##
# ## This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# web site for more information on licensing and terms of use.
#   http://metasploit.com/
##

require 'rex'
require 'msf/core'
require 'msf/core/auxiliary/report'

class Metasploit3 < Msf::Post

  include Msf::Auxiliary::Report

  def initialize(info={})
    super( update_info( info,
        'Name'	       => 'Windows Gather Active Directory Computers',
        'Description'  => %Q{
            This module will enumerate computers in the default AD directory.

            Optional Attributes to use in ATTRIBS:
            objectClass, cn, description, distinguishedName, instanceType, whenCreated,
            whenChanged, uSNCreated, uSNChanged, name, objectGUID,
            userAccountControl, badPwdCount, codePage, countryCode,
            badPasswordTime, lastLogoff, lastLogon, localPolicyFlags,
            pwdLastSet, primaryGroupID, objectSid, accountExpires,
            logonCount, sAMAccountName, sAMAccountType, operatingSystem,
            operatingSystemVersion, operatingSystemServicePack, serverReferenceBL,
            dNSHostName, rIDSetPreferences, servicePrincipalName, objectCategory,
            netbootSCPBL, isCriticalSystemObject, frsComputerReferenceBL,
            lastLogonTimestamp, msDS-SupportedEncryptionTypes

            ActiveDirectory has a MAX_SEARCH limit of 1000 by default. Split search up
            if you hit that limit.

            Possible filters:
            (objectClass=computer) # All Computers
            (primaryGroupID=516)  # All Domain Controllers
            (&(objectCategory=computer)(operatingSystem=*server*)) # All Servers

            No reason this can't enumerate users/groups with the right filters and attribs.
        },
        'License'      => MSF_LICENSE,
        'Author'       => [ 'Ben Campbell <eat_meatballs[at]hotmail.co.uk>' ],
        'Platform'     => [ 'win' ],
        'SessionTypes' => [ 'meterpreter' ],
        'References'	=>
        [
          ['URL', 'http://social.technet.microsoft.com/wiki/contents/articles/5392.active-directory-ldap-syntax-filters.aspx'],
        ]
      ))

    register_options([
      OptInt.new('MAX_SEARCH', [true, 'Maximum values to retrieve, 0 for all.', 50]),
      OptBool.new('STORE_LOOT', [true, 'Store file in loot.', false]),
      OptBool.new('STORE_DB', [true, 'Store file in DB (performance hit resolving IPs).', true]),
      OptString.new('ATTRIBS', [true, 'Attributes to retrieve.', 'dNSHostName,distinguishedName,description,operatingSystem,operatingSystemServicePack']),
      OptString.new('FILTER', [true, 'Search filter.', '(&(objectCategory=computer)(operatingSystem=*server*))'])
    ], self.class)
  end

  def run
    print_status("Connecting to default LDAP server")
    session_handle = bind_default_ldap_server(datastore['MAX_SEARCH'])

    return false unless session_handle

    print_status("Querying default naming context")

    query_result = query_ldap(session_handle, "", 0, "(objectClass=computer)", ["defaultNamingContext"])
    first_entry_attributes = query_result[0]['attributes']
    defaultNamingContext = first_entry_attributes[0]['values'] # Value from First Attribute of First Entry

    print_status("Default Naming Context #{defaultNamingContext}")

    attributes = datastore['ATTRIBS'].gsub(/\s+/,"").split(',')

    search_filter = datastore['FILTER']
    print_status("Querying #{search_filter} - Please wait...")
    results = query_ldap(session_handle, defaultNamingContext, 2, search_filter, attributes)

    print_status("Unbinding from LDAP service.")
    wldap32.ldap_unbind(session_handle)

    if results.nil? or results.empty?
      return
    end

    results_table = Rex::Ui::Text::Table.new(
        'Header'     => "#{defaultNamingContext} Domain Computers",
        'Indent'     => 1,
        'SortIndex'  => -1,
        'Columns'    => attributes
      )

    results.each do |result|
      row = []

      report = {}
      result['attributes'].each do |attr|
        if attr['values'].nil?
          row << ""
        else
          row << attr['values']

