mirror of
https://github.com/vanhoefm/fragattacks.git
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78 lines
2.4 KiB
Python
78 lines
2.4 KiB
Python
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#!/usr/bin/env python3
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import binascii, struct
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from Crypto.Hash import MD4, SHA
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from Crypto.Cipher import DES
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def des_encrypt(clear, key, offset):
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cNext = 0
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cWorking = 0
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hexKey = {}
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for x in range(0,8):
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cWorking = 0xFF & key[x + offset]
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hexKey[x] = ((cWorking >> x) | cNext | 1) & 0xFF
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cWorking = 0xFF & key[x + offset]
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cNext = ((cWorking << (7 - x)))
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newKey = b""
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for x in range(0, len(hexKey)):
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newKey += struct.pack(">B", hexKey[x])
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des = DES.new(newKey, DES.MODE_ECB)
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return des.encrypt(clear)
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def challenge_hash(peer_challenge, authenticator_challenge, username):
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challenge = SHA.new(peer_challenge + authenticator_challenge + username).digest()
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return challenge[0:8]
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def nt_password_hash(password):
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unicode_pw = password.encode("utf-16-le")
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return MD4.new(unicode_pw).digest()
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def hash_nt_password_hash(password_hash):
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md4 = MD4.new()
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md4.update(password_hash)
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return md4.digest()
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def challenge_response(challenge, pwhash):
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# for some reason in python we need to pad an extra byte so that
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# the offset works out correctly when we call DesEncrypt
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pwhash += b'\x00' * (22 - len(pwhash))
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response = b""
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for x in range(0, 3):
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encrypted = des_encrypt(challenge, pwhash, x * 7)
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response += encrypted
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return response
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def generate_nt_response_mschap2(authenticator_challenge, peer_challenge, username, password):
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challenge = challenge_hash(peer_challenge, authenticator_challenge, username)
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password_hash = nt_password_hash(password)
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return challenge_response(challenge, password_hash)
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def generate_authenticator_response(password, nt_response, peer_challenge, authenticator_challenge, username):
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magic1 = b"\x4D\x61\x67\x69\x63\x20\x73\x65\x72\x76\x65\x72\x20\x74\x6F\x20\x63\x6C\x69\x65\x6E\x74\x20\x73\x69\x67\x6E\x69\x6E\x67\x20\x63\x6F\x6E\x73\x74\x61\x6E\x74"
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magic2 = b"\x50\x61\x64\x20\x74\x6F\x20\x6D\x61\x6B\x65\x20\x69\x74\x20\x64\x6F\x20\x6D\x6F\x72\x65\x20\x74\x68\x61\x6E\x20\x6F\x6E\x65\x20\x69\x74\x65\x72\x61\x74\x69\x6F\x6E"
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password_hash = nt_password_hash(password)
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password_hash_hash = hash_nt_password_hash(password_hash)
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sha_hash = SHA.new()
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sha_hash.update(password_hash_hash)
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sha_hash.update(nt_response)
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sha_hash.update(magic1)
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digest = sha_hash.digest()
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challenge = challenge_hash(peer_challenge, authenticator_challenge, username)
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sha_hash = SHA.new()
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sha_hash.update(digest)
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sha_hash.update(challenge)
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sha_hash.update(magic2)
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digest = sha_hash.digest()
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return digest
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