SYS> create table michel.log (msg varchar2(1000));

Table created.

SYS> create or replace procedure michel.p (who in varchar2, what in varchar2)
  2  is
  3    pragma autonomous_transaction;
  4  begin
  5    insert into michel.log values (who||' modifies '||what||'''s password at '||systimestamp);
  6    commit;
  7  end;
  8  /

Procedure created.

SYS> CREATE OR REPLACE FUNCTION verify_function
  2  (username varchar2,
  3    password varchar2,
  4    old_password varchar2)
  5    RETURN boolean IS 
  6  BEGIN 
  7     michel.p (user, username);
  8     RETURN(TRUE);
  9  END;
 10  /

Function created.

SYS> ALTER PROFILE DEFAULT LIMIT PASSWORD_VERIFY_FUNCTION verify_function;

Profile altered.

SYS> alter user michel identified by michel;

User altered.

SYS> select * from michel.log;
MSG
--------------------------------------------------------------------------------------------------------------------
SYS modifies MICHEL's password at 16/02/2011 18:54:34.390 +01:00

1 row selected.

SYS> connect michel/michel
Connected.
MICHEL> password
Password changed
MICHEL> select * from michel.log;
MSG
--------------------------------------------------------------------------------------------------------------------
SYS modifies MICHEL's password at 16/02/2011 18:54:34.390 +01:00
MICHEL modifies MICHEL's password at 16/02/2011 18:55:04.093 +01:00

2 rows selected.