Apple has released a Java update that identifies and removes the most common variants of the Flashback malware that is reported to have infected over half a million Apple machines.
“This Java security update removes the most common variants of the Flashback malware.
This update also configures the Java web plug-in to disable the automatic execution of Java applets. Users may re-enable automatic execution of Java applets using the Java Preferences application. If the Java web plug-in detects that no applets have been run for an extended period of time it will again disable Java applets.
Java for OS X Lion 2012-003 delivers Java SE 6 version 1.6.0_31 and supersedes all previous versions of Java for OS X Lion.”
More info: http://support.apple.com/kb/HT5242