User:Banzaimonkey/Storage2

=Chapter 1: Combating Viruses= In this chapter you will get a good undserstanding about computer viruses including what they are, how they are written, what do they do, and how to fight back.

What is a computer virus?
A computer virus is a program which mutates/infects other trusted programs in such a way that they also become like it. A computer virus mainly consists of 2 main modules 1) A Replicator/Infector and 2) Payload/Bomb. But for a program to be considered a virus just having the first module is enough, payload or bomb can be null, even then the program would be considered a virus. This in effect means a program may be doing no harm to other (say it has no payload/bomb) but the fact that it is spreading itself by attaching itself to trusted programs makes it a virus.

This replication or capability to mutate trusted programs is important for a virus' survival.

Say there's a program which deletes all the files when run, the simple action you would take to get rid of it is do a search and delete all copies of it from your disk.

But a real computer virus works a little differently, it has got first the "Spread" stage, in which it infects other trusted programs by adding copies of its Replication module (so that these in turn can affect others) and Payload module. During this time, Payload module will not do anything but stay silent. Only when this "spread" stage is over by meeting "Virii Coders" criteria, like "Have we infected 10,000 files?", if yes, then its showtime. So when its in showtime stage, it would have already infected all your favourite programs like notepad, media player etc. Well, you know when a person is bitten by Dracula you see teeth marks on his/her neck, but there's no such easy identification way here. One needs to study the virus to come with such identification mechanisms known as Virus' Digital Signature, which is nothing but a byte patter that helps Anti-Virus programs identify it.

By the way, existence of FIRST virus program was demonstrated by Fred Cohen in 1983.

How is a computer virus written?
So all of you who think that a program which deletes all the files when run, is a VIRUS. Well, you are mistaken and let me show you some light. Here's a tiny-winy C program which can do that and I repeat this program cannot be considered a VIRUS. Compile it and when you get the .exe, scan it a zillion times with any of the Anti-Virus program you have got, be it, Norton, Macafee or any other, they just wont report it as a VIRUS, you know why? Because, its simply not a virus.

//=====Source Code for program which deletes all the files when run and is not a Virus ======== int main { system("del *.*"); return 0 ;} //================= Source code ends ==========================================================
 * 1) include
 * 2) include

Writing a real virus takes effort 100 times more than that. One needs to understand the machine and a lot about the targeted Operating System. So will you ever be able to write a Virus or understand its working to save the universe (I know you are all good people, why would you want to write a virus)? The answer is YES, if you spend atleast 12+ hours a day on computer doing some hardcore programming and reading about your machine, like Intel manuals etc.

You might on the other hand find some Virus source code floating around somewhere, but you will never be able to undersatnd it or to innovate upon it until the answer to above question is YES.