(CNN) - Apple has released a new software update to get rid of the so-called "Flashback" virus.
Last week, a Russian security company reported that as many as 600,000 Macs had been infected by the malware.
The Trojan horse virus infiltrates computers and secretly gives someone else remote access to them.
Flashback was first discovered in September, disguising itself as an Adobe Flash Player installer.
Apple recommends all Mac users who have Java installed to use the update.