ISO/IEC 27001, part of the growing ISO/IEC 27000 family of standards, is an Information Security Management System (ISMS) standard published in October 2005 by the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). Its full name is ISO/IEC 27001:2005 - Information technology -- Security techniques -- Information security management systems -- Requirements.
ISO/IEC 27001 formally specifies a management system that is intended to bring information security under explicit management control. Being a formal specification means that it mandates specific requirements. Organizations that claim to have adopted ISO/IEC 27001 can therefore be formally audited and certified compliant with the standard (more below).
How the standard works
Most organizations have a number of information security controls. Without an ISMS however, the controls tend to be somewhat disorganized and disjointed, having been implemented often as point solutions to specific situations or simply as a matter of convention. Security controls in operation typically address certain aspects of IT or data security, specifically, leaving non-IT information assets (such as paperwork and proprietary knowledge) less well protected on the whole. Business continuity planning and physical security, for examples, may be managed quite independently of IT or information security while Human Resources practices may make little reference to the need to define and assign information security roles and responsibilities throughout the organization.
ISO/IEC 27001 requires that management:
- Systematically examine the organization's information security risks, taking account of the threats, vulnerabilities and impacts;
- Design and implement a coherent and comprehensive suite of information security controls and/or other forms of risk treatment (such as risk avoidance or risk transfer) to address those risks that are deemed unacceptable; and
- Adopt an overarching management process to ensure that the information security controls continue to meet the organization's information security needs on an ongoing basis.
While other sets of information security controls may potentially be used within an ISO/IEC 27001 ISMS as well as, or even instead of, ISO/IEC 27002 (the Code of Practice for Information Security Management), these two standards are normally used together in practice. Annex A to ISO/IEC 27001 succinctly lists the information security controls from ISO/IEC 27002, while ISO/IEC 27002 provides additional information and implementation advice on the controls.
Organizations that implement a suite of information security controls in accordance with ISO/IEC 27002 are simultaneously likely to meet many of the requirements of ISO/IEC 27001, but may lack some of the overarching management system elements. The converse is also true, in other words, an ISO/IEC 27001 compliance certificate provides assurance that the management system for information security is in place, but says little about the absolute state of information security within the organization. Technical security controls such as antivirus and firewalls are not normally audited in ISO/IEC 27001 certification audits: the organization is essentially presumed to have adopted all necessary information security controls since the overall ISMS is in place and is deemed adequate by satisfying the requirements of ISO/IEC 27001. Furthermore, management determines the scope of the ISMS for certification purposes and may limit it to, say, a single business unit or location. The ISO/IEC 27001 certificate does not necessarily mean the remainder of the organization, outside the scoped area, has an adequate approach to information security management.
Other standards in the ISO/IEC 27000 family of standards provide additional guidance on certain aspects of designing, implementing and operating an ISMS, for example on information security risk management (ISO/IEC 27005).
Origins of ISO/IEC 27001
BS 7799 was a standard originally published by BSI Group in 1995. It was written by the United Kingdom Government's Department of Trade and Industry (DTI), and consisted of several parts.
The first part, containing the best practices for Information Security Management, was revised in 1998; after a lengthy discussion in the worldwide standards bodies, it was eventually adopted by ISO as ISO/IEC 17799, "Information Technology - Code of practice for information security management." in 2000. ISO/IEC 17799 was then revised in June 2005 and finally incorporated in the ISO 27000 series of standards as ISO/IEC 27002 in July 2007.
The second part of BS7799 was first published by BSI in 1999, known as BS 7799 Part 2, titled "Information Security Management Systems - Specification with guidance for use." BS 7799-2 focused on how to implement an Information security management system (ISMS), referring to the information security management structure and controls identified in BS 7799-2. This later became ISO/IEC 27001. The 2002 version of BS 7799-2 introduced the Plan-Do-Check-Act (PDCA) cycle (Deming cycle), aligning it with quality standards such as ISO 9000. BS 7799 Part 2 was adopted by ISO as ISO/IEC 27001 in November 2005.
BS 7799 Part 3 was published in 2005, covering risk analysis and management. It aligns with ISO/IEC 27001.
An ISMS may be certified compliant with ISO/IEC 27001 by a number of Accredited Registrars worldwide. Certification against any of the recognized national variants of ISO/IEC 27001 (e.g. JIS Q 27001, the Japanese version) by an accredited certification body is functionally equivalent to certification against ISO/IEC 27001 itself.
In some countries, the bodies that verify conformity of management systems to specified standards are called "certification bodies", while in others they are commonly referred to as "registration bodies", "assessment and registration bodies", "certification/ registration bodies", and sometimes "registrars".
The ISO/IEC 27001 certification, like other ISO management system certifications, usually involves a three-stage audit process:
- Stage 1 is a preliminary, informal review of the ISMS, for example checking the existence and completeness of key documentation such as the organization's information security policy, Statement of Applicability (SoA) and Risk Treatment Plan (RTP). This stage serves to familiarize the auditors with the organization and vice versa.
- Stage 2 is a more detailed and formal compliance audit, independently testing the ISMS against the requirements specified in ISO/IEC 27001. The auditors will seek evidence to confirm that the management system has been properly designed and implemented, and is in fact in operation (for example by confirming that a security committee or similar management body meets regularly to oversee the ISMS). Certification audits are usually conducted by ISO/IEC 27001 Lead Auditors. Passing this stage results in the ISMS being certified compliant with ISO/IEC 27001.
- Stage 3 involves follow-up reviews or audits to confirm that the organization remains in compliance with the standard. Certification maintenance requires periodic re-assessment audits to confirm that the ISMS continues to operate as specified and intended. These should happen at least annually but (by agreement with management) are often conducted more frequently, particularly while the ISMS is still maturing.