PL/SQL Package Execution Privileges

Hi Guys, a quick question. I have a plsql package owned by user A.

Permission to execute this is given to B via a role R.

B executes and appears as USER B in terms of connection to the database etc.

No problems so far...

Now I want user B to be able to execute an a new procedure which alters the password of a user.

As B doesn't have the privileges to ALTER ANY USER, we get an ORA-1031 insufficient privileges.

I don't want to grant this privilege - it would allow B to alter (I think) and user's password as well as quota, tablespace etc..

Question: if there is enough info here, how should I set this up? There are some users in the system that need to be able to change the passwords of other users (i.e. to reset them in the event of the user forgetting them). This is a web-based application using pl/sql toolkit.

Any contributions gratefully received!

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jeremy