Can Mac OS X get viruses?

Yes. Microsoft Word and Excel are susceptible to macro viruses. These are embedded within Word and Excel documents, and can mangle your Word or Excel settings or even erase the document you are working on. Since they can jump between Macs and Windows PCs, and since people commonly share Word and Excel documents, there is a pretty high risk of exposure. Both Word and Excel have had a preference for “Macro virus protection” for years. Make sure it is enabled. If you open a document and see a warning, be sure to click Disable macros to protect yourself from Macro viruses.

Although far less common, Mac OS X is also vulnerable to other types of viruses, such as Trojan horses and worms. These show up so infrequently on the Mac, it has a reputation for being “virus free.” But don’t use that as an excuse to backup less often.

In May 2011, MacDefender made headlines by tricking users into installing fake "anti-virus" software with the ultimate goal of collecting their credit card information when they paid for the fake software. A security update from Apple will automatically find and remove this malware and warn users before downloading it. Read "How to avoid Mac Defender malware" from Apple or just install Security Update 2011-003 by visiting your Software Update.

Most of the viruses that make headlines, taking over email and such, are specific to the Windows world. Even if you receive an infected file of this type, it can’t infect your Mac. Read "Do I need anti-virus software?" for which types of Mac users will definitely want to invest in extra protection.

Another threat is from bugs in the applications included with Mac OS X or in the system itself. Although most bugs only affect your ability to use the computer happily, there is a class of bugs that can open up your system to malicious outside users. To help avoid these situations, do the following:

• Install all security updates recommended by the Software Update application
• Keep a good password on your user account

Published March 24, 2009 12:00 PM
Last modified on May 31, 2011 4:54 PM