If you’re new to Mac, you’re probably thinking that it’s a no-brainer that you need some kind of anti-virus app. Once you start looking around the web for reviews, it’s inevitable that you’re going to come across the Great Mac AntiVirus Debate: in the one corner, those who say Mac users who forego antivirus protection are arrogant and just setting themselves up for a fall, and in the other those who’ve used Macs for umpteen years, never had or heard of any real threat, and consequently say AV software is a waste of time.
You can read round this debate for years and never come to a satisfying conclusion, largely because its as much about what you ‘ought’ to do as it is about what is the case. Just because you’ve never had any viruses, doesn’t mean you won’t get one tomorrow. And yet, there are NO viruses in the wild known to affect macs, and so when one does arrive, it will be unknown to your AV scanner. Hence, an AV Scanner is just a waste of system resources (and possibly money, if you paid for it). Yikes! What do I do!!
What you do is sidestep the whole debate and stop thinking only about virus scanners, which after all deal with only a small subset of all the possible attack vectors in the internet age, and start thinking in terms of vulnerability scanners. Unlike a simple virus scanner, a vulnerability scanner examines your system not only for malware but also for any vulnerabilities in commercial software, plug ins, your system setup (including network and other sharing settings) and other installed items. The scanner will not only explain the threat and its severity but also tell you what, if anything, you need to do, recommend patches and guide you to links for more info where available.
You can use something like Nessus for free if you are a home user, which will give you a far better insight into the possible attacks someone could implement on your system (and it will check your system against almost all of the major virus scanner databases like Symantec, etc).
Even better, a vulnerability scanner like Nessus won’t just examine your machine, it’ll look at everything else (and all the installed apps) of anything on your home network including phones (any platform), other computer systems (any OS), and even your router.