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Information technology — Security
techniques — Information security
management systems — Overview and
vocabulary
Technologies de l'information — Techniques de sécurité — Systèmes
de management de la sécurité de l'information — Vue d'ensemble et
vocabulaire
INTERNATIONAL
STANDARD
ISO/IEC
27000
Reference number
ISO/IEC 27000:2018(E)
Fifth edition
2018-02
© ISO/IEC 2018

ISO/IEC 27000:2018(E)

ii © ISO/IEC 2018 – All rights reserved
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ISO/IEC 27000:2018(E)

Foreword.........................................................................................................................................................................................................................................iv
Introduction...................................................................................................................................................................................................................................v
1	Scope..................................................................................................................................................................................................................................1
2	 Normative references.......................................................................................................................................................................................1
3	 Terms and definitions......................................................................................................................................................................................1
4	 Information security management systems..........................................................................................................................11
4.1	 General.........................................................................................................................................................................................................11
4.2	 What is an ISMS?.................................................................................................................................................................................11
4.2.1	 Overview and principles.........................................................................................................................................11
4.2.2	 Information........................................................................................................................................................................12
4.2.3	 Information security...................................................................................................................................................12
4.2.4	 Management......................................................................................................................................................................12
4.2.5	 Management system...................................................................................................................................................13
4.3	 Process approach................................................................................................................................................................................13
4.4	 Why an ISMS is important...........................................................................................................................................................13
4.5	 Establishing, monitoring, maintaining and improving an ISMS.................................................................14
4.5.1	 Overview...............................................................................................................................................................................14
4.5.2	 Identifying information security requirements..................................................................................14
4.5.3	 Assessing information security risks...........................................................................................................15
4.5.4	 Treating information security risks...............................................................................................................15
4.5.5	 Selecting and implementing controls..........................................................................................................15
4.5.6	 Monitor, maintain and improve the effectiveness of the ISMS...............................................16
4.5.7	 Continual improvement...........................................................................................................................................16
4.6	 ISMS critical success factors......................................................................................................................................................17
4.7	 Benefits of the ISMS family of standards........................................................................................................................17
5	 ISMS family of standards............................................................................................................................................................................18
5.1	 General information.........................................................................................................................................................................18
5.2	 Standard describing an overview and terminology: ISO/IEC 27000 (this document)..........19
5.3	 Standards specifying requirements....................................................................................................................................19
5.3.1	 ISO/IEC 27001.................................................................................................................................................................19
5.3.2	 ISO/IEC 27006.................................................................................................................................................................20
5.3.3	 ISO/IEC 27009.................................................................................................................................................................20
5.4	 Standards describing general guidelines.......................................................................................................................20
5.4.1	 ISO/IEC 27002.................................................................................................................................................................20
5.4.2	 ISO/IEC 27003.................................................................................................................................................................20
5.4.3	 ISO/IEC 27004.................................................................................................................................................................21
5.4.4	 ISO/IEC 27005.................................................................................................................................................................21
5.4.5	 ISO/IEC 27007.................................................................................................................................................................21
5.4.6	 ISO/IEC TR 27008........................................................................................................................................................21
5.4.7	 ISO/IEC 27013.................................................................................................................................................................22
5.4.8	 ISO/IEC 27014.................................................................................................................................................................22
5.4.9	 ISO/IEC TR 27016........................................................................................................................................................22
5.4.10	 ISO/IEC 27021.................................................................................................................................................................22
5.5	 Standards describing sector-specific guidelines.....................................................................................................23
5.5.1	 ISO/IEC 27010.................................................................................................................................................................23
5.5.2	 ISO/IEC 27011.................................................................................................................................................................23
5.5.3	 ISO/IEC 27017.................................................................................................................................................................23
5.5.4	 ISO/IEC 27018.................................................................................................................................................................24
5.5.5	 ISO/IEC 27019.................................................................................................................................................................24
5.5.6	 ISO 27799.............................................................................................................................................................................25
Bibliography..............................................................................................................................................................................................................................26
© ISO/IEC 2018 – All rights reserved iii
Contents Page

ISO/IEC 27000:2018(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www​
.iso​
.org/​
directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www​
.iso​
.org/​
patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: www​
.iso​
.org/​
iso/​
foreword​
.html.
This document was prepared by Technical Committee ISO/IEC JTC 1, Information technology, SC 27, IT
Security techniques.
This fifth edition cancels and replaces the fourth edition (ISO/IEC  27000:2016), which has been
technically revised. The main changes compared to the previous edition are as follows:
—	 the Introduction has been reworded;
—	 some terms and definitions have been removed;
—	 Clause 3 has been aligned on the high-level structure for MSS;
—	 Clause 5 has been updated to reflect the changes in the standards concerned;
—	 Annexes A and B have been deleted.

iv © ISO/IEC 2018 – All rights reserved

ISO/IEC 27000:2018(E)
Introduction
0.1   Overview
International Standards for management systems provide a model to follow in setting up and
operating a management system. This model incorporates the features on which experts in the field
have reached a consensus as being the international state of the art. ISO/IEC JTC 1/SC 27 maintains an
expert committee dedicated to the development of international management systems standards for
information security, otherwise known as the Information Security Management system (ISMS) family
of standards.
Through the use of the ISMS family of standards, organizations can develop and implement a framework
for managing the security of their information assets, including financial information, intellectual
property, and employee details, or information entrusted to them by customers or third parties. These
standards can also be used to prepare for an independent assessment of their ISMS applied to the
protection of information.
0.2   Purpose of this document
The ISMS family of standards includes standards that:
a)	 define requirements for an ISMS and for those certifying such systems;
b)	 provide direct support, detailed guidance and/or interpretation for the overall process to establish,
implement, maintain, and improve an ISMS;
c)	 address sector-specific guidelines for ISMS; and
d)	 address conformity assessment for ISMS.
0.3   Content of this document
In this document, the following verbal forms are used:
—	 “shall” indicates a requirement;
—	 “should” indicates a recommendation;
—	 “may” indicates a permission;
—	 “can” indicates a possibility or a capability.
Information marked as NOTE is for guidance in understanding or clarifying the associated
requirement. “Notes to entry” used in Clause 3 provide additional information that supplements the
terminological data and can contain provisions relating to the use of a term.

© ISO/IEC 2018 – All rights reserved v
Iso iec 27000_2018

Information technology — Security techniques —
Information security management systems — Overview
and vocabulary
1	Scope
This document provides the overview of information security management systems (ISMS). It also
provides terms and definitions commonly used in the ISMS family of standards. This document is
applicable to all types and sizes of organization (e.g. commercial enterprises, government agencies, not-
for-profit organizations).
The terms and definitions provided in this document
—	 cover commonly used terms and definitions in the ISMS family of standards;
—	 do not cover all terms and definitions applied within the ISMS family of standards; and
—	 do not limit the ISMS family of standards in defining new terms for use.
2	 Normative references
There are no normative references in this document.
3	 Terms and definitions
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
—	 ISO Online browsing platform: available at https://​
www​
.iso​
.org/​
obp
—	 IEC Electropedia: available at https://​
www​
.electropedia​
.org/​
3.1
access control
means to ensure that access to assets is authorized and restricted based on business and security
requirements (3.56)
3.2
attack
attempt to destroy, expose, alter, disable, steal or gain unauthorized access to or make unauthorized
use of an asset
3.3
audit
systematic, independent and documented process (3.54) for obtaining audit evidence and evaluating it
objectively to determine the extent to which the audit criteria are fulfilled
Note 1 to entry: An audit can be an internal audit (first party) or an external audit (second party or third party),
and it can be a combined audit (combining two or more disciplines).
Note 2 to entry: An internal audit is conducted by the organization itself, or by an external party on its behalf.
Note 3 to entry: “Audit evidence” and “audit criteria” are defined in ISO 19011.
INTERNATIONAL STANDARD ISO/IEC 27000:2018(E)
© ISO/IEC 2018 – All rights reserved 1

ISO/IEC 27000:2018(E)
3.4
audit scope
extent and boundaries of an audit (3.3)
[SOURCE: ISO 19011:2011, 3.14, modified — Note 1 to entry has been deleted.]
3.5
authentication
provision of assurance that a claimed characteristic of an entity is correct
3.6
authenticity
property that an entity is what it claims to be
3.7
availability
property of being accessible and usable on demand by an authorized entity
3.8
base measure
measure (3.42) defined in terms of an attribute and the method for quantifying it
Note 1 to entry: A base measure is functionally independent of other measures.
[SOURCE: ISO/IEC/IEEE 15939:2017, 3.3, modified — Note 2 to entry has been deleted.]
3.9
competence
ability to apply knowledge and skills to achieve intended results
3.10
confidentiality
property that information is not made available or disclosed to unauthorized individuals, entities, or
processes (3.54)
3.11
conformity
fulfilment of a requirement (3.56)
3.12
consequence
outcome of an event (3.21) affecting objectives (3.49)
Note 1 to entry: An event can lead to a range of consequences.
Note 2 to entry: A consequence can be certain or uncertain and, in the context of information security, is usually
negative.
Note 3 to entry: Consequences can be expressed qualitatively or quantitatively.
Note 4 to entry: Initial consequences can escalate through knock-on effects.
[SOURCE: ISO Guide 73:2009, 3.6.1.3, modified — Note 2 to entry has been changed after “and”.]
3.13
continual improvement
recurring activity to enhance performance (3.52)

2 © ISO/IEC 2018 – All rights reserved

ISO/IEC 27000:2018(E)
3.14
control
measure that is modifying risk (3.61)
Note 1 to entry: Controls include any process (3.54), policy (3.53), device, practice, or other actions which modify
risk (3.61).
Note 2 to entry: It is possible that controls not always exert the intended or assumed modifying effect.
[SOURCE: ISO Guide 73:2009, 3.8.1.1 — Note 2 to entry has been changed.]
3.15
control objective
statement describing what is to be achieved as a result of implementing controls (3.14)
3.16
correction
action to eliminate a detected nonconformity (3.47)
3.17
corrective action
action to eliminate the cause of a nonconformity (3.47) and to prevent recurrence
3.18
derived measure
measure (3.42) that is defined as a function of two or more values of base measures (3.8)
[SOURCE: ISO/IEC/IEEE 15939:2017, 3.8, modified — Note 1 to entry has been deleted.]
3.19
documented information
information required to be controlled and maintained by an organization (3.50) and the medium on
which it is contained
Note 1 to entry: Documented information can be in any format and media and from any source.
Note 2 to entry: Documented information can refer to
—	the management system (3.41), including related processes (3.54);
—	 information created in order for the organization (3.50) to operate (documentation);
—	 evidence of results achieved (records).
3.20
effectiveness
extent to which planned activities are realized and planned results achieved
3.21
event
occurrence or change of a particular set of circumstances
Note 1 to entry: An event can be one or more occurrences, and can have several causes.
Note 2 to entry: An event can consist of something not happening.
Note 3 to entry: An event can sometimes be referred to as an “incident” or “accident”.
[SOURCE: ISO Guide 73:2009, 3.5.1.3, modified — Note 4 to entry has been deleted.]

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ISO/IEC 27000:2018(E)
3.22
external context
external environment in which the organization seeks to achieve its objectives (3.49)
Note 1 to entry: External context can include the following:
—	 the cultural, social, political, legal, regulatory, financial, technological, economic, natural and competitive
environment, whether international, national, regional or local;
—	 key drivers and trends having impact on the objectives of the organization (3.50);
—	 relationships with, and perceptions and values of, external stakeholders (3.37).
[SOURCE: ISO Guide 73:2009, 3.3.1.1]
3.23
governance of information security
system by which an organization’s (3.50) information security (3.28) activities are directed and
controlled
3.24
governing body
person or group of people who are accountable for the performance (3.52) and conformity of the
organization (3.50)
Note 1 to entry: The governing body can, in some jurisdictions, be a board of directors.
3.25
indicator
measure (3.42) that provides an estimate or evaluation
3.26
information need
insight necessary to manage objectives (3.49), goals, risks and problems
[SOURCE: ISO/IEC/IEEE 15939:2017, 3.12]
3.27
information processing facilities
any information processing system, service or infrastructure, or the physical location housing it
3.28
information security
preservation of confidentiality (3.10), integrity (3.36) and availability (3.7) of information
Note 1 to entry: In addition, other properties, such as authenticity (3.6), accountability, non-repudiation (3.48),
and reliability (3.55) can also be involved.
3.29
information security continuity
processes (3.54) and procedures for ensuring continued information security (3.28) operations
3.30
information security event
identified occurrence of a system, service or network state indicating a possible breach of information
security (3.28) policy (3.53) or failure of controls (3.14), or a previously unknown situation that can be
security relevant
3.31
information security incident
single or a series of unwanted or unexpected information security events (3.30) that have a significant
probability of compromising business operations and threatening information security (3.28)

4 © ISO/IEC 2018 – All rights reserved

ISO/IEC 27000:2018(E)
3.32
information security incident management
set of processes (3.54) for detecting, reporting, assessing, responding to, dealing with, and learning
from information security incidents (3.31)
3.33
information security management system (ISMS) professional
person who establishes, implements, maintains and continuously improves one or more information
security management system processes (3.54)
3.34
information sharing community
group of organizations (3.50) that agree to share information
Note 1 to entry: An organization can be an individual.
3.35
information system
set of applications, services, information technology assets, or other information-handling components
3.36
integrity
property of accuracy and completeness
3.37
interested party (preferred term)
stakeholder (admitted term)
person or organization (3.50) that can affect, be affected by, or perceive itself to be affected by a decision
or activity
3.38
internal context
internal environment in which the organization (3.50) seeks to achieve its objectives
Note 1 to entry: Internal context can include:
—	 governance, organizational structure, roles and accountabilities;
—	 policies (3.53), objectives (3.49), and the strategies that are in place to achieve them;
—	 the capabilities, understood in terms of resources and knowledge (e.g. capital, time, people, processes (3.54),
systems and technologies);
—	 information systems (3.35), information flows and decision-making processes (both formal and informal);
—	 relationships with, and perceptions and values of, internal stakeholders (3.37);
—	 the organization's culture;
—	 standards, guidelines and models adopted by the organization;
—	 form and extent of contractual relationships.
[SOURCE: ISO Guide 73:2009, 3.3.1.2]
3.39
level of risk
magnitude of a risk (3.61) expressed in terms of the combination of consequences (3.12) and their
likelihood (3.40)
[SOURCE: ISO Guide 73:2009, 3.6.1.8, modified — “or combination of risks” has been deleted in the
definition.]