          # Only perform these actions if the database is connected and we want
          # to store in the DB.
          if db and datastore['STORE_DB']
            case attr['name']
            when 'dNSHostName'
              dns = attr['values']
              ip = resolve_hostname(dns)
              report.merge!( {:name => dns, :host => ip } )
            when 'operatingSystem'
              os = attr['values']
              index = os.index(/windows/i)
              unless index.nil?
                name = 'Microsoft Windows'
                flavour = os[index..-1]
                report.merge!( {:os_name => name, :os_flavor => flavour} )
              else
                # Incase there are non-windows domain computers?!
                report.merge!( {:os_name => os } )
              end
            when 'distinguishedName'
              if attr['values'] =~ /Domain Controllers/i
                report.merge!( {:purpose => "DC"} )
              end
            when 'operatingSystemServicePack'
              report.merge!( {:os_sp => attr['values']} )
            when 'description'
              report.merge!( {:info => attr['values']} )
            end
          end
        end
      end

      vprint_good("Database report: #{report.inspect}")
      if report.include? :host
        report_host(report)
      end

      results_table << row

    end

    print_line results_table.to_s
    if datastore['STORE_LOOT']
      stored_path = store_loot('ad.computers', 'text/plain', session, results_table.to_csv)
      print_status("Results saved to: #{stored_path}")
    end
  end

  # This really needs migrating to a meterpreter function
  def resolve_hostname(hostname)
    if client.platform =~ /^x64/
      size = 64
      addrinfoinmem = 32
    else
      size = 32
      addrinfoinmem = 24
    end

    begin
      vprint_status("Looking up IP for #{hostname}")
      result = client.railgun.ws2_32.getaddrinfo(hostname, nil, nil, 4 )
      if result['GetLastError'] == 11001
        return nil
      end
      addrinfo = client.railgun.memread( result['ppResult'], size )
      ai_addr_pointer = addrinfo[addrinfoinmem,4].unpack('L').first
      sockaddr = client.railgun.memread( ai_addr_pointer, size/2 )
      ip = sockaddr[4,4].unpack('N').first
      hostip = Rex::Socket.addr_itoa(ip)

      if hostip =~ /0\.0\.0\.0/
        hostip = client.session_host
      end
    rescue ::Exception => e
      print_error(e.to_s)
    end
    vprint_status("IP for #{hostname}: #{hostip}")
    return hostip
  end

  def wldap32
    return client.railgun.wldap32
  end

  def bind_default_ldap_server(size_limit)
    vprint_status ("Initializing LDAP connection.")
    session_handle = wldap32.ldap_sslinitA("\x00\x00\x00\x00", 389, 0)['return']
    vprint_status("LDAP Handle: #{session_handle}")

    if session_handle == 0
      print_error("Unable to connect to LDAP server")
      wldap32.ldap_unbind(session_handle)
      return false
    end

    vprint_status ("Setting Sizelimit Option")
    sl_resp = wldap32.ldap_set_option(session_handle, 0x03, size_limit) #0x03:LDAP_OPT_SIZELIMIT

    vprint_status ("Binding to LDAP server.")
    bind = wldap32.ldap_bind_sA(session_handle, nil, nil, 0x0486)['return'] #LDAP_AUTH_NEGOTIATE 0x0486

    if bind != 0
      print_error("Unable to bind to LDAP server")
      wldap32.ldap_unbind(session_handle)
      return false
    end

    return session_handle
  end

  def get_entry(pEntry)
    return client.railgun.memread(pEntry,41).unpack('LLLLLLLLLSCCC')
  end

  # Get BERElement data structure from LDAPMessage
  def get_ber(msg)
    ber = client.railgun.memread(msg[2],60).unpack('L*')

