Prior to 11g Passwords in Oracle are not case sensitive. Now from 11g Oracle passwords are Case sensitive. Parameter sec_case_sensitive_logon has been included in Oracle 11g.

sql> create user test identified by test;
sql> Grant create session to test;
SQL> show parameter logon
NAME                                       TYPE                              VALUE
—————————-     ———————-   ——————————
sec_case_sensitive_logon     boolean                           TRUE

SQL> conn test/TEST
ORA-01017: invalid username/password; logon denied
Warning: You are no longer connected to ORACLE.

SQL> conn test/test

Disable Password case sensitive:

SQL> alter system set sec_case_sensitive_logon=false;
System altered.

SQL> conn test/TEST