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ISO/IEC 27000:2018(E)
3.40
likelihood
chance of something happening
[SOURCE: ISO Guide 73:2009, 3.6.1.1, modified — Notes 1 and 2 to entry have been deleted.]
3.41
management system
set of interrelated or interacting elements of an organization (3.50) to establish policies (3.53) and
objectives (3.49) and processes (3.54) to achieve those objectives
Note 1 to entry: A management system can address a single discipline or several disciplines.
Note 2 to entry: The system elements include the organization’s structure, roles and responsibilities, planning
and operation.
Note 3 to entry: The scope of a management system may include the whole of the organization, specific and
identified functions of the organization, specific and identified sections of the organization, or one or more
functions across a group of organizations.
3.42
measure
variable to which a value is assigned as the result of measurement (3.43)
[SOURCE: ISO/IEC/IEEE 15939:2017, 3.15, modified — Note 2 to entry has been deleted.]
3.43
measurement
process (3.54) to determine a value
3.44
measurement function
algorithm or calculation performed to combine two or more base measures (3.8)
[SOURCE: ISO/IEC/IEEE 15939:2017, 3.20]
3.45
measurement method
logical sequence of operations, described generically, used in quantifying an attribute with respect to a
specified scale
Note 1 to entry: The type of measurement method depends on the nature of the operations used to quantify an
attribute (3.4). Two types can be distinguished:
—	 subjective: quantification involving human judgment; and
—	 objective: quantification based on numerical rules.
[SOURCE: ISO/IEC/IEEE 15939:2017, 3.21, modified — Note 2 to entry has been deleted.]
3.46
monitoring
determining the status of a system, a process (3.54) or an activity
Note 1 to entry: To determine the status, there may be a need to check, supervise or critically observe.
3.47
nonconformity
non-fulfilment of a requirement (3.56)
3.48
non-repudiation
ability to prove the occurrence of a claimed event (3.21) or action and its originating entities

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ISO/IEC 27000:2018(E)
3.49
objective
result to be achieved
Note 1 to entry: An objective can be strategic, tactical, or operational.
Note  2  to entry:  Objectives can relate to different disciplines (such as financial, health and safety, and
environmental goals) and can apply at different levels [such as strategic, organization-wide, project, product and
process (3.54)].
Note  3  to entry:  An objective can be expressed in other ways, e.g. as an intended outcome, a purpose, an
operational criterion, as an information security objective or by the use of other words with similar meaning (e.g.
aim, goal, or target).
Note 4 to entry: In the context of information security management systems, information security objectives are
set by the organization, consistent with the information security policy, to achieve specific results.
3.50
organization
person or group of people that has its own functions with responsibilities, authorities and relationships
to achieve its objectives (3.49)
Note 1 to entry: The concept of organization includes but is not limited to sole-trader, company, corporation, firm,
enterprise, authority, partnership, charity or institution, or part or combination thereof, whether incorporated
or not, public or private.
3.51
outsource
make an arrangement where an external organization (3.50) performs part of an organization’s function
or process (3.54)
Note 1 to entry: An external organization is outside the scope of the management system (3.41), although the
outsourced function or process is within the scope.
3.52
performance
measurable result
Note 1 to entry: Performance can relate either to quantitative or qualitative findings.
Note 2 to entry: Performance can relate to the management of activities, processes (3.54), products (including
services), systems or organizations (3.50).
3.53
policy
intentions and direction of an organization (3.50), as formally expressed by its top management (3.75)
3.54
process
set of interrelated or interacting activities which transforms inputs into outputs
3.55
reliability
property of consistent intended behaviour and results
3.56
requirement
need or expectation that is stated, generally implied or obligatory
Note  1  to entry:  “Generally implied” means that it is custom or common practice for the organization and
interested parties that the need or expectation under consideration is implied.
Note 2 to entry: A specified requirement is one that is stated, for example in documented information.

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ISO/IEC 27000:2018(E)
3.57
residual risk
risk (3.61) remaining after risk treatment (3.72)
Note 1 to entry: Residual risk can contain unidentified risk.
Note 2 to entry: Residual risk can also be referred to as “retained risk”.
3.58
review
activity undertaken to determine the suitability, adequacy and effectiveness (3.20) of the subject matter
to achieve established objectives (3.49)
[SOURCE: ISO Guide 73:2009, 3.8.2.2, modified — Note 1 to entry has been deleted.]
3.59
review object
specific item being reviewed
3.60
review objective
statement describing what is to be achieved as a result of a review (3.59)
3.61
risk
effect of uncertainty on objectives (3.49)
Note 1 to entry: An effect is a deviation from the expected — positive or negative.
Note 2 to entry: Uncertainty is the state, even partial, of deficiency of information related to, understanding or
knowledge of, an event, its consequence, or likelihood.
Note 3 to entry: Risk is often characterized by reference to potential “events” (as defined in ISO Guide 73:2009,
3.5.1.3) and “consequences” (as defined in ISO Guide 73:2009, 3.6.1.3), or a combination of these.
Note 4 to entry: Risk is often expressed in terms of a combination of the consequences of an event (including
changes in circumstances) and the associated “likelihood” (as defined in ISO Guide 73:2009, 3.6.1.1) of occurrence.
Note 5 to entry: In the context of information security management systems, information security risks can be
expressed as effect of uncertainty on information security objectives.
Note 6 to entry: Information security risk is associated with the potential that threats will exploit vulnerabilities
of an information asset or group of information assets and thereby cause harm to an organization.
3.62
risk acceptance
informed decision to take a particular risk (3.61)
Note 1 to entry: Risk acceptance can occur without risk treatment (3.72) or during the process (3.54) of risk
treatment.
Note 2 to entry: Accepted risks are subject to monitoring (3.46) and review (3.58).
[SOURCE: ISO Guide 73:2009, 3.7.1.6]
3.63
risk analysis
process (3.54) to comprehend the nature of risk (3.61) and to determine the level of risk (3.39)
Note 1 to entry: Risk analysis provides the basis for risk evaluation (3.67) and decisions about risk treatment (3.72).
Note 2 to entry: Risk analysis includes risk estimation.
[SOURCE: ISO Guide 73:2009, 3.6.1]

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ISO/IEC 27000:2018(E)
3.64
risk assessment
overall process (3.54) of risk identification (3.68), risk analysis (3.63) and risk evaluation (3.67)
[SOURCE: ISO Guide 73:2009, 3.4.1]
3.65
risk communication and consultation
set of continual and iterative processes (3.54) that an organization conducts to provide, share or obtain
information, and to engage in dialogue with stakeholders (3.37) regarding the management of risk (3.61)
Note  1  to entry:  The information can relate to the existence, nature, form, likelihood (3.41), significance,
evaluation, acceptability and treatment of risk.
Note 2 to entry: Consultation is a two-way process of informed communication between an organization (3.50) and
its stakeholders on an issue prior to making a decision or determining a direction on that issue. Consultation is
—	 a process which impacts on a decision through influence rather than power; and
—	 an input to decision making, not joint decision making.
3.66
risk criteria
terms of reference against which the significance of risk (3.61) is evaluated
Note 1 to entry: Risk criteria are based on organizational objectives, and external context (3.22) and internal
context (3.38).
Note 2 to entry: Risk criteria can be derived from standards, laws, policies (3.53) and other requirements (3.56).
[SOURCE: ISO Guide 73:2009, 3.3.1.3]
3.67
risk evaluation
process (3.54) of comparing the results of risk analysis (3.63) with risk criteria (3.66) to determine
whether the risk (3.61) and/or its magnitude is acceptable or tolerable
Note 1 to entry: Risk evaluation assists in the decision about risk treatment (3.72).
[SOURCE: ISO Guide 73:2009, 3.7.1]
3.68
risk identification
process (3.54) of finding, recognizing and describing risks (3.61)
Note 1 to entry: Risk identification involves the identification of risk sources, events (3.21), their causes and their
potential consequences (3.12).
Note 2 to entry: Risk identification can involve historical data, theoretical analysis, informed and expert opinions,
and stakeholders’ (3.37) needs.
[SOURCE: ISO Guide 73:2009, 3.5.1]
3.69
risk management
coordinated activities to direct and control an organization (3.50) with regard to risk (3.61)
[SOURCE: ISO Guide 73:2009, 2.1]

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ISO/IEC 27000:2018(E)
3.70
risk management process
systematic application of management policies (3.53), procedures and practices to the activities of
communicating, consulting, establishing the context and identifying, analysing, evaluating, treating,
monitoring and reviewing risk (3.61)
Note 1 to entry: ISO/IEC 27005 uses the term “process” (3.54) to describe risk management overall. The elements
within the risk management (3.69) process are referred to as “activities”.
[SOURCE: ISO Guide 73:2009, 3.1, modified — Note 1 to entry has been added.]
3.71
risk owner
person or entity with the accountability and authority to manage a risk (3.61)
[SOURCE: ISO Guide 73:2009, 3.5.1.5]
3.72
risk treatment
process (3.54) to modify risk (3.61)
Note 1 to entry: Risk treatment can involve:
—	 avoiding the risk by deciding not to start or continue with the activity that gives rise to the risk;
—	 taking or increasing risk in order to pursue an opportunity;
—	 removing the risk source;
—	 changing the likelihood (3.40);
—	 changing the consequences (3.12);
—	 sharing the risk with another party or parties (including contracts and risk financing);
—	 retaining the risk by informed choice.
Note  2  to entry:  Risk treatments that deal with negative consequences are sometimes referred to as “risk
mitigation”, “risk elimination”, “risk prevention” and “risk reduction”.
Note 3 to entry: Risk treatment can create new risks or modify existing risks.
[SOURCE: ISO Guide 73:2009, 3.8.1, modified — “decision” has been replaced by “choice” in Note 1
to entry.]
3.73
security implementation standard
document specifying authorized ways for realizing security
3.74
threat
potential cause of an unwanted incident, which can result in harm to a system or organization (3.50)
3.75
top management
person or group of people who directs and controls an organization (3.50) at the highest level
Note  1  to entry:  Top management has the power to delegate authority and provide resources within the
organization.
Note  2  to entry:  If the scope of the management system (3.41) covers only part of an organization, then top
management refers to those who direct and control that part of the organization.

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Note 3 to entry: Top management is sometimes called executive management and can include Chief Executive
Officers, Chief Financial Officers, Chief Information Officers, and similar roles.
3.76
trusted information communication entity
autonomous organization (3.50) supporting information exchange within an information sharing
community (3.34)
3.77
vulnerability
weakness of an asset or control (3.14) that can be exploited by one or more threats (3.74)
4	 Information security management systems
4.1	General
Organizations of all types and sizes:
a)	 collect, process, store, and transmit information;
b)	 recognize that information, and related processes, systems, networks and people are important
assets for achieving organization objectives;
c)	 face a range of risks that can affect the functioning of assets; and
d)	 address their perceived risk exposure by implementing information security controls.
All information held and processed by an organization is subject to threats of attack, error, nature (for
example, flood or fire), etc., and is subject to vulnerabilities inherent in its use. The term information
security is generally based on information being considered as an asset which has a value requiring
appropriate protection, for example, against the loss of availability, confidentiality and integrity.
Enabling accurate and complete information to be available in a timely manner to those with an
authorized need is a catalyst for business efficiency.
Protecting information assets through defining, achieving, maintaining, and improving information
security effectively is essential to enable an organization to achieve its objectives, and maintain and
enhance its legal compliance and image. These coordinated activities directing the implementation of
suitable controls and treating unacceptable information security risks are generally known as elements
of information security management.
As information security risks and the effectiveness of controls change depending on shifting
circumstances, organizations need to:
a)	 monitor and evaluate the effectiveness of implemented controls and procedures;
b)	 identify emerging risks to be treated; and
c)	 select, implement and improve appropriate controls as needed.
To interrelate and coordinate such information security activities, each organization needs to establish
its policy and objectives for information security and achieve those objectives effectively by using a
management system.
4.2	 What is an ISMS?
4.2.1	 Overview and principles
An ISMS consists of the policies, procedures, guidelines, and associated resources and activities,
collectively managed by an organization, in the pursuit of protecting its information assets. An ISMS is
a systematic approach for establishing, implementing, operating, monitoring, reviewing, maintaining

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and improving an organization’s information security to achieve business objectives. It is based on a
risk assessment and the organization’s risk acceptance levels designed to effectively treat and manage
risks. Analysing requirements for the protection of information assets and applying appropriate
controls to ensure the protection of these information assets, as required, contributes to the successful
implementation of an ISMS. The following fundamental principles also contribute to the successful
implementation of an ISMS:
a)	 awareness of the need for information security;
b)	 assignment of responsibility for information security;
c)	 incorporating management commitment and the interests of stakeholders;
d)	 enhancing societal values;
e)	 risk assessments determining appropriate controls to reach acceptable levels of risk;
f)	 security incorporated as an essential element of information networks and systems;
g)	 active prevention and detection of information security incidents;
h)	 ensuring a comprehensive approach to information security management;
i)	 continual reassessment of information security and making of modifications as appropriate.
4.2.2	Information
Information is an asset that, like other important business assets, is essential to an organization’s
business and, consequently, needs to be suitably protected. Information can be stored in many forms,
including: digital form (e.g. data files stored on electronic or optical media), material form (e.g. on
paper), as well as unrepresented information in the form of knowledge of the employees. Information
can be transmitted by various means including: courier, electronic or verbal communication. Whatever
form information takes, or the means by which it is transmitted, it always needs appropriate protection.
In many organizations, information is dependent on information and communications technology. This
technology is often an essential element in the organization and assists in facilitating the creation,
processing, storing, transmitting, protection and destruction of information.
4.2.3	 Information security
Information security ensures the confidentiality, availability and integrity of information. Information
security involves the application and management of appropriate controls that involves consideration
of a wide range of threats, with the aim of ensuring sustained business success and continuity, and
minimizing consequences of information security incidents.
Information security is achieved through the implementation of an applicable set of controls, selected
through the chosen risk management process and managed using an ISMS, including policies, processes,
procedures, organizational structures, software and hardware to protect the identified information
assets. These controls need to be specified, implemented, monitored, reviewed and improved where
necessary, to ensure that the specific information security and business objectives of the organization
are met. Relevant information security controls are expected to be seamlessly integrated with an
organization’s business processes.
4.2.4	Management
Management involves activities to direct, control, and continually improve the organization within
appropriate structures. Management activities include the act, manner, or practice of organizing,
handling, directing, supervising, and controlling resources. Management structures extend from one
person in a small organization to management hierarchies consisting of many individuals in large
organizations.

