Add module for adding/deleting computers via MS-SAMR

Gemfile.lock

@@ -445,7 +445,7 @@ GEM
     ruby-progressbar (1.11.0)
     ruby-rc4 (0.1.5)
     ruby2_keywords (0.0.5)
-    ruby_smb (3.1.3)
+    ruby_smb (3.1.5)
       bindata
       openssl-ccm
       openssl-cmac

documentation/modules/auxiliary/admin/dcerpc/samr_computer.md

@@ -0,0 +1,100 @@
+## Vulnerable Application
+Add, lookup and delete computer accounts via MS-SAMR. By default standard active directory users can add up to 10 new
+computers to the domain. Administrative privileges however are required to delete the created accounts.
+
+## Verification Steps
+
+1. From msfconsole
+2. Do: `use auxiliary/admin/dcerpc/samr_computer`
+3. Set the `RHOSTS`, `SMBUser` and `SMBPass` options
+   1. Set the `COMPUTER_NAME` option for `DELETE_COMPUTER` and `LOOKUP_COMPUTER` actions
+4. Run the module and see that a new machine account was added
+
+## Options
+
+### SMBDomain
+
+The Windows domain to use for authentication. The domain will automatically be identified if this option is left in its
+default value.
+
+### COMPUTER_NAME
+
+The computer name to add, lookup or delete. This option is optional for the `ADD_COMPUTER` action, and required for the
+`LOOKUP_COMPUTER` and `DELETE_COMPUTER` actions.
+
+### COMPUTER_PASSWORD
+
+The password for the new computer. This option is only used for the `ADD_COMPUTER` action. If left blank, a random value
+will be generated.
+
+## Actions
+
+### ADD_COMPUTER
+
+Add a new computer to the domain. This action will fail with status `STATUS_DS_MACHINE_ACCOUNT_QUOTA_EXCEEDED` if the
+user has exceeded the maximum number of computer accounts that they are allowed to create.
+
+After the computer account is created, the password will be set for it. If `COMPUTER_NAME` is set, that value will be
+used and the module will fail if the selected name is already in use. If `COMPUTER_NAME` is *not* set, a random value
+will be used.
+
+### DELETE_COMPUTER
+
+Delete a computer from the domain. This action requires that the `COMPUTER_NAME` option be set.
+
+### LOOKUP_COMPUTER
+
+Lookup a computer in the domain. This action verifies that the specified computer exists, and looks up its security ID
+(SID), which includes the relative ID (RID) as the last component.
+
+## Scenarios
+
+### Windows Server 2019
+
+First, a new computer account is created and its details are logged to the database.
+
+```
+msf6 auxiliary(admin/dcerpc/samr_computer) > set RHOSTS 192.168.159.96
+RHOSTS => 192.168.159.96
+msf6 auxiliary(admin/dcerpc/samr_computer) > set SMBUser aliddle
+SMBUser => aliddle
+msf6 auxiliary(admin/dcerpc/samr_computer) > set SMBPass Password1
+SMBPass => Password1
+msf6 auxiliary(admin/dcerpc/samr_computer) > show options 
+
+Module options (auxiliary/admin/dcerpc/samr_computer):
+
+   Name               Current Setting  Required  Description
+   ----               ---------------  --------  -----------
+   COMPUTER_NAME                       no        The computer name
+   COMPUTER_PASSWORD                   no        The password for the new computer
+   RHOSTS             192.168.159.96   yes       The target host(s), see https://github.com/rapid7/metasploit-framework/wiki/Using-Metasploit
+   RPORT              445              yes       The target port (TCP)
+   SMBDomain          .                no        The Windows domain to use for authentication
+   SMBPass            Password1        no        The password for the specified username
+   SMBUser            aliddle          no        The username to authenticate as
