The first chunk of those slides talk about library hijacking. Say, you define your own version of malloc, make sure the application links to your version of malloc, and play your tricks from there. Process isolation has not been violated.
Slide 4 is the difference: OSX is BSD running on top of Mach. So these techniques use the Mach layer to get around basic process protection. This is terribly insecure.
The last five slides seem to be doing this: http://www.blackhat.com/presentations/bh-usa-09/DAIZOVI/BHUS...
Slide 4 is the difference: OSX is BSD running on top of Mach. So these techniques use the Mach layer to get around basic process protection. This is terribly insecure.