Mac OS X is not invulnerable. It, like any other operating system, has security deficiencies in various aspects of the software. Some are technical in nature, and others lend themselves to social engineering trickery. However, the general architecture and design philosophy of Mac OS X, in addition to usage of open source components for most network-accessible services that receive intense peer scrutiny from the community, make Mac OS X a very secure operating system.  -   Dave Schroeder     Quotes
Mac OS X is not invulnerable. It, like any other operating system, has security deficiencies in various aspects of the software. Some are technical in nature, and others lend themselves to social engineering trickery. However, the general architecture and design philosophy of Mac OS X, in addition to usage of open source components for most network-accessible services that receive intense peer scrutiny from the community, make Mac OS X a very secure operating system. Dave Schroeder