I assume I should be able to log back in with the built-in admin account info, but I can’t find that password in the documentation. Anyone know it please?
Starting with 4.3.1 version there is a one time login option How to Reset Admin Password on Openfire version 4.3.1+
This should at least let you into console. But with LDAP integration there are no local users.
Is there a similar method for earlier versions, such as 4.2.3?
No. You can try setting setup tag to false in /openfire/conf/openfire.xml and rerun the web setup.