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In terms of an ISMS, management involves the supervision and making of decisions necessary to achieve
business objectives through the protection of the organization’s information assets. Management of
information security is expressed through the formulation and use of information security policies,
procedures and guidelines, which are then applied throughout the organization by all individuals
associated with the organization.
4.2.5	 Management system
A management system uses a framework of resources to achieve an organization’s objectives. The
management system includes organizational structure, policies, planning activities, responsibilities,
practices, procedures, processes and resources.
In terms of information security, a management system allows an organization to:
a)	 satisfy the information security requirements of customers and other stakeholders;
b)	 improve an organization’s plans and activities;
c)	 meet the organization’s information security objectives;
d)	 comply with regulations, legislation and industry mandates; and
e)	 manage information assets in an organized way that facilitates continual improvement and
adjustment to current organizational goals.
4.3	 Process approach
Organizations need to identify and manage many activities in order to function effectively and
efficiently. Any activity using resources needs to be managed to enable the transformation of inputs into
outputs using a set of interrelated or interacting activities; this is also known as a process. The output
from one process can directly form the input to another process and generally this transformation
is carried out under planned and controlled conditions. The application of a system of processes
within an organization, together with the identification and interactions of these processes, and their
management, can be referred to as a “process approach”.
4.4	 Why an ISMS is important
Risks associated with an organization’s information assets need to be addressed. Achieving information
security requires the management of risk, and encompasses risks from physical, human and technology
related threats associated with all forms of information within or used by the organization.
The adoption of an ISMS is expected to be a strategic decision for an organization and it is necessary
that this decision is seamlessly integrated, scaled and updated in accordance with the needs of the
organization.
The design and implementation of an organization’s ISMS is influenced by the needs and objectives of the
organization, the security requirements, the business processes employed and the size and structure
of the organization. The design and operation of an ISMS needs to reflect the interests and information
security requirements of all of the organization’s stakeholders including customers, suppliers, business
partners, shareholders and other relevant third parties.
Inaninterconnectedworld,informationandrelatedprocesses,systems,andnetworksconstitutecritical
business assets. Organizations and their information systems and networks face security threats from
a wide range of sources, including computer-assisted fraud, espionage, sabotage, vandalism, fire and
flood. Damage to information systems and networks caused by malicious code, computer hacking, and
denial of service attacks have become more common, more ambitious, and increasingly sophisticated.
An ISMS is important to both public and private sector businesses. In any industry, an ISMS is an
enabler that supports e-business and is essential for risk management activities. The interconnection of
public and private networks and the sharing of information assets increase the difficulty of controlling

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access to and handling of information. In addition, the distribution of mobile storage devices containing
information assets can weaken the effectiveness of traditional controls. When organizations adopt
the ISMS family of standards, the ability to apply consistent and mutually-recognizable information
security principles can be demonstrated to business partners and other interested parties.
Information security is not always taken into account in the design and development of information
systems. Further, information security is often thought of as being a technical solution. However, the
information security that can be achieved through technical means is limited, and can be ineffective
without being supported by appropriate management and procedures within the context of an ISMS.
Integrating security into a functionally complete information system can be difficult and costly. An ISMS
involves identifying which controls are in place and requires careful planning and attention to detail. As
an example, access controls, which can be technical (logical), physical, administrative (managerial) or a
combination, provide a means to ensure that access to information assets is authorized and restricted
based on the business and information security requirements.
The successful adoption of an ISMS is important to protect information assets allowing an organization to:
a)	 achieve greater assurance that its information assets are adequately protected against threats on a
continual basis;
b)	 maintain a structured and comprehensive framework for identifying and assessing information
security risks, selecting and applying applicable controls, and measuring and improving their
effectiveness;
c)	 continually improve its control environment; and
d)	 effectively achieve legal and regulatory compliance.
4.5	 Establishing, monitoring, maintaining and improving an ISMS
4.5.1	Overview
An organization needs to undertake the following steps in establishing, monitoring, maintaining and
improving its ISMS:
a)	 identify information assets and their associated information security requirements (see 4.5.2);
b)	 assess information security risks (see 4.5.3) and treat information security risks (see 4.5.4);
c)	 select and implement relevant controls to manage unacceptable risks (see 4.5.5);
d)	 monitor, maintain and improve the effectiveness of controls associated with the organization’s
information assets (see 4.5.6).
To ensure the ISMS is effectively protecting the organization’s information assets on an ongoing
basis, it is necessary that steps a) to d) be continually repeated to identify changes in risks or in the
organization’s strategies or business objectives.
4.5.2	 Identifying information security requirements
Within the overall strategy and business objectives of the organization, its size and geographical spread,
information security requirements can be identified through an understanding of the following:
a)	 identified information assets and their value;
b)	 business needs for information processing, storage and communication;
c)	 legal, regulatory, and contractual requirements.
Conducting a methodical assessment of the risks associated with the organization’s information
assets involves analysing threats to information assets, vulnerabilities to and the likelihood of a threat

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materializing to information assets, and the potential impact of any information security incident
on information assets. The expenditure on relevant controls is expected to be proportionate to the
perceived business impact of the risk materializing.
4.5.3	 Assessing information security risks
Managing information security risks requires a suitable risk assessment and risk treatment method
which can include an estimation of the costs and benefits, legal requirements, the concerns of
stakeholders, and other inputs and variables as appropriate.
Risk assessment should identify, quantify, and prioritize risks against criteria for risk acceptance
and objectives relevant to the organization. The results should guide and determine the appropriate
management action and priorities for managing information security risks and for implementing
controls selected to protect against these risks.
Risk assessment should include:
—	 the systematic approach of estimating the magnitude of risks (risk analysis); and
—	 the process of comparing the estimated risks against risk criteria to determine the significance of
the risks (risk evaluation).
Risk assessment should be performed periodically to address changes in the information security
requirements and in the risk situation, for example in the assets, threats, vulnerabilities, impacts, the
risk evaluation, and when significant changes occur. These risk assessments should be undertaken in a
methodical manner capable of producing comparable and reproducible results.
The information security risk assessment should have a clearly defined scope in order to be effective
and should include relationships with risk assessments in other areas, if appropriate.
ISO/IEC  27005 provides information security risk management guidance, including advice on risk
assessment, risk treatment, risk acceptance, risk reporting, risk monitoring and risk review. Examples
of risk assessment methodologies are included as well.
4.5.4	 Treating information security risks
Before considering the treatment of a risk, the organization should define criteria for determining
whether or not risks can be accepted. Risks can be accepted if, for example, it is assessed that the risk
is low or that the cost of treatment is not cost-effective for the organization. Such decisions should be
recorded.
For each of the risks identified following the risk assessment, a risk treatment decision needs to be
made. Possible options for risk treatment include the following:
a)	 applying appropriate controls to reduce the risks;
b)	 knowingly and objectively accepting risks, providing they clearly satisfy the organization’s policy
and criteria for risk acceptance;
c)	 avoiding risks by not allowing actions that would cause the risks to occur;
d)	 sharing the associated risks to other parties, for example insurers or suppliers.
For those risks where the risk treatment decision has been to apply appropriate controls, these controls
should be selected and implemented.
4.5.5	 Selecting and implementing controls
Once information security requirements have been identified (see 4.5.2), information security risks to
the identified information assets have been determined and assessed (see 4.5.3) and decisions for the

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ISO/IEC 27000:2018(E)
treatment of information security risks have been made (see 4.5.4), then selection and implementation
of controls for risk reduction apply.
Controls should ensure that risks are reduced to an acceptable level taking the following into account:
a)	 requirements and constraints of national and international legislation and regulations;
b)	 organizational objectives;
c)	 operational requirements and constraints;
d)	 their cost of implementation and operation in relation to the risks being reduced, and remaining
proportional to the organization’s requirements and constraints;
e)	 their objectives to monitor, evaluate and improve the efficiency and effectiveness of information
security controls to support the organization’s aims. The selection and implementation of controls
should be documented within a statement of applicability to assist with compliance requirements;
f)	 the need to balance the investment in implementation and operation of controls against the loss
likely to result from information security incidents.
The controls specified in ISO/IEC  27002 are acknowledged as best practices applicable to most
organizations and readily tailored to accommodate organizations of various sizes and complexities.
Other standards in the ISMS family of standards provide guidance on the selection and application of
ISO/IEC 27002 controls for the ISMS.
Information security controls should be considered at the systems and projects requirements
specification and design stage. Failure to do so can result in additional costs and less effective
solutions, and, in the worst case, inability to achieve adequate security. Controls can be selected from
ISO/IEC  27002 or from other control sets. Alternatively, new controls can be designed to meet the
specific needs of the organization. It is necessary to recognize the possibility that some controls not
be applicable to every information system or environment, and not be practicable for all organizations.
Sometimes, implementing a chosen set of controls takes time and, during that time, the level of risk can
be higher than can be tolerated on a long-term basis. Risk criteria should cover tolerability of risks on
a short-term basis while controls are being implemented. Interested parties should be informed of the
levels of risk that are estimated or anticipated at different points in time as controls are progressively
implemented.
It should be kept in mind that no set of controls can achieve complete information security. Additional
management actions should be implemented to monitor, evaluate and improve the efficiency and
effectiveness of information security controls to support the organization’s aims.
The selection and implementation of controls should be documented within a statement of applicability
to assist with compliance requirements.
4.5.6	 Monitor, maintain and improve the effectiveness of the ISMS
An organization needs to maintain and improve the ISMS through monitoring and assessing
performance against organizational policies and objectives, and reporting the results to management
for review. This ISMS review checks that the ISMS includes specified controls that are suitable to treat
risks within the ISMS scope. Furthermore, based on the records of these monitored areas, it provides
evidence of verification and traceability of corrective, preventive and improvement actions.
4.5.7	 Continual improvement
The aim of continual improvement of an ISMS is to increase the probability of achieving objectives
concerning the preservation of the confidentiality, availability and integrity of information. The focus
of continual improvement is seeking opportunities for improvement and not assuming that existing
management activities are good enough or as good as they can.

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Actions for improvement include the following:
a)	 analysing and evaluating the existing situation to identify areas for improvement;
b)	 establishing the objectives for improvement;
c)	 searching for possible solutions to achieve the objectives;
d)	 evaluating these solutions and making a selection;
e)	 implementing the selected solution;
f)	 measuring, verifying, analysing and evaluating results of the implementation to determine that the
objectives have been met;
g)	 formalizing changes.
Results are reviewed, as necessary, to determine further opportunities for improvement. In this way,
improvement is a continual activity, i.e. actions are repeated frequently. Feedback from customers and
other interested parties, audits and review of the information security management system can also be
used to identify opportunities for improvement.
4.6	 ISMS critical success factors
A large number of factors are critical to the successful implementation of an ISMS to allow an
organization to meet its business objectives. Examples of critical success factors include the following:
a)	 information security policy, objectives, and activities aligned with objectives;
b)	 an approach and framework for designing, implementing, monitoring, maintaining, and improving
information security consistent with the organizational culture;
c)	 visible support and commitment from all levels of management, especially top management;
d)	 an understanding of information asset protection requirements achieved through the application
of information security risk management (see ISO/IEC 27005);
e)	 an effective information security awareness, training and education programme, informing all
employees and other relevant parties of their information security obligations set forth in the
information security policies, standards, etc., and motivating them to act accordingly;
f)	 an effective information security incident management process;
g)	 an effective business continuity management approach;
h)	 a measurement system used to evaluate performance in information security management and
feedback suggestions for improvement.
An ISMS increases the likelihood of an organization consistently achieving the critical success factors
required to protect its information assets.
4.7	 Benefits of the ISMS family of standards
The benefits of implementing an ISMS primarily result from a reduction in information security risks
(i.e. reducing the probability of and/or impact caused by information security incidents). Specifically,
benefits realized for an organization to achieve sustainable success from the adoption of the ISMS
family of standards include the following:
a)	 a structured framework supporting the process of specifying, implementing, operating and
maintaining a comprehensive, cost-effective, value creating, integrated and aligned ISMS that
meets the organization’s needs across different operations and sites;

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ISO/IEC 27000:2018(E)
b)	 assistance for management in consistently managing and operating in a responsible manner
their approach towards information security management, within the context of corporate risk
management and governance, including educating and training business and system owners on the
holistic management of information security;
c)	 promotion of globally accepted, good information security practices in a non-prescriptive manner,
giving organizations the latitude to adopt and improve relevant controls that suit their specific
circumstances and to maintain them in the face of internal and external changes;
d)	 provision of a common language and conceptual basis for information security, making it easier to
place confidence in business partners with a compliant ISMS, especially if they require certification
against ISO/IEC 27001 by an accredited certification body;
e)	 increase in stakeholder trust in the organization;
f)	 satisfying societal needs and expectations;
g)	 more effective economic management of information security investments.
5	 ISMS family of standards
5.1	 General information
The ISMS family of standards consists of inter-related standards, already published or under
development, and contains a number of significant structural components. These components are
focused on:
—	 standards describing ISMS requirements (ISO/IEC 27001);
—	 certification body requirements (ISO/IEC  27006) for those certifying conformity with
ISO/IEC 27001; and
—	 additional requirement framework for sector-specific implementations of the ISMS (ISO/IEC 27009).
Other documents provide guidance for various aspects of an ISMS implementation, addressing a generic
process as well as sector-specific guidance.
Relationships between the ISMS family of standards are illustrated in Figure 1.

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Requirement
standards -
Clause 5.3
Guidelines standards
-
Clause 5.4
Vocabulary standard -
Clause 5.2
27009
27006
27001
27000
27002 27003 27004 27005 27007 TR 27008
27013 27014 TR 27016
27010 27011 27017 27018 27019
27021
2703x 2704x
Sector-speci ic
guidelines standards -
Clause 5.5
Control-speci ic guidelines standards
(out of the scope of this document)
ISMS
family
of
standards
Figure 1 — ISMS family of standards relationships
Each of the ISMS family standards is described below by its type (or role) within the ISMS family of
standards and its reference number.
5.2	 Standard describing an overview and terminology: ISO/IEC 27000 (this document)
Information technology — Security techniques — Information security management systems — Overview
and vocabulary
Scope: This document provides to organizations and individuals:
a)	 an overview of the ISMS family of standards;
b)	 an introduction to information security management systems; and
c)	 terms and definitions used throughout the ISMS family of standards.
Purpose: This document describes the fundamentals of information security management systems,
which form the subject of the ISMS family of standards and defines related terms.
5.3	 Standards specifying requirements
5.3.1	 ISO/IEC 27001
Information technology — Security techniques — Information security management systems —
Requirements
Scope: This document specifies the requirements for establishing, implementing, operating, monitoring,
reviewing, maintaining and improving formalized information security management systems (ISMS)
within the context of the organization’s overall business risks. It specifies requirements for the
implementation of information security controls customized to the needs of individual organizations
or parts thereof. This document can be used by all organizations, regardless of type, size and nature.

