COMPUTER VIRUS

A computer virus is a malware or a program that when executed has the ability to replicate itself and affect other file or programs by modifying or changing their execution mode in the system it attacks
A virus performs different kind of modification on the  host computer it attacks modification ranging from

1. taken hard disk space
2. modification of system programs
3. power consumption
4.corrupting data
5. displaying unwanted message on the screen
and so many more depending on how the maker creates the virus .

there are several type of various below is the list of the ten most common virus and the most dangerous

1. ILOVEYOU

The ILOVEYOU virus is considered one of the most virulent computer virus ever created and it’s not hard to see why. The virus managed to wreck havoc on computer systems all over t

2. Code Red

Code Red first surfaced on 2001 and was discovered by two eEye Digital Security employees. It was named Code Redbecause the the pair were drinking Code Red Mountain Dew at the time of discovery. The worm targeted computers with Microsoft IIS web server installed, exploiting a buffer overflow problem in the system. It leaves very little trace on the hard disk as it is able to run entirely on memory, with a size of 3,569 bytes. Once infected, it will proceed to make a hundred copies of itself but due to a bug in the programming, it will duplicate even more and ends up eating a lot of the systems resources.he world, causing damages totaling in at an estimate of $10 billion. 10% of the world’s Internet-connected computers were believed to have been infected. It was so bad that governments and large corporations took their mailing system offline to prevent infection.

3. Melissa

Named after an exotic dancer from Florida, it was created by David L. Smith in 1999. It started as an infected Word document that was posted up on the alt.sex usenet group, claiming to be a list of passwords for pornographic sites. This got people curious and when it was downloaded and opened, it would trigger the macro inside and unleash its payload. The virus will mail itself to the top 50 people in the user’s email address book and this caused an increase of email traffic, disrupting the email services of governments and corporations. It also sometimes corrupted documents by inserting a Simpsons reference into them.

4. Zeus

Zeus is a Trojan horse made to infect Windows computers so that it will perform various criminal tasks. The most common of these tasks are usually man-in-the-browser keylogging and form grabbing. The majority of computers were infected either through drive-by downloads or phishing scams. First identified in 2009, it managed to compromise thousands of FTP accounts and computers from large multinational corporations and banks such as Amazon, Oracle, Bank of America, Cisco, etc. Controllers of the Zeus botnet used it to steal the login credentials of social network, email and banking accounts.

5. Conficker

Also known as Downup or Downadup, Conficker is a worm of unknown authorship for Windows that made its first appearance in 2008. The name comes form the English word, configure and a German pejorative.It infects computers using flaws in the OS to create a botnet. The malware was able to infect more than 9 millions computers all around the world, affecting governments, businesses and individuals. It was one of the largest known worm infections to ever surface causing an estimate damage of $9 billion.