If the DBA lost the password of the SYSTEM user account, he/she can go to the Oracle server machine, and run SQL*Plus on server locally with the operating system authentication method to gain access to the database. The tutorial exercise below shows you how:

(Terminal server to the Oracle server machine)

(Start SQL*Plus)

SQL>CONNECT / AS SYSDBA

Connected.

SQL> ALTER USER SYSTEM IDENTIFIED BY ssap_lgg;

User altered.

Notice that the (/) in the CONNECT command tells SQL*Plus to use the current user on local operating system as the connection authentication method.