~Computer Virus~ The things you MUST know Brought to You By Sumanta Majumdar Dept. Of Electrical Engg. 2010,GNIT

Introduction About Virus Computer virus have become today’s headline news. With the increasing use of the internet, it has become easier for virus to spread. Virus show us loopholes in software. Most virus are targeted at the MS Windows OS

~ Classifying Computer Virus ~ A program designed to attach itself to a file, reproduce, and spread from one file to another, destroying data, displaying an irritating message, or otherwise disrupting computer operations. File Virus: A computer virus that infects executable files, that is programs with exe filename extensions Payload: The disruptive instructions or message delivered by a computer virus. Payloads can range from just being annoying to destroying data and files on a computer system. Boot Sector Virus: A computer virus that infects the sectors on a disk that contain the data a computer uses during the boot process. The virus spreads every time the infected disk is in the computer when it boots. Macro Virus: A computer virus that infects the macros that are attached to documents and spreadsheets. Trojan Horse: A computer program that appears to perform one function while actually doing something else, such as inserting a virus into a computer system or stealing a password.

* Virus through the Internet * Today almost 87% of all viruses are spread through the internet. Transmission time to a new host is relatively low, on the order of hours to days “Latent virus”

Symptoms of Virus Attack Computer no longer boots up. Screen sometimes flicker. Computer runs slower then usual. PC speaker beeps periodically. System crashes for no reason. Files/directories sometimes disappear. Denial of service (dos)….. & Many More.

~Computer Virus~ How They Spread A virus runs first when a legitimate program is executed. The virus loads itself into memory and looks to see if it can find any other programs on the disk. If it can find one, it modifies it to add the virus's code to the new program. Then the virus launches the "real program“. The user has no way to know that the virus ever ran. Unfortunately, the virus has now reproduced itself, so two programs are infected. The next time either of those programs gets executed, they infect other programs, and the cycle continues. When the infected program o is distributed by  floppy disk  uploaded to a bulletin board  zipped and delivered as an executable. then other programs get infected.

~Computer Virus~ How To Prevent Them Security features keep viruses away. Buy virus protection software. Avoid programs from unknown sources (like the Internet). Stick with commercial software purchased on CDs.

~Computer Virus~ How To Prevent Them With viruses o defense is personal discipline  Never double-click on an attachment that contains an executable program  Attachments that come in as  Word files (.DOC), spreadsheets (.XLS), images (.GIF and.JPG), etc., are data files  and they can do no damage

~Computer Virus~ How To Prevent Them Don’t victimize yourself o learn where to find legitimate information on hoaxes, myths etc.  do not forward warnings if you haven’t personally checked them out!

~Computer Virus~ How To Prevent Them Don’t fall for the "False Authority Syndrome” o Most people who claim to speak with authority about computer viruses have little or no genuine expertise.  The person feels competent to discuss viruses because of  his job title,  because of expertise in another computer field,  simply because he knows how to use a computer.

~Computer Virus~ How To Prevent Them is clearly the predominant vulnerability point for viruses o Current viruses are spread via security holes in Microsoft Outlook and Outlook Express  Free patches are available from Microsoft to address these problems  many people are reluctant to apply them. First, update your system with Windows Update and Office Update o or, buy a Mac Buy virus protection software

~Computer Virus~ How To Scan?

~Computer Virus~ Anti-Virus Is Scanning

~Computer Virus~ Finding Out A Virus

Computer Virus Acknowledgement My special thanks goes to Sri Supriyo Ghosh (Dept. of BCA,Techno India, Sec. V) for helping & suggesting me about different kind of computer viruses & their characteristics.

Computer Virus Be Original Kill Piracy.