Good idea! Yes, the database itself is 100% secure, there is no way to penetrate that. Ive been given advanced IP mods for the phpbb that allows me to view any IP activity anywhere on the site. It took me a long time editing phps and templates, and reviewing SQL documentation, but it is complete and working successfully. That particular mod will be submitted for review to the phpBB team once the rc1 comes out.
After contacting my ISP and server management people, they gave me a wealth of knowledge as far as tracking users that access the site. I highly recommend that you contact your isp and hosting provider and inquire, they have a bunch of slick tricks up their sleeve... much more advanced than I ever gave them credit, and I am in the network security field.
As for permissions, would you like to clarify about possible permissions compromise?