Worms are very similar to viruses in the manner that they are computer programs that replicate copies of themselves (usually to other computer systems via network connections). Viruses often, but not always, contain some functionality that will interfere with the normal use of a computer or a program. Unlike viruses, however, worms exist as separate entities; they do not attach themselves to other files or programs. Because of their similarity to viruses, worms are also often referred to as viruses. Some examples of the worst Worms that impacted the web are as follows:
- Jerusalem is one of the earliest worms that spread in 1987. It is also one of the most commonly known viruses. It used to delete files that were executed on each Friday the 13th. It was first detected in the city of Jerusalem.
- In 1991, thousands of machines running MS-DOS were hit by a new worm, Michelangelo. The virus would overwrite the hard disk or change the master boot record of infected hosts.
- In 2007 Storm Worm hit the computers. Once hit, your machine becomes part of a large botnet which performs automated tasks that range from gathering data on the host machine, to sending infected emails to others. About 1.2 billion emails were sent from the infected computers propagating infection.
Since Worms spread mostly through the email attachments, the best ways to avoid them is using caution in opening emails. If the email is from an unidentified source, it is always best to delete it. Most of the time worms attach themselves to email. Even the sender of email does not recognize what they have forwarded, as emails are sent automatically using all contact information in the user’s profile.
