Why do people write viruses and what’s to gain from spam messages?  This is a question I’m often asked, and without knowing the facts it’s easy to think that these people are simply malicious and want to cause disruption.

The main reason criminals write viruses is greed.   More often than not, viruses are a means to generate money from unsuspecting victims.   But how do they do it?  Well here are a few examples.


Example 1: Advertising Clicks

First a little background…

Websites often sell space on their pages to advertisers, a scheme dominated by Google Advertising.    For example, I have adverts on my Tech Tips blog at support.scotiasystems.com – it helps in a small way to pay for hosting the site.    The website takes a small commission if someone clicks on the ad (hint: if you’re on my website and see an ad of interest – please click on it!).   So, it benefits the website owner as more people click on ads.   Great – as a website owner, just sit there and click on all the ads on your pages??!   Well Google are smarter than that and can detect automated clicks and discount them.  Instead they’re looking for clicks from different computers.

Here’s where the virus comes in – if you can infect a computer you can turn it into what’s called a “bot”.   A Bot follows any command you send it.   Tell it to click on an ad and it will.   The more bots you control, the more clicks you likewise control.    A collection of bots is called a bot-net, and, can often consist of hundreds of thousands of infected computers.   And all these bots can convert clicks into a lot of money!


Example 2: Spam

Send a seemingly too good to be true offer to enough people and a small percentage will fall for the scam.   This is the intention of spam mails.   Send hundreds of thousands of spam mails and a few people will click a link, buy a product or download a virus.   This all means money, so the more emails you can send, the greater the return.   How do you send so many emails though?  You got it – Bot Nets!   These bots often sit in the background unbeknownst to the user, silently sending out thousands of spam emails.

In 2008, a research team from the University of California, Berkeley and UC, San Diego, took control of over 75 thousand machines in a bot net as a test.   After a month, they sent out over 350 million emails advertising fake Viagra tablets, which only resulted in 28 sales.   Those 28 sales however still netted them $100 per day!


Example 3: Infiltrate Online Banking

A recent virus attack I saw targeted online banking.   When you log on to a bank website, the traffic between you and the bank is encrypted for security.  However, a virus on your computer can intercept this secure channel and “listen in”.   By listening in, I mean tracing your key presses.   By doing this, the virus can learn your password, account numbers, and answers to security questions before it’s encrypted and sent to the bank.   In this case the virus successfully obtained enough information to give the hackers access to the online bank account.

Not only that, but the attack then sent the victim hundreds of thousands of automated emails from, yes, a bot-net.   The emails were basically garbage but were designed to fill the victim’s inbox to such an extent that important warning emails from the bank would be missed!  Cunning eh!


Example 4: Blackmail

This is one of the worst types of viruses/scams and I’ve seen a few cases.   One such case was a virus that set a password on the computer.  Without the password, the computer was useless, and the hackers demanded a ransom for the password (with no guarantee that when the ransom was paid – the password would be revealed).

And once again, bot-nets come in to play.   When you have control of hundreds of thousands of computers, you can direct them all to access a specific website.   This can swamp the website and render it useless.  The scammers then demand a ransom to stop the attack.   This is called a Denial Of Service (DoS) attack and is more common than you think!

There are other examples, including countries attacking other countries via viruses but that’s a whole other story!

All of this goes to show how important it is to have up to date Anti-Virus protection on your computer.   And if you’re running a business network it’s especially important to patch your computers as one infected machine can then infect all the others through unpatched vulnerabilities!

Until next time, check your antivirus and make sure it’s up to date and working properly!