AUDIT CONNECT creates CREATE SESSION audited privilege

The query to find out if auditing of succesful or unsuccessful logins is enabled and to find out what login activity has occured on an Oracle database is below. It queries against the dba_priv_audit_opts table for use of the "CREATE SESSION" privilege.

To audit successful and failed logins run
AUDIT CONNECT BY ACCESS

To find if this is already enabled query
SELECT * FROM DBA_PRIV_AUDIT_OPTS WHERE PRIVILEGE = 'CREATE SESSION'

USER_NAME        PROXY_NAME        PRIVILEGE     SUCCESS        FAILURE
        |          | CREATE SESSION        |    BY ACCESS        | BY ACCESS