Even though we believed, and later confirmed, the attacker had limited access, we undertook a comprehensive effort to rotate every production credential (more than 5,000 individual credentials), physically segment test and staging systems, performed forensic triages on 4,893 systems, reimaged and rebooted every machine in our global network including all the systems the threat actor accessed and all Atlassian products (Jira, Confluence, and Bitbucket).
This should be considered the gold standard for the response to and write-up on a security incident.