Saturday, March 27, 2010

Making A simple virus in C for Beginners


Hi everybody,at begining of the learning of computer programming it is a dream of almost all student to build a computer virus of his/her own.
Computer virus obviously is a thing that shouldnot be made and used on others computer it is completely illegal in all countries.So make and try this on your own machine.
Now let me explain what do the viruses do.There are several types of computer viruses with different functions(destructive obviously).Some of which delete computers' important files and folders,some change the configuration of your computer system like registry values,some occupy and engulf a large amount of memory space and dump your hard disc.There are some viruses too which can damage your RAM parmanently.
I am going to give here a simple virus program which has only a few lines bur has ability to jam your Hard disc.
The logic behind the program is nothing but making a self growing file which grows to a few MB in one tern and this growth will continue infinitely.
The require ment to make this virus is
OS:-Windows98/xp/2000 MS-DOS
Compiler:-Borland C(Which has Dos Shell)
Source Code:-
//START v.c
void main()

As you can see this is a very little programe.Compiling the programme we get v.exe file.This is our virus.
How it works?-The system call "dir>>â•ša.exe" will execute the dos command 'dir' and ridirect its output toa file â•ša.exe(the symbol â•š can be obtained by pressing 456 on numpad holding alt key).So running the program in a folder having many files and folder will increase the size of â•ša.exe in a great amount.This process will continue to infinity as this is in a while(1) loop;
Best try this on win98.then you cannot delete â•ša.exe from GUI.
For auto running place v.exe in the command folder in windows folder.
In autoexec.bat(win98) or autoexec.NT(winXP/2000) file simply write v.exe.
Each time your window starts v.exe will run automatically.
Try this on your own computer remember the â•ša.exe is the infected file which is growing in size continiously.So to recover, simply delete v.exe and â•ša.exe file from your computer.
For more informaton or any problem please write me.

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