Apple has issued an update to its Xprotect malware definitions, less than two days after it first posted the security update for Snow Leopard.
The update is designed to counter the mutation of Mac Defender which itself was an attempt to defeat the security update. The new Mac Defender variation was discovered by security software developer, Intego. It posted on its Mac Security blog that ‘The latest version comes in an installer package named mdinstall.pkg, and installs an application named MacGuard, which is the latest name that has been used for this malware.’
The blog post explained that the new version ‘manages to evade Apple’s signature-based malware detection system.’ The latest update to malware definitions will be downloaded automatically if you have ‘Automatically update safe downloads list’ in the Security pane of System Preferences (assuming you’re running Snow Leopard and have installed Tuesday’s Security Update).
Intego also spotted a bug in the Security Pane itself following the update ‘if you open the Security preference pane, unlock it, and wait for more than 30 seconds, any changes you make to this setting will not stick,’ it explained.
The solution is to make the change to settings as soon as you unlock the pane.
