What is ISO 27001 Audit? A Complete Guide

Consider a scenario; when one morning while trying to login you find your company’s confidential data inaccessible; at that time how would you respond? Could you prove your defences were robust enough to prevent such a breach? An ISO 27001 Audit offers exactly that assurance.

Far more than a simple checklist, this is a structured evaluation of an organisation’s Information Security Management System (ISMS). It identifies gaps in policies, and technical controls, helping you understand where your security stands. This blog breaks down each stage of the ISO 27001 Audit process: from defining scope and gathering evidence to reporting findings and tracking corrective actions.

Table of Contents

1) What is ISO 27001 Audit?

2) Importance of ISO 27001 Audit

3) What are the Types of Audits?

4) Stages of the ISO 27001 Audit

5) Performing ISO 27001 Audits

6) How to Prepare for an ISO 27001 Audit?

7) How Often do I Need to Conduct an Audit?

8) How Much Does a 27001 Audit Cost?

9) Conclusion

What is ISO 27001 Audit?

An ISO 27001 Audit is a checklist to see if a company is following the rules and steps of the ISO 27001 standard. This standard helps businesses keep their information safe. The audit looks at how well a company protects its data and if it is doing what it promised in its security plan.

Importance of ISO 27001 Audit

a) Helps check if your business is protecting data the right way

b) Finds weak points so you can fix them before problems happen

c) Builds trust with customers by showing you care about their data

d) Keeps your company safe from security risks and data loss

e) Makes sure your team follows the rules and policies

f) Helps meet legal and industry requirements

g) Supports getting or keeping ISO 27001 certification

What are the Types of Audits?

There are two main types of audits in ISO 27001: Internal Audit and External Audit. Both help make sure the company is keeping its data safe. Let's discuss in detail:

Internal Audit

An internal audit is done by someone inside the company or a hired person before the main audit. It helps find problems early and gives time to fix them. The goal is to check if the company is following its own security plan. It is like a practice check before the real one.

a) Done by the company’s own team or an outside helper

b) Helps find issues early and fix them

c) Prepares the company for the official audit

External Audit

An external audit is done by a certification body. This is the official check to decide if the company gets ISO 27001 certified. The Auditor looks at systems, documents, and staff practices. If everything is correct, the company gets the certificate

a) Done by a certified external Auditor

b) Needed to get ISO 27001 certification

c) Confirms the company is keeping data safe properly

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Stages of the ISO 27001 Audit

As an organisation prepares for the ISO 27001 Audit, it should focus on the two stages of the initial certification audit, determining the company's eligibility for ISO Certification. Usually, organisations hire an Auditor to support them in completing stage 1 compliance requirements before requesting an external audit from the certifying body for the second stage.

Here are the two stages of the initial certification audit:

Stage 1

The ISO Certification Audit's first stage is called the ISMS Design Review. The company must prepare adequately for the ISMS Design Review before it requests an ISMS Design audit. The company can also refer to the checklist for the ISO 27001 Audit to prepare itself for the first stage of the Audit.

The checklist comprises a framework containing a series of ten stages. The checklist helps IT security teams gather the necessary information for the Certification's preparation and streamline the process. A company can also streamline its process with the help of this checklist and ensure that the teams cover every aspect over four to twelve months. The time of coverage depends on the size of the organisation.

The company can then proceed to document all its processes, policies and guidelines for its ISMS depending on the requirements of ISO 27001. It can then assess its risk, followed by a risk treatment procedure and a gap analysis to submit the documentation.

The external Auditor will review the company’s documentation during the ISMS Design Review. They do this to make sure the documentation aligns with the ISO requirements. The Auditor's findings and suggestions for process improvement will be included in the audit report before starting Stage 2. Furthermore, the company’s employees may need to pursue additional security training to meet the audit standards for Stage 1.

