Malware Library. Threats targeting Macs.

Mac malware exists in all shapes and sizes and new digital parasites evolve every day. Whether it’s adware, trojan horses, keystroke loggers, viruses or other spyware, stay up-to-date and discover more information about the latest threats targeting your Mac here.

Viruses on Mac: What You Need to Know

As computer lingo and vernacular have grown, changed, and evolved, the true definition of a “computer virus” has been somewhat lost. Indeed, these days, the term “computer virus” is perhaps most often used as a catch-all for all types of malware—from worms to Trojan Horses to keyloggers and beyond. The true definition of a computer virus, however—and the type of malware program it was originally coined to describe—is a program that will infect programs and files throughout a computer system and change the way they behave and function.

Like worms, viruses are self-replicating and are adept at spreading throughout a computer system. Sometimes, viruses can even be self-modifying, making it possible for them to infect and cause problems with various different computer programs. For instance, viruses in the past have been known to corrupt files or programs, clog up hard drive space, access email programs and send spam messages to users’ contact lists, or even mess with sensitive system or boot sector data—thereby essentially making the computer impossible to use without a total reformatting of the disk.

A History of Viruses on Mac

Needless to say, computer viruses can be incredibly frustrating at best, and incredibly damaging at worst. The good news is that even as Trojan Horses, adware, and other types of malware become more common on the Mac OS X operating system, true “viruses” are still quite rare for Macs. Apple is fully aware this fact, and has actually used it as a marketing tactic to encourage consumers to switch to Mac from Windows PCs.

With that said, there have been a number of viruses written to target Mac computers over the years. In October of 2010, Taylor Thomas, writing for Top Ten Reviews, compiled a pretty stellar “History of Macintosh Viruses.” The article doesn’t list every single virus that has ever infected Mac computers, opting instead to focus on the most significant. It hasn’t been updated since 2011, so it isn’t the last word on the subject anymore, and it’s also labeled as a history of “viruses,” but actually includes segments on many Trojan Horses, as well as a couple of worms.

Still, in spite of its shortcomings, the piece is worth a look if you want to know a bit more about what a virus on a Mac might actually look like. Some of them are actually pretty amusing, like the first-ever Mac virus, which infected Apple II floppy drives back in 1982. The virus, dubbed “Elk Cloner” and written by a 15-year-old, resulted in a “short poem showing up every 50th boot.”

Another, a proof-of-concept virus created in 2006 to show that Macs can indeed get viruses, was dubbed the “OSX.Macarena,” after a ubiquitous Spanish dance pop song from the 1990s. The OSX.Macarena essentially posed no real threat to Macs, their users, or their files, but it could replicate itself and spread from folder to folder.

The Message: Install Antivirus on Your Mac

The message of the OSX.Macarena virus was clear: Mac users should not be lulled into a false sense of security just because so many people are saying that Macs “can’t get viruses.” While the virus itself wasn’t harmful and was never released “out into the wild,” a hacker with malicious intent could easily use a similar concept to create a virus that would be extremely harmful and very difficult to remove.

Mac users will probably always be less at risk for computer viruses than their PC-using counterparts. Windows PCs still beat Macs in market share, which means they are essentially the “bigger fish to fry” for virus writers. Furthermore, most virus writers are more familiar with Windows than they are with Mac OS X anyway, and the vast majority of the scripts and code templates they use to write viruses are already based around Windows.

Still, it only takes one computer virus to damage your computer or corrupt your files, and having antivirus software on your computer is just a smart safeguard to reduce your chances of getting infected. Naturally, not as many antivirus programs are available for Mac as Windows, but there are still a handful of good options on the market, including both free options and paid programs. Search for antivirus software on the Apple App Store to find specific apps, or visit our site at to learn more about the tools that you can use for this purpose.

With free and well-reviewed antivirus options available for Mac, there is really no reason for Mac users not to protect themselves against potential threats. Most antivirus programs don’t just guard against computer viruses either, but look out for other types of malware, too.