“Mac fans would have you believe Macs are immune to viruses and Windows is riddled with them. It's a lie. Macs are not immune, are no more secure, and do catch viruses. Granted, there's less for Macs, but that's only because no-one uses them. So all that being so, that's one less reason to choose a Mac over a Windows PC...
Before we launch into this, let's take a brief look at what a virus is.
What is a virus?
A computer virus (or worm) is a form of software of malicious intent, collectively known as 'malware'. The nature of a virus is that it can install on your computer without your knowledge or intervention, and can spread to other computers over the internet or a network, again, without yours or these other computer user's knowledge or intervention.
Viruses however, are not the only form of malware. Another common form of malware is a 'Trojan horse'. It can have similar effects to a virus, but unlike a virus, it cannot install covertly. It requires your intervention to install, like clicking a link on a webpage, or opening an e-mail attachment. It fools you into doing this by pretending to be something innocent. This is an important distinction which we'll look at later.
What does malware do?
Like any piece of software, when installed, malware can do anything its writer wants it to. Some forms of malware will be pretty benign in that it doesn't do much at all other than spread, just to prove it can be done. Or cause dramatic performance degradation and reduce system stability. But more likely, its intent will be much more malicious. For example:
- Installs 'spyware'. This keeps watch over, or interferes with what you do on your computer, and reports what it finds back to its author. More likely to be utilised by companies to target you with spam and popup ads.
- Installs a 'keylogger'. This logs what keys you press so it can collect passwords etc, and send them back to the author. Banking and credit card details are a primary target, for obvious reasons.
- Turn your computer into a 'zombie'. By leaving a 'back door' access into your computer, the author can take control to perform various nefarious activities, such as use your network connection to bulk send spam messages, or conduct denial-of-service attacks on commercial websites.
- Deletes or corrupts data. Usually created by individuals just for kicks or notoriety. Large corporations and government networks are a lucrative target here, but infecting large numbers of ordinary folk's computers also grab the desired headlines and kudos.
So, are Macs immune to viruses?
Remembering viruses aren't the only form of malware, a more pertinent question should be, are Macs immune to malware? The answer to that is simple: No, they're not. No OS is.
So, why would anyone think they are?
Firstly, we need to consider the distinction between viruses and trojans.
An OS can only do so much to prevent a user unwisely installing or opening something they shouldn't without unduly limiting functionality. And indeed, there have been example of malware on Macs that have exploited this.
However, a virus, in requiring no user intervention, has a much tougher time making their way onto a computer undetected, and requires a much more lax security model to hook into compared to the much easier time a trojan has. And in this respect, to date, OS X has seemingly not been susceptible to having malware installed in this way.
While there have been some trojan 'exploits' onto OS X, mainly via its ancillary applications (e.g. browsers, instant messengers), they have mostly only been somewhat toothless or benign proofs of concept, with no widespread infections into the wild...
Which all contrasts rather dramatically from the problems with malware on the Windows platform...
So why does Windows have more of a malware problem?
There's two main theories why Windows based PCs have more of a malware problem than Macs.
- The Mac's obscurity is its security. Windows is the much more common platform, so obviously, malware writers will concentrate most of their efforts there. Plus, having a denser population to infect, malware will have a much easier time spreading.
- OS X, with its industry strength UNIX underpinnings, has a more robust core security model compared to Windows. This particularly so for older Windows versions (pre Vista) still in widespread use.
Likely, the reason is a combination of the two, not just one or the other as some may proclaim.
What about Linux?
Of course, you could install and run a different OS on your PC, such as Linux. Just like OS X, it's UNIX based. Also just like OS X, while not totally invunerable to malware, is presently not a prime target. But it usually won't be the standard installation that comes with your new PC, and can be somewhat daunting to the average user. A newbies OS, it ain't!
But doesn't antivirus solve the problem?
Windows may be the biggest target, and arguably the more susceptible, but all is not lost. Security software exists from various sources either 3rd party applications, or built into the OS that will go a large way to protecting the user from such nastiness by keeping watch over what is happening under the surface where malware lurks. Or cleaning up tools for when it's all gone pear-shaped already.
However, these packages do need regularly keeping up to date to plug newly discovered vunerability. After all, the latest unplugged loopholes will be the one that allows the most widespread propagation. Also, they can be annoyingly intrusive and power sapping in everyday use if set too sensitively or poorly designed.
A chore they may be, but they are pretty much a necessary evil. Or at least they are if you run Windows. The question remains though, are they just as essential if you run a Mac?
Do you need to run antivirus on a Mac?
There is security software for Macs too, so the developers of these wares will strongly suggest you use them, for obvious self serving reasons. But pragmatically speaking, how imperative is it that you do?
There is no right or wrong answer here. Just opinions.
We've already ascertained that Macs are not invulnerable to attack, particularly from a trojan let in by a careless or duped user. But as we've also seen, for various reasons, the actual real world attacks are much less numerous or serious.
So the only question is, is it worth putting up with all the downsides of running security software, for the comparative small risk of a serious outbreak appearing tomorrow to exploit a previously undiscovered vulnerability? Better to be safe than sorry, or unnecessary paranoia?
As a tenuous analogy, wearing body armour all day might be wise if you live in Afghanistan, but if you live in Ohio, perhaps not quite so imperative? Living in Ohio doesn't make you invunerable to sniper attack, but how likely is it?
What else can you do?
The fact is, some Windows users will have constant problems with malware; often without even realising their machines are 'infected'. For others though, they have no more of a malware problem than Mac users. The biggest security risks come from ignorance and complacency.
With some knowledge of what forms malware takes and how it spreads, some good housekeeping, and a little common sense from everyone who's likely to use the PC, the malware threat can be reduced to a minimum, even without antivirus.
- Are you sure the link you're about to click on is what is says it is?
- Can you trust the source of the file or application you're about to open?
- Is your OS fully patched and up to date?
- Is your firewall turned on?
- Are you sure your passwords are not easy to guess?
- Are you sure your wireless network is encrypted?
- Do you really need to run on an admin or root account?
- Are all users of this computer fully up to speed with these precautions?
However, I must stress, it's just as wise to follow such precautions with a Mac as with Windows. The risks are less, but the risks are not zero.
So in summary...
...when anyone says Macs are immune to malware, they're wrong. What they really should say is that they're immune to Windows malware, of which there are many many many variants, compared to just a tiny few OS X variants.
The result is that there are many Windows based computers around the world infected with malware, whereas infections of Macs are rare, and often sensationally reported due to the novelty of such. Reasons why, and whether this will always be the case are open to debate. But right now, as has been for quite some time, that's the way it is!
Page content last updated 24 April 2011