As others have said, if you've already convinced the user to run untrusted unsandboxed code then it doesn't matter whether it installs an iTunes plugin to do it

As others have said, if you've already convinced the user to run untrusted unsandboxed code then it doesn't matter whether it installs an iTunes plugin to do its dirty business. I have an even easier to implement attack - a menu bar-less app that shows an iTunes password window after using system APIs to bring iTunes to the front. Make up some excuse in the text for why it needs your password. You don't even have to mess around with breakpoints, most users will probably type their password - and you don't even have to wait until they buy something from iTunes!