Ideally, the password of the user that runs the policy server is not set.
You should see this user in the /etc/passwd file having /sbin/nologin as bash environment if the password is not set.
This ensures that this user will not be used to login to the system.
However, you can also set a password for this user if you want to login with the policy server to interactively use shell.
If you do not know the password, please check that the user has permission to run the policy server without password within sudo:
sudo - smuser /opt/CA/siteminder/start-ps
Note:
You may need to check with your system admin as your query relates more to the system than siteminder.
Thank you,
Osarobo