How is a security incident defined?

A security incident is defined as an event that compromises information integrity, confidentiality, or availability. This definition highlights the critical aspects of security: protecting data from unauthorized access, ensuring its accuracy, and maintaining its availability when needed. An incident does not necessarily have to result in a breach to be classified as such; it could involve attempts to gain unauthorized access or disruptions that could potentially harm the systems or data.

The focus on integrity, confidentiality, and availability underscores the objectives of cybersecurity, which are often referred to as the "CIA triad." Incidents that threaten any of these areas must be addressed promptly to mitigate risks and protect organizational assets.

The other options do not accurately reflect the definition of a security incident. For instance, an event that increases system efficiency does not pertain to security; a successful cyberattack with no consequences implies no harm was done, thus not constituting an incident; and an event that does not require a response contradicts the nature of what qualifies as an incident since any event that poses a security threat necessitates attention.