1. Welcome

2. Topic

3. Overview
• What is anti virus? & short history of it.
• How an antivirus work?
• Configuring antivirus software?
• Some of the symptoms of an infected
computer?
• Deleting Identified Virus files manually?
• Antivirus Effectiveness.
• Antivirus Damaged files.
• Online Antivirus scanning.
• some popular Antivirus.

4. What is anti virus?
Antivirus Software is a computer program that
identify and remove computer viruses, and other
malicious software like Worms and Trojans from an
infected computer. Not only this, an antivirus
software also protects the computer from further
virus attacks.
The first anti-virus software in 1987. Fix, a German
astrophysicist and amateur computer programmer
developed software to combat the first computer
virus “in the wild," which means that the virus had
escaped the confines of the lab or network .

5. How an Antivirus works ?
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.

6. Configuring an antivirus software ?
Configuring your Antivirus software Adjust the
settings to scan all files. Also, ensure that real
time scanning is enabled by default. Create a
recovery/reference/cure disk because if a boot
sector or MBR virus attack the system, it may fail
to boot. In that case, recovery cure disk can be
used to boot the system and remove the virus.
Read the vendors manual. This will help you to
understand the advanced options and how to use
them according to your preference.

7. Some of the symptoms of infected
computer
Folder Options disappears from the Tools. Now,
hidden files cannot be viewed. Changing registry
values has no effect. Reedit doesn’t works, when
you try to invoke it from the RUN box. Task
Manager has been disabled by Administrator. In
My Computer, Auto play option appears instead
of Open in every drive you enter i.e. when you
click on your drive letters (C, D, E etc) a window
opens to select any one program to Open with.
Computer becomes slow and there is noticeable
delay in characters to appear on screen when you
press in keyboard.

8. Deleting Identified Virus files manually
Deleting Identified Virus files manually Identify files say like
autorun.inf or mswin32.dll.vbs in the root of all drives or in
your system drive. You can also delete a file from DOS. the
command DIR /w/a displays all hidden files and folders. with
command attrib -s -h -r <filename>.
Then del <filename> A virus also hides itself in the System
Volume Information and PREFETCH folder. So it might be a
good idea to turn off System Restore for a while. To prevent
future infections in your USB Drive, what you could try is
create an empty autorun.inf file and set read only attribute to
it. This should prevent a malicious autorun.inf taking its place .

9. Antivirus Effectiveness
Studies in December 2007 showed that the
effectiveness of antivirus software had decreased in
the previous year, particularly against unknown or zero
day attacks. The computer magazine c't found that
detection rates for these threats had dropped from 40-
50% in 2006 to 20-30% in 2007.
At that time, the only exception was the NOD32
antivirus, which managed a detection rate of 68
percent Anti-virus programs are not always effective
against new viruses, even those that use non-
signature-based methods that should detect new
viruses. The reason for this is that the virus designers
test their new viruses on the major anti-virus
applications to make sure that they are not detected
before releasing them into the wild.

10. Antivirus Damaged files
Files which have been damaged by computer
viruses are normally damaged beyond
recovery. Anti-virus software removes the
virus code from the file during
disinfection, but this does not always restore
the file to its undamaged state. In such
circumstances, damaged files can only be
restored from existing backups; installed
software that is damaged requires re-
installation.

11. Some popular Antivirus:

12. When select an Antivirus Software ?
An Antivirus Software Real-Time Scanning
antivirus software is automatically running in the
background on a continuous basis, scanning files
and folders for possible virus attacks as they are
opened or executed, and checking e-mails as they
are downloaded. Most commercial antivirus
software provide real time scanning.

13. Online Antivirus scanning
Some antivirus vendors maintain websites
with free online scanning capability of the
entire computer, critical areas only, local disks,
folders or files. Periodic online scanning is a
good idea for those that run antivirus
applications on their computers because
those applications are frequently slow to catch
threats.
.

14. Online Antivirus scanning cont….
• One of the first things that malicious software
does in an attack is disable any existing antivirus
software and sometimes the only way to know of
an attack is by turning to an online resource that
isn't already installed on the infected computer

15. Tha
nks
For Joining