Internet security experts have revealed that Apple has secretly updated the malware protection for its Mac OS X.
The Mac OS X 10.6.4 update included a fix for the Pinhead-B trojan, a virus distributed by hackers disguised as Apple's iPhoto application, which allows hackers to gain control over infected Macintosh computers.
Internet security firm Sophos reported that the trojan was capable of giving hackers remote access to infected Mac computers, allowing them to use the infected machine to send spam e-mail and take screenshots, as well as giving them the opportunity to steal usernames, passwords and credit card details.
Graham Cluley, senior security expert at Sophos, criticised Apple for not informing users about the update.
He said: “You have to wonder whether their keeping quiet about an anti-malware security update like this was for marketing reasons - 'Shh! Don't tell folks that we have to protect against malware on Mac OS X!'"