Back in August ’09, Apple had quietly added a malware blocker to Mac OS X (Snow Leopard). However, some six months after the feature was first introduced, it seems to have been abandoned by Apple.
Apple hasn’t released definition updates for the malware blocker in months. Although, malware for Snow Leopard are few in number, Snow Leopard isn’t completely virus free (as some Mac advertisements suggest). Most of the recent malware for Mac are DNS Changer threats. They alter Mac’s DNS system and are commonly used for phishing.
Technically, Apple never promised to provide full-fledged antimalware capabilities in Snow Leopard, However, malware for Mac are few and far in between. Surely, it wouldn’t take much of an effort to maintain a decent antimalware tool, which would immensely benefit Mac users.