Mac OS X Security Guides

These PDF OS X security guides came out a few months back at http://www.apple.com/support/security/guides/. Although primarily concerned with corporate environments, even a home user can benefit from reading these. I downloaded the Mac OS X Security Configuration Guide (there's another version for Server).

I learned a thing or two here. For example, I didn't know this:

Time Machine illustrates the difference between mandatory access controls and the user privilege model - it allows files within Time Machine backups to be deleted only by programs related to Time Machine. From the command line, no user - not even one logged in as root - can delete files in a Time Machine backup.

It's true:

 sh-3.2# pwd
 /Volumes/IOMEGA500/Backups.backupdb/MacBook/2008-09-17-105229/Macintosh HD/Users/tony/Desktop
 sh-3.2# rm -f *dmg
 rm: kerio-kms-6.2.0-1255-mac.dmg: Operation not permitted
 sh-3.2# 
 

So how do you get rid of ALL copies of a file you want to delete? You use Time Machine itself: the little gear icon functions differently here. When you highlight a file and pull down that menu, it has the choice "Delete from all backups".

Another thing I never thought of is using keychains on a portable drive. That's a little extreme for most of us, but if you travel with your system a lot, it might be worth the trouble:

Anyone attempting to access data on the portable computer needs the portable computer, portable drive, and password for the keychain stored on the portable drive. This provides an extra layer of protection if the laptop is stolen or misplaced.

This guide covers things like disabling wifi, bluetooth, usb and firewire support: even a home user might consider doing that for any of those you don't need to use.

It also covers "sandboxing" (see sandbox-exec), encrypting swap files and much more.

Worth reading.