While NET-NTLM is the name of the authentication or challenge/response protocol used between the client and the server. NTHash AKA NTLM hash is the currently used algorithm for storing passwords on windows systems. Obviously, the whole LM hashing stuff was based on the fact that no one will reverse it as well as no one will get into the internal network to be in a MITM position to capture it.Īs mentioned earlier, LM hashes are disabled by default since Windows Vista + Windows server 2008. You will notice that john got me the password “PASSWORD123” in upper case and not “password123”, and yeah, both are just true. Moreover, in case that the password is seven characters or less, the attacker doesn’t need to brute force the 2nd half as it has the fixed value of AAD3B435B51404EEĬreating hash for password123 and cracking it. Rainbow tables already exist containing all these possibilities, so cracking Lan Manager hashes isn’t a problem at all LM hash accepts only the 95 ASCII characters, but yet all lower case characters are converted to upper case, which makes it only 69 possibilities per character, which makes it just 7.5 trillion possibilities for each half instead of the total of 69^14 for the whole 14 characters. Len(map(''.join, itertools.product(*zip("Passwordpass123".upper(), "Passwordpass123".lower()))))Īlso, splitting the password into two halves makes it easier, as the attacker will be trying to brute force just a seven-character password! The upper and lowercase combinations will be more than 32000 possibilities, and all of them will have the same hash! Let’s assume a password like passwordpass123 Python -c 'from passlib.hash import lmhash print lmhash.hash("password")'Īs you may already think, this is a very weak algorithm,Įach hash has a lot of possibilities, for example, the hashes of the following passwords You can get the same result using the following python line. Let’s assume that the user’s password is PassWordġ – All characters will be converted to upper caseĢ – In case the password’s length is less than 14 characters it will be padded with null characters, so its length becomes 14, so the result will be PASSWORD000000ģ – These 14 characters will be split into 2 halvesĤ – Each half is converted to bits, and after every 7 bits, a parity bit (0) will be added, so the result would be a 64 bits key.Īs a result, we will get two keys from the 2 pre-generated halves after adding these parity bitsĥ – Each of these keys is then used to encrypt the string “ #$%” using DES algorithm in ECB mode so that the result would beĦ – The output of the two halves is then combined, and that makes out LM hash LM was a weak hashing algorithm for many reasons, You will figure these reasons out once You know how LM hashing works. It’s disabled by default since windows vista/windows server 2008. It was the dominating password storing algorithm on windows till windows XP/windows server 2003. This doesn’t contain all the details in the post but yet will get you the fundamentals you need to proceed with the next parts. I illustrated most of the concepts in this blog post in Arabic at the following video NTLM authentication in a windows domain environment.5 – Session Setup Request (Type 3 message).4 – Session Setup Response (Type 2 message).3 – Session Setup Request (Type 1 message).
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