Spyware for Linux
I'm sorry, I thought virii was the standard, like radii. I dunno where I got that. Anyway...
Spyware isn't really a big deal for servers, and is a somewhat different topic from viruses, but you did ask me to explain further about spyware on Linux, so here you go:
First, understand that it's an invited guest on Windows. This is a new problem so laws against it are slow for many reasons, so these are legally legit companies making the spyware and it makes economic sense to keep it legally legit cause it's too easy to make money legally to bother breaking any laws.
It just piggy-backs with other software. Included with Bearshare or whatever file sharing program you have, or it comes in as an IE\Firefox addon or ActiveX control that a website tells the user to allow so they can get some free knicknack like a desktop wallpaper or set of IM smileys. I've seen so many people fall for it, it's frightening.
Now, your uneducated home user will be more than happy to click on the .rpm or .deb file on the website if the website tells them to so they can get ____. It's just the computer nagging them about something they don't understand. They're more than used to clicking "okay" and "shutup and work already".
On Ubuntu or Fedora (or Vista...) this will automatically pop up the root login. They log in, the program installs, bam.
It can set itself up as a daemon with super user access, access all their firefox cache and records, or open popup windows. The sky's the limit. And all it took to make it legal was to stick a mention in that EULA that came with PirateMonster or whatever.
Not that it even needs super user access. If you can get the customer to run any program - which isn't hard - you can have it create a hidden directory (the classic "..." folder? A folder called ".glib"?) to store an adware program and wedge it into the local startup scripts or Gnome or KDE config files. (Both desktops can be configured to start an arbitrary program on login.)
Remember that when we're talking about a home user's computer, the fact that a program can't run as root means very little to a spyware because the data it wants is in userspace.
You may be thinking "well all I have to do is not install it". And you'd be right. That trick works on Windows too. Linux just plain isn't special here, and neither is Mac. Not by a long shot.
But obviously user downloaded spyware isn't the biggest problem for a server in a closet.
Lemme reiterate my original point; Obviously Mac can be hit, but if they've got redundant, incompatible systems, than they'll never all be brought down by the same virus at the same time.
Obviously if some really smart foreign intelligence agency is dead set on breaking into a given system, this won't help, but it's not supposed to. It's supposed to help with the epic fuckload of random malware floating around on the net.
That doesn't mean they're not worried about foreign intelligence. It only means this particular project isn't worried about foreign intelligence. The money they spend on commercials isn't geared towards thwarting foreign intelligence either. Obviously thwarting foreign intelligence is an important thing, but there are many other things the army has to worry about.
This is one of those 'other things'.