Trying to convert telnetenable.py to Python 3.6 in Windows 10 - python-3.x

Question

I have a Costco R4500 router that I am trying to open up telnet on. The older telnetenable.py script is what is needed to send a TCP packet to open it up. Then the router can be upgraded/updated, as the only release of firmware available for it from Netgear is terrible.
The new telnetenable2 using UDP packets does work on Windows 10, but does not work on this older firmware. The older exe, telnetenable, using TCP, does not run on Windows 10.
I figured out I had to install Python. Then I have to use Cryptodome instead of Crypto. And apparently Visual Studio. I am not a programmer.
Installed Python, then got the crypto error, then realized the PyCrypto package is not longer maintained, then installed PyCryptoDome, and modified the telnetenable.py somewhat. Only I am not a programmer, so I have very basic knowledge. I have read a lot on the current error I am getting, but have no idea what to do. I have looked at the script, and was hoping someone could tell me what is wrong with it.
copy of code in pastebin
# Copyright (c) 2009 Paul Gebheim...
import sys
import socket
import array
from optparse import OptionParser
from Cryptodome.Cipher import Blowfish
from Cryptodome.Hash import MD5
TELNET_PORT = 23
# The version of Blowfish supplied for the telenetenable.c implementation
# assumes Big-Endian data, but the code does nothing to convert the
# little-endian stuff it's getting on intel to Big-Endian
#
# So, since Crypto.Cipher.Blowfish seems to assume native endianness, we need
# to byteswap our buffer before and after encrypting it
#
# This helper does the byteswapping on the string buffer
def ByteSwap(data):
a = array.array('i')
if(a.itemsize < 4):
a = array.array('L')
if(a.itemsize != 4):
print("Need a type that is 4 bytes on your platform so we can fix the data!")
exit(1)
a.fromstring(data)
a.byteswap()
return a.tostring()
def GeneratePayload(mac, username, password=""):
# Pad the input correctly
assert(len(mac) < 0x10)
just_mac = mac.ljust(0x10, "\x00")
assert(len(username) <= 0x10)
just_username = username.ljust(0x10, "\x00")
assert(len(password) <= 0x10)
just_password = password.ljust(0x10, "\x00")
cleartext = (just_mac + just_username + just_password).ljust(0x70, '\x00')
md5_key = MD5.new(cleartext).digest()
payload = ByteSwap((md5_key + cleartext).ljust(0x80, "\x00"))
secret_key = "AMBIT_TELNET_ENABLE+" + password
return ByteSwap(Blowfish.new(secret_key, 1).encrypt(payload))
def SendPayload(ip, payload):
for res in socket.getaddrinfo(ip, TELNET_PORT, socket.AF_INET, socket.SOCK_STREAM, socket.IPPROTO_IP):
af, socktype, proto, canonname, sa = res
try:
s = socket.socket(af, socktype, proto)
except socket.error as msg:
s = None
continue
try:
s.connect(sa)
except socket.error as msg:
s.close()
s= None
continue
break
if s is None:
print ("Could not connect to '%s:%d'") % (ip, TELNET_PORT)
else:
s.send(payload)
s.close()
print ("Sent telnet enable payload to '%s:%d'") % (ip, TELNET_PORT)
def main():
args = sys.argv[1:]
if len(args) < 3 or len(args) > 4:
print ("usage: python telnetenable.py <ip> <mac> <username> [<password>]")
ip = args[0]
mac = args[1]
username = args[2]
password = ""
if len(args) == 4:
password = args[3]
payload = GeneratePayload(mac, username, password)
SendPayload(ip, payload)
main()
md5_key = MD5.new(cleartext).digest()
This is where I get the error:
Traceback (most recent call last):
File "telnetenable.py", line 113, in <module>
main()
File "telnetenable.py", line 110, in main
payload = GeneratePayload(mac, username, password)
File "telnetenable.py", line 64, in GeneratePayload
md5_key = MD5.new(cleartext).digest()
File "C:\Users\farme\AppData\Local\Programs\Python\Python36\lib\site-packages\Cryptodome\Hash\MD5.py", line 47, in __init__
self._h = _hash_new(*args)
TypeError: Unicode-objects must be encoded before hashing

Answer 1

It looks to me that the arguments you are passing to the script are in unicode and the MD5 object wants it encoded prior to processing it. I think the encoding will put one symbol per byte rather than allowing any confusion that any multi-byte characters might create if there is also a single byte option for that character.
Try something this:
md5_key = MD5.new(cleartext.encode('utf-8)).digest()