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Purpose: ISO/IEC  27001 provides normative requirements for the development and operation of
an ISMS, including a set of controls for the control and mitigation of the risks associated with the
information assets which the organization seeks to protect by operating its ISMS. Organizations
operating an ISMS may have its conformity audited and certified. The control objectives and controls
from ISO/IEC 27001:2013, Annex A shall be selected as part of this ISMS process as appropriate to cover
the identified requirements. The control objectives and controls listed in ISO/IEC 27001:2013, Table A.1
are directly derived from and aligned with those listed in ISO/IEC 27002:2013, Clauses 5 to 18.
5.3.2	 ISO/IEC 27006
Information technology — Security techniques — Requirements for bodies providing audit and certification
of information security management systems
Scope: This document specifies requirements and provides guidance for bodies providing audit and
ISMS certification in accordance with ISO/IEC 27001, in addition to the requirements contained within
ISO/IEC 17021. It is primarily intended to support the accreditation of certification bodies providing
ISMS certification according to ISO/IEC 27001.
The requirements contained in this document need to be demonstrated in terms of competence and
reliability by anybody providing ISMS certification, and the guidance contained in this document
provides additional interpretation of these requirements for anybody providing ISMS certification.
Purpose: ISO/IEC  27006 supplements ISO/IEC  17021 in providing the requirements by which
certification organizations are accredited, thus permitting these organizations to provide compliance
certifications consistently against the requirements set forth in ISO/IEC 27001.
5.3.3	 ISO/IEC 27009
Information technology  — Security techniques  — Sector-specific application of ISO/IEC 27001 —
Requirements
Scope: This document defines the requirements for the use of ISO/IEC 27001 in any specific sector
(field, application area or market sector). It explains how to include requirements additional to those
in ISO/IEC 27001, how to refine any of the ISO/IEC 27001 requirements, and how to include controls or
control sets in addition to ISO/IEC 27001:2013, Annex A.
Purpose: ISO/IEC 27009 ensures that additional or refined requirements are not in conflict with the
requirements in ISO/IEC 27001.
5.4	 Standards describing general guidelines
5.4.1	 ISO/IEC 27002
Information technology — Security techniques — Code of practice for information security controls
Scope: This document provides a list of commonly accepted control objectives and best practice
controls to be used as implementation guidance when selecting and implementing controls for achieving
information security.
Purpose: ISO/IEC 27002 provides guidance on the implementation of information security controls.
Specifically, Clauses 5 to 18 provide specific implementation advice and guidance on best practice in
support of the controls specified in ISO/IEC 27001:2013, A.5 to A.18.
5.4.2	 ISO/IEC 27003
Information technology — Security techniques — Information security management —Guidance
Scope: This document provides explanation and guidance on ISO/IEC 27001:2013.

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Purpose: ISO/IEC  27003 provides a background to the successful implementation of the ISMS in
accordance with ISO/IEC 27001.
5.4.3	 ISO/IEC 27004
Information technology — Security techniques — Information security management — Monitoring,
measurement, analysis and evaluation
Scope: This document provides guidelines intended to assist organizations to evaluate the information
security performance and the effectiveness of the ISMS in order to fulfil the requirements of
ISO/IEC 27001:2013, 9.1. It addresses:
a)	 the monitoring and measurement of information security performance;
b)	 the monitoring and measurement of the effectiveness of an information security management
system (ISMS) including its processes and controls;
c)	 the analysing and the evaluating of the results of monitoring and measurement.
Purpose: ISO/IEC 27004 provides a framework allowing an assessment of ISMS effectiveness to be
measured and evaluated in accordance with ISO/IEC 27001.
5.4.4	 ISO/IEC 27005
Information technology — Security techniques — Information security risk management
Scope: This document provides guidelines for information security risk management. The approach
described within this document supports the general concepts specified in ISO/IEC 27001.
Purpose: ISO/IEC  27005 provides guidance on implementing a process-oriented risk management
approach to assist in satisfactorily implementing and fulfilling the information security risk
management requirements of ISO/IEC 27001.
5.4.5	 ISO/IEC 27007
Information technology — Security techniques — Guidelines for information security management systems
auditing
Scope: This document provides guidance on conducting ISMS audits, as well as guidance on the
competence of information security management system auditors, in addition to the guidance contained
in ISO 19011, which is applicable to management systems in general.
Purpose: ISO/IEC  27007 will provide guidance to organizations needing to conduct internal or
external audits of an ISMS or to manage an ISMS audit programme against the requirements specified
in ISO/IEC 27001.
5.4.6	 ISO/IEC TR 27008
Information technology — Security techniques — Guidelines for auditors on information security controls
Scope: This document provides guidance on reviewing the implementation and operation of controls,
including technical compliance checking of information system controls, in compliance with an
organization’s established information security standards.
Purpose: This document provides a focus on reviews of information security controls, including checking
of technical compliance, against an information security implementation standard, which is established
by the organization. It does not intend to provide any specific guidance on compliance checking regarding
measurement, risk assessment or audit of an ISMS as specified in ISO/IEC  27004, ISO/IEC  27005 or
ISO/IEC 27007, respectively. This documentis not intended for management systems audits.

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5.4.7	 ISO/IEC 27013
Information technology — Security techniques — Guidance on the integrated implementation of
ISO/IEC 27001 and ISO/IEC 20000-1
Scope: This document provides guidance on the integrated implementation of ISO/IEC  27001 and
ISO/IEC 20000-1 for organizations that are intending to either:
a)	 implement ISO/IEC 27001 when ISO/IEC 20000-1 is already implemented, or vice versa;
b)	 implement both ISO/IEC 27001 and ISO/IEC 20000-1 together;
c)	 integrate existing management systems based on ISO/IEC 27001 and ISO/IEC 20000-1.
This document focuses exclusively on the integrated implementation of an information security
management system (ISMS) as specified in ISO/IEC 27001 and a service management system (SMS) as
specified in ISO/IEC 20000-1.
In practice, ISO/IEC 27001 and ISO/IEC 20000-1 can also be integrated with other management system
standards, such as ISO 9001 and ISO 14001.
Purpose: To provide organizations with a better understanding of the characteristics, similarities and
differences of ISO/IEC 27001 and ISO/IEC 20000-1 to assist in the planning of an integrated management
system that conforms to both International Standards.
5.4.8	 ISO/IEC 27014
Information technology — Security techniques — Governance of information security
Scope: This document will provide guidance on principles and processes for the governance of
information security, by which organizations can evaluate, direct and monitor the management of
information security.
Purpose: Information security has become a key issue for organizations. Not only are there increasing
regulatory requirements but also the failure of an organization’s information security measures can
have a direct impact on an organization’s reputation. Therefore, governing bodies, as part of their
governance responsibilities, are increasingly required to have oversight of information security to
ensure the objectives of the organization are achieved.
5.4.9	 ISO/IEC TR 27016
Information technology — Security techniques — Information security management — Organizational
economics
Scope: This document provides a methodology allowing organizations to better understand
economically how to more accurately value their identified information assets, value the potential
risks to those information assets, appreciate the value that information protection controls deliver to
these information assets, and determine the optimum level of resources to be applied in securing these
information assets.
Purpose: This document supplements the ISMS family of standards by overlaying an economics
perspective in the protection of an organization’s information assets in the context of the wider societal
environment in which an organization operates and providing guidance on how to apply organizational
economics of information security through the use of models and examples.
5.4.10	 ISO/IEC 27021
Information technology  — Security techniques  — Information security management  — Competence
requirements for information security management systems professionals

22 © ISO/IEC 2018 – All rights reserved

ISO/IEC 27000:2018(E)
Scope: This document specifies the requirements of competence for ISMS professionals leading or
involved in establishing, implementing, maintaining and continually improving one or more information
security management system processes that conforms to ISO/IEC 27001:2013.
Purpose: This document is intended for use by:
a)	 individuals who would like to demonstrate their competence as information security management
system (ISMS) professionals, or who wish to understand and accomplish the competence required
for working in this area, as well as wishing to broaden their knowledge,
b)	 organizations seeking potential ISMS professional candidates to define the competence required
for positions in ISMS related roles,
c)	 bodies to develop certification for ISMS professionals which need a body of knowledge (BOK) for
examination sources, and
d)	 organizations for education and training, such as universities and vocational institutions, to align
their syllabuses and courses to the competence requirements for ISMS professionals.
5.5	 Standards describing sector-specific guidelines
5.5.1	 ISO/IEC 27010
Information technology — Security techniques — Information security management for inter-sector and
inter-organizational communications
Scope: This document provides guidelines in addition to guidance given in the ISO/IEC  27000
family of standards for implementing information security management within information sharing
communities.
This document provides controls and guidance specifically relating to initiating, implementing,
maintaining, and improving information security in inter-organizational and inter-sector
communications.
Purpose: This document is applicable to all forms of exchange and sharing of sensitive information,
both public and private, nationally and internationally, within the same industry or market sector or
between sectors. In particular, it can be applicable to information exchanges and sharing relating to the
provision, maintenance and protection of an organization’s or state’s critical infrastructure.
5.5.2	 ISO/IEC 27011
Information technology — Security techniques — Code of practice for information security controls based
on ISO/IEC 27002 for telecommunications organizations
Scope: This document provides guidelines supporting the implementation of information security
controls in telecommunications organizations.
Purpose: ISO/IEC  27011 allows telecommunications organizations to meet baseline information
security management requirements of confidentiality, integrity, availability and any other relevant
security property.
5.5.3	 ISO/IEC 27017
Information technology — Security techniques — Code of practice for information security controls based
on ISO/IEC 27002 for cloud services
Scope: ISO/IEC 27017 gives guidelines for information security controls applicable to the provision and
use of cloud services by providing:
—	 additional implementation guidance for relevant controls specified in ISO/IEC 27002;

© ISO/IEC 2018 – All rights reserved 23

ISO/IEC 27000:2018(E)
—	 additional controls with implementation guidance that specifically relate to cloud services.
Purpose: This document provides controls and implementation guidance for both cloud service
providers and cloud service customers.
5.5.4	 ISO/IEC 27018
Information technology — Security techniques — Code of practice for protection of personally identifiable
information (PII) in public clouds acting as PII processors
Scope: ISO/IEC 27018 establishes commonly accepted control objectives, controls and guidelines for
implementing measures to protect personally identifiable information (PII) in accordance with the
privacy principles in ISO/IEC 29100 for the public cloud computing environment.
Purpose: This document is applicable to organizations, including public and private companies,
government entities and not-for-profit organizations, which provide information processing services
as PII processors via cloud computing under contract to other organizations. The guidelines in this
document can also be relevant to organizations acting as PII controllers. However, it is possible that PII
controllers be subject to additional PII protection legislation, regulations and obligations, not applying
to PII processors, and these are not covered in this document.
5.5.5	 ISO/IEC 27019
Information technology — Security techniques — Information security controls for the energy utility
industry
Scope: This document provides guidance based on ISO/IEC  27002:2013 applied to process control
systems used by the energy utility industry for controlling and monitoring the production or generation,
transmission, storage and distribution of electric power, gas, oil and heat, and for the control of
associated supporting processes. This includes in particular the following:
—	 central and distributed process control, monitoring and automation technology as well as
information systems used for their operation, such as programming and parameterization devices;
—	 digital controllers and automation components such as control and field devices or programmable
logic controllers (PLCs), including digital sensor and actuator elements;
—	 allfurthersupportinginformationsystemsusedintheprocesscontroldomain,e.g.forsupplementary
data visualization tasks and for controlling, monitoring, data archiving, historian logging, reporting
and documentation purposes;
—	 communication technology used in the process control domain, e.g. networks, telemetry, telecontrol
applications and remote control technology;
—	 advanced metering infrastructure (AMI) components, e.g. smart meters;
—	 measurement devices, e.g. for emission values;
—	 digital protection and safety systems, e.g. protection relays, safety PLCs, emergency governor
mechanisms;
—	 energy management systems, e.g. of distributed energy resources (DER), electric charging
infrastructures, in private households, residential buildings or industrial customer installations;
—	 distributed components of smart grid environments, e.g. in energy grids, in private households,
residential buildings or industrial customer installations;
—	 allsoftware,firmwareandapplicationsinstalledonabove-mentionedsystems,e.g.DMS(distribution
management system) applications or OMS (outage management system);
—	 any premises housing the above-mentioned equipment and systems;

24 © ISO/IEC 2018 – All rights reserved

ISO/IEC 27000:2018(E)
—	 remote maintenance systems for above-mentioned systems.
This document does not apply to the process control domain of nuclear facilities. This domain is covered
by IEC 62645.
This document also includes a requirement to adapt the risk assessment and treatment processes
described in ISO/IEC 27001:2013 to the energy utility industry-sector–specific guidance provided in
this document.
Purpose: In addition to the security objectives and measures that are set forth in ISO/IEC 27002, this
document provides guidelines for systems used by energy utilities and energy suppliers on information
security controls which address further, special requirements.
5.5.6	 ISO 27799
Health informatics — Information security management in health using ISO/IEC 27002
Scope: This document gives guidelines for organizational information security standards and
information security management practices including the selection, implementation and management
of controls taking into consideration the organization’s information security risk environment(s).
This document provides implementation guidance for the controls described in ISO/IEC  27002
and supplements them where necessary, so that they can be effectively used for managing health
information security.
Purpose: ISO 27799 provides health organizations with an adaptation of the ISO/IEC 27002 guidelines
unique to their industry sector which are additional to the guidance provided towards fulfilling the
requirements of ISO/IEC 27001:2013, Annex A.

© ISO/IEC 2018 – All rights reserved 25

ISO/IEC 27000:2018(E)
Bibliography
[1]	 ISO 9000:2015, Quality management systems — Fundamentals and vocabulary
[2]	 ISO/IEC/IEEE 15939:2017, Systems and software engineering — Measurement process
[3]	 ISO/IEC 17021, Conformity assessment — Requirements for bodies providing audit and certification
of management systems
[4]	 ISO 19011:2011, Guidelines for auditing management systems
[5]	 ISO/IEC  20000-1:2011, Information technology  — Service management  — Part  1: Service
management system requirements
[6]	 ISO/IEC 27001, Information technology — Security techniques — Information security management
systems — Requirements
[7]	 ISO/IEC 27002, Information technology — Security techniques — Code of practice for information
security controls
[8]	 ISO/IEC 27003, Information technology — Security techniques — Information security management
— Guidance
[9]	 ISO/IEC  27004, Information technology — Security techniques — Information security
management — Monitoring, measurement, analysis and evaluation
[10]	 ISO/IEC  27005, Information technology — Security techniques — Information security risk
management
[11]	 ISO/IEC  27006, Information technology — Security techniques — Requirements for bodies
providing audit and certification of information security management systems
[12]	 ISO/IEC  27007, Information technology — Security techniques — Guidelines for information
security management systems auditing
[13]	 ISO/IEC TR 27008, Information technology — Security techniques — Guidelines for auditors on
information security controls
[14]	 ISO/IEC  27009, Information technology  — Security techniques  — Sector-specific application of
ISO/IEC 27001 — Requirements
[15]	 ISO/IEC 27010, Information technology — Security techniques — Information security management
for inter-sector and inter-organizational communications
[16]	 ISO/IEC 27011, Information technology — Security techniques — Code of practice for information
security controls based on ISO/IEC 27002 for telecommunications organizations
[17]	 ISO/IEC  27013, Information technology — Security techniques — Guidance on the integrated
implementation of ISO/IEC 27001 and ISO/IEC 20000‑1
[18]	 ISO/IEC  27014, Information technology — Security techniques — Governance of information
security
[19]	 ISO/IEC  TR  27016, Information technology — Security techniques — Information security
management — Organizational economics
[20]	 ISO/IEC 27017, Information technology — Security techniques — Code of practice for information
security controls based on ISO/IEC 27002 for cloud services
[21]	 ISO/IEC 27018, Information technology — Security techniques — Code of practice for protection of
personally identifiable information (PII) in public clouds acting as PII processors

