The site Macworld gives a tip to force Snow Leopard to check his list of definitions of malware is updated and the check itself. The handling is first to open the Security pane of System Preferences, then in the General tab, uncheck then recheck with the option "Automatically update the list of safe downloads.
As this panel does not indicate the date of last update of this information (associated with this panel does not outright mention this new option). This requires running a command in the Terminal.
Copy and paste this and press the command line:
more / System / Library / CoreServices / CoreTypes.bundle / Contents / Resources / XProtect.meta.plist
In our case, before touching the election, the date returned was that of 26 May, after handling in preferences, the terminal indicates that the last update by Apple file malware of today.
need to check every day what is happening in this file, remember that the malware in question - MAC Defender and its variants - is not a virus, but an application masquerading as something it is not. But until a panel of preference may be more informative, it's always good to take a trick.
