1

Anti-Virus Software

2

Contents:

•What is Computer virus?•Types of Viruses•Introduction to Antivirus Program•How an Antivirus works?•What to do when suspecting virus attack?

3

What is a Computer Virus?

• A computer virus is a small program written to alter the way a

computer operates, without the permission or knowledge of theuser. With an ability to replicate itself, thus continuing to spread.Also, known as Malicious Software, a program that can causedamage to a computer.

• The computer viruses can damage or corrupt data, modify existingdata, or degrade the performance of the system by utilizingresources such as memory or disk space.

4

Classification of Computer Viruses:

•Boot sector virus•Master Boot Record (MBR) virus•File infector virus•Multipartite virus•Macro virus

In addition to Computer viruses, there are

two more types of malicious software.

These are :

Worms and Trojans

5

Anti-virus Software

•An antivirus software is a computer program that identify andremove computer viruses, and other malicious software like Wormsand Trojans from an infected computer. Not only this, an antivirussoftware also protects the computer from further virus attacks.

•We should regularly run an antivirus program to scan and removeany possible virus attacks from a computer.

6

7

McAfee Security Center

8

Avast!

9

AVG Internet Security!

10

How an Antivirus works

Using dictionary Approach:

The antivirus software examines each and every file in a computer and examines its content with the virus definitions stored in its virus dictionary.

A virus dictionary is an inbuilt file belonging to an antivirus software that contains code identified as a virus by the antivirus authors.

11

Some of the symptoms of an infected computer:

•Folder Options disappears from the Tools. Now, hidden files cannot be viewed. Changing registry values has no effect.

•Regedit doesn’t works, when you try to invoke it from the RUN box

•Task Manager has been disabled by Administrator.

•Command prompt doest open, if it does closes suddenly.

12

General precautions you should take

•When inserting removable media (floppy, CD, flash drive etc.) scan the whole device with the antivirus software before opening it.

•If you have internet access, make sure you use internet security software.

•Get Windows updates.

•From time to time, update your installed software to their latest version. E.g. (MS Office, Adobe Reader, java, Flash player etc.)