26 © ISO/IEC 2018 – All rights reserved

ISO/IEC 27000:2018(E)
[22]	 ISO/IEC 27019, Information technology — Security techniques — Information security controls for
the energy utility industry
[23]	 ISO/IEC 27021, Information technology — Security techniques — Competence requirements for
information security management systems professionals
[24]	 ISO 27799, Health informatics — Information security management in health using ISO/IEC 27002
[25]	 ISO Guide 73:2009, Risk management — Vocabulary

© ISO/IEC 2018 – All rights reserved 27

ISO/IEC 27000:2018(E)

© ISO/IEC 2018 – All rights reserved
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  • 1. Information technology — Security techniques — Information security management systems — Overview and vocabulary Technologies de l'information — Techniques de sécurité — Systèmes de management de la sécurité de l'information — Vue d'ensemble et vocabulaire INTERNATIONAL STANDARD ISO/IEC 27000 Reference number ISO/IEC 27000:2018(E) Fifth edition 2018-02 © ISO/IEC 2018
  • 2.  ISO/IEC 27000:2018(E)  ii © ISO/IEC 2018 – All rights reserved COPYRIGHT PROTECTED DOCUMENT © ISO/IEC 2018 All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of the requester. ISO copyright office CP 401 • Ch. de Blandonnet 8 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyright@iso.org www.iso.org Published in Switzerland
  • 3.  ISO/IEC 27000:2018(E)  Foreword.........................................................................................................................................................................................................................................iv Introduction...................................................................................................................................................................................................................................v 1 Scope..................................................................................................................................................................................................................................1 2 Normative references.......................................................................................................................................................................................1 3 Terms and definitions......................................................................................................................................................................................1 4 Information security management systems..........................................................................................................................11 4.1 General.........................................................................................................................................................................................................11 4.2 What is an ISMS?.................................................................................................................................................................................11 4.2.1 Overview and principles.........................................................................................................................................11 4.2.2 Information........................................................................................................................................................................12 4.2.3 Information security...................................................................................................................................................12 4.2.4 Management......................................................................................................................................................................12 4.2.5 Management system...................................................................................................................................................13 4.3 Process approach................................................................................................................................................................................13 4.4 Why an ISMS is important...........................................................................................................................................................13 4.5 Establishing, monitoring, maintaining and improving an ISMS.................................................................14 4.5.1 Overview...............................................................................................................................................................................14 4.5.2 Identifying information security requirements..................................................................................14 4.5.3 Assessing information security risks...........................................................................................................15 4.5.4 Treating information security risks...............................................................................................................15 4.5.5 Selecting and implementing controls..........................................................................................................15 4.5.6 Monitor, maintain and improve the effectiveness of the ISMS...............................................16 4.5.7 Continual improvement...........................................................................................................................................16 4.6 ISMS critical success factors......................................................................................................................................................17 4.7 Benefits of the ISMS family of standards........................................................................................................................17 5 ISMS family of standards............................................................................................................................................................................18 5.1 General information.........................................................................................................................................................................18 5.2 Standard describing an overview and terminology: ISO/IEC 27000 (this document)..........19 5.3 Standards specifying requirements....................................................................................................................................19 5.3.1 ISO/IEC 27001.................................................................................................................................................................19 5.3.2 ISO/IEC 27006.................................................................................................................................................................20 5.3.3 ISO/IEC 27009.................................................................................................................................................................20 5.4 Standards describing general guidelines.......................................................................................................................20 5.4.1 ISO/IEC 27002.................................................................................................................................................................20 5.4.2 ISO/IEC 27003.................................................................................................................................................................20 5.4.3 ISO/IEC 27004.................................................................................................................................................................21 5.4.4 ISO/IEC 27005.................................................................................................................................................................21 5.4.5 ISO/IEC 27007.................................................................................................................................................................21 5.4.6 ISO/IEC TR 27008........................................................................................................................................................21 5.4.7 ISO/IEC 27013.................................................................................................................................................................22 5.4.8 ISO/IEC 27014.................................................................................................................................................................22 5.4.9 ISO/IEC TR 27016........................................................................................................................................................22 5.4.10 ISO/IEC 27021.................................................................................................................................................................22 5.5 Standards describing sector-specific guidelines.....................................................................................................23 5.5.1 ISO/IEC 27010.................................................................................................................................................................23 5.5.2 ISO/IEC 27011.................................................................................................................................................................23 5.5.3 ISO/IEC 27017.................................................................................................................................................................23 5.5.4 ISO/IEC 27018.................................................................................................................................................................24 5.5.5 ISO/IEC 27019.................................................................................................................................................................24 5.5.6 ISO 27799.............................................................................................................................................................................25 Bibliography..............................................................................................................................................................................................................................26 © ISO/IEC 2018 – All rights reserved iii Contents Page
  • 4.  ISO/IEC 27000:2018(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www​ .iso​ .org/​ directives). Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www​ .iso​ .org/​ patents). Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement. For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISO's adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www​ .iso​ .org/​ iso/​ foreword​ .html. This document was prepared by Technical Committee ISO/IEC JTC 1, Information technology, SC 27, IT Security techniques. This fifth edition cancels and replaces the fourth edition (ISO/IEC  27000:2016), which has been technically revised. The main changes compared to the previous edition are as follows: — the Introduction has been reworded; — some terms and definitions have been removed; — Clause 3 has been aligned on the high-level structure for MSS; — Clause 5 has been updated to reflect the changes in the standards concerned; — Annexes A and B have been deleted.  iv © ISO/IEC 2018 – All rights reserved
  • 5.  ISO/IEC 27000:2018(E) Introduction 0.1   Overview International Standards for management systems provide a model to follow in setting up and operating a management system. This model incorporates the features on which experts in the field have reached a consensus as being the international state of the art. ISO/IEC JTC 1/SC 27 maintains an expert committee dedicated to the development of international management systems standards for information security, otherwise known as the Information Security Management system (ISMS) family of standards. Through the use of the ISMS family of standards, organizations can develop and implement a framework for managing the security of their information assets, including financial information, intellectual property, and employee details, or information entrusted to them by customers or third parties. These standards can also be used to prepare for an independent assessment of their ISMS applied to the protection of information. 0.2   Purpose of this document The ISMS family of standards includes standards that: a) define requirements for an ISMS and for those certifying such systems; b) provide direct support, detailed guidance and/or interpretation for the overall process to establish, implement, maintain, and improve an ISMS; c) address sector-specific guidelines for ISMS; and d) address conformity assessment for ISMS. 0.3   Content of this document In this document, the following verbal forms are used: — “shall” indicates a requirement; — “should” indicates a recommendation; — “may” indicates a permission; — “can” indicates a possibility or a capability. Information marked as NOTE is for guidance in understanding or clarifying the associated requirement. “Notes to entry” used in Clause 3 provide additional information that supplements the terminological data and can contain provisions relating to the use of a term.  © ISO/IEC 2018 – All rights reserved v
  • 7.  Information technology — Security techniques — Information security management systems — Overview and vocabulary 1 Scope This document provides the overview of information security management systems (ISMS). It also provides terms and definitions commonly used in the ISMS family of standards. This document is applicable to all types and sizes of organization (e.g. commercial enterprises, government agencies, not- for-profit organizations). The terms and definitions provided in this document — cover commonly used terms and definitions in the ISMS family of standards; — do not cover all terms and definitions applied within the ISMS family of standards; and — do not limit the ISMS family of standards in defining new terms for use. 2 Normative references There are no normative references in this document. 3 Terms and definitions ISO and IEC maintain terminological databases for use in standardization at the following addresses: — ISO Online browsing platform: available at https://​ www​ .iso​ .org/​ obp — IEC Electropedia: available at https://​ www​ .electropedia​ .org/​ 3.1 access control means to ensure that access to assets is authorized and restricted based on business and security requirements (3.56) 3.2 attack attempt to destroy, expose, alter, disable, steal or gain unauthorized access to or make unauthorized use of an asset 3.3 audit systematic, independent and documented process (3.54) for obtaining audit evidence and evaluating it objectively to determine the extent to which the audit criteria are fulfilled Note 1 to entry: An audit can be an internal audit (first party) or an external audit (second party or third party), and it can be a combined audit (combining two or more disciplines). Note 2 to entry: An internal audit is conducted by the organization itself, or by an external party on its behalf. Note 3 to entry: “Audit evidence” and “audit criteria” are defined in ISO 19011. INTERNATIONAL STANDARD ISO/IEC 27000:2018(E) © ISO/IEC 2018 – All rights reserved 1
  • 8.  ISO/IEC 27000:2018(E) 3.4 audit scope extent and boundaries of an audit (3.3) [SOURCE: ISO 19011:2011, 3.14, modified — Note 1 to entry has been deleted.] 3.5 authentication provision of assurance that a claimed characteristic of an entity is correct 3.6 authenticity property that an entity is what it claims to be 3.7 availability property of being accessible and usable on demand by an authorized entity 3.8 base measure measure (3.42) defined in terms of an attribute and the method for quantifying it Note 1 to entry: A base measure is functionally independent of other measures. [SOURCE: ISO/IEC/IEEE 15939:2017, 3.3, modified — Note 2 to entry has been deleted.] 3.9 competence ability to apply knowledge and skills to achieve intended results 3.10 confidentiality property that information is not made available or disclosed to unauthorized individuals, entities, or processes (3.54) 3.11 conformity fulfilment of a requirement (3.56) 3.12 consequence outcome of an event (3.21) affecting objectives (3.49) Note 1 to entry: An event can lead to a range of consequences. Note 2 to entry: A consequence can be certain or uncertain and, in the context of information security, is usually negative. Note 3 to entry: Consequences can be expressed qualitatively or quantitatively. Note 4 to entry: Initial consequences can escalate through knock-on effects. [SOURCE: ISO Guide 73:2009, 3.6.1.3, modified — Note 2 to entry has been changed after “and”.] 3.13 continual improvement recurring activity to enhance performance (3.52)  2 © ISO/IEC 2018 – All rights reserved
  • 9.  ISO/IEC 27000:2018(E) 3.14 control measure that is modifying risk (3.61) Note 1 to entry: Controls include any process (3.54), policy (3.53), device, practice, or other actions which modify risk (3.61). Note 2 to entry: It is possible that controls not always exert the intended or assumed modifying effect. [SOURCE: ISO Guide 73:2009, 3.8.1.1 — Note 2 to entry has been changed.] 3.15 control objective statement describing what is to be achieved as a result of implementing controls (3.14) 3.16 correction action to eliminate a detected nonconformity (3.47) 3.17 corrective action action to eliminate the cause of a nonconformity (3.47) and to prevent recurrence 3.18 derived measure measure (3.42) that is defined as a function of two or more values of base measures (3.8) [SOURCE: ISO/IEC/IEEE 15939:2017, 3.8, modified — Note 1 to entry has been deleted.] 3.19 documented information information required to be controlled and maintained by an organization (3.50) and the medium on which it is contained Note 1 to entry: Documented information can be in any format and media and from any source. Note 2 to entry: Documented information can refer to — the management system (3.41), including related processes (3.54); — information created in order for the organization (3.50) to operate (documentation); — evidence of results achieved (records). 3.20 effectiveness extent to which planned activities are realized and planned results achieved 3.21 event occurrence or change of a particular set of circumstances Note 1 to entry: An event can be one or more occurrences, and can have several causes. Note 2 to entry: An event can consist of something not happening. Note 3 to entry: An event can sometimes be referred to as an “incident” or “accident”. [SOURCE: ISO Guide 73:2009, 3.5.1.3, modified — Note 4 to entry has been deleted.]  © ISO/IEC 2018 – All rights reserved 3
  • 10.  ISO/IEC 27000:2018(E) 3.22 external context external environment in which the organization seeks to achieve its objectives (3.49) Note 1 to entry: External context can include the following: — the cultural, social, political, legal, regulatory, financial, technological, economic, natural and competitive environment, whether international, national, regional or local; — key drivers and trends having impact on the objectives of the organization (3.50); — relationships with, and perceptions and values of, external stakeholders (3.37). [SOURCE: ISO Guide 73:2009, 3.3.1.1] 3.23 governance of information security system by which an organization’s (3.50) information security (3.28) activities are directed and controlled 3.24 governing body person or group of people who are accountable for the performance (3.52) and conformity of the organization (3.50) Note 1 to entry: The governing body can, in some jurisdictions, be a board of directors. 3.25 indicator measure (3.42) that provides an estimate or evaluation 3.26 information need insight necessary to manage objectives (3.49), goals, risks and problems [SOURCE: ISO/IEC/IEEE 15939:2017, 3.12] 3.27 information processing facilities any information processing system, service or infrastructure, or the physical location housing it 3.28 information security preservation of confidentiality (3.10), integrity (3.36) and availability (3.7) of information Note 1 to entry: In addition, other properties, such as authenticity (3.6), accountability, non-repudiation (3.48), and reliability (3.55) can also be involved. 3.29 information security continuity processes (3.54) and procedures for ensuring continued information security (3.28) operations 3.30 information security event identified occurrence of a system, service or network state indicating a possible breach of information security (3.28) policy (3.53) or failure of controls (3.14), or a previously unknown situation that can be security relevant 3.31 information security incident single or a series of unwanted or unexpected information security events (3.30) that have a significant probability of compromising business operations and threatening information security (3.28)  4 © ISO/IEC 2018 – All rights reserved