+
+
+Auxiliary action:
+
+   Name          Description
+   ----          -----------
+   ADD_COMPUTER  Add a computer account
+
+
+msf6 auxiliary(admin/dcerpc/samr_computer) > run
+[*] Running module against 192.168.159.96
+
+[*] 192.168.159.96:445 - Using automatically identified domain: MSFLAB
+[+] 192.168.159.96:445 - Successfully created MSFLAB\DESKTOP-2X8F54QG$ with password MCoDkNALd3SdGR1GoLhqniEkWa8Me9FY
+[*] Auxiliary module execution completed
+msf6 auxiliary(admin/dcerpc/samr_computer) > creds
+Credentials
+===========
+
+host            origin          service        public             private                           realm   private_type  JtR Format
+----            ------          -------        ------             -------                           -----   ------------  ----------
+192.168.159.96  192.168.159.96  445/tcp (smb)  DESKTOP-2X8F54QG$  MCoDkNALd3SdGR1GoLhqniEkWa8Me9FY  MSFLAB  Password      
+
+msf6 auxiliary(admin/dcerpc/samr_computer) >
+```

modules/auxiliary/admin/dcerpc/samr_computer.rb

@@ -0,0 +1,249 @@
+##
+# This module requires Metasploit: https://metasploit.com/download
+# Current source: https://github.com/rapid7/metasploit-framework
+##
+
+require 'ruby_smb/dcerpc/client'
+
+class MetasploitModule < Msf::Auxiliary
+  include Msf::Exploit::Remote::SMB::Client::Authenticated
+  include Msf::Exploit::Remote::DCERPC
+  include Msf::Auxiliary::Report
+
+  def initialize(info = {})
+    super(
+      update_info(
+        info,
+        'Name' => 'SAMR Computer Management',
+        'Description' => %q{
+          Add, lookup and delete computer accounts via MS-SAMR. By default
+          standard active directory users can add up to 10 new computers to the
+          domain. Administrative privileges however are required to delete the
+          created accounts.
+        },
+        'License' => MSF_LICENSE,
+        'Author' => [
+          'JaGoTu', # @jagotu Original Impacket code
+          'Spencer McIntyre',
+        ],
+        'References' => [
+          ['URL', 'https://github.com/SecureAuthCorp/impacket/blob/master/examples/addcomputer.py'],
+        ],
+        'Notes' => {
+          'Reliability' => [],
+          'Stability' => [],
+          'SideEffects' => [ IOC_IN_LOGS ]
+        },
+        'Actions' => [
+          [ 'ADD_COMPUTER', { 'Description' => 'Add a computer account' } ],
+          [ 'DELETE_COMPUTER', { 'Description' => 'Delete a computer account' } ],
+          [ 'LOOKUP_COMPUTER', { 'Description' => 'Lookup a computer account' } ]
+        ],
+        'DefaultAction' => 'ADD_COMPUTER'
+      )
+    )
+
+    register_options([
+      OptString.new('COMPUTER_NAME', [ false, 'The computer name' ]),
+      OptString.new('COMPUTER_PASSWORD', [ false, 'The password for the new computer' ], conditions: %w[ACTION == ADD_COMPUTER]),
+      Opt::RPORT(445)
+    ])
+  end
+
+  def connect_samr
+    vprint_status('Connecting to Security Account Manager (SAM) Remote Protocol')
+    samr = @tree.open_file(filename: 'samr', write: true, read: true)
+
+    vprint_status('Binding to \\samr...')
+    samr.bind(endpoint: RubySMB::Dcerpc::Samr)
+    vprint_good('Bound to \\samr')
+
+    samr
+  end
+
+  def run
+    begin
+      connect
+    rescue Rex::ConnectionError => e
+      fail_with(Failure::Unreachable, e.message)
+    end
+
+    begin
+      smb_login
+    rescue Rex::Proto::SMB::Exceptions::Error, RubySMB::Error::RubySMBError => e
+      fail_with(Failure::NoAccess, "Unable to authenticate ([#{e.class}] #{e}).")
