t seems that viruses are getting smarter and smarter. This makes it more difficult for everyday computer users to recognize them and understand exactly what they do.

Many viruses are still being spread by e-mail attachments. In order to contract these viruses the recipient must open the attachment. So the virus-laden e-mail must do something to entice the computer user to open the attachment. Many previous viruses used sexy-sounding come-ons as a lure. Virus creators, however, are realizing that sex lures in e-mail are old hat. They are now trying new enticements. The MyDoom virus includes very technical-sounding text that is making recipients think that the e-mail is real.

Other new virus ploys are plentiful. One of the cleverest is to spoof the sender’s address when sending out the e-mail messages. Here’s how it works. The virus takes over the infected computer’s address book. It chooses one name from the address book and puts that name in the Sender line of the e-mail. Then it sends virus-laden e-mail to everyone in the address book. This makes it look like the e-mail is a known person so the recipient will be more likely to open the e-mail attachment.

This little trick also produces some e-mail that often confuses computer users.  Often a computer address book contains invalid or outdated e-mail addresses. When an e-mail message cannot be delivered it is returned to the sender. If your name and e-mail address happen to be in someone else’s address book, the virus could choose you as the Sender. Then when invalid e-mail is encountered it will be returned to you. There have been times when I have received as many as twenty or thirty “Undeliverable E-mail” messages. This did not mean that my computer had the virus. It only meant that the computer of someone who had my name in their address book was infected.

Another common trick of viruses is to install a key logger on an infected computer. A key logger is a program that keeps track of every key stroke that is typed into the computer. As you visit various Web sites, the key logger will track your keystrokes. If you enter a password or a credit card number that information will be recorded in the key logger for the virus creator to view. Voila! A simple virus can steal your passwords, banking information, and credit card numbers.

Here is one last trick you should be aware of. This is a deception that is perpetrated by scammers rather then virus creators. The scammer creates a bogus Web site that masquerades as legitimate one. The name of the Web site will be only slightly different from the real name. The Web site will be designed to look like the real site. The scammer then uses e-mail to direct people to these Web sites. You might receive an e-mail from your bank or credit card company that asks you to update your account information. When you click on the link given in the e-mail you are taken to the bogus Web site where everything you input will fall into the hands o the scammers. This type of online fraud has already produced domains similar to Citibank and Ebay which have fooled thousands of unsuspecting users.

Unfortunately, viruses and scams remain a part of our collective Internet experience. We can’t make them disappear, but we can learn about how they work so we can avoid their unpleasant consequences.