Skip to main content

1 in 5 Mac Computers Harbors Malware, Claims Sophos

What's scarier: 1 out of 5 Mac computers in a group of 100,000 found to be infected with malware, or that Sophos can take a snapshot of all 100,000 without each user's knowledge. Even if the security firm is trying to access the overall health of Apple's platform, installed software secretly taking snapshots of the computer's current condition sounds a little creepy nonetheless.

According to the latest report from Sophos, 100,000 Mac computers using the company's free anti-virus software were analyzed over a span of seven days. The firm discovered that 1 in 5 Macs were playing host to one or more instances of Windows-based malware while 1 in 36 (or 2.7-percent) were found to be carrying Mac OS X malware. The good news is that the Windows-based malware won't cause symptoms on Macs unless the user is also running Windows. The bad news is that it can still spread to other Macs.

"Some Mac users may be relieved that they are seven times more likely to have Windows viruses, spyware and Trojans on their Macs than Mac OS X-specific malware, but Mac malware is surprisingly commonly encountered," said Graham Cluley, senior technology consultant at Sophos. "Mac users need a wake-up call about the growing malware problem."

In a 7-day snapshot of 100,000 Macs, Sophos discovered that 75.1-percent were infected with the OSX/Flahplyr malware. Falling in second with 17.8-percent was OSX/FaveAV followed by OSX/RSPlug (5.5-percent), OSX/Jahlav (1.2-percent) and "other" (0.4-percent). This malware can spread via USB stick, email attachments, website download, or even a silent drive-by installation where the user doesn't realize their Mac's security has been subverted.

"Cybercriminals view Macs as a soft target, because their owners don’t typically run anti-virus software and are thought to have a higher level of disposable income than the typical Windows user," Cluley added. "Mac users must protect their computers now or risk making the malware problem on Macs as big as the problem on PCs."

On the Windows-based malware front, Mal/Bredo reigned as champ, residing on 12.2-percent of 100,000 Mac computers over a 7-day study. Other malware found include Mal/Phish (7.4-percent), Mal/FakeAV (3.8-percent), Troj/ObfJS (3.6-percent), Mal/ASFDldr (3.3-percent), Troj/Invo (3.0-percent), Troj/Wimad (2.6-percent), Mal/Iframe (1.5-percent), Mal/JavaGen (1.4-percent), and "other" (61.2-percent).

"Some of the malware discovered by Sophos on the 100,000 Mac computers sampled dates back to 2007, and would have been easily detected if the users had run an anti-virus product sooner," Sophos said in its report. "Bredo, a family of malicious programs sent out via spam, accounts for 12.2 percent of malware detected on Mac computers. The first Bredo variant was detected in 2009, and since then, countless variants have been released. Only last week, it was used in a malicious email campaign that purported to have attached a compromising picture of the recipient."

Naturally Sophos points to its own free anti-virus solution for Macs which can be downloaded and installed from here. Further information about these malware findings on Macs can be found on Sophos's Naked Security site at: