Shellcode Generation using C Post: 302139514

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Top Forums Programming Shellcode Generation using C Post 302139514 by Legend986 on Sunday 7th of October 2007 10:03:36 PM

10-07-2007

Registered User

Shellcode Generation using C

Hi,

I was just learning about buffer overflow attacks... I was curious as to how to generate a simple shellcode. I've written two codes - One is the typical program that has a vulnerability inside and the other is the shellcode.

main program:

Code:

void test();

int main() {
   test();
   return 0;
}

void test() {
   int *ret;
   ret = (int *)&ret + 2;
   (*ret) = (int)shellcode;
}

I was thinking of putting the shellcode into the shellcode found in the end which is a character array.

And as for the shellcode generation, I've written something like:

Code:

#include <unistd.h>

int main() {
  char buf[]="Hello World";
  write(1,buf,sizeof(buf));
  exit(0);
}

But I don't know how to generate the shellcode from this so that I can put it in the original program in the form of char shellcode[] = ...... How would I go about doing this? And yeah if this is the wrong forum, please move this post because I didn't know where else this has to be posted...

Legend986

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LEARN ABOUT DEBIAN

phalanx

PHALANX(6)							   Games Manual 							PHALANX(6)

NAME

       Phalanx - Chess playing program

SYNOPSIS

       phalanx [options] [<moves> <minutes> [<increment in seconds>]]
       phalanx [options] [<seconds per move>]
       phalanx bench
       phalanx bcreate [options]

DESCRIPTION

       This  manual  page  documents  briefly the phalanx program.  This manual page was written for the Debian GNU/Linux distribution (but may be
       used by others), because the original program does not have a manual page.

       phalanx is a chess playing program.  It is partially xboard compatible. Under xboard, it can play games,  force	&  undo  moves,  and  show
       thinking. In this version, you cannot set positions with xboard.

       It  is  also  possible  to run phalanx without xboard. Do phalanx -?  to get a list of command line options.  One important command of pha-
       lanx's ASCII interface is help.

       phalanx uses (traditional) 10x12 board implementation. There are three often used board	implementations:  "8x8"  (GNU  Chess),	"bitboard"
       (Crafty),  and  "10x12"	(Nimzo,  Phalanx).  In	short, "10x12" is easy to implement and the code is small (==fast on PC).  Opening book is
       small, simple, hand-written.

OPTIONS

       -t <transposition table size in kilobytes>

       -f <fixed search time in seconds>

       -x <+/->
	      xboard mode on/off	default: on

       -p <+/->
	      permanent brain on/off	default: off

       -s <+/->
	      show thinking on/off	default: off

       -c <+/->
	      cpu time			default: off

       -o <+/->
	      polling input		default: on

       -b <+/->
	      opening book		default: on

       -r <resign value in centipawns>
	      default: 0 (no resigning)

       -e <easy level 0...100>
	      default: 0 (best play)

       -l <+/->
	      learning on/off		default: on

       -v     print version and exit

       -P <primary book directory>

       -S <secondary book directory>

       -L <learning file directory>

       -g <log file name>

EXAMPLES

       phalanx -c+ -s+ -o - -x- -f 60 -t4000

       xboard -fcp "phalanx -l+ -r800"

SEE ALSO

       /usr/share/doc/phalanx, xboard(6)

AUTHOR

       Phalanx was written by Dusan  Dobes  <dobes@math.muni.cz>.  This manual page was written by Stephen Stafford <bagpuss@debian.org>  for  the
       Debian  GNU/Linux  project, but may be used by others.  It was written with the assistance of help2man(1) and then edited slightly to clean
       it up.

Phalanx XXII							     May 2001								PHALANX(6)