"Macs don't get malware" was a popular rallying cry around the same time those "I'm a Mac; I'm a PC" commercials were a thing, but it hasn't been true for a while. MacOS is susceptible to everything from Trojans to ransomware, and if you don't get a security suite to protect yourself, you could be the next victim.
The good news is that the vast majority of macOS protection programs offer excellent protection; the bad news is that a well-known program called MacKeeper does not, especially when dealing with run-of-the-mill malware.
This information comes from AV-TEST, a Madgeburg, Germany-based testing lab that periodically evaluates antivirus software across a variety of platforms. In April and May 2017, the company took a look at 10 of the most prominent masOS antivirus products. It discovered that nine of the products were up to snuff; furthermore, four of them had functionally perfect detection rates.
Bitdefender Antivirus for Mac, Intego Mac Internet Security X9, Kaspersky Internet Security for Mac and Symantec Norton Security all successfully detected every piece of malware that AV-TEST threw their way, without producing any false positives or putting undue stress on the system. Except for Intego, all also detected nearly 100 percent of Windows malware that might be lurking on a Mac. If you have one of those four programs, you're all set; if not, consider getting one.
At the other end of the spectrum was the ignominious MacKeeper, which detected only 85.9 percent of incoming threats. This may sound like a B grade, but AV-TEST sets its minimum threshold for recommendation at 90 percent with no false positives. (We'd put the minimum at 95 percent.)
While it's probably better to have MacKeeper than nothing at all, even that is open to debate, as many experts consider MacKeeper to be worse than useless. If you're going to pay money for an AV program, it may as well be one that detects almost every threat.
Trend Micro Antivirus for Mac came in at second place with 99.5 percent of malware detected. Canimaan Software ClamXav Sentry, ESET Endpoint Security and Sophos Central Endpoint tied for third with 98.4 detection rates each. Any of those programs should protect you just fine.
But ProtectWorks AntiVirus scored a 94.6 percent detection rates, which is lower than what we're comfortable with. With antivirus software, what matters is how much slips through, and in that respect, ProtectWorks did three times as badly as ClamXav, ESET or Sophos.
It's worth noting that all of the macOS AV programs tested worked in conjunction with the built-in macOS security protocols, which include the Gatekeeper application screener and the XProtect signature-based malware checker. (This isn't the case with Windows, which requires you to either accept its built-in security suite or install a third-party one.)
Installing a third-party AV program on your Mac will not compromise the protection that already Apple offers. It's to your advantage to install something — as long as it's something other than MacKeeper or ProtectWorks.