Over the years I’ve worked on lots of computers that exhibited all the classic signs of a malware infection.

And as you might expect, many of the owners of those machines insisted that the problem couldn’t possibly be malware because they regularly scan their systems with antivirus programs.

But when I ran my own scans on those systems, I often discovered that they were indeed infected, some of them with dozens of viruses, spyware objects, malicious toolbars and other digital nasties.

How could that be? [Read more…]