  • 11.  ISO/IEC 27000:2018(E) 3.32 information security incident management set of processes (3.54) for detecting, reporting, assessing, responding to, dealing with, and learning from information security incidents (3.31) 3.33 information security management system (ISMS) professional person who establishes, implements, maintains and continuously improves one or more information security management system processes (3.54) 3.34 information sharing community group of organizations (3.50) that agree to share information Note 1 to entry: An organization can be an individual. 3.35 information system set of applications, services, information technology assets, or other information-handling components 3.36 integrity property of accuracy and completeness 3.37 interested party (preferred term) stakeholder (admitted term) person or organization (3.50) that can affect, be affected by, or perceive itself to be affected by a decision or activity 3.38 internal context internal environment in which the organization (3.50) seeks to achieve its objectives Note 1 to entry: Internal context can include: — governance, organizational structure, roles and accountabilities; — policies (3.53), objectives (3.49), and the strategies that are in place to achieve them; — the capabilities, understood in terms of resources and knowledge (e.g. capital, time, people, processes (3.54), systems and technologies); — information systems (3.35), information flows and decision-making processes (both formal and informal); — relationships with, and perceptions and values of, internal stakeholders (3.37); — the organization's culture; — standards, guidelines and models adopted by the organization; — form and extent of contractual relationships. [SOURCE: ISO Guide 73:2009, 3.3.1.2] 3.39 level of risk magnitude of a risk (3.61) expressed in terms of the combination of consequences (3.12) and their likelihood (3.40) [SOURCE: ISO Guide 73:2009, 3.6.1.8, modified — “or combination of risks” has been deleted in the definition.]  © ISO/IEC 2018 – All rights reserved 5
  • 12.  ISO/IEC 27000:2018(E) 3.40 likelihood chance of something happening [SOURCE: ISO Guide 73:2009, 3.6.1.1, modified — Notes 1 and 2 to entry have been deleted.] 3.41 management system set of interrelated or interacting elements of an organization (3.50) to establish policies (3.53) and objectives (3.49) and processes (3.54) to achieve those objectives Note 1 to entry: A management system can address a single discipline or several disciplines. Note 2 to entry: The system elements include the organization’s structure, roles and responsibilities, planning and operation. Note 3 to entry: The scope of a management system may include the whole of the organization, specific and identified functions of the organization, specific and identified sections of the organization, or one or more functions across a group of organizations. 3.42 measure variable to which a value is assigned as the result of measurement (3.43) [SOURCE: ISO/IEC/IEEE 15939:2017, 3.15, modified — Note 2 to entry has been deleted.] 3.43 measurement process (3.54) to determine a value 3.44 measurement function algorithm or calculation performed to combine two or more base measures (3.8) [SOURCE: ISO/IEC/IEEE 15939:2017, 3.20] 3.45 measurement method logical sequence of operations, described generically, used in quantifying an attribute with respect to a specified scale Note 1 to entry: The type of measurement method depends on the nature of the operations used to quantify an attribute (3.4). Two types can be distinguished: — subjective: quantification involving human judgment; and — objective: quantification based on numerical rules. [SOURCE: ISO/IEC/IEEE 15939:2017, 3.21, modified — Note 2 to entry has been deleted.] 3.46 monitoring determining the status of a system, a process (3.54) or an activity Note 1 to entry: To determine the status, there may be a need to check, supervise or critically observe. 3.47 nonconformity non-fulfilment of a requirement (3.56) 3.48 non-repudiation ability to prove the occurrence of a claimed event (3.21) or action and its originating entities  6 © ISO/IEC 2018 – All rights reserved
  • 13.  ISO/IEC 27000:2018(E) 3.49 objective result to be achieved Note 1 to entry: An objective can be strategic, tactical, or operational. Note  2  to entry:  Objectives can relate to different disciplines (such as financial, health and safety, and environmental goals) and can apply at different levels [such as strategic, organization-wide, project, product and process (3.54)]. Note  3  to entry:  An objective can be expressed in other ways, e.g. as an intended outcome, a purpose, an operational criterion, as an information security objective or by the use of other words with similar meaning (e.g. aim, goal, or target). Note 4 to entry: In the context of information security management systems, information security objectives are set by the organization, consistent with the information security policy, to achieve specific results. 3.50 organization person or group of people that has its own functions with responsibilities, authorities and relationships to achieve its objectives (3.49) Note 1 to entry: The concept of organization includes but is not limited to sole-trader, company, corporation, firm, enterprise, authority, partnership, charity or institution, or part or combination thereof, whether incorporated or not, public or private. 3.51 outsource make an arrangement where an external organization (3.50) performs part of an organization’s function or process (3.54) Note 1 to entry: An external organization is outside the scope of the management system (3.41), although the outsourced function or process is within the scope. 3.52 performance measurable result Note 1 to entry: Performance can relate either to quantitative or qualitative findings. Note 2 to entry: Performance can relate to the management of activities, processes (3.54), products (including services), systems or organizations (3.50). 3.53 policy intentions and direction of an organization (3.50), as formally expressed by its top management (3.75) 3.54 process set of interrelated or interacting activities which transforms inputs into outputs 3.55 reliability property of consistent intended behaviour and results 3.56 requirement need or expectation that is stated, generally implied or obligatory Note  1  to entry:  “Generally implied” means that it is custom or common practice for the organization and interested parties that the need or expectation under consideration is implied. Note 2 to entry: A specified requirement is one that is stated, for example in documented information.  © ISO/IEC 2018 – All rights reserved 7
  • 14.  ISO/IEC 27000:2018(E) 3.57 residual risk risk (3.61) remaining after risk treatment (3.72) Note 1 to entry: Residual risk can contain unidentified risk. Note 2 to entry: Residual risk can also be referred to as “retained risk”. 3.58 review activity undertaken to determine the suitability, adequacy and effectiveness (3.20) of the subject matter to achieve established objectives (3.49) [SOURCE: ISO Guide 73:2009, 3.8.2.2, modified — Note 1 to entry has been deleted.] 3.59 review object specific item being reviewed 3.60 review objective statement describing what is to be achieved as a result of a review (3.59) 3.61 risk effect of uncertainty on objectives (3.49) Note 1 to entry: An effect is a deviation from the expected — positive or negative. Note 2 to entry: Uncertainty is the state, even partial, of deficiency of information related to, understanding or knowledge of, an event, its consequence, or likelihood. Note 3 to entry: Risk is often characterized by reference to potential “events” (as defined in ISO Guide 73:2009, 3.5.1.3) and “consequences” (as defined in ISO Guide 73:2009, 3.6.1.3), or a combination of these. Note 4 to entry: Risk is often expressed in terms of a combination of the consequences of an event (including changes in circumstances) and the associated “likelihood” (as defined in ISO Guide 73:2009, 3.6.1.1) of occurrence. Note 5 to entry: In the context of information security management systems, information security risks can be expressed as effect of uncertainty on information security objectives. Note 6 to entry: Information security risk is associated with the potential that threats will exploit vulnerabilities of an information asset or group of information assets and thereby cause harm to an organization. 3.62 risk acceptance informed decision to take a particular risk (3.61) Note 1 to entry: Risk acceptance can occur without risk treatment (3.72) or during the process (3.54) of risk treatment. Note 2 to entry: Accepted risks are subject to monitoring (3.46) and review (3.58). [SOURCE: ISO Guide 73:2009, 3.7.1.6] 3.63 risk analysis process (3.54) to comprehend the nature of risk (3.61) and to determine the level of risk (3.39) Note 1 to entry: Risk analysis provides the basis for risk evaluation (3.67) and decisions about risk treatment (3.72). Note 2 to entry: Risk analysis includes risk estimation. [SOURCE: ISO Guide 73:2009, 3.6.1]  8 © ISO/IEC 2018 – All rights reserved
  • 15.  ISO/IEC 27000:2018(E) 3.64 risk assessment overall process (3.54) of risk identification (3.68), risk analysis (3.63) and risk evaluation (3.67) [SOURCE: ISO Guide 73:2009, 3.4.1] 3.65 risk communication and consultation set of continual and iterative processes (3.54) that an organization conducts to provide, share or obtain information, and to engage in dialogue with stakeholders (3.37) regarding the management of risk (3.61) Note  1  to entry:  The information can relate to the existence, nature, form, likelihood (3.41), significance, evaluation, acceptability and treatment of risk. Note 2 to entry: Consultation is a two-way process of informed communication between an organization (3.50) and its stakeholders on an issue prior to making a decision or determining a direction on that issue. Consultation is — a process which impacts on a decision through influence rather than power; and — an input to decision making, not joint decision making. 3.66 risk criteria terms of reference against which the significance of risk (3.61) is evaluated Note 1 to entry: Risk criteria are based on organizational objectives, and external context (3.22) and internal context (3.38). Note 2 to entry: Risk criteria can be derived from standards, laws, policies (3.53) and other requirements (3.56). [SOURCE: ISO Guide 73:2009, 3.3.1.3] 3.67 risk evaluation process (3.54) of comparing the results of risk analysis (3.63) with risk criteria (3.66) to determine whether the risk (3.61) and/or its magnitude is acceptable or tolerable Note 1 to entry: Risk evaluation assists in the decision about risk treatment (3.72). [SOURCE: ISO Guide 73:2009, 3.7.1] 3.68 risk identification process (3.54) of finding, recognizing and describing risks (3.61) Note 1 to entry: Risk identification involves the identification of risk sources, events (3.21), their causes and their potential consequences (3.12). Note 2 to entry: Risk identification can involve historical data, theoretical analysis, informed and expert opinions, and stakeholders’ (3.37) needs. [SOURCE: ISO Guide 73:2009, 3.5.1] 3.69 risk management coordinated activities to direct and control an organization (3.50) with regard to risk (3.61) [SOURCE: ISO Guide 73:2009, 2.1]  © ISO/IEC 2018 – All rights reserved 9
  • 16.  ISO/IEC 27000:2018(E) 3.70 risk management process systematic application of management policies (3.53), procedures and practices to the activities of communicating, consulting, establishing the context and identifying, analysing, evaluating, treating, monitoring and reviewing risk (3.61) Note 1 to entry: ISO/IEC 27005 uses the term “process” (3.54) to describe risk management overall. The elements within the risk management (3.69) process are referred to as “activities”. [SOURCE: ISO Guide 73:2009, 3.1, modified — Note 1 to entry has been added.] 3.71 risk owner person or entity with the accountability and authority to manage a risk (3.61) [SOURCE: ISO Guide 73:2009, 3.5.1.5] 3.72 risk treatment process (3.54) to modify risk (3.61) Note 1 to entry: Risk treatment can involve: — avoiding the risk by deciding not to start or continue with the activity that gives rise to the risk; — taking or increasing risk in order to pursue an opportunity; — removing the risk source; — changing the likelihood (3.40); — changing the consequences (3.12); — sharing the risk with another party or parties (including contracts and risk financing); — retaining the risk by informed choice. Note  2  to entry:  Risk treatments that deal with negative consequences are sometimes referred to as “risk mitigation”, “risk elimination”, “risk prevention” and “risk reduction”. Note 3 to entry: Risk treatment can create new risks or modify existing risks. [SOURCE: ISO Guide 73:2009, 3.8.1, modified — “decision” has been replaced by “choice” in Note 1 to entry.] 3.73 security implementation standard document specifying authorized ways for realizing security 3.74 threat potential cause of an unwanted incident, which can result in harm to a system or organization (3.50) 3.75 top management person or group of people who directs and controls an organization (3.50) at the highest level Note  1  to entry:  Top management has the power to delegate authority and provide resources within the organization. Note  2  to entry:  If the scope of the management system (3.41) covers only part of an organization, then top management refers to those who direct and control that part of the organization.  10 © ISO/IEC 2018 – All rights reserved
  • 17.  ISO/IEC 27000:2018(E) Note 3 to entry: Top management is sometimes called executive management and can include Chief Executive Officers, Chief Financial Officers, Chief Information Officers, and similar roles. 3.76 trusted information communication entity autonomous organization (3.50) supporting information exchange within an information sharing community (3.34) 3.77 vulnerability weakness of an asset or control (3.14) that can be exploited by one or more threats (3.74) 4 Information security management systems 4.1 General Organizations of all types and sizes: a) collect, process, store, and transmit information; b) recognize that information, and related processes, systems, networks and people are important assets for achieving organization objectives; c) face a range of risks that can affect the functioning of assets; and d) address their perceived risk exposure by implementing information security controls. All information held and processed by an organization is subject to threats of attack, error, nature (for example, flood or fire), etc., and is subject to vulnerabilities inherent in its use. The term information security is generally based on information being considered as an asset which has a value requiring appropriate protection, for example, against the loss of availability, confidentiality and integrity. Enabling accurate and complete information to be available in a timely manner to those with an authorized need is a catalyst for business efficiency. Protecting information assets through defining, achieving, maintaining, and improving information security effectively is essential to enable an organization to achieve its objectives, and maintain and enhance its legal compliance and image. These coordinated activities directing the implementation of suitable controls and treating unacceptable information security risks are generally known as elements of information security management. As information security risks and the effectiveness of controls change depending on shifting circumstances, organizations need to: a) monitor and evaluate the effectiveness of implemented controls and procedures; b) identify emerging risks to be treated; and c) select, implement and improve appropriate controls as needed. To interrelate and coordinate such information security activities, each organization needs to establish its policy and objectives for information security and achieve those objectives effectively by using a management system. 4.2 What is an ISMS? 4.2.1 Overview and principles An ISMS consists of the policies, procedures, guidelines, and associated resources and activities, collectively managed by an organization, in the pursuit of protecting its information assets. An ISMS is a systematic approach for establishing, implementing, operating, monitoring, reviewing, maintaining  © ISO/IEC 2018 – All rights reserved 11
  • 18.  ISO/IEC 27000:2018(E) and improving an organization’s information security to achieve business objectives. It is based on a risk assessment and the organization’s risk acceptance levels designed to effectively treat and manage risks. Analysing requirements for the protection of information assets and applying appropriate controls to ensure the protection of these information assets, as required, contributes to the successful implementation of an ISMS. The following fundamental principles also contribute to the successful implementation of an ISMS: a) awareness of the need for information security; b) assignment of responsibility for information security; c) incorporating management commitment and the interests of stakeholders; d) enhancing societal values; e) risk assessments determining appropriate controls to reach acceptable levels of risk; f) security incorporated as an essential element of information networks and systems; g) active prevention and detection of information security incidents; h) ensuring a comprehensive approach to information security management; i) continual reassessment of information security and making of modifications as appropriate. 4.2.2 Information Information is an asset that, like other important business assets, is essential to an organization’s business and, consequently, needs to be suitably protected. Information can be stored in many forms, including: digital form (e.g. data files stored on electronic or optical media), material form (e.g. on paper), as well as unrepresented information in the form of knowledge of the employees. Information can be transmitted by various means including: courier, electronic or verbal communication. Whatever form information takes, or the means by which it is transmitted, it always needs appropriate protection. In many organizations, information is dependent on information and communications technology. This technology is often an essential element in the organization and assists in facilitating the creation, processing, storing, transmitting, protection and destruction of information. 4.2.3 Information security Information security ensures the confidentiality, availability and integrity of information. Information security involves the application and management of appropriate controls that involves consideration of a wide range of threats, with the aim of ensuring sustained business success and continuity, and minimizing consequences of information security incidents. Information security is achieved through the implementation of an applicable set of controls, selected through the chosen risk management process and managed using an ISMS, including policies, processes, procedures, organizational structures, software and hardware to protect the identified information assets. These controls need to be specified, implemented, monitored, reviewed and improved where necessary, to ensure that the specific information security and business objectives of the organization are met. Relevant information security controls are expected to be seamlessly integrated with an organization’s business processes. 4.2.4 Management Management involves activities to direct, control, and continually improve the organization within appropriate structures. Management activities include the act, manner, or practice of organizing, handling, directing, supervising, and controlling resources. Management structures extend from one person in a small organization to management hierarchies consisting of many individuals in large organizations.  12 © ISO/IEC 2018 – All rights reserved
