Macs infected with Flashback malware after users were redirected to a rogue website from a compromised site. Macs should not be targeted using malware in the same way that viruses, Trojans and worms are built to target Windows systems. Mac OS is based upon the Berkley Software Distribution (BSD) of Unix, surrounded by a nice graphical user interface. Windows has had address space layout randomisation (ASLR) which is implemented so as to obscure most of what an attacker needs to conduct, for example, shell code injection.”]
Source: https://nakedsecurity.sophos.com/2012/04/10/macs-safer-than-pcs/