Think your Apple computer is immune? Think different.

A nasty bit of malware called Flashback has infected approximately 600,000 Macintosh computers worldwide through a Java security flaw, according to a Russian security firm — and Apple itself is hard at work on a fix, the company said Tuesday.

“Apple is developing software that will detect and remove the Flashback malware,” the company wrote in a support document on its site addressing the Flashback malware.

“Apple released a Java update on April 3, 2012 that fixes the Java security flaw for systems running OS X v10.7 and Mac OS X v10.6” — the most recent versions of the operating system, the company noted. But software will still be required to remove Flashback from systems that are already infected.