#!/usr/bin/env python3

"""

SHELLCODE-EXTRACTOR

Tool used to extract shellcode and lenght from an object/binary file.

Copyright (C) 2017 Neetx

This file is part of Shellcode-Extractor.

Shellcode-Extractor is free software: you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation, either version 3 of the License, or

(at your option) any later version.

Shellcode-Extractor 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.

You should have received a copy of the GNU General Public License

along with this program. If not, see <http://www.gnu.org/licenses/>

CONTACTS:

- neetx@protonmail.com

"""

import sys, re

usage_message = "\nError! \n Usage: objdump -d example.o | python shellcode_extractor.py \n"

if not sys.stdin.isatty():

try:

shellcode = ""

length = 0

while True:

item = sys.stdin.readline()

if item:

if re.match("^[ ]*[0-9a-f]*:.*$",item):

item =item.split(":")[1].lstrip()

x = item.split("\t")

opcode = re.findall("[0-9a-f][0-9a-f]",x[0])

for i in opcode:

shellcode += "\\x" + i

length += 1

else:

break

if shellcode == "":

print("Nothing to extract")

else:

print("\n" + shellcode)

print("\nLength: " + str(length) + "\n")

print("Dumping shellcode to shelltest.c ...")

shelltest_text = """

#include <stdio.h>

#include <string.h>

#include <sys/mman.h>

#include <unistd.h>

/*

* This program originally appeared in Dr. Alexandros Kapravelos' CSC 405 class, at NC State

* University.

*/

unsigned char print_unity_shellcode[] = "%s";

int main()

{

int pagesize = getpagesize(); // Get the page size for this system

void *addrOfThePage = print_unity_shellcode - ((unsigned int)print_unity_shellcode %% pagesize); // calculate the address of the page code is on

mprotect(addrOfThePage, pagesize, PROT_EXEC | PROT_WRITE); // Set the premissions for the page to be EXECUABLE (PROT_EXEC flag)

int (*ret)() = (int(*)())print_unity_shellcode;

ret();

}

""" % shellcode

with open("shelltest.c", "w+") as f:

f.write(shelltest_text)

f.close()

except Exception as e:

print(e)

pass

else:

print(usage_message)