[maqr]

Sometimes these things are easier to explain if you look at it like an attacker:

If you're a regular user of an OSX system before 10.10.3, and you want to become root (admin user), you can use this exploit to become root.

If you're an author of malicious OSX software, and a user without admin permissions installs your malware, you can use this exploit to make your malware run as root.

Once you have root, you can do anything on a system.

If the system you're attacking is 10.10.3 or later, you won't be able to use this exploit because Apple has a fix in 10.10.3.

Apple will not make the fix available to anyone on 10.9 or earlier.