  • 19.  ISO/IEC 27000:2018(E) In terms of an ISMS, management involves the supervision and making of decisions necessary to achieve business objectives through the protection of the organization’s information assets. Management of information security is expressed through the formulation and use of information security policies, procedures and guidelines, which are then applied throughout the organization by all individuals associated with the organization. 4.2.5 Management system A management system uses a framework of resources to achieve an organization’s objectives. The management system includes organizational structure, policies, planning activities, responsibilities, practices, procedures, processes and resources. In terms of information security, a management system allows an organization to: a) satisfy the information security requirements of customers and other stakeholders; b) improve an organization’s plans and activities; c) meet the organization’s information security objectives; d) comply with regulations, legislation and industry mandates; and e) manage information assets in an organized way that facilitates continual improvement and adjustment to current organizational goals. 4.3 Process approach Organizations need to identify and manage many activities in order to function effectively and efficiently. Any activity using resources needs to be managed to enable the transformation of inputs into outputs using a set of interrelated or interacting activities; this is also known as a process. The output from one process can directly form the input to another process and generally this transformation is carried out under planned and controlled conditions. The application of a system of processes within an organization, together with the identification and interactions of these processes, and their management, can be referred to as a “process approach”. 4.4 Why an ISMS is important Risks associated with an organization’s information assets need to be addressed. Achieving information security requires the management of risk, and encompasses risks from physical, human and technology related threats associated with all forms of information within or used by the organization. The adoption of an ISMS is expected to be a strategic decision for an organization and it is necessary that this decision is seamlessly integrated, scaled and updated in accordance with the needs of the organization. The design and implementation of an organization’s ISMS is influenced by the needs and objectives of the organization, the security requirements, the business processes employed and the size and structure of the organization. The design and operation of an ISMS needs to reflect the interests and information security requirements of all of the organization’s stakeholders including customers, suppliers, business partners, shareholders and other relevant third parties. Inaninterconnectedworld,informationandrelatedprocesses,systems,andnetworksconstitutecritical business assets. Organizations and their information systems and networks face security threats from a wide range of sources, including computer-assisted fraud, espionage, sabotage, vandalism, fire and flood. Damage to information systems and networks caused by malicious code, computer hacking, and denial of service attacks have become more common, more ambitious, and increasingly sophisticated. An ISMS is important to both public and private sector businesses. In any industry, an ISMS is an enabler that supports e-business and is essential for risk management activities. The interconnection of public and private networks and the sharing of information assets increase the difficulty of controlling  © ISO/IEC 2018 – All rights reserved 13
  • 20.  ISO/IEC 27000:2018(E) access to and handling of information. In addition, the distribution of mobile storage devices containing information assets can weaken the effectiveness of traditional controls. When organizations adopt the ISMS family of standards, the ability to apply consistent and mutually-recognizable information security principles can be demonstrated to business partners and other interested parties. Information security is not always taken into account in the design and development of information systems. Further, information security is often thought of as being a technical solution. However, the information security that can be achieved through technical means is limited, and can be ineffective without being supported by appropriate management and procedures within the context of an ISMS. Integrating security into a functionally complete information system can be difficult and costly. An ISMS involves identifying which controls are in place and requires careful planning and attention to detail. As an example, access controls, which can be technical (logical), physical, administrative (managerial) or a combination, provide a means to ensure that access to information assets is authorized and restricted based on the business and information security requirements. The successful adoption of an ISMS is important to protect information assets allowing an organization to: a) achieve greater assurance that its information assets are adequately protected against threats on a continual basis; b) maintain a structured and comprehensive framework for identifying and assessing information security risks, selecting and applying applicable controls, and measuring and improving their effectiveness; c) continually improve its control environment; and d) effectively achieve legal and regulatory compliance. 4.5 Establishing, monitoring, maintaining and improving an ISMS 4.5.1 Overview An organization needs to undertake the following steps in establishing, monitoring, maintaining and improving its ISMS: a) identify information assets and their associated information security requirements (see 4.5.2); b) assess information security risks (see 4.5.3) and treat information security risks (see 4.5.4); c) select and implement relevant controls to manage unacceptable risks (see 4.5.5); d) monitor, maintain and improve the effectiveness of controls associated with the organization’s information assets (see 4.5.6). To ensure the ISMS is effectively protecting the organization’s information assets on an ongoing basis, it is necessary that steps a) to d) be continually repeated to identify changes in risks or in the organization’s strategies or business objectives. 4.5.2 Identifying information security requirements Within the overall strategy and business objectives of the organization, its size and geographical spread, information security requirements can be identified through an understanding of the following: a) identified information assets and their value; b) business needs for information processing, storage and communication; c) legal, regulatory, and contractual requirements. Conducting a methodical assessment of the risks associated with the organization’s information assets involves analysing threats to information assets, vulnerabilities to and the likelihood of a threat  14 © ISO/IEC 2018 – All rights reserved
  • 21.  ISO/IEC 27000:2018(E) materializing to information assets, and the potential impact of any information security incident on information assets. The expenditure on relevant controls is expected to be proportionate to the perceived business impact of the risk materializing. 4.5.3 Assessing information security risks Managing information security risks requires a suitable risk assessment and risk treatment method which can include an estimation of the costs and benefits, legal requirements, the concerns of stakeholders, and other inputs and variables as appropriate. Risk assessment should identify, quantify, and prioritize risks against criteria for risk acceptance and objectives relevant to the organization. The results should guide and determine the appropriate management action and priorities for managing information security risks and for implementing controls selected to protect against these risks. Risk assessment should include: — the systematic approach of estimating the magnitude of risks (risk analysis); and — the process of comparing the estimated risks against risk criteria to determine the significance of the risks (risk evaluation). Risk assessment should be performed periodically to address changes in the information security requirements and in the risk situation, for example in the assets, threats, vulnerabilities, impacts, the risk evaluation, and when significant changes occur. These risk assessments should be undertaken in a methodical manner capable of producing comparable and reproducible results. The information security risk assessment should have a clearly defined scope in order to be effective and should include relationships with risk assessments in other areas, if appropriate. ISO/IEC  27005 provides information security risk management guidance, including advice on risk assessment, risk treatment, risk acceptance, risk reporting, risk monitoring and risk review. Examples of risk assessment methodologies are included as well. 4.5.4 Treating information security risks Before considering the treatment of a risk, the organization should define criteria for determining whether or not risks can be accepted. Risks can be accepted if, for example, it is assessed that the risk is low or that the cost of treatment is not cost-effective for the organization. Such decisions should be recorded. For each of the risks identified following the risk assessment, a risk treatment decision needs to be made. Possible options for risk treatment include the following: a) applying appropriate controls to reduce the risks; b) knowingly and objectively accepting risks, providing they clearly satisfy the organization’s policy and criteria for risk acceptance; c) avoiding risks by not allowing actions that would cause the risks to occur; d) sharing the associated risks to other parties, for example insurers or suppliers. For those risks where the risk treatment decision has been to apply appropriate controls, these controls should be selected and implemented. 4.5.5 Selecting and implementing controls Once information security requirements have been identified (see 4.5.2), information security risks to the identified information assets have been determined and assessed (see 4.5.3) and decisions for the  © ISO/IEC 2018 – All rights reserved 15
  • 22.  ISO/IEC 27000:2018(E) treatment of information security risks have been made (see 4.5.4), then selection and implementation of controls for risk reduction apply. Controls should ensure that risks are reduced to an acceptable level taking the following into account: a) requirements and constraints of national and international legislation and regulations; b) organizational objectives; c) operational requirements and constraints; d) their cost of implementation and operation in relation to the risks being reduced, and remaining proportional to the organization’s requirements and constraints; e) their objectives to monitor, evaluate and improve the efficiency and effectiveness of information security controls to support the organization’s aims. The selection and implementation of controls should be documented within a statement of applicability to assist with compliance requirements; f) the need to balance the investment in implementation and operation of controls against the loss likely to result from information security incidents. The controls specified in ISO/IEC  27002 are acknowledged as best practices applicable to most organizations and readily tailored to accommodate organizations of various sizes and complexities. Other standards in the ISMS family of standards provide guidance on the selection and application of ISO/IEC 27002 controls for the ISMS. Information security controls should be considered at the systems and projects requirements specification and design stage. Failure to do so can result in additional costs and less effective solutions, and, in the worst case, inability to achieve adequate security. Controls can be selected from ISO/IEC  27002 or from other control sets. Alternatively, new controls can be designed to meet the specific needs of the organization. It is necessary to recognize the possibility that some controls not be applicable to every information system or environment, and not be practicable for all organizations. Sometimes, implementing a chosen set of controls takes time and, during that time, the level of risk can be higher than can be tolerated on a long-term basis. Risk criteria should cover tolerability of risks on a short-term basis while controls are being implemented. Interested parties should be informed of the levels of risk that are estimated or anticipated at different points in time as controls are progressively implemented. It should be kept in mind that no set of controls can achieve complete information security. Additional management actions should be implemented to monitor, evaluate and improve the efficiency and effectiveness of information security controls to support the organization’s aims. The selection and implementation of controls should be documented within a statement of applicability to assist with compliance requirements. 4.5.6 Monitor, maintain and improve the effectiveness of the ISMS An organization needs to maintain and improve the ISMS through monitoring and assessing performance against organizational policies and objectives, and reporting the results to management for review. This ISMS review checks that the ISMS includes specified controls that are suitable to treat risks within the ISMS scope. Furthermore, based on the records of these monitored areas, it provides evidence of verification and traceability of corrective, preventive and improvement actions. 4.5.7 Continual improvement The aim of continual improvement of an ISMS is to increase the probability of achieving objectives concerning the preservation of the confidentiality, availability and integrity of information. The focus of continual improvement is seeking opportunities for improvement and not assuming that existing management activities are good enough or as good as they can.  16 © ISO/IEC 2018 – All rights reserved
  • 23.  ISO/IEC 27000:2018(E) Actions for improvement include the following: a) analysing and evaluating the existing situation to identify areas for improvement; b) establishing the objectives for improvement; c) searching for possible solutions to achieve the objectives; d) evaluating these solutions and making a selection; e) implementing the selected solution; f) measuring, verifying, analysing and evaluating results of the implementation to determine that the objectives have been met; g) formalizing changes. Results are reviewed, as necessary, to determine further opportunities for improvement. In this way, improvement is a continual activity, i.e. actions are repeated frequently. Feedback from customers and other interested parties, audits and review of the information security management system can also be used to identify opportunities for improvement. 4.6 ISMS critical success factors A large number of factors are critical to the successful implementation of an ISMS to allow an organization to meet its business objectives. Examples of critical success factors include the following: a) information security policy, objectives, and activities aligned with objectives; b) an approach and framework for designing, implementing, monitoring, maintaining, and improving information security consistent with the organizational culture; c) visible support and commitment from all levels of management, especially top management; d) an understanding of information asset protection requirements achieved through the application of information security risk management (see ISO/IEC 27005); e) an effective information security awareness, training and education programme, informing all employees and other relevant parties of their information security obligations set forth in the information security policies, standards, etc., and motivating them to act accordingly; f) an effective information security incident management process; g) an effective business continuity management approach; h) a measurement system used to evaluate performance in information security management and feedback suggestions for improvement. An ISMS increases the likelihood of an organization consistently achieving the critical success factors required to protect its information assets. 4.7 Benefits of the ISMS family of standards The benefits of implementing an ISMS primarily result from a reduction in information security risks (i.e. reducing the probability of and/or impact caused by information security incidents). Specifically, benefits realized for an organization to achieve sustainable success from the adoption of the ISMS family of standards include the following: a) a structured framework supporting the process of specifying, implementing, operating and maintaining a comprehensive, cost-effective, value creating, integrated and aligned ISMS that meets the organization’s needs across different operations and sites;  © ISO/IEC 2018 – All rights reserved 17
  • 24.  ISO/IEC 27000:2018(E) b) assistance for management in consistently managing and operating in a responsible manner their approach towards information security management, within the context of corporate risk management and governance, including educating and training business and system owners on the holistic management of information security; c) promotion of globally accepted, good information security practices in a non-prescriptive manner, giving organizations the latitude to adopt and improve relevant controls that suit their specific circumstances and to maintain them in the face of internal and external changes; d) provision of a common language and conceptual basis for information security, making it easier to place confidence in business partners with a compliant ISMS, especially if they require certification against ISO/IEC 27001 by an accredited certification body; e) increase in stakeholder trust in the organization; f) satisfying societal needs and expectations; g) more effective economic management of information security investments. 5 ISMS family of standards 5.1 General information The ISMS family of standards consists of inter-related standards, already published or under development, and contains a number of significant structural components. These components are focused on: — standards describing ISMS requirements (ISO/IEC 27001); — certification body requirements (ISO/IEC  27006) for those certifying conformity with ISO/IEC 27001; and — additional requirement framework for sector-specific implementations of the ISMS (ISO/IEC 27009). Other documents provide guidance for various aspects of an ISMS implementation, addressing a generic process as well as sector-specific guidance. Relationships between the ISMS family of standards are illustrated in Figure 1.  18 © ISO/IEC 2018 – All rights reserved
  • 25.  ISO/IEC 27000:2018(E) Requirement standards - Clause 5.3 Guidelines standards - Clause 5.4 Vocabulary standard - Clause 5.2 27009 27006 27001 27000 27002 27003 27004 27005 27007 TR 27008 27013 27014 TR 27016 27010 27011 27017 27018 27019 27021 2703x 2704x Sector-speci ic guidelines standards - Clause 5.5 Control-speci ic guidelines standards (out of the scope of this document) ISMS family of standards Figure 1 — ISMS family of standards relationships Each of the ISMS family standards is described below by its type (or role) within the ISMS family of standards and its reference number. 5.2 Standard describing an overview and terminology: ISO/IEC 27000 (this document) Information technology — Security techniques — Information security management systems — Overview and vocabulary Scope: This document provides to organizations and individuals: a) an overview of the ISMS family of standards; b) an introduction to information security management systems; and c) terms and definitions used throughout the ISMS family of standards. Purpose: This document describes the fundamentals of information security management systems, which form the subject of the ISMS family of standards and defines related terms. 5.3 Standards specifying requirements 5.3.1 ISO/IEC 27001 Information technology — Security techniques — Information security management systems — Requirements Scope: This document specifies the requirements for establishing, implementing, operating, monitoring, reviewing, maintaining and improving formalized information security management systems (ISMS) within the context of the organization’s overall business risks. It specifies requirements for the implementation of information security controls customized to the needs of individual organizations or parts thereof. This document can be used by all organizations, regardless of type, size and nature.  © ISO/IEC 2018 – All rights reserved 19
