Computer viruses: All you need to know

Computer viruses: All you need to know

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  In 1949, when computing was just about a decade old, Hungarian-American scientist Johnvon Neumann theorised the possibility of writing a self-replicating program, which later came to be known as a computer virus. These programmes, which need a host to function, are designed to make unauthorised and undesirable modifications in infected computers.Initially, viruses were designed and tested in university computer labs. The first virus that went 'in the wild' -outside the lab computer in which it was designed -- was Elk Cloner which was written by Richard Skrenta, a school student in the US. Viruses written during the period were spread through floppy disks and hence never caused a major security threat.

• 1. Since when are viruses being spread through the internet?

  The first major attack was in 1999 when an American, David L Smith, designed the Melissa virus (named after an exotic dancer) that could spread through email. It required a host to run properly, which in this case was a word document attached to an email. Once opened, the virus replicated and sent itself to 50 people in the email ad dress book. The increased email traffic because of thousands of infected computers forced some companies to shut down email services.

• 2. How is a worm different from a virus?

  A worm doesn't need a host program. It is an application that can replicate itself and send itself through computer networks. In May 2000, a worm commonly referred to as Love Bug, Love Letter or ILOVEYOU attacked several computers in the Philippines and then the rest of the world. It travelled through emails and unlike Melissa did not require a host. It attacked computers by overwriting files and hiding its copies in different locations. It then used email to send itself to addresses stored in the computer.

• 3. What are malware, Trojan horses and spyware?

  Malware is the generic name given to all malicious software that infects computers.It includes viruses, worms, Trojan Horses, spyware and so on. A Trojan horse is a program used to hack computers by misleading users about its actual content. A Trojan can be used for a plethora of purposes. For instance, in 2007, a Trojan horse identified as Storm Worm was released by its developers. It was spread by using an email message with a subject about a weather disaster, "230 dead as storms batters Europe."
  
  Once opened, the Trojan installs itself in the computer and opens a backdoor for the hacker who can then turn the computer into a zombie or bot and use to it for spamming others. A Trojan payload can also have a spyware, a program that tracks internet habits of the user and accordingly takes himher to certain websites. It can also be used for identity theft.

• 4. What is ransomware?

  Ransomware is malware used for cyber extortion. Once installed in a computer, the Trojan installs a ransomware that encrypts the data stored in the computer. Victims are then notified through a screen alert that demands a ransom to be paid in Bitcoins to use their data. Bitcoin is a digital currency made by an unknown programmer or group of programmers known as Satoshi Nakamoto.
  
  This currency is not dependent on the global financial system for exchange among its users and hence very hard to track. The "WannaCry" ransomware lately in the news uses a flaw in Microsoft software to infiltrate victim computers. Incidentally , this flaw was discovered by the US National Security Agency and then leaked by hackers. The malware encrypts the data in a hacked computer and then asks for ransom to be paid in Bitcoins.