ISO/IEC 27001 Audit Types and How They are Conducted

There are two main categories of audits: internal and external. Audits are a key component for becoming ISO certified and you must have internal auditors, and pass the 2-stage registrar audit by an external party in order to become ISO/IEC 27001 certified. Below we will break down the different ways audits can be conducted and discuss internal, external and certification audits.

Audits can be conducted three ways:

  • On-site audits are performed in full days.  The number of days needed for an audit depends on several factors including size, complexity, risk, and nature of an organization. The International Accreditation Forum (IAF) has provided guidelines for registrars to calculate audit time.
  • Remote audits may be performed via web meetings, teleconferencing or electronic verification of processes. Remote audits are less common and typically not as effective as on-site audits.
  • Self-audits do not always mean an internal audit. A self-audit can be requested of your customer to eliminate the need for them to use their resources and still offer some assurance that you are meeting requirements.

Audit Types

Internal audits are audits that are performed by your organization and are a self-examination of your organization’s ISMS, performed on-site. Internal audits have many benefits including preparing your organization for external audits. The internal auditor must be independent of the area being audited to ensure objective results. (It is recommended to have more than one auditor to ensure no one is auditing his or her area of responsibilities). Internal audits are an ISO/IEC 27001 requirement and they are critical to the success of your ISMS. (We offer an internal audit training package to ensure your internal auditors are able to perform an effective internal audit as well as an audit checklist to help guide your internal auditors on covering all areas of your ISMS.)

Internal audits will be used to assess conformity, evaluate the effectiveness and identify opportunities for improvement. When you perform an internal audit, you will be able to compare your information safety management system to the requirements and understand if there are any non-conformances. This will allow you to correct your ISMS and ensure that your organization will meet the requirements for the external auditor and allow for certification.

External audits include customer, supplier, certification and surveillance. A customer audit is where an existing, or potential customer, audits your organization to verify you can or are meeting their requirements. If you are auditing an existing or potential supplier, we consider this a supplier audit. 

A certification audit is an audit your selected registrar will conduct to verify conformance against the ISO/IEC 27001 standard before they issue your official ISO/IEC 27001 certificate. Certification audits are most often broken into two stages. The stage one audit is performed to determine an organization’s readiness for stage two of the audit. Stage one is often conducted remotely in order to not spend additional costs on travel. If the auditor determines you meet the minimum criteria for the stage one audit, your organization will proceed with the stage two audit. The stage two audits are almost always on-site audits. This is where the auditor will interview your staff and review your documented information (procedures, records, etc.) to verify you are meeting all of the ISO/IEC 27001 requirements. Certification audits are typically conducted every three years.

After certification, your registrar will check-up on your periodically using surveillance audits to verify you are still upholding your ISMS and the ISO requirements. Surveillance audits are very much like certification audits, with the exception that they are not issuing or re-issuing a certificate. These are typically conducted by your registrar annually.



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