Sophos, a multi-os anti-malware company recently conducted a study on over 100,000 mac computers and found that as many as 20 percent of mac computers have some sort of windows based malware on them. While this isn’t a problem for mac owners, the mac computers can act as a conduit to spread infection over a network to windows computers. It also found that as many as 1 in 36 macs have some sort of native mac focused malware on them.
The most common type of malware for macs is actually a fake anti virus that prompts the user to pay money to remove fake virus’s that it finds. Mac users are generally seen to have more disposable income, especially with the price difference in comparably build specs between a mac and a PC so it makes sense that this sort of virus is the type that is dominating the mac landscape.