Digitally Transmitted Diseases 101

These days, more and more people seem to be asking me, “Tristan, I want to become a shark-fighting, syrup-chugging, moose-herding, tree-felling Canadian, too. But first, I’m confused – Can you explain the difference between a virus, a trojan, and spyware?”

You may have read a post I wrote on the digital clap a couple of years ago, Discount Pharmaceuticals – Get ‘em While They’re Hot! Consider this a sequel, if you will. Previously, I offered some helpful tips on protecting yourself online. Now, I’m going to help you understand what you’re protecting yourself against.

Turns out, the digital clap isn’t the only digitally transmitted disease out there. Here’s a brief explanation of the most common types, better known as “malware” (malicious software, get it?).

The Infamous Computer Virus

The virus is so widely known, that people often group all other forms of malware into this one category. However, it’s important to understand that a virus is just one form of malicious software that wants to settle in on your computer.

It’s easy to see why the virus is so widely known, since it’s been around the longest. Before internet use was widespread, viruses were often spread on floppy disks, and other portable media. Today, they most often spread over networks.

They make changes to systems whose results range from simple annoyance to outright destruction of data, and they’re also injected into other files, including Microsoft Word and Excel files.

Since the virus was, essentially, the first form of malware, how do the other forms differ?

The Trojan

The Trojan Horse of Greek mythology seemed, to the inhabitants of the city of Troy, to be a gift. However, concealed inside were enemy soldiers that used it as a ruse to gain entry to the city and destroy it.

Think of a trojan as the software version of that horse – A piece of software designed to seem harmless on the outside, in an attempt to get you to run or install it. Once you do, you’re opening yourself up to attack. Trojans are often used to steal information, or even enable an outside party to gain remote access to your computer. You want that about as much as you want the real clap.

The Worm

Worms are viruses that spread by any means necessary – Usually, over a network directly, or by harvesting your address book and sending itself to your friends. Trust me, they’ll love you for that.

Spyware and Adware

While not usually as destructive as other forms of malware, spyware isn’t any less dangerous. It’ll sit on your computer, collecting information about your habits on the internet, such as what sites you visit, and send that data elsewhere.

Why is this a problem? It’s a privacy violation. How many other people do you really want aware of that embarrassing Google search you did last week about that rash on your buttocks? And for advertising data, no less?

Adware is designed simply to display advertisements on your computer. And where do you think they get the data to target the ads towards you, personally? Bingo. The most annoying fact about spyware and adware is that it’s often installed with software such as browser toolbars, which many people elect to install themselves. The MyWebSearch toolbar is a perfect example of this.

The Rogue Antivirus Application

An example of a piece of rogue antivirus software, pretending to be a legitimate scanner.

Rogue antivirus software likes to get all dressed up for a night on the town. In this case, the “town” is your computer. These tricky bastards are designed to look like legitimate antivirus applications, such as Vipre or (heaven forbid) Norton Antivirus.

What’s funny about these ones is that they actually tell you that you’re infected, in an attempt to get you buy bogus software. Tricky, indeed.

Of course, if they were legitimate, they’d make it easy for you to remove them. Too bad it just isn’t that easy. They often block key programs that would otherwise make stopping or removing them a simple task.

The Keylogger

I don’t have to explain this one, do I? It should go without saying that you do not want to enter a password to your bank account on a computer that’s secretly recording every keystroke on your keyboard, and sending that data to someone on the internet.

Last but not least: The Rootkit!

Always save the best for last, right? Just kidding. Seriously.

A rootkit camouflages itself among your computer’s core systems. It integrates itself into a part of your operating system, and hides itself so well that it is often incredibly difficult to detect, much less remove. Of all the forms of malware out there, the rootkit is most often the one that will make your IT guy throw his hands up in defeat, and just wipe a computer entirely.

It’s not that you can’t remove a rootkit, it’s just that in the time it usually takes to make progress against one, you can often just wipe a computer and reinstall its operating system and applications anyway. Removing rootkits usually ends up being a frustrating exercise that can even lead to significant damage to an operating system, anyway.

The More You Know

This topic is one that confuses a lot of people outside the IT industry, but that’s ok. It isn’t your area of expertise, but you want to better understand what threatens your computer, and even your business.

I hope that I’ve been of some help in this area. And as I said in Part 1, I’m always around if you have questions. Comments, email, Twitter… Get at me.