This document defines malware and describes common types like viruses, trojans, worms, spyware, and adware. It explains that malware is hostile software installed without consent that can harm systems. Viruses replicate by inserting copies into other programs and files, while trojans and worms spread automatically but don't replicate on their own. Spyware and adware track users' online activities and display unwanted ads. The document also outlines how antivirus software uses virus definitions and behavior monitoring to detect and remove malware, and provides examples of popular antivirus programs.

1. Computer Viruses & Anti Virus

2. Malware
● Malware is a software designed to harm or secretly access
a computer system without the owner's informed consent.
● Malware, short for malicious software,also known as
pestware.
● In general term used by computer professionals to mean a
variety of forms of hostile, intrusive, or annoying software
or program code

3. Types of Malware
● Trojan Horse
● Worms
● Spyware
● Adware
● Backdoor
● Virus

4. Malware Categories

5. Trojan horses
● A Trojan horse is simply a computer program. The
program claims to do one thing (it may claim to be a
game) but instead does damage when you run it (it may
erase your hard disk). Trojan horses have no way to
replicate automatically.

6. Worms
• A worm is a small piece of software that uses
computer networks and security holes to replicate
itself. A copy of the worm scans the network for
another machine that has a specific security hole. It
copies itself to the new machine using the security
hole, and then starts replicating from there, as well.

7. Spyware
● Spyware is malicious computer program that does exactly
what its name implies Eg:, spies on you.
● After downloading itself onto your computer either through
an email you opened, website you visited or a program you
downloaded, spyware scans your hard drive for personal
information and your internet browsing habits.
● Some spyware programs contain keyloggers that will record
personal data you enter in to websites, such as your login
usernames and passwords, email addresses, browsing history
as well as sensitive banking and credit information.

8. Adware
● Adware is any software that, once installed on your
computer, tracks your internet browsing habits and
sends you popup containing advertisements related to
the sites and topics you've visited.
● While this type of software may sound innocent, and
even helpful, it consumes and slows down your
computer's processor and internet connection speed.
● Additionally, some adware has keyloggers and spyware
built into the program, leading to greater damage to
your computer and possible invasion of your private
data.

9. Backdoor
● A backdoor is a method of bypassing normal
authentication procedures.
● Once a system has been compromised one or more
backdoors maybe installed in order to allow easier access
in the future.
● Backdoors may also be installed prior to malicious
software, to allow attackers entry.
● Crackers typically use backdoors to secure remote access
to a computer, while attempting to remain hidden from
casual inspection.

10. ● A computer virus is a type of malware that, when executed,
replicates by inserting copies of itself (possibly modified) into
other computer programs, data files, or the boot sector of the
hard drive; when this replication succeeds, the affected areas
are then said to be "infected".
● Viruses often perform some type of harmful activity on
infected hosts, such as stealing hard disk space or CPU time,
accessing private information, corrupting data, displaying
political or humorous messages on the user's screen,
spamming their contacts, or logging their keystrokes.
Virus

11. World’s 1st Computer Virus
● The first ever computer virus was developed in 1986 by
two Pakistani brothers in Lahore Pakistan.
● It was named “Brain” and was designed by Amjad
Farooq Alvi and Basit Farooq Alvi with the intention of
discouraging the piracy of a software written by them.

12. Types Of Computer Virus
• Boot sector virus
• Master Boot Record (MBR) virus
• File infector virus
• Macro virus

13. BOOT SECTOR VIRUS: Boot sector viruses generally hide
in the boot sector, either in the bootable disk or the hard drive.
It attaches itself to the primary active partition of the hard disk
that is read by the computer upon boot up.
MASTER BOOT RECORD VIRUS: MBR viruses are
memory-resident viruses that infect disks in the same manner
as boot sector viruses. However it, infects the MBR of the
system, gets activated when the BIOS activates the Master
boot code. MBR infectors normally save a legitimate copy of
the master boot record in an different location.
Types Of Computer Virus

14. File Infector Virus: File Infector viruses infect program
files. Normally infect executable code, such as .COM, .SYS,
.BAT and .EXE files. They can infect other files when an
infected program is run from floppy, hard drive, or from the
network. Many of these viruses are memory resident. After
memory becomes infected, any uninfected executable file that
runs becomes infected.
Types Of Computer Virus

15. Types Of Computer Virus
Macro Virus: Macro are mini-programs which make it
possible to automate series of operations so that they are
performed as a single action, thereby saving the user from
having to carry them out one by one.
Macro viruses infect files that are created using
certain applications or programs that contain macros.
They are platform-independent since the virus itself are
written in language of the application and not the operating
system.
They infect documents created from Microsoft
Office Word, Excel, PowerPoint and Access files.

16. Solution to Computer Viruses

17. An 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.
We should regularly run an antivirus program to scan
and remove any possible virus attacks from a computer.
AntiVirus

18. They can provide real time protection against the installation
of spywares on the computer. This type of spyware protection
works the same way as that of anti-virus protection. It scans
and blocks all incoming network threats as it comes across.
It can be used solely for detection and removal of
Spyware that has already been installed into the computer.
Anti spyware scans the contents of the windows registry,
operating system files, and installed programs on computer
and will provide a list of any threats found.
Anti-Spyware

19. 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.
How an AntiVirus Works…

20. How an AntiVirus Works…
Using Suspicious Behavior Approach:
•Antivirus software will constantly monitors the activity of all
the programs.
•If any program tries to write data on an executable file, the
antivirus software will flag the program having a suspicious
behavior, means the suspected program will be marked as a
virus.
•The advantage of this approach is that it can safeguard the
computer against unknown viruses also.
•The disadvantage is that it may create several false alerts too.

21. Popular Anti-Virus And Anti-Spyware Softwares

22. Anti-Virus & Anti-Spyware Is The Bodyguard Of Your System
It Is Us Who Rules, Not Malwares

23. • http://www.tech-faq.com/history-of-computer-viruses.html
• http://spamlaws.com/history.html
• http://en.wikipedia.org/wiki/Computer_virus#History
• http://www.infoplease.com/ipa/A0872842.html
References

24. Thank You