What are Viruses?
Computer Viruses are the digital versions of their biological counterparts.
A Virus in a human body is a ‘particle’ that reproduces by infecting other human cells. This reproduction causes the cells in our body to die. They also cause harmful diseases.
A computer virus on the other hand, ‘infects’ a computer by copying itself to it, without the knowledge of the user operating it. The virus, then, typically spreads around trying to infect other computers.
Some terms to keep in mind when talking about viruses:
(i) A host is the computer on which the virus resides.
(ii) A vector is typically the computer on which the virus stays, before causing any harm. The vector is the mode of transmission.
(iii) A worm is a special kind of malicious program that mainly spreads via a network of computers.
Why are they created?
Unlike their biological counterparts, viruses don’t come completely of the blue, but are ‘engineered’ by humans! Humans have long been greedy and revengeful. It is our nature, we have to live with it, and face it.
Viruses are typically created to frustrate users for the joy of the creator. However, many
virus developers are quite serious in their purpose. They might have created it for a variety of reasons:
(i) To expose the ill-functioning of software
(ii) To vent their frustration against corporate firms
(iii) Financial gain : By executing a virus program on an unaware user’s computer, the attacker could get hold of sensitive information like email-passwords, credit card numbers and could misuse them. Read more.
(iv) To become famous!
(v) Some people believe that writing viruses is an ‘art’!
How do they work?
The complexity of viruses can be very intriguing. Let us consider a ‘worm’ that wrecked havoc in the year 2001. This worm spreads rapidly via email and was written in a scripting language called VBScript. The worm comes from a host to one's email inbox and the mail contained the following text
Kindly check the attached LOVELETTER coming from me
Naturally, any curious human would LOVE to read the letter to see what it contained. Few knew that it was a malicious program that will install itself when opened in Windows, by copying itself to the System Folders. It would also make sure that it ran each time the computer was switched on, and it would overwrite many files on the computer by placing a copy of itself there. It spreads by attaching itself to every email that was sent from the victim's computer via Outlook. This method was very effective and soon many email servers around the world were clogged with the ILOVEYOU emails. Several companies had to shell out lots of money to clean up the mess.
How are they detected?
Just like humans, who show symptoms when they are infected with viruses, computers also show symptoms by behaving strangely when infected. However, viruses could remain dormant for a long time to avoid detection and then blow up at a particular time to initiate a massive attack.
Modern computers are now equipped with special software called ‘Anti-Virus’ software that does exactly what it claims. It tries its best to protect its host by ‘monitoring’ for malicious activities. When it finds one, it notifies the user immediately before it does any harm. These softwares are very complicated and they have evolved into a profit making business.
Ways to avoid virus attacks
Prevention is always better than a cure. One should be very careful when visiting websites, or downloading software from the web.
(i) You must be very confident that the file you are downloading is from a trusted source. If you are unable to decide, ask your friend, or an experienced individual.
(ii) If the file is in your email, double check it with your contact to make sure that he/she was the one who sent it to you, as it is quite easy to fake email addresses. If you feel that your system has been compromised, shutdown your computer immediately and ask for professional help!
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