Riding on the coattails of Apple's wildly successful iPod, iPhone, and iPad, sales of the company's Macintosh computers have outpaced the personal computer industry as a whole.

Part of the attraction to the Mac has been the belief that they are immune to the ongoing security assault that affects Windows users.

So far, that's been a good bet. Mac users have been able to sit back and watch while their Windows-using colleagues suffer from viruses, spyware, scareware, and multiple infestations of malware.

Some of that has been the result of what might be called security by obscurity - there is much less payoff to the bad guys in targeting the much smaller Mac user-base. Equally the case: Mac OS X, like alternative PC operating system Linux, is based on Unix, which is designed for multiple users with security in mind and thus harder to infect.

Windows, despite Microsoft's ongoing efforts to beef up security, remains at its core a less secure system.

Macs and Linux PCs running Windows in virtual sessions are as vulnerable to infections as any Windows system.

Mac (and Linux) users are subject to just as much spam and phishing scam email as anyone else and can inadvertently pass on virus-bearing email attachments to their more vulnerable Windows-using colleagues. (Macs and Linux PCs running Windows in virtual sessions are as vulnerable to infections as any Windows system.) Despite this, few Mac users bother to install any sort of security software, and they generally haven't suffered any consequences.

Sophos Anti-Virus

Security vendor Sophos (headquartered in the UK, with a major facility in downtown Vancouver) thinks the time has come for Mac users to take security more seriously. In a Sophos-sponsored survey, 95% of respondents believed that the honeymoon was over, feeling that Macs would be increasingly targeted in the future.

At the beginning of November, the company released Sophos Anti-Virus for Mac Home Edition, which is free for home users. It claims to protect users from all known malware, "both Mac- and Windows-specific threats including Trojan-horses, viruses, worms and spyware."

While only a small number of Mac-specific threats have been identified, Sophos notes that Macs have recently been targeted by faux versions of commercial software on pirate download sites and erotic video sites that require specific viewer software that contains malicious code.

Sophos' free software runs in the background without requiring manual system scans and can disinfect existing infections. It can clean Windows malware from infested USB flash drives plugged into a Mac.

Home users can download the free product. It runs on current Intel-based Macs and on older PowerPC Macs, running operating system versions 10.4 Tiger, 10.5 Leopard, and 10.6 Snow Leopard. The company also offers Sophos Antivirus ($165 per year - free trial available) for Mac and Windows small-business users, along with a variety of other security programs.

Panda Antivirus

Sophos is not alone in hoping Mac users will become more security conscious. In October, Panda Security released Panda Antivirus for Mac (free trial, from $50 per year, requires OS X 10.5 or later). Panda vice-president Ivan Fermon predicts that when the Mac's worldwide market share reaches 15% - it currently hovers around 10% - "hackers will begin to aggressively target attacks."

Panda claims to have identified 5,000 strains of Mac-specific malware, a number that is growing by about 500 each month. (By comparison, Panda Labs is identifying 55,000 new Windows-focused threats each day.) A nice feature: Panda's Mac product will check a connected iPhone or iPad for malware - devices that are likely to be increasingly targeted in the future.

Other Options

Another alternative is ClamXav, a free Mac OS X antivirus application based on the open source ClamAV program. Version 1.1.1 supports OS X 10.4 and 10.5 but is not compatible with 10.6. Version 2 is in public beta and supports 10.4, 10.5, and 10.6.

Other options include iAntiVirus (from $30, no system requirements listed), Intego VirusBarrier X6 (free trial, $50 for 2 Macs, requires OS X 10.5 or later), McAfee VirusScan for Mac (free trial, $110 for 3 Macs, requires OS X 10.4.6 or later), and ProtectMac AntiVirus (free trial, $45 for 3 Macs, requires OS X 10.4.7 or later).

Editor's note: We believe the Macintosh platform remains safe, although that may change in the future. Installing antivirus software before that happens can be viewed as a good preventative step and a way to keep you from spreading malware-laden files to Windows users. The software list above is not exhaustive, and inclusion of an application does not mean that Low End Mac has tested it or recommends it. Until OS X comes under attack, we won't know how effective any of these programs will be against Mac malware. dk

Linux Antivirus

While there are fewer Linux users than Mac users, they might also want to install security software. Perhaps the easiest to use: Avast for Linux - again, free for home use. (The Czech company also offers free and paid products for Windows.)

There is also the free, open source ClamAV program, mentioned above.

Antivirus Is Essential for Windows

While security software is increasingly being recommended for Mac and Linux users, for Windows users, it's an absolute necessity. For home and small-business users, my recommendation is the free Microsoft Security Essentials.

First published in Business in Vancouver November 23-29, 2010 issue #1100