ISO 27001 Internal Audits: A Guide to Master ISMS Audits

According to IBM, the global average cost of a data breach in 2024 was approximately USD 4.88 million, underscoring the critical need for robust information security measures. One way to tackle such cyber threats is to implement the ISO 27001 standard.

A study published in Computers in Industry analyzed the financial impact of ISO/IEC 27001 certification on 143 US-listed firms and found that it improves profitability, labor productivity, and sales performance.

Read on to learn what exactly are ISO 27001 standards, their types, how to conduct effective internal audits to prepare your organization for ISO certification, and how an audit management software like GoAudits can streamline the process, making it more efficient and accurate.

What is an ISMS Audit?

An ISMS (Information Security Management System) audit comprehensively evaluates an organization’s information security practices, focusing on how well it manages risks and complies with standards. The audit reviews the effectiveness of security controls, identifies gaps, ensures legal and regulatory compliance, and drives continuous improvement in security practices.

Unlike other audits that focus on specific security controls, an ISMS audit takes a broader, more systematic approach. It assesses the entire ISMS against international standards. The ultimate goal is to achieve ISO 27001 certification, confirming that an organization meets recognized standards for managing information security effectively. 

What is an ISO 27001 Audit?

An ISO 27001 audit is a rigorous review process that ensures your organization’s Information Security Management System (ISMS) meets the internationally recognized gold standard for data security—ISO/IEC 27001:2022. Organizations have to complete a series of internal and external audits to get ISO certified. Moreover, they must complete surveillance and recertification audits for ongoing compliance.

ISO 27001 is a part of the broader ISO/IEC 27000 series created by experts from the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). Applicable to businesses of any size, adherence to ISO 27001 demonstrates an organization’s commitment to data protection and privacy.

Why is It Important for Organizations to Implement ISO 27001?

ISO 27001 is a benchmark against which companies finetune their ISMS framework based on their needs. It sets the minimum standards that organizations must meet to build a robust ISMS, regardless of their industry, size, or location.

An ISO 27001 certification validates your efforts toward data security and helps you maintain a competitive edge in the industry. Furthermore, maintaining ISO 27001 certification requires regular ISMS audits, allowing you to identify and address potential risks and demonstrate your company’s commitment to continuous improvement.

Types of ISO 27001 ISMS Audits

In order to achieve and maintain the ISO 27001 certification, companies are required to complete a series of certification and ongoing compliance audits, making it a cyclical process.

ISO 27001 External Audits/Certification Audits

Accredited bodies conduct an external ISO 27001 audit to ensure your organization’s compliance, and to issue the official certification.

Companies aiming to get ISO 27001 certification typically undergo three types of external audits:

1. Initial Certification Audit
2. Surveillance Audit
3. Recertification Audit

Here’s what an ISO 27001 certification audit process looks like:

1. ISO 27001 Initial Certification Audit

Once your business is ready for an ISMS audit, you’ll request an ISO 27001 audit from a certifying body recognized in your country. The auditor will conduct the ISO 27001 audit in two stages:

• ISO 27001 Stage 1 Audit (Document Review): The auditor will review your organization’s documentation, processes, designs, etc.
• ISO 27001 Stage 2 Audit (Certification Audit): At this stage, the auditor will walk through all the procedures and controls implemented through a site review to ensure they meet ISO 27001 requirements and 114 primary controls referenced in Annex A.

Completing both stages will make your organization eligible for certification.

2. ISO 27001 Surveillance Audit

These are periodic audits conducted by certifying bodies to maintain compliance. During ISO 27001 surveillance audits, auditors randomly test data samples to ensure they follow the processes and procedures mentioned in the documentation.

3. ISO 27001 Recertification Audit

Organizations are required to complete an extensive ISO 27001 recertification audit every three years to maintain their eligibility. Unlike a Surveillance Audit, this audit covers all areas of the ISMS and mimics the initial Certification Audit.

ISO 27001 Internal Audits

As the name suggests, these audits are conducted by the company’s internal auditors using their own resources. In cases where the company lacks competent and objective staff auditors, ISO 27001 internal audit programs may be outsourced to contractual suppliers.

Understanding ISO 27001 ISMS Internal Audits 

ISO 27001 requires organizations to conduct internal audits as specified in Clause 9.2. This clause mandates that internal audits be performed at planned intervals to:

• Ensure that the ISMS conforms to both the organization’s own requirements and the ISO 27001 standard.
• Verify if the ISMS is effectively implemented and maintained.

Purpose of Internal ISO 27001 Compliance Audit

The primary purpose of internal audits under ISO 27001 is to evaluate the effectiveness of the ISMS and ensure compliance with established policies and procedures. 

They help organizations identify weaknesses within their security management practices, verify that security controls are functioning as intended, and provide assurance to stakeholders regarding the company’s commitment to information security.

How Often Should You Do an ISO 27001 Internal Audit?

While ISO 27001 does not specify a fixed frequency for internal audits, it is generally recommended that organizations conduct them at least annually. This frequency allows you to continuously monitor their ISMS, address any potential risks, and ensure ongoing compliance.

Some organizations may choose to perform ISO 27001 compliance audits more frequently, such as quarterly or biannually, depending on their specific risk environment and operational needs.

ISO 27001 Audit Process: Steps to Conduct Effective Internal Audits

Let’s see which steps you need to take during the ISO 27001 internal audit procedure.

1. Preparing for the ISMS Internal Audit

Preparation is key for a successful ISO 27001 internal audit. Start by defining the audit scope, which includes the processes, departments, or locations to be audited.

Develop an ISO 27001 audit program that outlines the objectives, timeline, and resources required. Identify the audit team and ensure they are familiar with ISO 27001 requirements and the organization’s ISMS policies and procedures.

2. Document Review

In this step, auditors examine the ISMS documentation to:

• Understand the existing policies, processes, and controls.
• Identify any non-conformities in the documentation against ISO 27001 standards.

This involves reviewing policies, procedures, risk assessments, and compliance records to verify alignment with organizational and regulatory requirements. This step helps auditors familiarize themselves with the ISMS framework before the main audit.

3. Creating the Checklist

The audit checklist is developed alongside the document review. It includes specific items from the ISMS documentation to be verified during the main audit. For example, if the Backup Policy requires backups every six hours, this should be noted in the checklist to verify compliance during the audit.

How an Audit Software Like GoAudits Can Help

GoAudits simplifies checklist creation and audit execution by offering customizable templates tailored to ISO 27001. With features like automated checklists, real-time data capture, and centralized documentation, GoAudits helps streamline the ISMS audit process, reduces errors, and ensures comprehensive reporting.

4. Conducting the Audit

The main audit involves practical evaluation:

• Interview employees to test if they understand and follow ISMS processes.
• Verify physical and technical controls, such as access control, server security, and equipment use.
• Inspect physical security measures, such as surveillance and restricted access areas.

The checklist serves as a guide to ensure no critical aspects are missed during this phase. Detailed notes should be taken for accurate reporting later.

5. ISO 27001 Internal Audit Reporting

Once the audit is complete, compile all findings into an Internal Audit Report. The report should include:

• Summary of the audit scope and objectives.
• Nonconformities or gaps identified.
• Recommendations for corrective actions.

This report serves as the basis for initiating corrective actions and helps management understand areas needing improvement.

6. Follow-Up Activities

After the internal audit, follow up on the corrective actions to ensure they are implemented effectively. The auditor must verify that all nonconformities have been addressed and closed.

Using tools like GoAudits, organizations can track corrective actions and set reminders for follow-ups, ensuring compliance with ISO 27001 requirements. Only when all issues are resolved can the internal audit cycle be considered complete.

Best Practices for Effective ISO 27001 Security Audits

ISO 27001 security audits are essential for maintaining a compliant and effective ISMS. Adopting best practices ensures that audits not only identify gaps but also foster meaningful improvements in information security.

• Continuous Improvement: Organizations should regularly update their ISMS based on audit findings to address nonconformities and prevent recurring issues. For example, if the audit reveals inefficiencies in access control, the organization must review and strengthen its policies, implement better technical controls, and monitor their effectiveness over time.
• Stakeholder Engagement: Employees, managers, and IT teams must understand their roles within the ISMS. Engaging personnel in the audit process helps uncover practical insights and encourages a sense of responsibility toward maintaining information security. Tools like GoAudits enhance this process with features such as Workflow, which facilitates collaboration by assigning tasks, tracking progress, and notifying stakeholders about corrective actions.
• Utilizing Technology: Advanced audit management tools can automate tasks like checklist creation, data collection, and reporting. These tools also ensure real-time visibility into audit progress and findings. For instance, GoAudits provides pre-built ISO 27001 templates, centralized documentation, and dashboards for actionable insights.

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