Mac malware discovered hidden inside PDF

Security experts have warned Mac users to be on their guard after discovering a new piece of malware specifically crafted for the platform disguised as a PDF file and designed to give hackers remote access to the infected PC.

The malware initially opens as a PDF to distract the victim from seeing the malicious activity occurring alongside, according to Finnish security vendor F-Secure.

The content of the document, which is written in Chinese, apparently relates to the disputed territory of Diaoyu (Senkaku) Islands between Japan and South Korea.

"This malware may be attempting to copy the technique implemented by Windows malware, which opens a PDF file containing a .pdf.exe extension and an accompanying PDF icon," said F-Secure in a blog post.

"However, there is another possibility. It is slightly different in Mac, where the icon is stored in a separate fork that is not readily visible in the OS. The extension and icon could have been lost when the sample was submitted to us. If this is the case, this malware might be even stealthier than in Windows because the sample can use any extension it desires."

The malware installs a backdoor on the infected PC, suggesting that the hackers are aiming to gain remote access.

The discovery marks yet another evolution in Mac malware, and should serve as a warning that cyber criminals are increasingly targeting the operating system.

Earlier this year a widespread fake anti-virus family was discovered aimed specifically at Mac users.