BS (Hons.) Information TechnologySemester-I

Topic: Viruses and anti viruses

Submitted By Hira Mehar (3006)

Irsam Nageen(3041)Hafsa(3031)

Warda Irum(3028) Submitted To

Mr. Khurshid AsgharLecturer Computer Science

UNIVERSITY OF EDUCATION, LAHOREOKARA-CAMPUS

Dated: December ,2013

TOPIC OUTLINESAnti-Virus Names of

antivirusBit Defender Norton

McAfee Sophos Avast Kasperski

Working of antivirus

Types of anti virus

Specific scanning

Generic scanning

Virus History Symptoms Types

Logic Bomb Chernobel Virus Redlof

Trojan Horse Boot Sector Effects Danger

VIRUS

Sick of Computer Viruses?

What they are…Where they come from…

Why they’re here…

Computer virusA computer virus is a program that may

disturb the normal working of a computer system.

• Virus attaches its self to files stored on floppy disks, email attachments and hard disks.

• Viruses can make your computer run slow, display odd behavior or allow people to monitor what you

do when logged in.

INDEX

History1

Symptoms of Virus Attack2

Types of Infections3

4 Control on Viruses

History of Computer Viruses

• The first computer virus was called “creeper.”• It was invented in the early 1970’s.

• Since then, millions of viruses have been invented.

Symptoms of Virus Attack

• Computer runs slower then usual• Computer no longer boots up• Screen sometimes flicker• PC speaker beeps periodically• System crashes for no reason• Files/directories sometimes disappear

Virus

Redlof

Logic bomb

Trojan Horse

Types of Infections

Chernobal

Boot sector

Logic bombs

Logic bomb is also called time bomb.It differs from other viruses .

It is activated at a certain date and time.

Michelangelo is an important logic bomb.It destroys data on the hard disk on march 06

• The famous chernobal virus deletes all Microsoft office files.

Chernobal virus

• It also deletes the partition information from the disk that causes a major loss of data.

Redlof• Redlof is a polymorphic virus. It is written in Visual

Basic Script.• It relies on the Microsoft ActiveX Component to

execute it self.• It locates Folders.htt and infects that file.• Folder.htt is part of MS Windows Active Desktop

feature.

What Is a Trojan horse?• Trojan horse hide it self as useful

program.• It contains hidden instruction to erase

data or cause other damage.• It executes illegal, destructive

instruction in the middle of a program such as computer game.

• Format C is an example of Trojan horse.

Boot sector virus

•The boot sector virus modifies the program in the boot sector.•It Is loaded into memory whenever computer is turned on.•This virus is attach with the executable files like .exe, .com and .dll files.•When the user uses these files, the virus attaches with these files is activated.•It infects other files and perform destructive commands and destroys data files .

Effects of viruses

A virus may detect some special information like passwords or sensitive

data , it may send the data to some other user on a

network.E.G a virus may read the

pin cord or credit card no. and then sent it to other

user

A virus may also make

some resources unavailable to the users

e.g. a virus may start sending data on a

network. The network may become unavailable

for the users

The Danger

• A virus can change the way your computer behaves.

• A virus can glean information from what you do on your computer.

• A virus can infect a single computer or a whole network of computers.

• A virus can make your computer or network to run slow or it can render it completely useless.

What Would the Doctor Prescribe?

• Install anti-virus software on your computer, such as MacAfee, Norton, Symantec, Avast etc.

• Use caution when viewing unknown files, websites or storage devices.

• Never open an e-mail attachment from someone you don't know.

Anti-VIRUSSoftware

Bit defender

KasperskiAvast

Types of Anti-viruses

Sophos

NortonMcAfee

What is Antivirus Software?

A type of software that is used to detect and remove viruses is called antivirus software.

Antivirus programs contain information about different known viruses. They can detect viruses and remove them.

The Best Defense• The best defense against computer viruses,

spyware, hackers and spam is an antivirus program called Bit Defender.

• It has a user-friendly interface that scans all existing files on your computer, all incoming and

outgoing emails, and even IM transfers.• Features include privacy protection and web

scanning for internet use.

Norton Antivirus• The most widely used software is the Norton AntiVirus. (NAV)

• Since its release in 1990, over 100 million people around the world have used it.

• It’s a free program but in order to receive live updates, a valid subscription is needed.

McAfee

McAfee Virus Scan is another popular antivirus

program.

It is designed for home and home-office use.

It is used specifically on a Microsoft Windows platform.

Sophos

•Sophos Anti Virus is an antivirus and anti-

spyware program that is primarily aimed at

corporate environments or businesses.

• It includes a number of

security tools and

advice.• It also includes 24/7

support including upgrade alerts.

is a preemium antivirus computer program available to Microsoft Windows, Mac OS X and Linux users, with a user interface available in 41 languages.

The name Avast is an acronym of "Anti-Virus – Advanced Set".The official, and current logo of Avast! is a white orb with the letter 'a' on it and an orange circle around it, sticking out to four directions.

Avast

KasperskyFor the average home user

and advanced users the Kaspersky antivirus

software has an easy to use interface.

The program uses 3 tabs for protection, settings and

support.

It updates itself on an hourly basis and is one of the

fastest antivirus programs available.

Working of Anti-Virus

Like penicillin, antivirus applications act as a

guard over your system, scanning incoming files

and applications, cleaning up unwanted

viruses looking to cause harm to your system.

Antivirus software is considered to be an aid that detects, fixes and even prevents viruses

and worms from spreading to your

computer as well as connecting computers.

Why is software an issue?

Some antivirus

software can considerably

reduce performance

There should not be more than one

antivirus software installed on a single

computer at any given time

It’s sometimes necessary to

temporarily disable virus protection when

installing major updates

There are different types of antivirus software for different computers

some are designed for personal computers

Some are for servers and for enterprises

There are mainly two types of antivirus software: specific and generic

Specific Scanning Specific scanning or signature detection

The application scans files to look for known viruses matching definitions in a “virus dictionary”

When the antivirus looks at a file it refers to a dictionary of known viruses and matches a piece of code (specific

patterns of bytes) from the new file to the dictionary. After recognizing the malicious software the antivirus software

can take one of the following actions

1. Attempt to repair the file by removing the virus itself from the file.

2. Quarantine the file.3. Or by delete the file completely

Generic Scanning

Generic scanning is also referred to as the suspicious behavior approach.

generic Scanning is used when new viruses appear.

In this method the software does not look for a specific signature but instead

monitors the behavior of all applications.

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