Severe vulnerability hits Mac OSX

Exploit published for gaping DMG hole.

A serious vulnerability found in the DMG handling on fully up-to-date installations of

Apple

‘s

OSX

is threatening to upset the platform’s reputation for security.

The bug, for which an example exploit is available from the

Month of Kernel Bugs

site where it was first unveiled, uses a flaw in the handling of corrupted DMG disk image files by the AppleDiskImageController.

Mac

users browsing to a site carrying a suitably crafted file could find it automatically loading, possibly causing denial of service or even granting remote users kernel-mode system access.

The flaw has not been patched by

Apple

, but a simple workaround is available, involving the disabling of an option to automatically load ‘safe’ files.

Secunia

has labelled the problem ‘highly critical’; its alert is

here

, while the original release, with examples, is

here

.

Another similar flaw found by the same researcher, this time involving corrupted UDTO HFS+ image structures and with less critical consequences, is described

here

and

here

.

Elsewhere in the

Mac

security arena,

F-Secure

has reported a ‘feature’ in

OSX

which allows a proof-of-concept piece of adware to silently hook itself to every application, launching a browser pointed to the ad site each time one is opened. Their blog entry can be found

here

.

Posted on 23 November 2006 by

Virus Bulletin