Software Engineering Institute

Apple Mac OS X contains a vulnerability that may be exploited when a user mounts a specially crafted AppleSingleEncoding disk image file. According to Apple security document 305214 :

An integer overflow vulnerability exists in the handler for AppleSingleEncoding disk images. By enticing a local user to open a maliciously-crafted disk image, an attacker could trigger the overflow which may lead to an unexpected application termination or arbitrary code execution. This update addresses the issue by performing additional validation of AppleSingleEncoding disk images.

A remote, unauthenticated attacker may be able to execute arbitrary code or cause a denial-of-service condition. The crafted AppleSingleEncoding disk image may be supplied on a webpage or in email for the victim to select, or by some other means designed to encourage them to mount the exploit file.

Upgrade

Apple has published Mac OS X 10.4.9 for Mac OS X 10.4 (Tiger) systems and Security Update 2007-003 for Mac OS X 10.3 (Panther) systems in response to this issue. See Apple Security Update 2007-003 for more details.

Do not open untrusted Apple disk images

Do not open unfamiliar or unexpected Apple disk images, particularly those hosted on web sites or delivered as email attachments. Please see Cyber Security Tip ST04-010.

Disable "Open 'safe' files after downloading"

Disable the option "Open 'safe' files after downloading," as specified in the Securing Your Web Browser document. This will help prevent automatic exploitation of this and other vulnerabilities.