISO 27001 certification or want to strengthen your security posture, we can help.

Book a consultation today to discuss how ISO 27001 can benefit your business.

What does ISO 27001 cost? Read our article on the cost of ISO 27001.