Remove Association of a Custom Technique
CTIX enables you to remove the association of the custom techniques from the respective layers as they become irrelevant. However, you cannot delete them.
To remove the association of the custom techniques, do the following:
From Main Menu, select ATT&CK Navigator under Analysis.
Select a layer.
Select the custom technique to remove its association.
Click Remove All Associations.
The custom technique is now removed from all associations. However, you can still search and re-associate the attack pattern in Main Menu > Threat Data.
For more details about associating the attack pattern with the layers, refer to Associate Attack Pattern with MITRE.