Apple on Tuesday shipped the promised update to help remove the MacDefender malware, and in a surprise move, also added functionality to Mac OS X that will now check for new malware definitions daily.
The move by Apple to add daily malware checks is a significant shift in the way that the company handles malware and potential infections of its customers. Until now, Apple has handled such incidents on a case by case basis and pushed OS changes when it needed to address a new problem. But now the company has essentially included an auto-updating anti-malware system with OS X.
The security update that Apple released Tuesday performs several specific tasks. It adds a new definition to the existing anti-malware checks in OS X, and also will automatically remove any instances of the MacDefender malware that it finds on the machine. But most significantly, security update 2011-003 adds the automatic daily checks for new malware signatures.
“Apple maintains a list of known malicious
software that is used during the safe download check to determine if a
file contains malicious software. The list is stored locally, and with
Security Update 2011-003 is updated daily by a background process,” the company said in its advisory about the change.
“If you do not wish to receive these
updates, you can disable daily update by unchecking “Automatically
update safe downloads list” in the Security pane, in System Preferences.
This option appears in Security preferences after Security Update
2011-003 is installed.”
Apple first added an anti-malware function to OS X in 2009, but has not had to add many updates to the system since then.