What is a free and open transport mechanism that standardizes the automated exchange of cyber threat information?

A free and open transport mechanism that standardizes the automated exchange of cyber threat information is TAXII (Trusted Automated Exchange of Indicator Information). TAXII is a protocol and a set of specifications that enable organizations to share cyber threat information in a structured and standardized way, promoting interoperability and information sharing within the cybersecurity community. It facilitates the exchange of indicators of compromise (IOCs) and other threat intelligence data between different entities in a standardized format.