COMPUTER VIRUS FOR JSS3

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COMPUTER VIRUS FOR JSS3

Definition of Virus
1. A computer virus is a small software program that interferes with computer operation and spreads from one computer to another.
2. A virus is a self replicating program that copies itself and that can infect other programs by modifying them or their environment such that a call to an infected programs implies a call to a virus
3. Computer viruses are executable computer programs written by software developers to check piracy on some of their system and application software.

The History of Computer Virus

Robert Thomas, an engineer at BBN Technologies developed the first known computer virus in the year 1971. The first virus was christened as the “Creeper” virus, and the experimental program carried out by Thomas infected mainframes on ARPANET (Advanced Research Projects Agency Network). The teletype message displayed on the screens read, “I’m the creeper: Catch me if you can.” But the original wild computer virus, probably the first one to be tracked down in the history of computer viruses was “Elk Cloner.” The Elk Cloner infected Apple II operating systems through floppy disks. The message displayed on infected Apple Computers was a humorous one. The virus was developed by Richard
Skrenta, a teenager in the year 1982. Even though the computer viruses were designed as a prank, it also enlightened how a malicious program could be installed in a computer’s memory and stop users from removing the program. It was Fred Cohen, who coined the term “computer virus” and it was after a year in 1983. The term came into being when he attempted to write an academic paper titled “Computer Viruses – Theory and Experiments” detailing about the malicious programs in his work.
1. Boot Sector Virus: This type of virus infects the master boot record. It is challenging and a complex task to remove this virus and often requires the system to be formatted. Mostly it spreads through removable media.
2. Direct Action Virus: This is also called non-resident virus, when executed scans the disks for targets, infects them, and then exit (i.e. it does not remain in the memory after it is done executing).
3. Resident Virus: Resident virus installs itself as part of the operating system when executed, after which it remain in the RAM from the time the computer is booted up to when it is shut down.
4. Multipartite Virus: This type of virus spreads through multiple ways. It infects both the boot sector and executable files at the same time.
5. Polymorphic Virus: These types of viruses are difficult to identify with a traditional anti-virus program. This is because the polymorphic viruses alter its signature pattern whenever it replicates.
6. Overwrite Virus: This type of virus deletes all the files that it infects. The only possible mechanism to remove is to delete the infected files and the end-user has to lose all the contents in it. Identifying the overwrite virus is difficult as it spreads through emails.
7. Space filler Virus: This is also called “Cavity Viruses”. This is called so as they fill up the empty spaces between the codes and hence does not cause any damage to the file.
8. Macro viruses: As the name suggests, the macro viruses particularly target macro language commands in applications like Microsoft Word. The same is implied on other programs too.


Examples of Viruses
Some of the known viruses are:
a. Trojan horse virus
b. Sleeper
c. Logic bomb Alabama virus
d. Christmas virus
e. Jerusalem virus
f. Resident virus
g. Nonresident virus
h. Code Red
i. I love you
j. Creeper virus
k. Stone
l. November 17
Sources of Virus
These are the means through which viruses could be spread from one system to the other.
i. Infected memory devices
ii. E-mails attachments
iii. Internet downloads
iv. Computer network
v. Illegal duplication of software/cracked software.
Virus warning signs
Some of the virus warning signs are listed below
i. Slowing down of response time
ii. Presence of tiny dots
iii. Wandering cursor across the screen
iv. Incomplete saving of file
v. Corruption of the system set-up instruction
vi. Appearance of strange characters
vii. Insufficient memory space in a hard disk when you have enough memory space

Virus Detection (Anti-Virus)

Anti-viruses are also written programs by software developers to stop and curb the spread of virus in a system. Antivirus software is a type of utility software used for scanning and removing viruses from your computer. Once an anti-virus is installed on a system, it will be hard for a virus to enter the system except if the antivirus is outdated. All antivirus can be updated on the internet.

Examples of antivirus are:
a. Norton Anti-virus
b. McAfee
c. AVG
d. Dr. Solomon’s Tool Kit
e. Penicillin
f. Avast
g. Windows defender
Other Virus preventive measures include:
1. Timely update of operating system.
2. Timely update of antivirus software
3. Installation of only trusted or licensed software
4. Exercise care when browsing the internet

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