If you download an executable file on a Mac, the system comes up with a message asking if you're sure you want to download it. It then appears in a disk image and you have to double click on the installer to run it. It will ask for your password when you run the installer to upgrade privileges sufficiently to install it.
I don't think there is as much protection if you download an executable in an email. Then again, I don't remember ever receiving a Mac executable in an email so it may not be considered a useful vector.
In any event, you would have to actually download and deliberately run it for it to work. There is no system that allows for a "drive by download" because the Mac has no equivalent to Active-X controls.
Microsoft's decision to make Internet Explorer integral to the operating system appears to have been the worst possible security mistake. There is no technical reason to make a web browser capable of updating the OS. In MacOS X, system updates are performed in a way entirely unrelated to the web browser and so there is no way a web browser can update the OS.
The ability to make Windowsupdate work from the web forces horrible security vulerabilities since it means that Windows has to be updateable from the browser environment. Browser helper objects, the things that create those ghastly popups, can be downloaded automatically thanks to these same technologies.
Since there's nothing like them on the Mac, the Mac is inherently far more secure than a Windows machine.
In addition, the Mac's email software does not have a javaScript interpreter and so you can't script emails. Outlook was fully scriptable via emails, which again was a huge and very costly mistake.
Did that help?
D
Yup. Thanks!
I know Entourage askes if you really want to open attached files.