If a bad guy can persuade you to run his program on your computer, it is not your computer any more.
It is an unfortunate fact of computers that when a computer program runs, it will do what it is programmed to do, even if it is programmed to be harmful. When you choose to run a program, you are making a decision to turn over control of your computer to it. Once a program is running, it can do anything, up to the limits of what you yourself can do on the computer. It could monitor your keystrokes and send them to a website. It could open every document on the computer, and change the word “will” to “will not” in all of them. It could install a virus. It could create a “back door” that lets someone remotely control your computer. Or it could just reformat your hard drive.
That is why it is important to never run, or even download, a program from an untrusted source and by “source,” we mean the person who wrote it, not the person who gave it to you.
There is a nice analogy between running a program and eating a sandwich. If a stranger walked up to you and handed you a sandwich, would you eat it? Probably not. How about if your best friend gave you a sandwich? Maybe you would, maybe you would not it depends on whether she made it or found it lying in the street. Apply the same critical thought to a program that you would to a sandwich, and you will usually be safe.
Computer System Coordinator | Medicine | Psychiatry
The University of British Columbia | Pt. Grey Campus
Phone 604 822 7374