VIRUSES - types, how computer virus spreads, damages virus causes, some common viruses and preventions.

1. FUNDAMENTAL OF
COMPUTERS AND IT
Viruses
Submitted by -
TANU GUJJAR

2. Viruses
Computer virus is a malicious
program that requires a host and is
designed to make a system sick, just
like a real virus. They cause damage
To data and files on a system.

3. Types of Viruses
Broadly there are three types of viruses :
1. File infectors - attach themselves to a program file.
2. Boot sector viruses - install themselves on the
beggining tracks of a hard drive.
3. Macro viruses - infect data files

4. How Computer Viruses Spread ?
Infected e-mail attachments - Computer viruses can’t infect your computer through
a text-only email. However, if an email includes an attachment or clickable link, those could be vehicles for
a virus. If you open an attachment or click a link, your computer downloads that information. If that
attachment or link includes a virus, your computer is now infected.
Removable Media - When you attach a memory card, USB flash drive, external hard drive or any
other kind of removable media to your system, you face the potential of importing a virus. If a hacker
attached a virus to a program or file on the drive, you’ll also install the virus when you plug in the media.
Internet Downloads - When you download anything off of the internet, you’re installing new files
and code on your computer. Many viruses are attached to freebie downloads, including free software trials
or, ironically, free virus protection. Anything downloaded illegally, like music, movies or games, is an easy
target for hackers because you’ll probably be getting that file in a peer-to-peer format. Even your antivirus
program may not be able to stop it.

5. Damage that Viruses cause
Viruses’ main objective is to make your system unstable and cause harm to data :
Slower operating speed Programs running in the background slow down a computer’s speed. Since
viruses are designed to run in the background and perform multiple actions, a performance slump is
inevitable.
Issues with programs and files
Among the numerous hazards of computer viruses are data deletion and modification. Missing files, unable
to open certain apps, unknown programs start when you turn on your computer Or, have new files, folders,
or apps appeared on your hard drive out of nowhere etc.
Hang system
It can cause the system to hang so that it does not respond to any keyboard or mouse movements.

6. Some common Viruses
Trojan Horses - A trojan horse is code hidden in a program such as a game
or spreadsheet that looks safe to run but has hidden side effects.When the program is
run ,it seems to function as the user expects,but in actuality is destroying,damaging or
altering information in the background.
Worms - A worm is a program designed to replicate. It is self-contained and does not
require a host. Most worms disrupt services and create system management problems.
Spam - A spam refers to electronic junk mail or junk newsgroup postings. Also called
unsolicited usually commercial e-mail sent to a large number of addresses.

7. Virus Prevention
Anti-virus Software is a computer program that detects, prevents,and takes action
to disarm or remove malicious software programs such as viruses and worms.
You can protect your computer against viruses by using antivirus software, such as
Microsoft Security Essentials, Quick Heal, KasperSky, McCafee Antivirus etc.
Some other preventions :
● Never use a “foreign” disk or CD without scanning it for viruses.
● Always scan files downloaded from internet or other sources.
● Password protect your PC to prevent unattended modifications.
● Make regular backups.
● Install and use up to date antivirus software.

8. THANK YOU !
THANK YOU!