The NCSC defines a cyber incident as a breach of a system's security policy in order to effect its integrity or availability and/or the unauthorised access or attempted access to a system or systems; in line with the Computer Misuse Act (1990).
In general, types of activity that are commonly recognised as being breaches of a typical security policy are:
1. Attempts to gain unauthorised access to a system and/or to data.
2. The unauthorised use of systems for the processing or storing of data.
3. Changes to a systems firmware, software or hardware without the system owners consent.
4. Malicious disruption and/or denial of service.