MITRE ATT&CK is a public knowledgebase of adversarial tactics and techniques, which can be used as a foundation for the development of specific cyber threat models and methodologies.
In short, it helps the industry define and standardise how to describe an attacker’s approach. MITRE ATT&CK collects and categorizes common attack tactics, techniques, and procedures (TTPs), then organises this information into a framework. This framework can be used to help explain how adversaries behave, what they are trying to do, and how they are trying to do it.