Neither the firm or users are entirely sure how the function works, but a screenshot shows the feature working with a file downloaded via Safari. The antimalware tool detected a version of the RSPlug Trojan horse in a downloaded disk image.
This is an interesting discovery, considering Apple's long-held stance that PCs are insecure and virus-riddled, whereas Macs "just work." This message is endlessly propagated in Cupertino's "Get a Mac" campaign, where they portray Macs as being trouble-free in the malware department.
While that may be largely true, most would argue that OS X is no more secure than any other operating system, it's just less circulated. With Microsoft Windows installed on 90-plus-percent of computers, it's the obvious target of malware authors.