If you still remember what your last ias_admin password then to change it, you can use emct, eg:
emctl set password <old_password> <new_password>
or login to Oracle Enterprise Manager <version>- Application Server Control then click on Preferences on top right to open “Change Password” screen.
If you have forgot what the password then you must read this,
ias_admin password stored in XML file (JAZN-XML – Java AuthoriZatioN). First, backup the file, located in $ORACLE_HOME/sysman/j2ee/config/jazn-data.xml. Open and find
then update it to
or you can remove it and then run %ORACLE_HOME%\bin\emctl set password reset <new_password> , restart computer.
Note : Exclamation Mark in front of password means that password is stored in plain text, so the current password is “adminpass”