A computer virus is a program that may disturbed the normal working of that may computer system without the knowledge or permission of a user. Virus attaches itself to a file in a flash drive hardware and email attachment.

1. Abdullah shahzad

2. Computer virus:
 Computer virus:
 A computer virus is a program that may disturbed the
normal working of that may computer system without
the knowledge or permission of a user. Virus attaches
itself to a file in a flash drive hardware and email
attachment

3. Type of virus
 Worm:
 A worm is a harmful program that resides in the active
memory of the computer and duplicates itself. It can
propagate without human intervention, sending
copies of themselves to other computers by e-mail or
Internet Relay Chat

4. Trojan Horses:
A Trojan horse is a program in which malicious code is
hidden inside a seemingly harmless program. The
program’s harmful payload can enable the hacker to
destroy hard drives, corrupt files, control the computer
remotely, launch attacks against other computers, steal
passwords or Social Security numbers, and spy on
users by recording keystrokes and transmitting them
to a server operated by a third party. It can be delivered
as an e-mail attachment, downloaded from a Web site,
or contracted via a removable media device such as a
CD/DVD or USB memory stick.

5. Bot nets:
 Bot nets:
 A botnets is a large group of computer controlled from
one or more remote locations by hackers, without the
knowledge or consent of their owners.
 - Are frequently used to distribute spam and malicious
code.
 Cutwail, a large botnet, controlled approximately one
million active bots at a time.

6. Root kits:
 A root kits is a set of programs that enables its user to
gain administrator level access to a computer without
the end user’s consent or knowledge.
 Attackers can use the root kits to execute files, access
logs, monitor users activity, and change the computer’s
configuration. Root kits are one part of a blended
threat, consisting of the dropper, loader and root kit.

7. Spam:
 E-mail spam is the abuse of e-mail systems to send
unsolicited e-mail to large numbers of people.
 Most are in a form of low-cost commercial advertising
 It is also an extremely inexpensive method of
marketing used by many legitimate organizations.
 It may also be used to deliver harmful worms or other
malware.

8. Logic bomb:
 Logic bomb is also called a logic bomb. Its differ from
other viures.it is activated at a certain date and time
.its destroy data on the hard disk march 6.