For a very long time Mac OS X was very, very safe. Still no known viruses today, and very little malware, mostly exploiting Java, Flash, or SilverLight. That was due to two huge advantages: 1) a vastly more secure operating system than Microsoft Windows, and 2) a tiny user base not worth targeting with slimy malware.
Now Mac OS X is the most popular full computer operating system in the world on new computers. If you include tablets, OS X is in third place behind Android variants and iOS. While this is a huge success for Apple, it brings with it a giant new status as target for malware writers… and although the operating system is still very, very secure… social engineering (tricking humans to install malware) has become vastly more sophisticated….
I need to read this in more detail, but the brave new world of malware and crud has arrived for OS X users… be careful where you get your applications from and verify it is only from trusted sources.
Fun assertion: “Java was responsible for 91% of attacks in 2013.”