Intego, which makes Internet security and privacy software, says
Apple's QuickTime, the media software used to play music and movies
on Mac OS X and Windows, has recently been update to version 7.5.5,
but a serious bug has already been discovered that may be used as a
vector for malicious attacks.

Here's what Intego has to say about it: "The "(? quicktime type= ?)"
tag fails to handle long strings, which can lead to a heap overflow
in QuickTime Player, iTunes, or any other program that attempts to
display media using a QuickTime plug-in. This can be a browser, such
as Apple's Safari, Microsoft Internet Explorer or Mozilla Firefox,
or, on Mac OS X, could be any program that displays graphics or
movies inline, such as Mail, or even the Finder if a user tries to
view a file with Quick Look.

"For now, files which contain offending strings will crash programs
attempting to display them, but malicious code could be added to such
files, and may be executed with no user interaction, other than an
attempt to view a file. This bug can be remote or local, as QuickTime
parses any supplied file for a recognized header even if the header
does not correspond to the file type; for example, a malicious user
could put XML content in an MP4 or MOV file, or could add a QuickTime
media file to a web page which could then cause a browser to crash
while executing malicious code."

Intego's Virus Monitoring Center is reportedly keeping a close eye on
this bug and whether malicious users are attempting to add payload to
QuickTime files. Intego says it will update the virus definitions for
Intego VirusBarrier X5 if this occurs. Intego will be posting more
information, as it becomes available, on the Intego Mac Security Blog
(http://blog.intego.com).