Virus, popularly understood in computer terminology, is that which has the corrupting influence. That which hinders, interrupts and sometimes totally destroys the files on a network files system which is accessed by another computer. Virus is a program that has the capacity to interfere and it can copy itself and infect a computer. When its host is taken to the target computer, it spreads from one computer to another. Once it seizes the computer, it proceeds to create its inherent nuisance value to the removable accessories like, a floppy disk, DVD, CD or USB Drive.
Some of the notable computer viruses are:
- Creeper (1971): This is perhaps the first ever noticed computer virus. It found its way to infect computers on ARPANET. This virus is mostly harmless.
- Elk Cloner (1982): Marketing Divisions of every computer company explains its ‘fool-proof’ systems to guard against viruses, but some viruses beat them all and establish their abodes within the computer systems. This virus is one of them that infected the boot sector of Apple II floppies.
- Jerusalem (1987): Discovered on October 1, 1987. On Friday the 13 1988, many companies and universities in a number of countries ‘got acquainted’ with the ‘Jerusalem’ virus. It destroyed many files when attempt was made to run the computer. Computers from Europe, the Middle East and America were affected. Its origin was supposed to be in a Hebrew University but in 1991 further light was thrown about its existence. Italy was the country of its first traces. It infects both .EXE and .COM files. It considerably slows down the machine. Identify the virus by noticing two lines on the monitor.
- The Morris Internet Worm (1988): This is known as the grandfather of computer worms. This infects the UNIX system and was famous for its “accidental” capacity to do extreme harm to the systems.
- Melissa (1999): This 20th century virus is the most dangerous one, being a Word macro category. It reaches out and spreads through e-mails sent to contacts from the address books of the infected users. With the single click of the mouse, thousands of e-mails are sent and this virus is capable of causing damage of colossal magnitude.
- ILOVEYOU (2000): “Beware, before you walk on the path of “I Love You”, This virus has led many computers to the grave!” This is a fast spreading virus identified ever, and its channel is through e-mail. It arrives as a downloadable enclosure sent by a known person, from the contact list of the receiver of the mail. It was detected for the first time in Philippines on May 4, 2000. On the very first day, about 10% of the internet users were affected. Its arrival channel was through an e-mail attachment which said, “LOVE-LETTER-FOR-YOU.TXT.vbs”. Upon activating, it quickly spread to all files on the host.
- Nimda (2001): This virus employs all sorts of methods to establish its authority and does its ill-conceived job fast and most effectively. Its area of influence is wide and it is one amongst the most feared viruses.
- Blaster (2003): Attacks the vulnerability of the Windows operating system. It arrives with a warning of shutdown and thus users have the clue of its presence
- SQL Slammer (2003): This spreads very fast. It causes infection in servers running Microsoft’s SQL Server Desktop Engines.
- Sasser (2004): Sasser’s playing field was a superfluous overflow and from there it spread by reaching out to port 445 on Windows systems networks. It created total chaos and the systems either crashed or restarted.
Computers provide platform for several ‘actors’ (devises) to play. With the devises lacking a fool-proof anti-virus system, the computer is mostly at the receiving end. It becomes vulnerable to virus attacks. Another major threat is the availability in abundance of duplicates of every computer-related product.