Apple OSX: Take Your Leopards In For a Checkup

Summary:

• These vulnerabilities affect: All current versions of OS X 10.5.x (Leopard) and OS X 10.6.x (Snow Leopard)
• How an attacker exploits them: Multiple vectors of attack, including enticing your users to visit a malicious web site, or into downloading and viewing various documents or images
• Impact: Various results; in the worst case, an attacker executes code on your user’s computer
• What to do: OS X administrators should download, test and install OS X 10.6.8 or Security Update 2011-004 as soon as possible, or let Apple’s Software updater do it for you.

Exposure:

Today, Apple released a security update to fix vulnerabilities in all current versions of OS X. The update fixes around 39 (number based on CVE-IDs) security issues in 22 components that ship as part of OS X or OS X Server, including Airport, Quicktime, and MobileMe. Some of the fixed vulnerabilities include:

• Two ImageIO Code Execution Flaws. ImageIO is one of the components that helps OS X handle various image file types. Unfortunately, it also suffers from two security vulnerabilities involving the way it handles certain types of image files (such as a buffer overflow vulnerabilities). Though these vulnerabilities differ technically, they generally share the same scope and impact. If an attacker can get a victim to view a specially crafted image file (perhaps hosted on a malicious website), he could exploit any of these flaws to either crash an application or to execute attack code on the victim’s computer. By default, the attacker would only execute code with that user’s privileges. The affected image types include JEPG2000, and TIFF.

• ATS Buffer Overflow Vulnerability. The Apple Type Service (ATS) helps OS X machines handle fonts. ATS suffers from a buffer overflow vulnerability having to do with the way it handles embedded fonts TrueType fonts. By tricking one of your users into downloading and viewing a malicious document containing a specially crafted font, an attacker can exploit this flaw to execute code on that user’s computer. By default, the attacker would only execute code with that user’s privileges.

• Five Quicktime Vulnerabilities. Quicktime is the popular video and media player that ships with OS X (and iTunes). Quicktime suffers from five security issues  involving how it handles certain image,audio, and video files. While the vulnerabilities differ technically, they share the same basic scope and impact. If an attacker can trick one of your users into viewing a maliciously crafted media in QuickTime, he could exploit any of these flaws to execute code on that user’s computer, with that user’s privileges.

Apple’s alert also describes many other code execution vulnerabilities, as well as some Denial of Service (DoS) flaws, privilege escalation vulnerabilities, and information disclosure flaws. Components patched by this security update include:

Please refer to Apple’s OS X 10.5.x and 10.6.x alert for more details.

Solution Path:

Apple has released OS X Security Update 2011-004 and OS X 10.6.8 to fix these security issues. OS X administrators should download, test, and deploy the corresponding update as soon as they can.

• Security Update 2011-004 (Leopard)
• Security Update 2011-004 (Leopard Server)
• OS X 10.6.8 Update
• OSX Server 10.6.8 Update
• OS X 10.6.8 Update Combo
• OSX Server 10.6.8 Update Combo

Note: If you have trouble figuring out which of these patches corresponds to your version of OS X, we recommend that you let OS X’s Software Update utility pick the correct updates for you automatically.

For All Users:

These flaws enable many diverse exploitation methods. Some of the exploits are local, meaning that your perimeter firewall never encounters the attack (unless you use firewalls internally between departments). Installing these updates, therefore, is the most secure course of action.

Status:

Apple has released updates to fix these flaws.

References:

• June 2011 OS X 10.5x and 10.6.x Security Update

This alert was researched and written by Corey Nachreiner, CISSP. (@SecAdept)

Share This: