IPv6 Local Neighbor Discovery

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

class MetasploitModule < Msf::Auxiliary
  include Msf::Exploit::Remote::Ipv6
  include Msf::Exploit::Remote::Capture
  include Msf::Auxiliary::Report
  include Msf::Auxiliary::Scanner


  def initialize
    super(
      'Name'        => 'IPv6 Local Neighbor Discovery',
      'Description' => %q{
        Enumerate local IPv6 hosts which respond to Neighbor Solicitations with a link-local address.
        Note, that like ARP scanning, this usually cannot be performed beyond the local
        broadcast network.
    },
    'Author'      => 'belch',
    'License'     => MSF_LICENSE
    )

    register_options(
      [
        OptString.new('SHOST', [false, "Source IP Address"]),
        OptString.new('SMAC', [false, "Source MAC Address"]),
        OptInt.new('TIMEOUT', [true, 'The number of seconds to wait for new data', 5]),
    ])

    deregister_options('SNAPLEN', 'FILTER')
  end

  def run_batch_size
    datastore['BATCHSIZE'] || 256
  end

  def run_batch(hosts)
    open_pcap({'SNAPLEN' => 68, 'FILTER' => "arp[6:2] == 0x0002"})

    @netifaces = true
    if not netifaces_implemented?
      print_error("WARNING : Pcaprub is not up-to-date, some functionality will not be available")
      @netifaces = false
    end

    print_status("Discovering IPv4 nodes via ARP...")

    @interface = datastore['INTERFACE'] || Pcap.lookupdev
    @shost = datastore['SHOST']
    @shost ||= get_ipv4_addr(@interface) if @netifaces
    raise 'SHOST should be defined' unless @shost

    @smac  = datastore['SMAC']
    @smac ||= get_mac(@interface) if @netifaces
    raise 'SMAC should be defined' unless @smac

    addrs = []

    begin
      found = {}
      hosts.each do |dhost|

        probe = buildprobe(@shost, @smac, dhost)
        capture.inject(probe)
        while(reply = getreply())
          next unless reply.is_arp?
          if not found[reply.arp_saddr_ip]
            print_good(sprintf("  %16s ALIVE",reply.arp_saddr_ip))
            addrs << [reply.arp_saddr_ip, reply.arp_saddr_mac]
            report_host(:host => reply.arp_saddr_ip, :mac=>reply.arp_saddr_mac)
            found[reply.arp_saddr_ip] = true
          end
        end
      end

      etime = ::Time.now.to_f + datastore['TIMEOUT']

      while (::Time.now.to_f < etime)
        while(reply = getreply())
          next unless reply.is_arp?
          if not found[reply.arp_saddr_ip]
            print_good(sprintf("  %16s ALIVE",reply.arp_saddr_ip))
            addrs << [reply.arp_saddr_ip, reply.arp_saddr_mac]
            report_host(:host => reply.arp_saddr_ip, :mac=>reply.arp_saddr_mac)
            found[reply.arp_saddr_ip] = true
          end
        end

        ::IO.select(nil, nil, nil, 0.50)
      end

    ensure
      close_pcap()
    end

    neighbor_discovery(addrs)
  end

  def map_neighbor(nodes, adv)
    nodes.each do |node|
      ipv4_addr, mac_addr = node
      next unless adv.eth_saddr == mac_addr
      ipv6_addr = adv.ipv6_saddr
      return {:eth => mac_addr, :ipv4 => ipv4_addr, :ipv6 => ipv6_addr}
    end
    nil
  end

  def neighbor_discovery(neighs)
    print_status("Discovering IPv6 addresses for IPv4 nodes...")
    print_status("")

    smac  = @smac
    open_pcap({'SNAPLEN' => 68, 'FILTER' => "icmp6"})

    begin
      neighs.each do |neigh|
        host, dmac = neigh

        shost = ipv6_linklocaladdr(smac)
        neigh = ipv6_linklocaladdr(dmac)

        probe = buildsolicitation(smac, shost, neigh)

        capture.inject(probe)
        Kernel.select(nil,nil,nil,0.1)

        while(adv = getadvertisement())
          next unless adv.is_ipv6?

          addr = map_neighbor(neighs, adv)
          next if not addr

          print_status(sprintf("  %16s maps to %s",addr[:ipv4], addr[:ipv6]))
          report_note(
            :host   => addr[:ipv4],
            :type   => 'host.ipv4.ipv6.mapping',
            :data   => "system with IPv4 address #{addr[:ipv4]} matches to IPv6 address #{addr[:ipv6]}"
          )	# with this we have the results in our database

        end
      end

      etime = ::Time.now.to_f + (neighs.length * 0.5)

      while (::Time.now.to_f < etime)
        while(adv = getadvertisement())
          next if not adv

          addr = map_neighbor(neighs, adv)
          next if not addr

          print_status(sprintf("  %16s maps to %s",addr[:ipv4], addr[:ipv6]))
        end
        ::IO.select(nil, nil, nil, 0.50)
      end

    ensure
      close_pcap()
    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_saddr_mac = p.eth_saddr
    p.arp_daddr_mac = p.eth_daddr
    p.arp_saddr_ip = shost
    p.arp_daddr_ip = dhost
    p.to_s
  end

  def getreply
    pkt = capture.next
    Kernel.select(nil,nil,nil,0.1)
    return if not pkt
    p = PacketFu::Packet.parse(pkt)
    return unless p.is_arp?
    return unless p.arp_opcode == 2
    p
  end

  def buildsolicitation(smac, shost, neigh)
    dmac = ipv6_soll_mcast_mac(neigh)
    dhost = ipv6_soll_mcast_addr6(neigh)

    p = PacketFu::IPv6Packet.new
    p.eth_saddr = smac
    p.eth_daddr = dmac
    p.ipv6_saddr = shost
    p.ipv6_daddr = dhost
    p.ipv6_next = 0x3a
    p.ipv6_hop = 255
    p.payload = ipv6_neighbor_solicitation(
      IPAddr.new(neigh).to_i,
      p.eth_src
    )
    p.ipv6_len = p.payload.size
    ipv6_checksum!(p)
    p.to_s
  end

  def getadvertisement
    pkt = capture.next
    Kernel.select(nil,nil,nil,0.1)
    return if not pkt
    p = PacketFu::Packet.parse(pkt)
    return unless p.is_ipv6?
    return unless p.ipv6_next == 0x3a
    return unless p.icmpv6_type == 136 && p.icmpv6_code == 0
    p
  end
end