Introduction of computer virus and its key terminologies

1. BY: Prabesh Shrestha

3.  It is the program which infects and
potentially damage the files in the computer
that receives it.
 It replicates and spreads by attaching itself
to other programs.
 A simple virus can make a copy of itself over
and over again.

4.  To take control of a computer and use it for
specific tasks
 To steal sensitive information (credit card
numbers, passwords, personal details, data
etc.)
 To prove that it can be done, to prove ones
skill
 For revenge purposes
 To cripple a computer or network
 For fun
 To earn fast money using malware

5.  From infected email attachments
 Downloading infected program from the
internet
 Using infected pen drives, CD, DVD etc.
 Transferring infected program over the
network and running it.
 Using pirated and illegal programs and
installing it into the computer
 Not having any updated antivirus programs to
control the virus infection

6.  Applications take longer time to load or may not
work at all
 Getting unusual error messages like Write Protect
Error
 Computer gets slow, freezes and crash some times.
 Important files or folders get changed or deleted
for no reason
 File size changes
 An increase in the number of files on the system
when nothing has been added
 Reformatting the hard disk
 Strange movements or patterns are seen on the
computer screen

7.  Use software from original CD or DVD.
 Do not use any pirated software as they may
contain virus.
 Use updated antivirus program.
 Always scan the downloaded files before
using them.
 Scan e-mail attachments before executing
them
 Do not use the removable disk such as pen
drives, floppy before scanning for virus
 Do not open any unknown and suspicious
websites or links.

8. 1) Boot Sector Virus
 It infects the first sector i.e. boot sector of the
hard disk or floppy disk.
 It can also infect MBR (Master Boot Record)
 It changes the instructions stored in the boot
sector
 It prevents the computer to turn on
 It works when we turn on or restart the
computer
 Eg: Disk Killer, Michelangelo, Stoned, Bouncing
Ball

9. 2) File Infecting Virus
 It infects the executable files having .exe,
.com, .drv, .sys, .ovl, .dll as extension name.
 It changes the contents of executable files.
 It replicates itself and infects files on the disk.
 It is spread by removable disks, through
network etc.
 It is easy to be detected because it changes the
size of the file.
 Eg: Friday the 13th, Enigma, Nemesis, Cascade
etc.

10.  It is a program designed to detect and
remove viruses from the computer system.
 It scans hard disk, removable disks, CD, DVD
etc.
 It needs to be updated regularly or from time
to time to ensure the smooth running of the
computer system.
 Eg: Norton antivirus, AVG, Kaspersky, Avast,
Avira, NOD32, Panda etc.

11.  It is a program that hides its purpose — it
claims to do one thing but really does
another
 It contains malicious or harmful codes which
can control and cause damage such as ruining
File Allocation Table(FAT) on hard disk.

13.  It is a malicious program which gets
transmitted by computer networks.
 Once it is installed it generates additional
email messages containing copies of the
worm.