Buffer Generator

Buffer Generator akan dibutuhkan saat kita ingin mengetahui byte ke berapa aplikasi mengalami crash saat melakukan buffer overflow exploitation dengan metode fuzzing.

Buat sebuah file dengan nama buftool.py dengan isi skrip sebagai berikut:

#!/usr/bin/python

#######################################################
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License version 2, 1991 as published by
# the Free Software Foundation.
# 
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
# details.
# 
# A copy of the GNU General Public License can be found at:
# [url="http://www.gnu.org/licenses/gpl.html"]http://www.gnu.org/licenses/gpl.html[/url]
# or you can write to:
# Free Software Foundation, Inc.
# 59 Temple Place - Suite 330
# Boston, MA 02111-1307
# USA.
#
#######################################################

#
# buftool.py:  By Linuxchuck
#
# Inspired by genbuf.pl, which uses Pex::Text::PatternCreate and also by
#   pattern_offset.rb found in the Metasploit Framework 3 tools directory.
#
# This script combines the function of both scripts into one package.

import sys
import string

def usage():
    print "Usage: ", sys.argv[0], "  [string]"
    print "    is the size of the buffer to generate."
    print "   [string] is the optional string to search for in the buffer."
    print ""
    print "   If [string] is provided, the buffer will not be printed, only the location"
    print "     of where the string starts in the buffer.  This search is CASE SENSITIVE!"
    sys.exit()

try:
    dummy = int(sys.argv[1])
except:
    usage()

if len(sys.argv) > 3:
    usage

if len(sys.argv) == 3:
    search = "TRUE"
    searchstr = sys.argv[2]
else:
    search = "FALSE"

stop = int(sys.argv[1]) / 3 + 1
patend = int(sys.argv[1])
patrange = range(0,stop,1)
first = 65
second = 97
third = 0
item = ""

for i in patrange:
    reset_first = "FALSE"
    reset_second = "FALSE"
    if third == 10:
        third = 0
        second += 1
    if second == 123:
        first +=1
        reset_second = "TRUE"
    if first == 92:
        reset_first = "TRUE"
    item += chr(first)
    item += chr(second)
    item += str(third)
    third += 1
    if reset_first == "TRUE":
        first = 65
    if reset_second == "TRUE":
        second = 97

if search != "TRUE":
    sys.stdout.write(item[0:patend])
else:
    location = item.find(searchstr)
    if location == -1:
        print sys.argv[2] + " not found in buffer."
        sys.exit()
    print location

untuk menjalankan aplikasi tersebut di konsol, cukup dengan format ./buftool.py <jumlah karakter>