What is a Computer Virus?

They're there. Lurking in your inbox, behind that photo attachment, inside that program- the fearsome computer virus! Viruses in the physical world are microbes that are self-replicating. Viruses in the digital world are small programs that are self-replicating. A virus in your computer takes advantages of weaknesses in your security in much the same way a real virus takes advantage of weaknesses in your immune system.

A virus can do anything, or even nothing. Some sit there doing nothing but slowing down your computer, some will corrupt your data, others will take over your computer for someone else's use. Regardless of what it does, it's not a computer virus unless it self-replicates, meaning it makes a copy of itself and sends it on to another computer. I've compiled a small glossary of commonly used and misused terms related to this topic:

• Virus- A program that self-replicates (typically) through computer programs and usually does harm to your computer.
• Trojan- A program that claims to be one kind of file (like a game or music file), but is actually doing harm.
• Worm- A program that self-replicates through a computer network, not through programs. Usually does not harm the network itself.
• Adware- A program that pops up advertisements even when you are not connected to the internet.
• Spyware- A program that spies on you, reporting your activity to an outside source without your consent.
• Malware- A program that does bad things. This is a general name for all of the above terms.
• Phishing- An attempt- usually via email or webpage- to trick you into giving your information to a fraudulent source.

The last one, phishing, usually isn't a program at all, and thus is one of the most dangerous ones since there is no program to keep you from giving your own information away. One of the most common tricks is an email that appears to be from your bank saying your password has expired and needs to be changed. It then links to you what looks like your bank's webpage, and then asks for your log in, old password and new password. Once you hit submit, your banking ID and password is now available to whoever sent that email.

Practical Tip of the Day:
If you do ever receive an email from your bank asking for you to log in, do not follow the attached links, but rather navigate to the bank site as you normally would and log in from there. This keeps you from being navigated to a fraudulent site. Be suspicious of anything that asks for personal information of any kind. Most companies have a strict policy of not asking for log-in or personal information via email. If in doubt, call the company to verify the email.