worms

Worm :

Worm is a malicious program that infects a computer without using carrier file. Worms have more capacity to damage computer networks by spreading through the LAN because they are not dependent on the user action. Worm has a capacity to slow down computer as well as entire network and can spread to other networks also.

Types of Worms:

Worms can be classified according to the propagation method they use, i.e., how they deliver copies of themselves to new victim machines. Worms can also be classified by installation method, launch method etc.

e-mail worms:

e-mail worms spread via infected computers e-mail network. The worm may be in the form of an attachment or the email may contain a link to an infected website. However, in both cases, email is the vehicle. In the first case the worm will be activated when the user clicks on the attachment. In the second case, the worm will be activated when the user clicks on the link leading to the infected site.

Instant Massaging Worms:

These worms have a single propagation method. They spread using instant messaging applications by sending links to infected websites to everyone on the local contact list. The only difference between these worms and email worms which send links is the media chosen to send the links.

Internet Worms:

Internet worms are truly autonomous virtual viruses, spreading across the net, breaking into computers and replicating without human assistance and usually without human knowledge. An Internet worm can be contained in any kind of virus, programmer script. Sometimes their inventor will release them into the wild.

IRC Worms:

These worms target chat channels, IRC worms also use the propagation methods listed above - sending links to infected websites or infected files to contacts harvested from the infected user. Sending infected files is less effective as the recipient needs to confirm receipt, save the file and open it before the worm is able to penetrate the victim machine.