MD5 hash in Python

Question

I have been given a file with user and passwords in the format: $id$salt$hashed.

Where ID stands for the type of encryption and id=1 stands for FreeBSD-style MD5.

There is an example in which I know the password= "alice"

jsmith: $1$kDHTx$WKRXXT1P7UtjvU7CQ9eWs/:10063:0:99999:7:::

So I have done this in Python to check

import hashlib passw='alice' salt='kDHTx' hashed= hashlib.md5(salt+passw).hexdigest() print('What i get is: '+hashed) print('What i should: '+'WKRXXT1P7UtjvU7CQ9eWs')

But I dont even get the format correctly:

What i get is: ba359e6dd36371c4dc5c187aac11e0d8 What i should: WKRXXT1P7UtjvU7CQ9eWs

What am I doing wrong? Or even understanding wrong from the begining?

Why do you think you should get WKRXXT1P7UtjvU7CQ9eWs? The result from python looks correct, because the result has to be hexadecimal (I didn't calculate the hash myself). Maybe that result you provided uses some other encoding. — The Quantum Physicist
– The Quantum Physicist, Commented Nov 21, 2018 at 16:13
It is the example I have been given, and at least the format of the Hashed should be the same. — 19mike95
– 19mike95, Commented Nov 21, 2018 at 16:15
Just one recommendation: Don't use md5 for hashing because that's vulnerable to gpu and asics attacks. Use something advanced like argon2. Check what I did here. — The Quantum Physicist
– The Quantum Physicist, Commented Nov 21, 2018 at 16:18
I am not hashing for security its just an exercise where i have to get as many passwords as possible from the /etc/shadow file. And regarding my initial question, can it be any kind of format issue? — 19mike95
– 19mike95, Commented Nov 21, 2018 at 16:23
Note: Neither md5 nor shadow are encryption, and this is not a hexdigest since it has both uppercase and lowercase letters. — Max
– Max, Commented Nov 21, 2018 at 16:37

Adam · Accepted Answer · 2020-03-18 21:08:24Z

5

You need to use the crypt library instead of hashlib.

>>> import crypt >>> crypt.crypt('alice', crypt.METHOD_MD5) $1$tlyP8ine$I9F3AiUCIgOjREqbx6WUg0

The salt is generated by the function when you pass in crypt.METHOD_MD5.

To re-create an existing hash, you can pass it in as the second argument:

>>> crypt.crypt('alice', '$1$kDHTx$WKRXXT1P7UtjvU7CQ9eWs/') $1$kDHTx$WKRXXT1P7UtjvU7CQ9eWs/

edited Mar 18, 2020 at 21:08

answered Nov 21, 2018 at 16:28

Adam

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6 Comments

Max Over a year ago

It looks like you can pass the whole $1$... source password as the 'salt' in python 3.x's crypt function to reuse the salt:

Since a few crypt(3) extensions allow different values, with different sizes in the salt, it is recommended to use the full crypted password as salt when checking for a password.

Adam Over a year ago

Nice, I'll add that to the post

19mike95 Over a year ago

By the way, is crypt just for Python 3 or superior?

Adam Over a year ago

crypt was added in Python 2.7 but there were significant improvements from Python 3.3 and onwards. You can check the Python3 documentation on the Python site.

19mike95 Over a year ago

And a final doubt, this method works for SHA256($5$), SHA512($6$)... etc?

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