antiviruses

1. Presented by Maryam Zahid
Presented to Mam Maria Ramzan

2. And
Anti Viruses

3.  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 Computer Virus..??
Computer viruses are small software programs that are
designed to spread from one computer to another and to
interfere with computer operation. It is a program or
piece of code that is loaded onto your computer without
your knowledge and runs against your wishes. A
computer virus might corrupt or delete data on your
computer, use your email program to spread itself to
other computers, or even erase everything on your hard
disk.

5. Viruses – Types and Examples
1. Boot viruses:
This virus infects the hard disks or floppy drives boot sector. This would
make the computer unable to boot. These viruses can, however, be
avoided by ensuring that the floppy disks and hard drive is well protected.
Never start the computer using an unknown disk drive or floppy disk.
Examples: the brain virus -it is the very first wild virus to be created.
2.Overwrite Viruses:
These types of viruses delete any information in a file they infect, leaving
them partially or completely useless once they are infected. Once in the
computer, they replace all the file content but the file size doesn’t change.
Unfortunately, you would only clean the infected file by deleting it
completely, therefore losing original content.
Examples: Trj. Reboot ,Way and Trivial.88.D

6. 3 .Memory Resident Viruses:
They usually fix themselves inside the computer memory. They get
activated every time the OS runs and end up infecting other opened
files. Their effects include corrupting programs and files that are closed,
opened, renamed or copied. They hide in RAM.
Example: CMJ, Meve, Randex and Mrklunky
4 .Direct Action Viruses
These viruses mainly replicate or take action once they are executed.
When a certain condition is met, the viruses will act by infecting the files
in the directory or the folder specified in the AUTOEXEC.BAT. The
viruses are generally found in the hard disk’s root directory, but they
keep on changing location.
Example: Vienna virus

7. 5 .Program Viruses:
These infect executable program files, such as those with extensions like
BIN, COM, EXE, OVL, DRV (driver) and .SYS (device driver). These
programs are loaded in memory during execution, taking the virus with
them. The virus becomes active in memory, making copies of itself
and infecting files on disk.
Examples: Sunday and Cascade
6. Macro Viruses
These viruses infect the files created using some applications or programs that
contain macros such as doc, pps, xls and mdb. They automatically infect the files
with macros and also templates and documents that are contained in the file. They
hide in documents shared through e-mail and networks.
Examples: Relax, bablas and 097M/Y2K

8. Virus Hoaxes
Trojan Horses
Worms
Spam
Adware
Spyware
Malware

9. How Do Computer Viruses Spread?
Computer viruses usually spread in one of three
ways:-
•From Removable media.
•From Downloads off the Internet.
•From e-mail attachments.

10. I. When a virus begins to spread, many program files can
become unstable and display warnings.
II. The operating system may not launch properly.
III. Critical files may get deleted automatically and the
computer may be running slower than usual.
Computer Virus Symptoms:-
Computer is infected with a virus, it may begin to show a
series of Computer Virus symptoms that indicate that a
virus is present.

11. Virus can damage your system:-
A computer virus can do a lot of damage to your system before
you even realize that it happened.
Computer Viruses: Quickly spreads from one computer to
another computer. It starts by attaching and loading itself onto
the computer without your knowledge.
A computer virus can be duplicated.

12. How to remove a computer virus?
Install and Update the antivirus software on the
computer. Then, perform a thorough scan of the
computer by using the antivirus software.
Install the latest updates from Microsoft Update
on the computer.
Download, install, and then run the Malicious
Software Removal Tool to remove existing viruses
on the computer.

13. How to protect your computer against viruses:-
On the computer, turn on the firewall.
Keep the computer operating system
up-to-date.
Use updated antivirus software on
the computer.

14. Conclusion..!!

15. TopicTopic

16. 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 .

17. 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.

18. Anti-virus applications maintain a database of
known viruses and compare scanned files that
match the characteristics of known viruses. If a
scanned files matches those characteristics of
known viruses. If a scanned file matches those
characteristics, it is quarantined (which means
moved to a new, presumably safe location on disk
and renamed, so you can find it should you ever
need it) so that it cannot affect other files on your
system.

19. 1.AVG
AVG is one of the most popular antivirus programs that can be
obtained for free and is easy to download directly from the Internet. It
can also work with a number of different Windows systems. It has the
ability to hold virus files in quarantine so that they cannot do any harm
before they can be checked and deleted.
2.McAfee
McAfee Virus Scan has been the second most popular antivirus
programs on the market. It provides for spyware and virus protection
under one program, rather than separately as many other programs
do. It is necessary downloads when they are required.

20. 3.Norton
There are a number of Norton antivirus programs available which are
all produced by Symantec. They have quickly proven themselves to be
a market leader when it comes to computer system security. Norton
Anti-Virus software programs that searches the computer and deletes
any viruses that it finds.
4.Kaspersky
Though Kaspersky is not the most popular of all the antivirus
protection programs. However, they still provide a very effective
product in the protection against viruses, spyware and Trojan horses.
.

21. 5.AdAware
Ad Aware provides protection against a large number of cyber security
threats that arise from using the Internet. In addition to finding and
removing viruses and spyware that can detect key strokes and
passwords, it will protect against trojan horses.

23. 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.

24. Conclusion

25. For Joining