Here is a great story from Slashdot.org:

IT: Apple Adds Memory Randomization To Leopard

Posted by kdawson on Thursday October 18, @08:37AM
from the shuffling-the-wormholes dept.

.mack notes a ZDNet blog outlining some of the security features added to OSX Leopard (10.5). Here’s Apple’s brief description of all 11 new security features. “Apple has announced plans to add code-scrambling diversity to Mac OS X Leopard, a move aimed at making the operating system more resilient to virus and worm attacks. The security technology, known as ASLR (address space layout randomization), randomly arranges the positions of key data areas to prevent malware authors from predicting target addresses. Another new feature coming in Leopard is Sandboxing (systrace), which limits an application’s access to the system by enforcing access policies for system calls.”