I'm trying to find the best means of stopping dmg files mounting in OS X 10.6. I was shown a system where 'no mountable filesystem,' would pop up whenever a user tried to mount a dmg but I can't recall how it was achieved. I'm currently using parental controls but it keeps getting circumvented. Any help appreciated.
As Administrator user, remove read access from
/Applications/Utilities/Disk Utility.app to be on the safe side) for "Everyone" (in the Get Info dialog in the Finder).
1) Rather than remove read access Disk Utility.app, use Parental Controls to prevent it from being accessed. (however it does not seem possible to restrict DiskImageMounter using Parental Controls).
2) You should to block access to: