Viruses and other types of malware seem largely confined to Windows in the real world. Even on a Windows 8 PC, you can still get infected with malware. But how vulnerable are other operating systems to malware?

When we say “viruses,” we’re actually talking about malware in general. There’s more to malware than just viruses, although the word virus is often used to talk about malware in general.

Why Are All the Viruses For Windows?

Not all of the malware out there is for Windows, but most of it is. We’ve tried to cover why Windows has the most viruses in the past. Windows’ popularity is definitely a big factor, but there are other reasons, too. Historically, Windows was never designed for security in the way that UNIX-like platforms were — and every popular operating system that’s not Windows is based on UNIX.

Windows also has a culture of installing software by searching the web and downloading it from websites, whereas other platforms have app stores and Linux has centralized software installation from a secure source in the form of its package managers.

Do Macs Get Viruses?

The vast majority of malware is designed for Windows systems and Macs don’t get Windows malware. While Mac malware is much more rare, Macs are definitely not immune to malware. They can be infected by malware written specifically for Macs, and such malware does exist.

At one point, over 650,000 Macs were infected with the Flashback Trojan. [Source] It infected Macs through the Java browser plugin, which is a security nightmare on every platform. Macs no longer include Java by default.

Apple also has locked down Macs in other ways. Three things in particular help:

• Mac App Store: Rather than getting desktop programs from the web and possibly downloading malware, as inexperienced users might on Windows, they can get their applications from a secure place. It’s similar to a smartphone app store or even a Linux package manager.
• Gatekeeper: Current releases of Mac OS X use Gatekeeper, which only allows programs to run if they’re signed by an approved developer or if they’re from the Mac App Store. This can be disabled by geeks who need to run unsigned software, but it acts as additional protection for typical users.
• XProtect: Macs also have a built-in technology known as XProtect, or File Quarantine. This feature acts as a blacklist, preventing known-malicious programs from running. It functions similarly to Windows antivirus programs, but works in the background and checks applications you download. Mac malware isn’t coming out nearly as quick as Windows malware, so it’s easier for Apple to keep up.

Macs are certainly not immune to all malware, and someone going out of their way to download pirated applications and disable security features may find themselves infected. But Macs are much less at risk of malware in the real world.

Android is Vulnerable to Malware, Right?

Android malware does exist and companies that produce Android security software would love to sell you their Android antivirus apps. But that isn’t the full picture. By default, Android devices are configured to only install apps from Google Play. They also benefit from antimalware scanning — Google Play itself scans apps for malware.

You could disable this protection and go outside Google Play, getting apps from elsewhere (“sideloading”). Google will still help you if you do this, asking if you want to scan your sideloaded apps for malware when you try to install them.

In China, where many, many Android devices are in use, there is no Google Play Store. Chinese Android users don’t benefit from Google’s antimalware scanning and have to get their apps from third-party app stores, which may contain infected copies of apps.

The majority of Android malware comes from outside Google Play. The scary malware statistics you see primarily include users who get apps from outside Google Play, whether it’s pirating infected apps or acquiring them from untrustworthy app stores. As long as you get your apps from Google Play — or even another secure source, like the Amazon App Store — your Android phone or tablet should be secure.

What About iPads and iPhones?

Apple’s iOS operating system, used on its iPads, iPhones, and iPod Touches, is more locked down than even Macs and Android devices. iPad and iPhone users are forced to get their apps from Apple’s App Store. Apple is more demanding of developers than Google is — while anyone can upload an app to Google Play and have it available instantly while Google does some automated scanning, getting an app onto Apple’s App Store involves a manual review of that app by an Apple employee.

The locked-down environment makes it much more difficult for malware to exist. Even if a malicious application could be installed, it wouldn’t be able to monitor what you typed into your browser and capture your online-banking information without exploiting a deeper system vulnerability.

Of course, iOS devices aren’t perfect either. Researchers have proven it’s possible to create malicious apps and sneak them past the app store review process. [Source] However, if a malicious app was discovered, Apple could pull it from the store and immediately uninstall it from all devices. Google and Microsoft have this same ability with Android’s Google Play and Windows Store for new Windows 8-style apps.

Does Linux Get Viruses?

Malware authors don’t tend to target Linux desktops, as so few average users use them. Linux desktop users are more likely to be geeks that won’t fall for obvious tricks.

As with Macs, Linux users get most of their programs from a single place — the package manager — rather than downloading them from websites. Linux also can’t run Windows software natively, so Windows viruses just can’t run.

Linux desktop malware is extremely rare, but it does exist. The recent “Hand of Thief” Trojan supports a variety of Linux distributions and desktop environments, running in the background and stealing online banking information. It doesn’t have a good way if infecting Linux systems, though — you’d have to download it from a website or receive it as an email attachment and run the Trojan. [Source] This just confirms how important it is to only run trusted software on any platform, even supposedly secure ones.

What About Chromebooks?

Chromebooks are locked down laptops that only run the Chrome web browser and some bits around it. We’re not really aware of any form of Chrome OS malware. A Chromebook’s sandbox helps protect it against malware, but it also helps that Chromebooks aren’t very common yet.

It would still be possible to infect a Chromebook, if only by tricking a user into installing a malicious browser extension from outside the Chrome web store. The malicious browser extension could run in the background, steal your passwords and online banking credentials, and send it over the web. Such malware could even run on Windows, Mac, and Linux versions of Chrome, but it would appear in the Extensions list, would require the appropriate permissions, and you’d have to agree to install it manually.

And Windows RT?

Microsoft’s Windows RT only runs desktop programs written by Microsoft. Users can only install “Windows 8-style apps” from the Windows Store. This means that Windows RT devices are as locked down as an iPad — an attacker would have to get a malicious app into the store and trick users into installing it or possibly find a security vulnerability that allowed them to bypass the protection.

Malware is definitely at its worst on Windows. This would probably be true even if Windows had a shining security record and a history of being as secure as other operating systems, but you can definitely avoid a lot of malware just by not using Windows.

Of course, no platform is a perfect malware-free environment. You should exercise some basic precautions everywhere. Even if malware was eliminated, we’d have to deal with social-engineering attacks like phishing emails asking for credit card numbers.

Image Credit: stuartpilbrow on Flickr, Kansir on Flickr