Thinking that Mac computers are the safest? Think again because internet security researchers just discovered a malware that spies on Mac computers. According to the experts, the prying malicious software might have been lurking on the devices way before 2014.

Some Mac computers have been found out infected by a malware called FruitFly, which records onscreen activities, sees users through the camera, and keep tabs on key strokes. This piece of malware is a byproduct to what security company Malwarebytes exposed earlier this year of the same name.

Synack chief security researcher Patrick Wardle divulged that 400 computers were strained by a new FruitFly and much more computers could also be in danger, CNN reported. On Twitter, Wardle posted a screen grabbed part of the infected computers list, showing censored IP addresses and computer names of affected iMac, MacBook, MacBook Air, and MacBook Pro computers.

It remains a mystery how FruitFly was able to penetrate these computers, and there has been no information either as to when exactly FruitFly started to infiltrate these computers.

But, experts believe that the malware could be lurking in these computers longer than they seem to be. The ensnared bits of malware were discovered having altered codes to upset the Mac Yosemite operating system, which implies that FruitFly could have existed way before Yosemite was launched in October 2014.

Wardle, however, is still blank of the people behind the spying malware. Malwarebytes' Thomas Reed told CNN that he has not seen anything like FruitFly even before they discovered an earlier version of it.

With Apple devices touted to be much safer than any other brands in the market, Wardle noted that this situation proves that no one is invincible to security attacks on the internet. "Mac users are over-confident. We might not be as careful as we should be on the internet or opening up email attachments", says Wardle.

Wardle, a former US National Security Agency analyst, warns the US Federal Bureau of Investigation on this matter as a national hacking spree could happen. He also believes that money is not entirely at the centre of this threat but pure espionage on people, which he described as "a lot more insidious and sick".

Apple, meanwhile, has not responded yet to a request for comment.