This document discusses 9 types of computer viruses: multipartite, polymorphic, overwrite, spacefiller, and FAT viruses. A multipartite virus simultaneously infects both the boot sector and executable files, making the computer inoperable. Polymorphic viruses are self-encrypting to avoid detection, modifying copies of itself. Overwrite viruses destroy the original program by overwriting data. Spacefiller viruses install in empty file sections. FAT viruses infect the file allocation table to gain control over all system files. Examples of each virus type are provided.

1. COMPUTER VIRUSES
DONE BY: ANAMIKA PRIYA,ALENA JOHN

2. There are mainly 9 types of viruses.
The viruses we are going to be discussing today
are:
● MULTIPARTITE VIRUS
● POLYMORPHIC VIRUS
● OVERWRITE VIRUS
● SPACEFILLER VIRUS
● FAT VIRUS

3. MULTIPARTITE VIRUS
● A multipartite virus is a fast-moving virus that uses file infectors or boot
infectors to attack the boot sector and executable files simultaneously.
● The multipartite virus can affect both the boot sector and the program files at
the same time.
● A multipartite virus is also known as a hybrid virus.
● The effects of a multipartite virus can be far-reaching and very damaging to a
computer system.
● A virus is launched at various points in time, making the computer inoperable
for even the simplest tasks.
● The program files may be cleaned up, but the boot sector may not be. If this
is the case, the multipartite virus will reproduce as it did when it originated
within the system.

4. ❏ THE FIRST MULTIPARTITE VIRUS WAS GHOSTBALL
VIRUS.
❏ EXAMPLES OF MULTIPARTITE VIRUS ARE
FLIP,INVADER,TEQUILA.

5. POLYMORPHIC VIRUS
● A polymorphic virus is a complicated computer virus that
affects data types and functions.
● It is a self-encrypted virus designed to avoid detection by
a scanner.
● Upon infection, the polymorphic virus duplicates itself by
creating usable, albeit slightly modified, copies of itself.
● Removing polymorphic viruses requires that programmers
rewrite language strings, which can be time-consuming,
complex and costly.

6. ● EXAMPLES OF VIRUSES INCLUDE
MARBURG,TUAREG,SATAN BUG,ELKERN

7. OVERWRITE VIRUS
● An overwriting virus is a malicious program which, after infection, will
effectively destroy the original program code, typically by overwriting data in
the system's memory.
● The only way to remove the virus is by deleting the infected file and therefore
the user loses its contents.
● It can infect a specific file in a software or a whole software.
● Spreads via email.
● It was active in targeting Windows NT and Windows 2000 systems in the
2000s.

8. ❏ The trojan virus and Trj.reboot are some of the
examples of multipartite virus.

9. SPACEFILLER VIRUS
● a spacefiller virus is a rare type of computer virus that
attempts to install itself by filling in the empty sections of a
file.
● By only using empty sections of a file, the virus can infect
a file without the size of the file changing, making it more
difficult to detect.
● In the past this was difficult to do properly, but new file
formats make it easier.
● Also known as cavity virus.

10. ● The lehigh virus is an example of spacefiller virus.

11. FAT VIRUS
● Short for file allocation table, FAT
● FAT viruses infect the file allocation systems of the computer and gain access
to the location of all the files.
● A lot of important files are split or fragmented into a number of parts. FAT
viruses are capable of detecting and tracking all of these fragments and
therefore effectively gain control over all the files on the system.
● As soon as the FAT makes contact with the corrupt file, the virus is triggered
infecting the system.
● A lot of FAT viruses are created to destroy or overwrite entire directories
which can result in permanent loss of data.
● Fat viruses have the ability to spread to other files and infect other sectors of
the system.

12. ● FAT 12 & FAT 6 are some of the examples of file
allocation table (FAT) virus.

13. QUESTION
TIME………..