As stated in "Oracle Database: Change Password Expiration" when installing DB I usually change password expiration for DEFAULT profile from 180days to UNLIMITED.
This is because if you create users that uses DEFAULT profile after 180days Oracle gives you:
ORA-28001: the password has expired
So...you can edit DEFAULT profile in two ways:
1) Via Enterprise Manager Console as stated in Oracle Database: Change Password Expiration
2) Via SQLPlus
In this post I explain how to recover a locked user via SQLPlus and set DEFAULT profile with an unlimited password expiration time.
Connect to the instance:
[oracle@oracle ~]$ sqlplus
SQL> conn sys/password@sid as sysdba
SQL> select username,account_status from dba_users;
The above command will return all dba users and their corresponding status presenting them in a view similar to this:
Now let's unlock the user(s):
SQL> alter user [user_name] identified by [password] account unlock;
Then modify DEFAULT profile setting the password expiration time to UNLIMITED:
SQL> alter profile DEFAULT limit PASSWORD_LIFE_TIME UNLIMITED;