    # BER Pointer is different between x86 and x64
    if client.platform =~ /x86/
      ber_data = client.railgun.memread(ber[3], ber[0])
    else
      ber_data = client.railgun.memread(ber[4], ber[0])
    end

    return ber_data
  end

  # Search through the BER for our Attr string. Pull the values.
  def get_values_from_ber(ber_data, attr)
    attr_offset = ber_data.index(attr)

    if attr_offset.nil?
      vprint_status("Attribute not found in BER.")
      return nil
    end

    # Value starts after our attribute string
    values_offset = attr_offset + attr.length
    values_start_offset = values_offset + 8
    values_len_offset = values_offset + 5
    curr_len_offset = values_offset + 7

    values_length =  ber_data[values_len_offset].unpack('C')[0]
    values_end_offset = values_start_offset + values_length

    curr_length = ber_data[curr_len_offset].unpack('C')[0]
    curr_start_offset = values_start_offset
    curr_end_offset = curr_start_offset + curr_length

    values = []
    while (curr_end_offset < values_end_offset)
      values << ber_data[curr_start_offset..curr_end_offset]

      break unless ber_data[curr_end_offset] == "\x04"

      curr_len_offset = curr_end_offset + 1
      curr_length = ber_data[curr_len_offset].unpack('C')[0]
      curr_start_offset = curr_end_offset + 2
      curr_end_offset = curr_end_offset + curr_length + 2
    end

    # Strip trailing 0 or \x04 which is used to delimit values
    values.map! {|x| x[0..x.length-2]}

    return values
  end

  def query_ldap(session_handle, base, scope, filter, attributes)
    vprint_status ("Searching LDAP directory.")
    search = wldap32.ldap_search_sA(session_handle, base, scope, filter, nil, 0, 4)
    vprint_status("search: #{search}")

    if search['return'] == 0x04 # LDAP_SIZELIMIT_EXCEEDED - parse out what we found anyway...
      print_error("LDAP_SIZELIMIT_EXCEEDED, parsing what we retrieved, try increasing the MAX_SEARCH value [0:LDAP_NO_LIMIT]")
    elsif search['return'] != 0
      print_error("No results")
      wldap32.ldap_msgfree(search['res'])
      return
    end

    search_count = wldap32.ldap_count_entries(session_handle, search['res'])['return']

    if(search_count == 0)
      print_error("No entries retrieved")
      wldap32.ldap_msgfree(search['res'])
      return
    end

    print_status("Entries retrieved: #{search_count}")

    vprint_status("Retrieving results...")

    pEntries = []
    entry_results = []

    if datastore['MAX_SEARCH'] == 0
      max_search = search_count
    else
      max_search = [datastore['MAX_SEARCH'], search_count].min
    end

    0.upto(max_search - 1) do |i|

      if(i==0)
        pEntries[0] = wldap32.ldap_first_entry(session_handle, search['res'])['return']
      end

      if(pEntries[i] == 0)
        print_error("Failed to get entry.")
        wldap32.ldap_unbind(session_handle)
        wldap32.ldap_msgfree(search['res'])
        return
      end

      vprint_status("Entry #{i}: 0x#{pEntries[i].to_s(16)}")

      entry = get_entry(pEntries[i])

      # Entries are a linked list...
      if client.platform =~ /x86/
        pEntries[i+1] = entry[3]
      else
        pEntries[i+1] = entry[4]
      end

      ber = get_ber(entry)

      attribute_results = []
      attributes.each do |attr|
        vprint_status("Attr: #{attr}")
        value_results = ""

        values = get_values_from_ber(ber, attr)

        values_result = ""
        values_result = values.join(',') unless values.nil?
        vprint_status("Values #{values}")

        attribute_results << {"name" => attr, "values" => values_result}
      end

      entry_results << {"id" => i, "attributes" => attribute_results}
    end

    return entry_results
  end
end