A senha foi marcada como 'EXPIRED' ou com 'EXPIRY_DATE' em dba_users. Você terá que mudar isso. Você pode configurá-lo novamente para a mesma senha. A maneira mais fácil seria definir a senha "por valores". Isso geralmente ignora a verificação do histórico.
12:28:33 SQL> select * from dba_users where username = 'MYUSER1';
USERNAME USER_ID PASSWORD
------------------------------ ---------- ------------------------------
ACCOUNT_STATUS LOCK_DATE EXPIRY_DATE
-------------------------------- ------------------ ------------------
DEFAULT_TABLESPACE TEMPORARY_TABLESPACE CREATED
------------------------------ ------------------------------ ------------------
PROFILE INITIAL_RSRC_CONSUMER_GROUP
------------------------------ ------------------------------
EXTERNAL_NAME
--------------------------------------------------------------------------------
MYUSER1 338 66856982BE5CD23F
OPEN
USERS TEMP 17-JAN-11
DEFAULT DEFAULT_CONSUMER_GROUP
Elapsed: 00:00:00.03
12:28:43 SQL> alter user myuser1 password expire;
User altered.
Elapsed: 00:00:00.00
12:29:11 SQL> select * from dba_users where username = 'MYUSER1';
USERNAME USER_ID PASSWORD
------------------------------ ---------- ------------------------------
ACCOUNT_STATUS LOCK_DATE EXPIRY_DATE
-------------------------------- ------------------ ------------------
DEFAULT_TABLESPACE TEMPORARY_TABLESPACE CREATED
------------------------------ ------------------------------ ------------------
PROFILE INITIAL_RSRC_CONSUMER_GROUP
------------------------------ ------------------------------
EXTERNAL_NAME
--------------------------------------------------------------------------------
MYUSER1 338 66856982BE5CD23F
EXPIRED 17-JAN-11
USERS TEMP 17-JAN-11
DEFAULT DEFAULT_CONSUMER_GROUP
Elapsed: 00:00:00.03
12:29:14 SQL>
O formato disso é "alterar usuário USER identificado pelos valores 'hash de dba_users.password';"
[TEST] C:\>sqlplus system
SQL*Plus: Release 10.2.0.4.0 - Production on Mon Jan 17 12:18:16 2011
Copyright (c) 1982, 2007, Oracle. All Rights Reserved.
Enter password:
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
new: showmode BOTH
12:18:17 SQL> prompt end of LOGIN.SQL
end of LOGIN.SQL
12:18:17 SQL> create user myuser1 identified by mypassword1;
User created.
Elapsed: 00:00:00.01
12:18:21 SQL> grant connect, resource to myuser1;
Grant succeeded.
Elapsed: 00:00:00.01
12:18:30 SQL> connect myuser1/mypassword1
Connected.
12:18:39 SQL> connect system
Enter password:
Connected.
12:18:51 SQL> alter user myuser1 password expire;
User altered.
Elapsed: 00:00:00.00
12:19:05 SQL> connect myuser1/mypassword1
ERROR:
ORA-28001: the password has expired
Changing password for myuser1
New password:
Retype new password:
Password changed
Connected.
12:19:16 SQL> connect myuser1/mypassword1
ERROR:
ORA-01017: invalid username/password; logon denied
Warning: You are no longer connected to ORACLE.
12:19:21 SQL> connect system
Enter password:
Connected.
12:19:34 SQL> alter user myuser1 identified by mypassword1;
User altered.
Elapsed: 00:00:00.01
12:19:49 SQL> alter user myuser1 identified by mypassword1 password expire;
User altered.
Elapsed: 00:00:00.01
12:20:26 SQL> select username, password from dba_users where username = 'MYUSER1';
USERNAME PASSWORD
------------------------------ ------------------------------
MYUSER1 66856982BE5CD23F
Elapsed: 00:00:00.01
12:20:36 SQL> alter user myuser1 identified by values '66856982BE5CD23F' ;
User altered.
Elapsed: 00:00:00.01
12:21:01 SQL> connect myuser1/mypassword1
Connected.
12:21:13 SQL> exit
Disconnected from Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options