  • 26.  ISO/IEC 27000:2018(E) Purpose: ISO/IEC  27001 provides normative requirements for the development and operation of an ISMS, including a set of controls for the control and mitigation of the risks associated with the information assets which the organization seeks to protect by operating its ISMS. Organizations operating an ISMS may have its conformity audited and certified. The control objectives and controls from ISO/IEC 27001:2013, Annex A shall be selected as part of this ISMS process as appropriate to cover the identified requirements. The control objectives and controls listed in ISO/IEC 27001:2013, Table A.1 are directly derived from and aligned with those listed in ISO/IEC 27002:2013, Clauses 5 to 18. 5.3.2 ISO/IEC 27006 Information technology — Security techniques — Requirements for bodies providing audit and certification of information security management systems Scope: This document specifies requirements and provides guidance for bodies providing audit and ISMS certification in accordance with ISO/IEC 27001, in addition to the requirements contained within ISO/IEC 17021. It is primarily intended to support the accreditation of certification bodies providing ISMS certification according to ISO/IEC 27001. The requirements contained in this document need to be demonstrated in terms of competence and reliability by anybody providing ISMS certification, and the guidance contained in this document provides additional interpretation of these requirements for anybody providing ISMS certification. Purpose: ISO/IEC  27006 supplements ISO/IEC  17021 in providing the requirements by which certification organizations are accredited, thus permitting these organizations to provide compliance certifications consistently against the requirements set forth in ISO/IEC 27001. 5.3.3 ISO/IEC 27009 Information technology  — Security techniques  — Sector-specific application of ISO/IEC 27001 — Requirements Scope: This document defines the requirements for the use of ISO/IEC 27001 in any specific sector (field, application area or market sector). It explains how to include requirements additional to those in ISO/IEC 27001, how to refine any of the ISO/IEC 27001 requirements, and how to include controls or control sets in addition to ISO/IEC 27001:2013, Annex A. Purpose: ISO/IEC 27009 ensures that additional or refined requirements are not in conflict with the requirements in ISO/IEC 27001. 5.4 Standards describing general guidelines 5.4.1 ISO/IEC 27002 Information technology — Security techniques — Code of practice for information security controls Scope: This document provides a list of commonly accepted control objectives and best practice controls to be used as implementation guidance when selecting and implementing controls for achieving information security. Purpose: ISO/IEC 27002 provides guidance on the implementation of information security controls. Specifically, Clauses 5 to 18 provide specific implementation advice and guidance on best practice in support of the controls specified in ISO/IEC 27001:2013, A.5 to A.18. 5.4.2 ISO/IEC 27003 Information technology — Security techniques — Information security management —Guidance Scope: This document provides explanation and guidance on ISO/IEC 27001:2013.  20 © ISO/IEC 2018 – All rights reserved
  • 27.  ISO/IEC 27000:2018(E) Purpose: ISO/IEC  27003 provides a background to the successful implementation of the ISMS in accordance with ISO/IEC 27001. 5.4.3 ISO/IEC 27004 Information technology — Security techniques — Information security management — Monitoring, measurement, analysis and evaluation Scope: This document provides guidelines intended to assist organizations to evaluate the information security performance and the effectiveness of the ISMS in order to fulfil the requirements of ISO/IEC 27001:2013, 9.1. It addresses: a) the monitoring and measurement of information security performance; b) the monitoring and measurement of the effectiveness of an information security management system (ISMS) including its processes and controls; c) the analysing and the evaluating of the results of monitoring and measurement. Purpose: ISO/IEC 27004 provides a framework allowing an assessment of ISMS effectiveness to be measured and evaluated in accordance with ISO/IEC 27001. 5.4.4 ISO/IEC 27005 Information technology — Security techniques — Information security risk management Scope: This document provides guidelines for information security risk management. The approach described within this document supports the general concepts specified in ISO/IEC 27001. Purpose: ISO/IEC  27005 provides guidance on implementing a process-oriented risk management approach to assist in satisfactorily implementing and fulfilling the information security risk management requirements of ISO/IEC 27001. 5.4.5 ISO/IEC 27007 Information technology — Security techniques — Guidelines for information security management systems auditing Scope: This document provides guidance on conducting ISMS audits, as well as guidance on the competence of information security management system auditors, in addition to the guidance contained in ISO 19011, which is applicable to management systems in general. Purpose: ISO/IEC  27007 will provide guidance to organizations needing to conduct internal or external audits of an ISMS or to manage an ISMS audit programme against the requirements specified in ISO/IEC 27001. 5.4.6 ISO/IEC TR 27008 Information technology — Security techniques — Guidelines for auditors on information security controls Scope: This document provides guidance on reviewing the implementation and operation of controls, including technical compliance checking of information system controls, in compliance with an organization’s established information security standards. Purpose: This document provides a focus on reviews of information security controls, including checking of technical compliance, against an information security implementation standard, which is established by the organization. It does not intend to provide any specific guidance on compliance checking regarding measurement, risk assessment or audit of an ISMS as specified in ISO/IEC  27004, ISO/IEC  27005 or ISO/IEC 27007, respectively. This documentis not intended for management systems audits.  © ISO/IEC 2018 – All rights reserved 21
  • 28.  ISO/IEC 27000:2018(E) 5.4.7 ISO/IEC 27013 Information technology — Security techniques — Guidance on the integrated implementation of ISO/IEC 27001 and ISO/IEC 20000-1 Scope: This document provides guidance on the integrated implementation of ISO/IEC  27001 and ISO/IEC 20000-1 for organizations that are intending to either: a) implement ISO/IEC 27001 when ISO/IEC 20000-1 is already implemented, or vice versa; b) implement both ISO/IEC 27001 and ISO/IEC 20000-1 together; c) integrate existing management systems based on ISO/IEC 27001 and ISO/IEC 20000-1. This document focuses exclusively on the integrated implementation of an information security management system (ISMS) as specified in ISO/IEC 27001 and a service management system (SMS) as specified in ISO/IEC 20000-1. In practice, ISO/IEC 27001 and ISO/IEC 20000-1 can also be integrated with other management system standards, such as ISO 9001 and ISO 14001. Purpose: To provide organizations with a better understanding of the characteristics, similarities and differences of ISO/IEC 27001 and ISO/IEC 20000-1 to assist in the planning of an integrated management system that conforms to both International Standards. 5.4.8 ISO/IEC 27014 Information technology — Security techniques — Governance of information security Scope: This document will provide guidance on principles and processes for the governance of information security, by which organizations can evaluate, direct and monitor the management of information security. Purpose: Information security has become a key issue for organizations. Not only are there increasing regulatory requirements but also the failure of an organization’s information security measures can have a direct impact on an organization’s reputation. Therefore, governing bodies, as part of their governance responsibilities, are increasingly required to have oversight of information security to ensure the objectives of the organization are achieved. 5.4.9 ISO/IEC TR 27016 Information technology — Security techniques — Information security management — Organizational economics Scope: This document provides a methodology allowing organizations to better understand economically how to more accurately value their identified information assets, value the potential risks to those information assets, appreciate the value that information protection controls deliver to these information assets, and determine the optimum level of resources to be applied in securing these information assets. Purpose: This document supplements the ISMS family of standards by overlaying an economics perspective in the protection of an organization’s information assets in the context of the wider societal environment in which an organization operates and providing guidance on how to apply organizational economics of information security through the use of models and examples. 5.4.10 ISO/IEC 27021 Information technology  — Security techniques  — Information security management  — Competence requirements for information security management systems professionals  22 © ISO/IEC 2018 – All rights reserved
  • 29.  ISO/IEC 27000:2018(E) Scope: This document specifies the requirements of competence for ISMS professionals leading or involved in establishing, implementing, maintaining and continually improving one or more information security management system processes that conforms to ISO/IEC 27001:2013. Purpose: This document is intended for use by: a) individuals who would like to demonstrate their competence as information security management system (ISMS) professionals, or who wish to understand and accomplish the competence required for working in this area, as well as wishing to broaden their knowledge, b) organizations seeking potential ISMS professional candidates to define the competence required for positions in ISMS related roles, c) bodies to develop certification for ISMS professionals which need a body of knowledge (BOK) for examination sources, and d) organizations for education and training, such as universities and vocational institutions, to align their syllabuses and courses to the competence requirements for ISMS professionals. 5.5 Standards describing sector-specific guidelines 5.5.1 ISO/IEC 27010 Information technology — Security techniques — Information security management for inter-sector and inter-organizational communications Scope: This document provides guidelines in addition to guidance given in the ISO/IEC  27000 family of standards for implementing information security management within information sharing communities. This document provides controls and guidance specifically relating to initiating, implementing, maintaining, and improving information security in inter-organizational and inter-sector communications. Purpose: This document is applicable to all forms of exchange and sharing of sensitive information, both public and private, nationally and internationally, within the same industry or market sector or between sectors. In particular, it can be applicable to information exchanges and sharing relating to the provision, maintenance and protection of an organization’s or state’s critical infrastructure. 5.5.2 ISO/IEC 27011 Information technology — Security techniques — Code of practice for information security controls based on ISO/IEC 27002 for telecommunications organizations Scope: This document provides guidelines supporting the implementation of information security controls in telecommunications organizations. Purpose: ISO/IEC  27011 allows telecommunications organizations to meet baseline information security management requirements of confidentiality, integrity, availability and any other relevant security property. 5.5.3 ISO/IEC 27017 Information technology — Security techniques — Code of practice for information security controls based on ISO/IEC 27002 for cloud services Scope: ISO/IEC 27017 gives guidelines for information security controls applicable to the provision and use of cloud services by providing: — additional implementation guidance for relevant controls specified in ISO/IEC 27002;  © ISO/IEC 2018 – All rights reserved 23
  • 30.  ISO/IEC 27000:2018(E) — additional controls with implementation guidance that specifically relate to cloud services. Purpose: This document provides controls and implementation guidance for both cloud service providers and cloud service customers. 5.5.4 ISO/IEC 27018 Information technology — Security techniques — Code of practice for protection of personally identifiable information (PII) in public clouds acting as PII processors Scope: ISO/IEC 27018 establishes commonly accepted control objectives, controls and guidelines for implementing measures to protect personally identifiable information (PII) in accordance with the privacy principles in ISO/IEC 29100 for the public cloud computing environment. Purpose: This document is applicable to organizations, including public and private companies, government entities and not-for-profit organizations, which provide information processing services as PII processors via cloud computing under contract to other organizations. The guidelines in this document can also be relevant to organizations acting as PII controllers. However, it is possible that PII controllers be subject to additional PII protection legislation, regulations and obligations, not applying to PII processors, and these are not covered in this document. 5.5.5 ISO/IEC 27019 Information technology — Security techniques — Information security controls for the energy utility industry Scope: This document provides guidance based on ISO/IEC  27002:2013 applied to process control systems used by the energy utility industry for controlling and monitoring the production or generation, transmission, storage and distribution of electric power, gas, oil and heat, and for the control of associated supporting processes. This includes in particular the following: — central and distributed process control, monitoring and automation technology as well as information systems used for their operation, such as programming and parameterization devices; — digital controllers and automation components such as control and field devices or programmable logic controllers (PLCs), including digital sensor and actuator elements; — allfurthersupportinginformationsystemsusedintheprocesscontroldomain,e.g.forsupplementary data visualization tasks and for controlling, monitoring, data archiving, historian logging, reporting and documentation purposes; — communication technology used in the process control domain, e.g. networks, telemetry, telecontrol applications and remote control technology; — advanced metering infrastructure (AMI) components, e.g. smart meters; — measurement devices, e.g. for emission values; — digital protection and safety systems, e.g. protection relays, safety PLCs, emergency governor mechanisms; — energy management systems, e.g. of distributed energy resources (DER), electric charging infrastructures, in private households, residential buildings or industrial customer installations; — distributed components of smart grid environments, e.g. in energy grids, in private households, residential buildings or industrial customer installations; — allsoftware,firmwareandapplicationsinstalledonabove-mentionedsystems,e.g.DMS(distribution management system) applications or OMS (outage management system); — any premises housing the above-mentioned equipment and systems;  24 © ISO/IEC 2018 – All rights reserved
  • 31.  ISO/IEC 27000:2018(E) — remote maintenance systems for above-mentioned systems. This document does not apply to the process control domain of nuclear facilities. This domain is covered by IEC 62645. This document also includes a requirement to adapt the risk assessment and treatment processes described in ISO/IEC 27001:2013 to the energy utility industry-sector–specific guidance provided in this document. Purpose: In addition to the security objectives and measures that are set forth in ISO/IEC 27002, this document provides guidelines for systems used by energy utilities and energy suppliers on information security controls which address further, special requirements. 5.5.6 ISO 27799 Health informatics — Information security management in health using ISO/IEC 27002 Scope: This document gives guidelines for organizational information security standards and information security management practices including the selection, implementation and management of controls taking into consideration the organization’s information security risk environment(s). This document provides implementation guidance for the controls described in ISO/IEC  27002 and supplements them where necessary, so that they can be effectively used for managing health information security. Purpose: ISO 27799 provides health organizations with an adaptation of the ISO/IEC 27002 guidelines unique to their industry sector which are additional to the guidance provided towards fulfilling the requirements of ISO/IEC 27001:2013, Annex A.  © ISO/IEC 2018 – All rights reserved 25
  • 32.  ISO/IEC 27000:2018(E) Bibliography [1] ISO 9000:2015, Quality management systems — Fundamentals and vocabulary [2] ISO/IEC/IEEE 15939:2017, Systems and software engineering — Measurement process [3] ISO/IEC 17021, Conformity assessment — Requirements for bodies providing audit and certification of management systems [4] ISO 19011:2011, Guidelines for auditing management systems [5] ISO/IEC  20000-1:2011, Information technology  — Service management  — Part  1: Service management system requirements [6] ISO/IEC 27001, Information technology — Security techniques — Information security management systems — Requirements [7] ISO/IEC 27002, Information technology — Security techniques — Code of practice for information security controls [8] ISO/IEC 27003, Information technology — Security techniques — Information security management — Guidance [9] ISO/IEC  27004, Information technology — Security techniques — Information security management — Monitoring, measurement, analysis and evaluation [10] ISO/IEC  27005, Information technology — Security techniques — Information security risk management [11] ISO/IEC  27006, Information technology — Security techniques — Requirements for bodies providing audit and certification of information security management systems [12] ISO/IEC  27007, Information technology — Security techniques — Guidelines for information security management systems auditing [13] ISO/IEC TR 27008, Information technology — Security techniques — Guidelines for auditors on information security controls [14] ISO/IEC  27009, Information technology  — Security techniques  — Sector-specific application of ISO/IEC 27001 — Requirements [15] ISO/IEC 27010, Information technology — Security techniques — Information security management for inter-sector and inter-organizational communications [16] ISO/IEC 27011, Information technology — Security techniques — Code of practice for information security controls based on ISO/IEC 27002 for telecommunications organizations [17] ISO/IEC  27013, Information technology — Security techniques — Guidance on the integrated implementation of ISO/IEC 27001 and ISO/IEC 20000‑1 [18] ISO/IEC  27014, Information technology — Security techniques — Governance of information security [19] ISO/IEC  TR  27016, Information technology — Security techniques — Information security management — Organizational economics [20] ISO/IEC 27017, Information technology — Security techniques — Code of practice for information security controls based on ISO/IEC 27002 for cloud services [21] ISO/IEC 27018, Information technology — Security techniques — Code of practice for protection of personally identifiable information (PII) in public clouds acting as PII processors  26 © ISO/IEC 2018 – All rights reserved
  • 33.  ISO/IEC 27000:2018(E) [22] ISO/IEC 27019, Information technology — Security techniques — Information security controls for the energy utility industry [23] ISO/IEC 27021, Information technology — Security techniques — Competence requirements for information security management systems professionals [24] ISO 27799, Health informatics — Information security management in health using ISO/IEC 27002 [25] ISO Guide 73:2009, Risk management — Vocabulary  © ISO/IEC 2018 – All rights reserved 27
  • 34.  ISO/IEC 27000:2018(E)  © ISO/IEC 2018 – All rights reserved ICS 01.040.35; 03.100.70; 35.030 Price based on 27 pages