Mac malware disguised as iPhoto

A new variant of a malware program designed to run on the Mac OS has been uncovered.

Called HellRTS or Pinhead, it opens a backdoor on the system that could allow hackers to take over the Mac and is a variation of a program first spotted in 2004.

Security experts are warning that the malware comes disguised as an installer for iPhoto, an image-organisation tool for Mac OS.

The attack was discovered by security firm Intego, a company that specialises in security for Macs.

"This backdoor requires installation on a Mac, which could be carried out via a Trojan horse, or by exploiting a vulnerability in a program that accesses the internet (such as a web browser)," Intego said in a statement.

"While Intego has not found any instances of Macs being infected by this in the wild, the fact that this malware is being distributed on a number of forums shows that it will be accessible to a large number of malicious users who may attempt to use it to attack Macs," the statement continued.

Despite the malware being classified as low-risk, Mac owners are advised to install security software on their systems and keep it up to date.

"As always, be careful about the origin of applications you run on your computer, and keep your protection up to date. As many Mac users do not presently run any anti-virus software at all, they could be considered a soft target for more attacks like this in the future," said Graham Cluley of Sophos.