Can Macs Get Viruses?

Since launching its first Mac in January 1984, Apple has built a loyal following around simplicity of design and ease of use. Talk to most people who use a Mac, and they'll swear they're impervious to the attacks Windows users are used to. It just wouldn't happen to them. It couldn't. Could it?

Biological viruses are those unwholesome, parasitic creatures that make us miserable when we catch the flu or a cold. Computer viruses are just a digital version. Surely an operating system like the Mac's could never get a virus, right? I mean, look at the design of the screen. And that beautiful case. So clean. So simple.

It's completely true that Macs aren't affected by PC malware or viruses. Unfortunately that clean, stylish design does not protect Macs from Mac viruses. That smooth facade offers no more protection to a computer being attacked by a Mac virus than a pretty paint job does to protect a car in a head-on collision. So why don't Macs get infected more often? There must be something else going on.

In the 1980s, authors of the first computer virus, Brain, designed it to destroy only illegal copies of their software. Unfortunately, Brain took on a life of its own and actually started to reproduce itself. Things moved more slowly then, though — you had to install a new diskette into the computer to get it to reproduce [source: Goodwins].

It didn't take long for more malicious hackers to see the potential in viruses. Using the internet to spread, a well-crafted virus can infect millions of computers amazingly quickly and do a lot of damage. The "I Love You" virus mentioned earlier infected more than 50 million computers and billions of dollars were spent fixing the problems it caused. And that was just one virus.

A virus does this kind of damage basically by inserting itself into the actual code of a program. Whenever the infected program is run, the virus reproduces and tries to infect other computers. To do this, it needs permission from the operating system as well as plenty of other computers running the same software. Under the right circumstances, a virus can infect any computer.

So if viruses are so clever and can infect anything, why haven't they affected more Apple users?

No computer system is immune to viruses (at least not yet). After all, viruses are just programs and all computers were designed to run programs. But Macs have had several factors in their favor in the fight to stay healthy?

Some suggest that Macs keep such a stellar reputation due to market share [source: Poremba]. Who'd want to write a virus for 100 computers when you could reach 1 million? The disparity isn't that big between the number of Macs and PCs, but you get the point. Not everyone agrees with the market share theory, though, claiming that Macs really do offer fewer opportunities for malicious code to spread [source: Porten]. The bottom line: Macs are not invulnerable and can get infected.

Another myth revolves around the UNIX foundation of Mac OSX (Mac operating system ten). Architecturally, UNIX is built with a more robust permission structure that prevents unauthorized execution of software. While Microsoft Windows will try to run a program any way it can, even if a virus is redirecting things, UNIX will stop in its tracks when it detects an unauthorized redirection and limit any damage [source: Perrin].

This is great, but it doesn't make your computer immune. It's similar to how exercising and eating right will help you stay healthier, but if a strong enough flu bug comes around you're still in for some misery. To infect a Mac, the viruses just need to be written well enough to get around the architecture. Not easy, but completely do-able [source: Rooney].

Even Apple devotees are beginning to realize that Macs are not only vulnerable, but increasingly likely to be targeted by hackers. Trying to capitalize on this vague awareness, in 2011, someone released a Trojan called Mac Defender, a fake program that tried to pass itself off as antivirus software.

Once it gets onto your computer, it throws an annoying array of pop-up ads at you until you buy the fake software. It's not likely to fool many people, but it's still annoying and a sign of more to come.

Just because Apple viruses exist doesn't mean all hope is lost. Let's look at some effective ways to keep your Mac and your data secure.

Even though Macs aren't as secure as you may have thought, there are plenty of ways you can protect your computer. In this battle, your first line of defense is yourself. Most security lapses can be prevented if you're conscientious when downloading software or allowing system files onto your computer.

For example, most Mac malware arrives in the form of Trojan horses, which come attached to e-mails or files you download from the internet. This is a reference to the Greek epic "The Aenid," where the Greeks gave the Trojans a large wooden horse as a gift to honor the supposed Trojan victory over the Greeks. Greek soldiers poured out of the horse during the night to let the Greek army into Troy, taking the city by storm.

Similarly, Trojan horse malwares are contained within seemingly benign files, like a note from a long-lost friend (which is fake) or a picture of a celebrity. Note that this type of malicious software only gets in through negligence or poor judgment. In other words, be careful about what you click on in an e-mail, or what files you open if you're not sure about the source.

Look out for risky sites on the web, too. Ever look at the status bar at the bottom of your browser? It'll usually show you the URL of the website you'll go to if you follow the link you're hovering over. If the link domain ends in .cc or .co, be careful. Viruses and other malware threats often originate from these domains [source: Keizer].

Regardless of the domain, use your common sense and take a look at a website's URL before clicking on any search results. Redirects based on popular search terms are a common trick, too.

But don't worry, you're not alone in your fight against the bad guys. Beyond your Mac computer's built-in security features, you can purchase Mac antivirus software to protect your assets. Trusted brands, such as Norton and BitDefender, offer security software that protects Apple devices with strong antivirus protection against most digital threats.

Better yet, these packages typically include a malware removal tool, which can rid your Mac computer of potentially unwanted programs or other online threats. Many of these trusted antivirus software options can be found at the Mac app store.

If you're new to antivirus software (and most Mac users are), you might want to try a free option to learn more about what's available to you.