For my fellow Macintosh users - here's a little education about malware.
If you own Macs like me, you have very little to worry about when it comes to viruses and malware. Notice I said "very little" and not "nothing" to worry about.
Yes, there is malware out there that can infect OS X, but it is very rare. Plus, since OS X is based on UNIX, the only way to infect the System is by intentionally allowing the malware to be installed, which would require entering your Administrator name and password at least once. Pretty simple - if you weren't installing software or modifying a System preference of some kind, then don't enter your password.
Many of my clients still worry. Clicking a link in a suspect email or visiting a malicious website can certainly open you up to infection, but using common sense should be all the protection you need. With that said, there are a couple of anti-virus/anti-malware applications for OS X out there that work well and are free of charge.
The first is made by Malwarebytes. Windows users are probably familiar with the name. They make a free utility for Mac called Malwarebytes Anti-Malware. It is very small and light, and will quickly scan your Mac for all known malware and remove any it finds. You run it, deal with anything it finds, and quit. No muss, no fuss - but that's all it does.
For protection that covers more than just the generic internet malware variety and can also actively protect your Mac in realtime, there is Sophos Home. Again, Sophos is a familiar name in the Windows anti-virus world. Sophos Home for Mac is also free. It will scan your entire drive for all known malware, including viruses, worms and the like. It can also check in realtime whenever a file is accessed, block websites that are known threats, and detect potentially dangerous applications and prevent them from installing or running.
Here's the rub - I do not recommend using any of that stuff, and I advise my clients who use Sophos Home to turn off ALL of the realtime protection, and simply use it to scan your drive.
This applies to every antivirus utility out there - realtime protection will significantly slow down your entire computer. It literally interrupts every single process, from opening a Word document to copying a file to launching Safari and visiting any web site.
My professional opinion is that such a hit in overall performance isn't worth the "protection." Instead, use common sense and be vigilant. Don't click a link in an email unless you know where it's from. Mouse over the link to see where it plans to take you before clicking on it. If the email looks like it's from Amazon, yet the link is to something like amaz0nDOTcn or .ru, then you'll know it's a phishing attempt.
Paying for software and then continuing to pay a "subscription" to update it with the latest virus definitions is a complete waste of money if you use a Mac. You should send me the money instead, and I'll scan your Mac regularly for you. ;)
The exact opposite applies to Windows users. They need to be protected every second of every day, and must constantly keep their operating system and their antivirus software updated to recognize the latest threats.