Hardening Guides

Welcome to the Atlassian Community!

Generally, it's not really Jira you need to harden, it's the service and networking.

Broadly though:

Run it on https and think carefully about where that is "terminated" - a very common setup is to have a proxy that does all the SSL stuff, and then has a plain http connection back to Jira, one that is network hardened - the server can only be reached on the http connection by the proxy and your network admins.  But you could also run the service on HTTPS itself.

Use multi-factor authentication

Make sure you are in full control of all the access your users might have, and your Jira admins are fully aware of how permissions work

There's a few other bits to look at on the proxy or Tomcat - https://geekflare.com/apache-tomcat-hardening-and-security-guide/ is in my bookmarks as things to look up in more detail.