The Verse - Volume 10
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Tech Tips – What are Viruses, Worms and Trojans?

Quite simply, viruses, worms, and Trojan horses are damage-causing programs. They can damage your computer and/or information on your computer, slow down your Internet surfing and might even use your computer to spread themselves to your friends, family, co-workers, and anyone else on the Web. However, you can protect yourself by practicing safe computing – which includes using an Antivirus software and not opening attachments you did not expect to be sent to you.

What is a Virus?
A virus is computer code that attaches itself to a program or file so it can spread from computer to computer, infecting as it travels. Viruses can damage your software, your hardware and your files.

Like biological viruses, computer viruses can be mild, like the common cold or as devastating as Ebola. Fortunately, a computer virus cannot be spread without human intervention such as sharing a file or sending an e-mail.

What is a worm?
Just like a virus, a worm is designed to copy itself from one computer to another. It is designed to do this automatically by taking control of features on the computer that can transport files or information. Once you have a worm in your system it can spread itself without your help. This ability to replicate in large volumes is what makes worms so dangerous. A worm can send out copies of itself to everyone listed in your e-mail address book and their computers would then do the same. This exponential effect can be devastating to businesses networks and even the Internet as a whole. New worms spread very quickly and can consume computer memory or network bandwidth

Because worms don't need to travel via a "host" program or file, they can also tunnel into your system and allow somebody else to take control of your computer remotely. Recent examples of worms included the Sasser worm and the Blaster worm.

What is a Trojan horse?
Trojan horses are computer programs that appear to be useful software, but instead they compromise your security and cause a lot of damage. A recent Trojan horse came in the form of an e-mail that included attachments claiming to be Microsoft security updates, but turned out to be viruses that attempted to disable antivirus and firewall software.

Trojan horses spread when people are lured into opening a program because they think it comes from a legitimate source. For example, Microsoft often sends out security bulletins via e-mail, but they will never contain attachments.

Trojan horses can also be included in software that you download for free. Never download software from a source that you don't trust. Always download Microsoft updates and patches from Microsoft Windows Update or Microsoft Office Update.

How do worms and other viruses spread?
Virtually all viruses and many worms cannot spread unless you open or run an infected program.

Many of the most dangerous viruses are spread through e-mail attachments—the files that are sent along with an e-mail message. You can usually tell if your e-mail includes an attachment because you'll see a paperclip icon that represents the attachment and includes its name. Photos, letters written in Microsoft Word, and even Excel spreadsheets are just some of the file types you might receive through e-mail each day. The virus is launched when you open the file attachment.

If you receive an e-mail with an attachment from someone you don't know you should delete it immediately. Unfortunately, you're no longer safe opening attachments from people you do know. Viruses and worms have the ability to steal the information out of e-mail programs and send themselves to everyone listed in your address book. So, if you get an e-mail from someone with a message you don't understand or a file you weren't expecting, always contact the person and confirm the contents of the attachment before you open it. The best policy to follow is to never open any attachment unless you were expecting it and you know the contents of the file.

Other, less common ways to get infected are by downloading programs from the Internet or from computer disks that you borrow from friends.

How can I tell if I have a worm or a virus?
When you open and run an infected program, you might not know immediately that you now have a virus. Your computer may slow down, stop responding, or crash and restart every few minutes. Sometimes a virus will attack the files you need to start up a computer. In this case, you might press the power button and find yourself staring at a blank screen.

Beware of messages warning you that you sent e-mail that contained a virus. This may mean that the virus has listed your e-mail address as the sender of a tainted e-mail. This does not necessarily mean you have a virus. Some viruses have the ability to fake or “spoof” e-mail addresses.

Unless you have up-to-date antivirus software installed on your computer, there is no sure way to know if you have a virus or not. Nothing will guarantee the security of your computer 100 percent. However, you can vastly improve your computer's security by keeping your software up to date and maintaining a current antivirus software subscription.