Hi there
@TimV's post from a couple of years back is still relevant: Accidentally deleted .security index for x-pack - #3 by TimV. Note that step 2
From a security point of view, you now have a "new" cluster, so the reserved users
elasticandkibanawill have reset to their default "changeme" passwords.
doesn't apply anymore since we do not have default passwords for the built-in users, but the rest of the instructions are good to go !