Apple is planning to release an update specifically designed to protect users against the MacDefender malware that has been circulating for the last couple of weeks. The update for Mac OS X will automatically find and remove the malware on an infected machine and also will warn users if another infection attempt is detected. Apple is telling concerned users that if they notice an infection attempt, they should try to close their browser or even force quit the application and then delete the installer. Apple did not specify when the update will be available, but said that it will be delivered through the Software Update mechanism or the Support Downloads Web site.
Source: https://threatpost.com/apple-plans-update-address-macdefender-malware-052511/75269/