+    end
+    report_service(
+      host: rhost,
+      port: rport,
+      host_name: simple.client.default_name,
+      proto: 'tcp',
+      name: 'smb',
+      info: "Module: #{fullname}, last negotiated version: SMBv#{simple.client.negotiated_smb_version} (dialect = #{simple.client.dialect})"
+    )
+
+    begin
+      @tree = simple.client.tree_connect("\\\\#{sock.peerhost}\\IPC$")
+    rescue RubySMB::Error::RubySMBError => e
+      fail_with(Failure::Unreachable, "Unable to connect to the remote IPC$ share ([#{e.class}] #{e}).")
+    end
+
+    begin
+      @samr = connect_samr
+      @server_handle = @samr.samr_connect
+    rescue RubySMB::Dcerpc::Error::FaultError => e
+      elog(e.message, error: e)
+      fail_with(Failure::UnexpectedReply, "Connection failed (DCERPC fault: #{e.status_name})")
+    end
+
+    if datastore['SMBDomain'].blank? || datastore['SMBDomain'] == '.'
+      all_domains = @samr.samr_enumerate_domains_in_sam_server(server_handle: @server_handle).map(&:to_s).map(&:encode)
+      all_domains.delete('Builtin')
+      if all_domains.empty?
+        fail_with(Failure::NotFound, 'No domains were found on the SAM server.')
+      elsif all_domains.length > 1
+        print_status("Enumerated domains: #{all_domains.join(', ')}")
+        fail_with(Failure::BadConfig, 'The SAM server has more than one domain, the target must be specified.')
+      end
+
+      @domain_name = all_domains.first
+      print_status("Using automatically identified domain: #{@domain_name}")
+    else
+      @domain_name = datastore['SMBDomain']
+    end
+
+    @domain_sid = @samr.samr_lookup_domain(server_handle: @server_handle, name: @domain_name)
+    @domain_handle = @samr.samr_open_domain(server_handle: @server_handle, domain_id: @domain_sid)
+    send("action_#{action.name.downcase}")
+  rescue RubySMB::Dcerpc::Error::DcerpcError => e
+    elog(e.message, error: e)
+    fail_with(Failure::UnexpectedReply, e.message)
+  rescue RubySMB::Error::RubySMBError
+    elog(e.message, error: e)
+    fail_with(Failure::Unknown, e.message)
+  end
+
+  def random_hostname(prefix: 'DESKTOP')
+    "#{prefix}-#{Rex::Text.rand_base(8, '', ('A'..'Z').to_a + ('0'..'9').to_a)}$"
+  end
+
+  def action_add_computer
+    if datastore['COMPUTER_NAME'].blank?
+      computer_name = random_hostname
+      4.downto(0) do |attempt|
+        break if @samr.samr_lookup_names_in_domain(domain_handle: @domain_handle, names: [ computer_name ]).nil?
+
+        computer_name = random_hostname
+        fail_with(Failure::BadConfig, 'Could not find an unused computer name.') if attempt == 0
+      end
+    else
+      computer_name = datastore['COMPUTER_NAME']
+      if @samr.samr_lookup_names_in_domain(domain_handle: @domain_handle, names: [ computer_name ])
+        fail_with(Failure::BadConfig, 'The specified computer name already exists.')
+      end
+    end
+
+    result = @samr.samr_create_user2_in_domain(
+      domain_handle: @domain_handle,
+      name: computer_name,
+      account_type: RubySMB::Dcerpc::Samr::USER_WORKSTATION_TRUST_ACCOUNT,
+      desired_access: RubySMB::Dcerpc::Samr::USER_FORCE_PASSWORD_CHANGE | RubySMB::Dcerpc::Samr::MAXIMUM_ALLOWED
+    )
+
+    user_handle = result[:user_handle]
+    if datastore['COMPUTER_PASSWORD'].blank?
