Last week, almost 42,000 Mac owners got the shock of their life when they found their computers had been infected by a form of malware. Now, not only are thousands of Macs still infected, but there’s another virus that’s been found to take advantage of similar security issues.

Patched by Apple last week, Flashback is no longer the same threat it was when computer security makers realised that over half a million computers worldwide were affected by the Mac-specific virus. A fix has been released to all Apple computers, fixing the issue even if the customer didn’t have it, but Symantec – the makers of Norton Internet Security – have said that there are still 140,000 computers affected.

“Many people think Macs can’t get infected, but the recent Flashback outbreak has made it clear that no operating system is immune to attack,” said John McDonald, Symantec’s Security Response Manager.

“Any Internet-connected device, whether it’s PC, Mac, tablet or smartphone, should have up-to-date security software installed.  While this is the largest malware outbreak we’ve ever seen on the Mac platform to date, additional infections are possible if Mac users don’t install appropriate security measures.”

That last statement is more true than it ever has been, with a new infection being discovered called “Sabpab”, taking advantage of a hole in Microsoft Word for Mac. While Symantec’s virus risk page puts this infection at a rating of “low”, it can still be used to open back doors to your computer.

In a way, this is like the hordes of viruses that we saw a decade ago, taking advantage of Microsoft Word and holes in the Windows operating system.

Back then – when this journalist was fixing computers as opposed to writing about them – the infections were large in number and generally affecting anyone who didn’t take the time to invest in anti-virus and security software.

“Traditionally, it has been the interest of the attackers to dedicate their time and effort into victimising Windows users,” said Mr. McDonald. “Attackers are now moving their attention to Mac users perhaps because they feel Mac has reached critical mass and possibly due to the fact that Mac users are an easier target as they are unaccustomed to facing malware threats, making the OS an attractive platform to attack.

“Consumers should understand now, more than ever, the importance of protecting their personal information, regardless of the device or platform they are using to access the Internet.”