http://www.apple.com/getamac/viruses.html said:People attempting to break into computers may disguise a malicious program as a picture, movie, or other seemingly harmless file. You might download such files from the web or get them via mail or chat. A PC just blindly downloads them without a peep. A Mac, however, will let you know that you may be getting a wolf in sheep’s clothing. The Mac web browser, Safari, can tell the difference between a file and a program, and alerts you whenever you’re downloading the latter.
http://www.channelregister.co.uk/2008/03/28/mac_hack/ said:A brand-new MacBook Air running a fully patched version of Leopard was the first to fall in a contest that pitted the security of machines running OS X, Vista and Linux. The exploit took less than two minutes to pull off.
Charlie Miller, who was the first security researcher to remotely exploit the iPhone, felled the Mac by tapping a security bug in Safari. The exploit involved getting an end user to click on a link, which opened up a port that he was then able to telnet into. Once connected, he was able to remotely run code of his choosing.
Maybe it's time to review those claims, Apple?