Information security controls are imperfect in various ways: controls can be overwhelmed or undermined (e.g. by competent hackers, fraudsters, or malware), fail in service (e.g. authentication failures), work partially or poorly (e.g. slow anomaly detection), or be more or less completely missing (e.g. not [yet] fully implemented, not [yet] fully operational, or never even conceived due to failures upstream in risk identification and analysis). Consequently, information security incidents are bound to occur to some extent, even in organisations that take their information security extremely seriously.
Managing incidents effectively involves detective and corrective controls designed to recognize and respond to events and incidents, minimize adverse impacts, gather forensic evidence (where applicable), and in due course ‘learn the lessons in terms of prompting improvements to the ISMS, typically by improving the preventive controls or other risk treatments.
Information security incidents commonly involve the exploitation of previously unrecognised and/or uncontrolled vulnerabilities, hence vulnerability management (e.g. applying relevant security patches to IT systems and addressing various control weaknesses in operational and management procedures) is part preventive and part corrective action.
Scope and purpose
The standard covers the processes for managing information security events, incidents, and vulnerabilities.
The standard expands on the information security incident management section of ISO/IEC 27002. It cross-references that section and explains its relationship to the ISO27k eForensics standards.
Structure and content
The standard lays out a process with 5 key stages:
- Prepare to deal with incidents e.g. prepare an incident management policy, and establish a competent team to deal with incidents;
- Identify and report information security incidents;
- Assess incidents and make decisions about how they are to be addressed e.g. patch things up and get back to business quickly, or collect forensic evidence even if it delays resolving the issues;
- Respond to incidents i.e. contain them, investigate them and resolve them;
- Learn the lessons – more than simply identifying the things that might have been done better, this stage involves actually making changes that improve the processes.
The standard provides template reporting forms for information security events, incidents and vulnerabilities.
Status of the standard
ISO/IEC 27035 replaced ISO TR 18044. It was first published in 2011 as a single standard then revised and split, initially into three parts and then four …
Part 1: Principles of incident management
Scope & purpose: part 1 outlines the concepts and principles underpinning information security incident management and introduces the remaining part/s of the standard. It describes an information security incident management process consisting of five phases and says how to improve incident management.
Content: the incident management process is described in five phases closely corresponding to the five phases in ISO/IEC 27035:2011 …
- Plan and prepare: establish an information security incident management policy, form an Incident Response Team etc.
- Detection and reporting: someone has to spot and report “events” that might be or turn into incidents;
- Assessment and decision: someone must assess the situation to determine whether it is in fact an incident;
- Responses: contain, eradicate, recover from and forensically analyse the incident, where appropriate;
- Lessons learned: make systematic improvements to the organisation’s management of information risks as a consequence of incidents experienced.
Annexes give examples of information security incidents and cross-references to the eForensics and ISO/IEC 27001 standards
- Part 1 is currently being revised to reflect ISO/IEC 27002:2022. The revision is at the Draft International Standard stage. The title will become “Information technology – Information security incident management – Part 1: Principles and process”. It is due to be published in 2023.
- The next version will [probably] have just two main sections: overview and process. Some of the current part 1 content may be transferred to other parts of ‘27035. The revised part 1 may cover:
- Incident management framework – an overall conceptual structure
- Crisis management in the immediate aftermath of a serious incident
- A point of contact to liaise, inform and assist with coordinating activities
Part 2: Guidelines to plan and prepare for incident response
- Scope & purpose: this part concerns assurance that the organisation is in fact ready to respond appropriately to information security incidents that may yet occur. It addresses the rhetorical question “Are we ready to respond to an incident?” and promotes learning from incidents to improve things for the future. It covers the Plan and Prepare and Lessons Learned phases of the process laid out in part 1 – the start and end.
- Content: 8 main clauses:
- Establishing information security incident management policy
- Updating of information security and risk management policies
- Creating an information security incident management plan
- Establishing an Incident Response Team
- Defining technical and other support
- Creating information security incident awareness and training
- Testing (or rather exercising) the information security incident management plan
- Lessons Learned
- Part 2 is being revised to align with the 2022 version of ISO/IEC 27002, with a new section on “Establishing internal and external relationships” and a shorter title omitting “Security techniques”.
Part 3: Guidelines for ICT incident response operations
- Abstract: “This document gives guidelines for information security incident response in ICT security operations. This document does this by firstly covering the operational aspects in ICT security operations from a people, processes, and technology perspective. It then further focuses on information security incident response in ICT security operations including information security incident detection, reporting, triage, analysis, response, containment, eradication, recovery and conclusion …” [Source: ISO/IEC 27035-3:2020]
- Scope & purpose: Part 3 concerns ‘security operations, specifically the organisation and processes necessary for the information security function to prepare for, and respond to, ICT security events and incidents – mostly active, deliberate attacks in fact.
- Content: section-by-section the standard steps through the core parts of the typical incident response process i.e. incident detection; notification; triage; analysis; containment, eradication and recovery; and reporting.
- Status: Part 3 was published in 2020. Unusually (and possibly in contravention of ISO directives?), the standard’s title includes an abbreviation.
Part 4: Coordination
- Scope & purpose: managing major incidents (such as botnet or phishing attacks) usually involves coordinating responses between the Incident Response Teams of several organisations (often in different countries) affected or involved in various ways e.g. Internet and cloud service providers, plus law enforcement, plus the targeted organisation/s.
- Content: the standard discusses the concept of Coordinated Incident Management and its application throughout the full incident management lifecycle – from response planning to lessons learned – by ‘communities’ (supply chains or networks) with common interests.
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