There is really big MYTH that Macs don’t get viruses. We know today that this is false. Apple malware has existed for Mac since 1987 with the appearance of the nVIR virus, which started with the sharing of floppy disks (remember those) that were infected. This is when the first anti-virus tools began to appear.
Fast forward to 1998 when the AutoStart 9805 spread very rapidly in the desktop publishing community, once again using removable media. With the release of OS X just around the corner the bad guys would have to go back to the drawing board with their attacks. When OS X was released, the first malware script Renepo worm, also known as Opener was unleashed. This was a nasty one. It would disable your firewall then download the hacker’s dream software tools including but not limited to, password sniffers and crackers. This would give hackers admin-level access to your machine. The latest baddy was BlackHole RAT in 2011. This was a Trojan, and a lot like Renepo, it allowed unauthorized users to take control of your Mac.
The most common malware I see is fake anti-virus or system maintenance software that boast they will speed up your mac or clean your mac. When it runs it finds all types of “problems” with instructions to call a number to get a resolution for problems that don’t actually exist. Enter the heroes of this story: the anti-virus software. This tech has two recommendations. The first one is Sophos. Sophos stands out from the crowd with its light weight and updated virus definitions. It also looks for Windows based virus so you don’t inadvertently send something nasty to your DOS-based buddies. The next is ClamXav which is basically the same thing as Sophos, but it does not have the virus definitions update like Sophos.
The biggest thing you to protect yourself from this is user education on what is going on with your Mac. I recommend you read this article from lifehacker. Surf safe, friends!