Seminar report on

Computer virus

Submitted by Nimmi Verma C.S. final year

IntroductionVIRUS stands for ”Vital Information Resource Under Siege ”.A computer virus is a computer program that can replicate itself and spread from one computer to another. A computer program loaded to your computer with-out your knowledge or permission and runs against your wishes. All computer viruses are manmade. Even such a simple virus is dangerous because it will use all the available memory and bring the system to the holt. The virus stays active in the background and infect new hosts those files are accessed by other program or the operating system itself.

The computer runs slower than usual.The computer crashes, and then it restarts everyfew minutes.Applications on the computer do not work correctly.Disks or disk drives are inaccessible.You see unusual error messages.An antivirus program cannot be installed on the computer, or the antivirus program will not run.New icons appear on the desktop that you did not putIncreases the use of disk space and growth in file size as virus gets attached itself to many files.

Symptoms of a computer virus:

ClassificationViruses can be divided into two types based on their behavior when they are executed. ResidentNonresidentResident Virus:- Resident viruses do not search for hosts when they are started. Instead, a resident virus loads itself into memory on execution and transfers control to the host program.  Non-Resident Virus:- Nonresident viruses immediately search for other hosts that can be infected, infect those targets, and finally transfer control to the application program they infected.

Types Of Computer VirusThere are different types of computer virus.

WormsTrojan Horses

Macro virusesFile infectors

Trojan Horses:-Trojan Horses are actually normal computer program. This is different from a regular virus because it does not attempt to reproduce itself. Trojan Horses do not affect a great number of people because they are discover quickly.

Worms:-It has been made copy itself from one computer to another over network. It is very harmful virus because it has reproduce nature.Macro Virus:-Marco virus spread much more than other type of viruses as people frequently share data files, it spread round the word in two hours effecting tens of millions of computer

File Infectors:-A block of code which attaches itself to another program and it can copy itself in to subsequent applications that you run.

How Dose A Computer Get Virus

On downloading files from the Internet. On opening an e-mail attachment. On copying programs or files from any other infected computer.

Virus infect a file in computer 

-:Different Phase Of A Virus:-Most viruses have two phases to their existence, the “infection phase” and the “attack phase”. All viruses have an infection phase, but not all have an attack phase.Infection Phase:-During the infection phase, the virus spreads itself.

Ex:-"Your friend gives you a game on a disk. The game has an infected file that you don't know about. Each time you play the game, the virus copies itself into another program without you knowing. Now, whenever either of the programs are executed, the virus is copied. This continues as the virus infects the rest of the computer. If any of the files are transferred to a floppy disk or e-mail attachment, and they are put on another computer, the process starts again"

Attack Phase:-The attack phase is set off by a trigger, such as a time or date. The attack phase is when the virus causes damage or other unwanted system behavior. In order to make sure it has spread, viruses often delay the attack phase, sometimes for years.

Protecting computer form virus:-Here are some tips that can help prevent a computer virus from attacking your system.Your first line of defense is to install anti-virus software. . This software can scan all your drives for viruses and neutralize them.Install updated and good quality Anti-Virus software that provides complete protection from spyware, adware and malware too.Schedule a complete system scan at least once a week to keep your system clean.Schedule a complete system scan at least once a week to keep your system clean

Some antivirus program name:-

Kasper Sky Anti VirusBit Defender Anti VirusTrend MicroNorton Anti Virus\ Internet SecurityMcAfee AntivirusPanda Anti Virus Pro 2009Zone Alarm Anti VirusF-Secure Anti VirusAVG Anti VirusESET NOD32 Anti Virus

Thank You