Breach

11/09/2025

Author: Stuart Barker | ISO 27001 Expert and Thought Leader

breach, in the context of information security, is a security event where the confidentiality, integrity, or availability of an information asset has been compromised. It’s often the result of a successful cyber attack or an internal mistake, leading to unauthorised access, disclosure, or destruction of information.

Types & Examples

  • Data Breach: The most common type, involving the unauthorised exposure of sensitive information.
    • Example: A hacker gains access to a database and steals customer credit card numbers.
  • Confidentiality Breach: Unauthorised disclosure of information.
    • Example: An employee accidentally emails a confidential report to a competitor.
  • Integrity Breach: The unauthorised modification or destruction of data.
    • Example: A virus corrupts a company’s financial records, or an unauthorised user alters a patient’s medical history.
  • Availability Breach: A disruption that makes information or systems unavailable.
    • Example: A distributed denial-of-service (DDoS) attack that takes down a company’s website, preventing customers from accessing online services.

Context

While the ISO 27001 standard itself doesn’t use the term “breach” as frequently as “incident,” it is a severe type of information security incident. The standard’s requirements for incident management (ISO 27001 Annex A 5.24 Information Security Incident Management Planning and Preparation), assessing incidents (ISO 27001 Annex A 5.25 Assessment And Decision On Information Security Events, responding to incidents (ISO 27001 Annex A 5.26 Response To Information Security Incidents) and learning from incidents (ISO 27001 Annex A 5.27 Learning From Information Security Incidents) are designed to help organisations prepare for, detect, and respond to breaches effectively, minimising their impact.

About the author

Stuart Barker is an information security practitioner of over 30 years. He holds an MSc in Software and Systems Security and an undergraduate degree in Software Engineering. He is an ISO 27001 expert and thought leader holding both ISO 27001 Lead Implementer and ISO 27001 Lead Auditor qualifications. In 2010 he started his first cyber security consulting business that he sold in 2018. He worked for over a decade for GE, leading a data governance team across Europe and since then has gone on to deliver hundreds of client engagements and audits.

He regularly mentors and trains professionals on information security and runs a successful ISO 27001 YouTube channel where he shows people how they can implement ISO 27001 themselves. He is passionate that knowledge should not be hoarded and brought to market the first of its kind online ISO 27001 store for all the tools and templates people need when they want to do it themselves.

In his personal life he is an active and a hobbyist kickboxer.

His specialisms are ISO 27001 and SOC 2 and his niche is start up and early stage business.