For businesses using an intranet or Web apps specifically built for one browser, Clymer recommends using two browsers: one for the corporate tasks and another for everything else. That way, an exploit targeting a user's personal Web surfing won't spill over to the corporate data and applications.
But Mac OS itself has some troubling attributes. For example, the firewall in Snow Leopard, the current version, is not turned on by default.
"The platform is all about sharing," Clymer says. Apple creates a fairly "noisy" network, with wireless communication among iTunes, AirPlay, Apple TV and the like.
"That stuff is very noisy and is blasted across the network," Clymer says. "When I see 'Bonjour' stuff flying across the network, I get pretty happy as an attacker because there is a lot of information there."
Mac OS X is a Unix-based operating system, with some open source components. One way attackers can exploit Macs, Clymer says, is to identify open source projects that run on Mac (such as Perl), look up the security fixes made in the last year, and then see if the same fixes have been made to the Mac versions.
While open source developers churn out quick changes to improve functionality and minimize security threats, Apple's updates are fewer and farther between, Clymer says. That's not entirely a bad thing. As the producer of a commercial product, Apple must thoroughly test updates before rolling them out to millions of users. But this can leave security holes exposed.
The Mac Defender Trojan, luckily, is pretty easy to remove. The question is whether things will get worse. Observers have been predicting for years that the Mac was on the verge of a giant security problem, but it's never gotten nearly as bad as the constant threats targeted at Windows users.
What's different now? Clymer says proliferation of iOS will lead to more attacks, even though so far Android is being harder hit. Although Apple's app store is more locked down than the Android one, that does not mean Apple performs an in-depth code review of phone and tablet applications, Clymer says.
Macs may also become more frequent targets of financially motivated malware, he said, simply because expensive Mac computers are often purchased by people with higher incomes. "If there's a Mac in a company, it's a graphics guy, an executive, or both," Clymer says. "It makes it a tempting target."
Windows, obviously, has been a tempting target for years. Windows also lacks a simple backup feature like the Mac's Time Machine, which makes it easy for Mac users to roll back to a previous, clean state of the operating system in the event of attack.