Restricting ODBC access to specific user(s)

Cache / Ensemble version 2016.2.2.853.0

I have a need to restrict ODBC access to certain users to prevent unwanted access to our cache database.

We have a limited number of legacy applications that use ODBC to connect to read data and are currently not in a position to have these amended any time soon so in the interim, I am hoping someone will be able to provide me with some assistance.

Any suggestions on where to start?