MITRE Engenuity has released ATT&CK Workbench, an open source tool that allows organizations to customize their local instance of the MITRE ATT/CK database of cyber adversary behavior. The tool allows users to add notes, and create new or extend existing objects ‘ matrices, techniques, tactics, mitigations, groups, and software ‘ with new content. The contents of the knowledge base are accessed via a REST API, making it possible to integrate tools into the local database.
Source: https://www.helpnetsecurity.com/2021/06/23/customize-attck/