Worms are malicious programs that make copies of themselves over and over, on the local drive, network, email, or Internet. In other words, the sole purpose of a worm is to reproduce, unlike a virus which attempts to infect, i.e. embed its code into, other files.
The most common type of worm is the email worm. True to its type, worm, email worms do not infect other files as do viruses but rather they simply make copies of themselves over and over again. Again true to its type, email worms do this via email, by sending themselves to email addresses found on the infected user’s system.
Email worms can spread globally within moments by using this simple tactic. Consider one person who becomes infected but happens to have twenty email addresses found on his system. All twenty of those addresses will be sent a copy of the worm. If any of the recipients become infected, they will also unwittingly spread copies of the worm to all their friends, colleagues, and business associates whose email addresses happen to be on their system.
Common myths:
I don’t use Outlook or Outlook Express, so I am safe. Email worms seldom care what mail client you use. All that is usually required for their spread is a user willing to open an attachment – whether it’s via Yahoo, Eudora, Outlook, or any other email client or web-based mail service.
I heard you could add !0000 or AAAAA.AAA to your address book and that would stop a worm. This is incorrect information. At best, it will do no good. At worst, it can lead to a false sense of security that in turn can lead to a greater risk of infection. For further details on why this “tip” fails, see the article !0000: Trick or Treat.
Protecting against email worms:
There is no quick and easy fix-all for the problem of email worms. The best defense against email worms is exercising common sense about email attachments, keeping your system patched, securing your mail client, and making sure your antivirus software definitions are always up to date. For more information on email worms and prevention, see the article Email: Pandora’s Box
For tips on securing your mail client, choose from one of the following:
