Sophos has an interesting breakdown of the types of malware currently reported to them as being found on Macs. While the impact of OSX/Flashback seems to have dwindled dramatically (at any rate on the machines on which Sophos has information) from 75% to 2.4%. However, the company has noted plenty of other current malware, including a shedload of fake AV and fake codecs, as well as Mac-specific spearphishing, spyware and multiplatform attacks.
David Harley CITP FBCS CISSP
