New research released by Sophos has revealed a disturbingly high level of malware on Mac computers -- with both Windows and Mac threats being discovered.
Sophos experts analyzed a snapshot of 100,000 Mac computers running its free anti-virus software, and discovered that one in five machines was found to be carrying one or more instances of Windows malware.

Although Windows malware on Macs will not cause symptoms (unless users also run Windows on their computer), it can still be spread to other computers. Additionally, Sophos's analysis shows that 2.7 percent (one in thirty six) of Macs were found to be carrying Mac OS X malware.

For years Apple Mac users have felt smug that their computers didn't need any security software installed, unlike their poor Windows counterparts which were always coming down with a cold. This they believed is because their beloved operating system is inherently more secure than leaky old Windows (which it used to be). This smug feeling has been especially strong over the last decade, since the release of Mac OS X in 2001, as it's based on Unix which has always had security baked into it. They therefore felt safe from the multitude of viruses, keyloggers, trojans and various other nasties that the bad guys like to infect operating systems with. However, there have been successful attacks in the past on every Apple Mac operating system since the first one in 1984, just nowhere near the number of attacks as on Windows. Of course, what Windows users, Linux users and other OS users have also been saying for years is that Apple's operating systems simply weren't popular enough to bother with and aren't particularly secure. After all, the hackers do this for fun and financial profit, so why aim for a little teeny tiny target, when you can aim for a big, fat one like Windows?