A computer virus is a program that affects various areas of the computer system, making it function abnormally .Computer viruses can cause great damage to a computer. They affect the performance of a computer and lead to loss of data. Here are three most harmful viruses:
Melissa was the 1st mass-mailing virus for the new age of e-mailing. The virus became popular in the1990s. Created by David L and based on a Microsoft Word macro, the virus was spread in an email attachment form by the name “list.doc.” Clicking the attachment allowed the virus to replicates itself and looks for the Microsoft Outlook address book. It then e-mailed itself to at least 50 names on the list.
ILOVEYOU was perhaps one of the most dangerous computer virus ever made. It was a standalone program that used to replicate itself. Initially, the virus traveled the internet via e-mail and succeeded in crashing thousands of computers all across the world.
Sasser was discovered in 2004 and its main target was the windows operating system. Unlike other viruses, it did not spread through email. Once it attacked a computer, the virus looked for other susceptible systems. It contacted such systems, instructing them to download the virus.