Security-software experts at Symantec said new infections rates have fallen to 270,000, as many of the domain names in charge of the botnets have been taken over.

But a new variant called "Sabpab" that takes advantage of the same vulnerability has already been spotted, and security experts have warned Mac users that cybercriminals are increasingly targeting them.

This story is part of Federal News Radio's daily Cybersecurity Update. For more cybersecurity news, click here.