This indicates an attempt to exploit a heap overflow vulnerability in Apple Quicktime.
The vulnerability can be triggered when parsing .mov file 'crgn' atoms, resulting in a heap based buffer overflow. Viewing a maliciously crafted MOV image may lead to arbitrary code execution.
Apple Quicktime 7.4.1 or prior.
System Compromise: remote attackers can gain control of vulnerable systems.
Upgrade to the latest version of QuickTime, 7.4.5.