Of Computer Virus, Malware, Trojan Horses, Spyware and Ransomware

A computer virus is a self-replicating program, that requires a host to function. These programs are written in such a way that make unauthorised changes to the working of the host computer and may send or receive data on behalf of the user without his or her knowledge.

The idea that such computer programs could be written was first theorised by Hungarian-American scientist Johnvon Neumann. In later years, the virus was transmitted across computers using floppy disks. As technology improved, the types of viruses and their destructive power too developed to new levels that could escape the best of anti-virus software. Hence, it became a never-ending battle of wits between the virus creators and those writing the anti-virus code. Here, we shall try to understand the basic terminology about the types of viruses and the destruction they could cause.

A Worm And A Virus

We have learnt that a virus needs a host program to replicate and infect a computer. Unlike a virus, a worm replicates itself and sends itself through computer networks. A classic example of a worm is the "LOVE BUG" or "Love Letter" worm that attacked scores of computers in the Philippines in May 2000. It attacked computers by overwriting files and also used email to send itself to addresses stored in that computer.

Trojans And Spyware

A Trojan is another form of virus where it misleads the user about the program's content. Once the unsuspecting user clicks on the program, it installs on the computer and allows the hacker or Trojan creator complete access to the user's files and data. A Trojan program can also have spyware - that is it sends back data about the user's internet habits and other personal data. The general term given to all such viruses that infiltrate and infect the computers is Malware.

Ransomware

Another form of the Trojan is Ransomware. As the name suggests, this program installs on the user's computer and encrypts all data on it. When the user tries to access his information, the software demands ransom in Bitcoins. It is a form of cyber extortion, wherein a user can only get back his data when he pays the ransom.