Macs and Malware: What You Can Do to Stay Safe

By

Joanna Stern

Joanna Stern
The Wall Street Journal
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Mar 9, 2016 8:00 am ET

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It’s a bit of a nightmare. Over the past weekend, a Mac app called Transmission was infected with “ransomware.” If you had downloaded the app, hackers could have taken over your computer and demanded you pay to unlock it.

Before you freak out, you should know that the creator of the app says only about 6,500 people downloaded the software. Apple quickly disabled the certificate that allowed the software to be installed to a Mac computer. It’s likely that many hadn’t run it by that time. Apple confirmed to me that, to date, no one was impacted by the attack.

Still, it raises serious security concerns for many Mac users who believed they were immune to malware. Everyone should undertake my colleague Geoff’s series of steps to improve your personal digital security. For Mac owners, here are some specific to-dos to add to that checklist.

Know your apps
You should always use your best judgment when downloading new apps. But you can also make sure your Mac stops you from automatically running apps that Apple itself doesn’t know. Click on System Preferences > Security and Privacy > General. Here, you’ll see three safety levels based on where apps come from.

If you select “Mac App Store,” you will only be able to automatically run apps that have been screened and distributed by Apple.

If you select “Mac App Store and identified developers,” your Mac will also launch apps made by developers whose identity Apple has confirmed. These apps are slightly more risky because Apple did not test their security. However, if an app from an identified developer is compromised like in the case of Transmission, Apple can take steps to block it.

If you select “Anywhere,” your Mac won’t stop you from running any software you download from the Internet. You are on your own.

Keep your system up to date
Your Mac’s reminders to update your system may seem annoying but please don’t ignore them. Downloading updates is the most surefire way your operating system can defend itself from the bad guys. To check for outstanding updates, open the App Store, select the Updates tab and then click Update All. To turn on automatic update, go to System Preferences > App Store. Then select “Download newly available updates in the background.”

Scan for malware
New viruses arrive at such a fast clip, old-school antivirus software isn’t as helpful as it once was. Also, many attacks come directly to you through the Web browser or email, in the form of phishing. Apple’s Mac OS X has built-in anti-malware protection called XProtect, but if you want to be sure you haven’t picked up any dangerous worms, trojans or other nasty stuff, you can also download malware scanning software such as MalwareBytes.