Mac OS X Security Update Removes MacDefender Malware & Maintains Anti-Malware Definitions List

Apple has released a Mac OS X software update labeled “Security Update 2011-003” for Mac OS X 10.6.7 that includes a native malware removal tool.

The focus of the update is on the MacDefender malware scam and its variants, now referred to as “OSX.MacDefender.A”. Once the update is installed your Mac will be scanned for instances of the malware, which will then be removed and prevented from running. From there after, a list of variants will be updated daily by Apple automatically, and if you encounter MacDefender or a variation of it, you will get a dialog warning you to move the afflicted file to the Trash.

Download Anti-Malware Security Update 2011-003

You have two options to get the anti-MacDefender update:

• Users can download the Security Update via Software Update from the Apple menu
• Download directly from Apple (2.36 MB DMG file)

Apple recommends all Snow Leopard users install the security update, and it does not require a restart to install unless an infection is found. An abbreviated description of the update is as follows:

Security Update 2011-003 provides additional protection by checking for the MacDefender malware and its known variants. If MacDefender malware is found, the system will quit this malware, delete any persistent files, and correct any modifications made to configuration or login files.

Even without this software update MacDefender is easy to remove and avoid completely. Furthermore, release notes in the latest Mac OS X 10.6.8 developer build indicate that the malware protection will also be baked into the upcoming 10.6.8 update.

You can read more about this update on Apple’s Support page.