##
# $Id$
##

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


require 'msf/core'


class Metasploit3 < Msf::Auxiliary

	include Msf::Auxiliary::Report
	include Msf::Auxiliary::Scanner

	def initialize
		super(
			'Name'        => 'NTP Monitor List Scanner',
			'Version'     => '$Revision$',
			'Description' => 'Obtain the list of recent clients from an NTP server',
			'Author'      => 'hdm',
			'License'     => MSF_LICENSE
		)

		register_options(
		[
			Opt::RPORT(123),
			Opt::CHOST,
			OptInt.new('BATCHSIZE', [true, 'The number of hosts to probe in each set', 256])
		], self.class)


		register_advanced_options(
		[
			OptBool.new('StoreNTPClients', [true, 'Store NTP clients as host records in the database', 'false'])
		], self.class)
	end


	# Define our batch size
	def run_batch_size
		datastore['BATCHSIZE'].to_i
	end

	# Fingerprint a single host
	def run_batch(batch)

		@results = {}
		@aliases = {}

		print_status("Sending probes to #{batch[0]}->#{batch[-1]} (#{batch.length} hosts)")

		begin
			udp_sock = nil
			idx = 0

			# Create an unbound UDP socket if no CHOST is specified, otherwise
			# create a UDP socket bound to CHOST (in order to avail of pivoting)
			udp_sock = Rex::Socket::Udp.create( { 'LocalHost' => datastore['CHOST'] || nil } )

			# Try three times since NTP servers can be a bit busy
			1.upto(3)  do
			batch.each do |ip|
				next if @results[ip]

				begin
					data = probe_pkt_ntp(ip)
					udp_sock.sendto(data, ip, datastore['RPORT'].to_i, 0)
				rescue ::Interrupt
					raise $!
				rescue ::Rex::HostUnreachable, ::Rex::ConnectionTimeout, ::Rex::ConnectionRefused
					nil
				end

				if (idx % 30 == 0)
					while (r = udp_sock.recvfrom(65535, 0.1) and r[1])
						parse_reply(r)
					end
				end

				idx += 1
			end
			end

			while (r = udp_sock.recvfrom(65535, 10) and r[1])
				parse_reply(r)
			end

		rescue ::Interrupt
			raise $!
		rescue ::Exception => e
			print_status("Unknown error: #{e.class} #{e}")
		end

		@results.keys.each do |k|

			report_service(
				:host  => k,
				:proto => 'udp',
				:port  => datastore['RPORT'].to_i,
				:name  => 'NTP'
			)

			report_note(
				:host  => k,
				:proto => 'udp',
				:port  => datastore['RPORT'].to_i,
				:type  => 'ntp.monlist',
				:data  => {:monlist => @results[k]}
			)

			if (@aliases[k] and @aliases[k].keys[0] != k)
				report_note(
					:host  => k,
					:proto => 'udp',
					:port  => datastore['RPORT'].to_i,
					:type  => 'ntp.addresses',
					:data  => {:addresses => @aliases[k].keys}
				)
			end

			if (datastore['StoreNTPClients'])
				print_status("#{k} Storing #{@results[k].length} NTP client hosts in the database...")
				@results[k].each do |r|
					maddr,mport,mserv = r
					report_note(:host => maddr, :type => 'ntp.client.history', :data => {:address => maddr, :port => mport, :server => mserv})
				end
			end
		end

	end

	def parse_reply(pkt)

		# Ignore "empty" packets
		return if not pkt[1]

		if(pkt[1] =~ /^::ffff:/)
			pkt[1] = pkt[1].sub(/^::ffff:/, '')
		end

		data = pkt[0]
		host = pkt[1]
		port = pkt[2]

		return if pkt[0].length < (72 + 16)
		ntp_flags, ntp_auth, ntp_vers, ntp_code = data.slice!(0,4).unpack('C*')
		pcnt, plen, hlen, tmp = data.slice!(0,12).unpack('nnNN')
		return if plen != 72

		idx = 0
		1.upto(pcnt) do
			tmp1,mcnt,madd,sadd,tmp3,tmp4,mport = data[idx, plen].unpack("NNNNn3")
			@results[host] ||= []
			@aliases[host] ||= {}
			@results[host] << [ Rex::Socket.addr_itoa(madd), mport, Rex::Socket.addr_itoa(sadd) ]
			@aliases[host][Rex::Socket.addr_itoa(sadd)] = true
			print_status("#{host}:#{port} #{Rex::Socket.addr_itoa(madd)}:#{mport} (#{Rex::Socket.addr_itoa(sadd)})")
			idx += plen
		end
	end


	def probe_pkt_ntp(ip)
		data =
			"\x17\x00\x03\x2a\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +
			"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +
			"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +
			"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +
			"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +
			"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +
			"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +
			"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +
			"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +
			"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +
			"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +
			"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +
			"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" +
			"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
		return data
	end

end