I have a Virus? On a Mac?

MacOS 9 did indeed have a couple, although the MacOS 9 exploit that did the most damage was actually a worm: the AutoStart Worm. I remember cleansing some customer computers of it.

The AutoStart worm would propagate without having to manipulate people into running an app or entering their password: it infected computers the moment infected CDs, Zip cartridges, other removable media were inserted. (Then infected any subsequent removable media if it wasn’t read-only).

As far as I last heard, the MacOS X exploits all operate by misleading users into installing them, e.g., “Your version of Flash (or whatever) needs to be updated to play this video; click here to install. Your password please?”

I guess you’re right though, most people don’t distinguish between one flavor of malware and another and refer to them all as “viruses”. So in that colloquial sense, yeah, we’ve got them.

And Free BSD is not that different from Linux. Sure, there are under the hood differences, but the actual OS as users experience it is very nearly the same.

So if you want to distinguish them, you probably should also distinguish that the DOS of Windows 9x was actually more of a boot loader. Applications could be written to use the underlying DOS, but they need not be. Hence why most still work on 64-bit Windows which has no DOS whatsoever.

This makes very little sense.
Sure, at the command line OS X and Linux are almost identical, because both are (for the most part) POSIX-compliant. However, the vast majority of users interact with the OS though a GUI, and OS X’s GUI is significantly different from the various Linux GUIs. Also, from the perspective of malware, the GUI isn’t very important - it’s “what’s under the hood” that is. So, it pays to highlight the pedigree of the different OSs.

Just a word of explanation about “from” fields in e-mail: The “from” field of e-mail has exactly the same security as the return address on an envelope, which is to say, none at all. I could send you a letter with the return address “1600 Pennsylvania Avenue, Washington DC”, and there’d be nothing to stop me. Everyone knows this, and has gotten used to it, and so doesn’t worry about it. By exactly the same token, I could also send you an e-mail with the “from” field listed as “president@whitehouse.gov”, and it wouldn’t mean any more than the snail mail letter.