This indicates an attack attempt to exploit a Buffer Overflow vulnerability in Apple QuickTime.
The vulnerability is due to an error when the vulnerable software handles a maliciously crafted MPEG file. An attacker can trick an unsuspecting user into opening a malicious MPEG file and execute arbitrary code within the context of the application.
Apple Computer Quicktime prior to 7.7.2
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.