ISO/IEC 27001 is an information security standard, part of the ISO/IEC 27000 family of standards, of which the last version was published in 2013, with a few minor updates since then. It is published by the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) under the joint ISO and IEC subcommittee, ISO/IEC JTC 1/SC 27.
ISO/IEC 27001 specifies a management system that is intended to bring information security under management control and gives specific requirements. Organizations that meet the requirements may be certified by an accredited certification body following successful completion of an audit.
How the standard works
Most organizations have a number of information security controls. However, without an information security management system (ISMS), 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 protected on the whole. Moreover, business continuity planning and physical security 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.
Note that ISO/IEC 27001 is designed to cover much more than just IT.
What controls will be tested as part of certification to ISO/IEC 27001 is dependent on the certification auditor. This can include any controls that the organisation has deemed to be within the scope of the ISMS and this testing can be to any depth or extent as assessed by the auditor as needed to test that the control has been implemented and is operating effectively.
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).
The PDCA Cycle
- Plan (establishing the ISMS)
- Establish the policy, the ISMS objectives, processes and procedures related to risk management and the improvement of information security to provide results in line with the global policies and objectives of the organization.
- Do (implementing and workings of the ISMS)
- Implement and exploit the ISMS policy, controls, processes and procedures.
- Check (monitoring and review of the ISMS)
- Assess and, if applicable, measure the performances of the processes against the policy, objectives and practical experience and report results to management for review.
- Act (update and improvement of the ISMS)
- Undertake corrective and preventive actions, on the basis of the results of the ISMS internal audit and management review, or other relevant information to continually improve the said system.
All references to PDCA were removed in ISO/IEC 27001:2013. Its use in the context of ISO/IEC 27001 is no longer mandatory.
History of ISO/IEC 27001
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 27001:2005. 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 27001:2005.
Very little reference or use is made to any of the BS standards in connection 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".
- 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.
- Ongoing 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.
ISO/IEC 27001:2005 Domains
Note that the 2005 version of ISO/IEC 27001 is obsolete and no longer in use.
A.5 Security Policy
A.6 Organisation of information Security
A.7 Asset Management
A.8 Human Resources
A.9 Physical and environmental security
A.10 Communications and operations management
A.11 Access Control
A.12 Information systems acquisition, development and maintenance
A.13 Information security incident management
A.14 Business continuity management
Structure of the standard
The official title of the standard is "Information technology — Security techniques — Information security management systems — Requirements"
ISO/IEC 27001:2013 has ten short clauses, plus a long annex, which cover:
- 1. Scope of the standard
- 2. How the document is referenced
- 3. Reuse of the terms and definitions in ISO/IEC 27000
- 4. Organizational context and stakeholders
- 5. Information security leadership and high-level support for policy
- 6. Planning an information security management system; risk assessment; risk treatment
- 7. Supporting an information security management system
- 8. Making an information security management system operational
- 9. Reviewing the system's performance
- 10. Corrective action
- Annex A: List of controls and their objectives
This structure mirrors other management standards such as ISO 22301 (business continuity management) and this helps organizations comply with multiple management systems standards if they wish. Annexes B and C of 27001:2005 have been removed.
Changes from the 2005 standard
The 2013 standard has a completely different structure than the 2005 standard which had five clauses. The 2013 standard puts more emphasis on measuring and evaluating how well an organization's ISMS is performing, and there is a new section on outsourcing, which reflects the fact that many organizations rely on third parties to provide some aspects of IT. It does not emphasize the Plan-Do-Check-Act cycle that 27001:2005 did. Other continuous improvement processes like Six Sigma's DMAIC method can be implemented. More attention is paid to the organizational context of information security, and risk assessment has changed. Overall, 27001:2013 is designed to fit better alongside other management standards such as ISO 9000 and ISO/IEC 20000, and it has more in common with them.
- A.6.1.5 Information security in project management
- A.12.6.2 Restrictions on software installation
- A.14.2.1 Secure development policy
- A.14.2.5 Secure system engineering principles
- A.14.2.6 Secure development environment
- A.14.2.8 System security testing
- A.15.1.1 Information security policy for supplier relationships
- A.15.1.3 Information and communication technology supply chain
- A.16.1.4 Assessment of and decision on information security events
- A.16.1.5 Response to information security incidents
- A.17.2.1 Availability of information processing facilities
Clause 6.1.3 describes how an organization can respond to risks with a risk treatment plan; an important part of this is choosing appropriate controls. A very important change in ISO/IEC 27001:2013 is that there is now no requirement to use the Annex A controls to manage the information security risks. The previous version insisted ("shall") that controls identified in the risk assessment to manage the risks must have been selected from Annex A. Thus almost every risk assessment ever completed under the old version of ISO/IEC 27001 used Annex A controls but an increasing number of risk assessments in the new version do not use Annex A as the control set. This enables the risk assessment to be simpler and much more meaningful to the organization and helps considerably with establishing a proper sense of ownership of both the risks and controls. This is the main reason for this change in the new version.
There are now 114 controls in 14 clauses and 35 control categories; the 2005 standard had 133 controls in 11 groups.
- A.5: Information security policies (2 controls)
- A.6: Organization of information security (7 controls)
- A.7: Human resource security - 6 controls that are applied before, during, or after employment
- A.8: Asset management (10 controls)
- A.9: Access control (14 controls)
- A.10: Cryptography (2 controls)
- A.11: Physical and environmental security (15 controls)
- A.12: Operations security (14 controls)
- A.13: Communications security (7 controls)
- A.14: System acquisition, development and maintenance (13 controls)
- A.15: Supplier relationships (5 controls)
- A.16: Information security incident management (7 controls)
- A.17: Information security aspects of business continuity management (4 controls)
- A.18: Compliance; with internal requirements, such as policies, and with external requirements, such as laws (8 controls)
The new and updated controls reflect changes to technology affecting many organizations—for instance, cloud computing—but as stated above it is possible to use and be certified to ISO/IEC 27001:2013 and not use any of these controls.
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