Stage 2

The organisation may proceed to Stage 2 upon Auditor's recommendation for certification after completing Stage 1. In the second stage of the ISO 27001 Audit, the certifying body's Auditor conducts a field review to confirm the alignment of business processes and Security Controls with approved procedures in Stage 1.

A random data sampling is then done as evidence to confirm the ISMS's effective operation, compliance with ISO 27001 requirements, and mandatory ISO 27001 controls stated in Annex A. The evidence should prove that business procedures work as documented.

Key stakeholders responsible for ISMS management, Internal Audit members, and compliance teams are interviewed as part of the Audit Process. Auditors also request prior Audit Reports and any rectifications made based on Stage 1 results. The Auditors interpret any non-conformities from these reports, while Management Audits confirm post-audit improvements' implementation.

After certification in Stage 2, organisations can define their processes, including security awareness training and the Internal Audit process. These two parts must be documented for achieving and maintaining continuous compliance with ISO 27001 Standards.

Organisations are ISO certified for three years upon successfully clearing Stage 2 of ISO Certification. They must still submit annual surveillance audits to follow the internal audit schedule to the certification body and prove the continuous operation of their controls as intended.

Performing ISO 27001 Audits

The ISO 27001 Audits need to be done by experienced ISO 27001 Lead Auditors who can demonstrate their knowledge of the ISO standard. Although formal certifications generally prove Auditor’s knowledge, the certifying body can choose to approve them based on their competence with ISO 27001 Audit questions.

The Auditors will need to belong to a team outside the stakeholders for the Internal Audits, and this ensures that they are not performing self-reviews and maintaining the ISMS standard. Companies that do not have a separate auditing team will typically hire a formally experienced firm to assist with the Internal Audit process. The formally trained firms generally employ Auditors who are certified in the ISO 27001 Lead Auditor course.

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How to Prepare for an ISO 27001 Audit?

Getting ready for an ISO 27001 Audit involves a few steps that help your business show it meets the standard. These steps include:

1) Identify Key Processes to be Audited

Start by defining the scope of your Information Security Management System (ISMS). This means deciding which departments, locations, or services are included. Then, find out which processes are important to your ISMS — especially those that handle critical data or involve high risks. Talk to process owners and other team members to better understand how these processes work and how they affect your information security.

a) Define the boundaries and scope of your ISMS

b) Focus on high-risk and business-critical processes

c) Speak with process owners and teams for more insights

2) Gather Required Documents

The ISO 27001 standard requires several documents that must be ready for the audit. These include your security policy, scope, risk assessment, and risk treatment plan. You’ll also need evidence of incident handling, backups, access control policies, and more. These documents prove that your business follows the required rules and has strong security practices.

a) Collect required documents like policies, plans, and logs

b) Keep risk assessments and treatment plans up to date

c) Ensure all audit-related documents are organised and accessible

3) Provide Training for Employees and Contractors

Make sure your team and any contractors are trained on your security policies and their responsibilities. Everyone should know how to follow the rules and understand why security is important. Regular training and updates will help your people stay aware and prepared, especially before an audit.

a) Train staff on their roles in information security

b) Provide updates on changes in policies and procedures

c) Ensure everyone understands their part in the ISMS

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How Often do I Need to Conduct an Audit?

You should conduct an internal audit at least once a year. Some companies may do it more often, depending on risks or business needs. Regular audits help keep your information security system strong and up to date.

How Much Does a 27001 Audit Cost?

The cost of an ISO 27001 audit depends on your company’s size and complexity. On average, it can range from £5,000 to £20,000 for small to medium-sized companies. Larger organisations with more complex systems may pay £30,000 or more. Costs also include certification, training, and preparation work.

Conclusion

The ISO 27001 Audit helps companies keep their security compliance standards in check with the ISO guidelines. Regular Audits need to be conducted within companies by external certified bodies to retain their certifications. Considering the lengthy nature of the audit process, companies can proactively prepare themselves by training the teams regularly.

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