+      password = Rex::Text.rand_text_alphanumeric(32)
+    else
+      password = datastore['COMPUTER_PASSWORD']
+    end
+
+    user_info = RubySMB::Dcerpc::Samr::SamprUserInfoBuffer.new(
+      tag: RubySMB::Dcerpc::Samr::USER_INTERNAL4_INFORMATION_NEW,
+      member: RubySMB::Dcerpc::Samr::SamprUserInternal4InformationNew.new(
+        i1: {
+          password_expired: 1,
+          which_fields: RubySMB::Dcerpc::Samr::USER_ALL_NTPASSWORDPRESENT | RubySMB::Dcerpc::Samr::USER_ALL_PASSWORDEXPIRED
+        },
+        user_password: {
+          buffer: RubySMB::Dcerpc::Samr::SamprEncryptedUserPasswordNew.encrypt_password(
+            password,
+            @simple.client.application_key
+          )
+        }
+      )
+    )
+    @samr.samr_set_information_user2(
+      user_handle: user_handle,
+      user_info: user_info
+    )
+
+    user_info = RubySMB::Dcerpc::Samr::SamprUserInfoBuffer.new(
+      tag: RubySMB::Dcerpc::Samr::USER_CONTROL_INFORMATION,
+      member: RubySMB::Dcerpc::Samr::UserControlInformation.new(
+        user_account_control: RubySMB::Dcerpc::Samr::USER_WORKSTATION_TRUST_ACCOUNT
+      )
+    )
+    @samr.samr_set_information_user2(
+      user_handle: user_handle,
+      user_info: user_info
+    )
+    print_good("Successfully created #{@domain_name}\\#{computer_name} with password #{password}")
+    report_creds(@domain_name, computer_name, password)
+  end
+
+  def action_delete_computer
+    fail_with(Failure::BadConfig, 'This action requires COMPUTER_NAME to be specified.') if datastore['COMPUTER_NAME'].blank?
+    computer_name = datastore['COMPUTER_NAME']
+
+    details = @samr.samr_lookup_names_in_domain(domain_handle: @domain_handle, names: [ computer_name ])
+    fail_with(Failure::BadConfig, 'The specified computer was not found.') if details.nil?
+    details = details[computer_name]
+
+    handle = @samr.samr_open_user(domain_handle: @domain_handle, user_id: details[:rid])
+    @samr.samr_delete_user(user_handle: handle)
+    print_good('The specified computer has been deleted.')
+  end
+
+  def action_lookup_computer
+    fail_with(Failure::BadConfig, 'This action requires COMPUTER_NAME to be specified.') if datastore['COMPUTER_NAME'].blank?
+    computer_name = datastore['COMPUTER_NAME']
+
+    details = @samr.samr_lookup_names_in_domain(domain_handle: @domain_handle, names: [ computer_name ])
+    if details.nil?
+      print_error('The specified computer was not found.')
+      return
+    end
+    details = details[computer_name]
+    sid = @samr.samr_rid_to_sid(object_handle: @domain_handle, rid: details[:rid]).to_s
+    print_good("Found #{@domain_name}\\#{computer_name} (SID: #{sid})")
+  end
+
+  def report_creds(domain, username, password)
+    service_data = {
+      address: datastore['RHOST'],
+      port: datastore['RPORT'],
+      service_name: 'smb',
+      protocol: 'tcp',
+      workspace_id: myworkspace_id
+    }
+
+    credential_data = {
+      module_fullname: fullname,
+      origin_type: :service,
+      private_data: password,
+      private_type: :password,
+      username: username,
+      realm_key: Metasploit::Model::Realm::Key::ACTIVE_DIRECTORY_DOMAIN,
+      realm_value: domain
+    }.merge(service_data)
+
+    credential_core = create_credential(credential_data)
+
+    login_data = {
+      core: credential_core,
+      status: Metasploit::Model::Login::Status::UNTRIED
+    }.merge(service_data)
+
+    create_credential_login(login_data)
+  end
+end