One can view the password change history by querying oracle’s internal table SYS.USER_HISTORY$, note this table gets updated only if the user is assigned a profile that has password reuse limit (i.e. PASSWORD_REUSE_TIME set not to UNLIMITED)
SYS@TEST> SELECT name, password_date
FROM sys.user$, sys.user_history$
WHERE user$.user# = user_history$.user#;
NAME PASSWORD_
—————————— ———–
SCOTT 31-JAN-08
SCOTT 11-JUN-08
Here i found method to track password history.
http://www.acehints.com/2014/06/method-to-track-oracle-schema-user.html