Marking Definition

The marking-definition object represents a specific marking. Data markings typically represent handling or sharing requirements for data and are applied in the object_marking_refs and granular_markings properties on STIX Objects, which reference a list of IDs for marking-definition objects.

Two marking definition types are defined in this specification: TLP, to capture TLP markings, and Statement, to capture text marking statements. In addition, it is expected that the FIRST Information Exchange Policy (IEP) will be included in a future version once a machine-usable specification for it has been defined.

Unlike other STIX Objects, Marking Definition objects cannot be versioned because it would allow for indirect changes to the markings on a STIX Object. For example, if a Statement marking is changed from "Reuse Allowed" to "Reuse Prohibited", all STIX Objects marked with that Statement marking would effectively have an updated marking without being updated themselves. Instead, a new Statement marking with the new text should be created and the marked objects updated to point to the new marking.

The JSON MTI serialization uses the JSON Object type [RFC8259] when representing marking-definition.