#34661: Peppering user passwords
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Reporter: Fatih Erikli | Owner: nobody
Type: Uncategorized | Status: new
Component: contrib.auth | Version: 4.2
Severity: Normal | Resolution:
Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Description changed by Fatih Erikli:
Old description:
> Currently a user's password stored in database in this format:
>
> > <algorithm>$<iterations>$<salt>$<hash>
>
> The salt is a random generated string per user. Hash (Last column) is the
> password hashed with the stored in previous column.
>
> Example, these are two computed passwords, stored on database, for the
> same password of two users.
>
> >
> pbkdf2_sha256$600000$fb9cUsHWK4EMZ7VWGBAcGD$2uwiVefFwanIhxLrv+/t3sKvP4X6tDKEMw/ysHD5dIc=
> >
> pbkdf2_sha256$600000$HgWHWrF2qQD9Owj4XeEkjY$rh0qzfo+/ZCzWbL9ZJa8aKhiO5xoEMfT4EtP/+A+LzI=
>
> The password is **123456**.
>
> Imagine I am an attacker, who got the database of different django
> project, I want to look up the users who have the chosen the password
> 123456.
>
> I have the salts of users stored in database.
>
> > make_password('123456', 'fb9cUsHWK4EMZ7VWGBAcGD')
> >
> pbkdf2_sha256$600000$fb9cUsHWK4EMZ7VWGBAcGD$2uwiVefFwanIhxLrv+/t3sKvP4X6tDKEMw/ysHD5dIc=
>
> > make_password('123456', 'HgWHWrF2qQD9Owj4XeEkjY')
> >
> pbkdf2_sha256$600000$HgWHWrF2qQD9Owj4XeEkjY$rh0qzfo+/ZCzWbL9ZJa8aKhiO5xoEMfT4EtP/+A+LzI=
>
> These are correct password combinations. I am able to lookup the users
> who have their passwords exposed in public.
>
> There is one more element needed for hashing the password, **pepper**,
> should be django project specific. Even when a database is exposed, the
> attacker will not be able to lookup the known passwords, since they don't
> have the secret pepper key.
>
> Is this a known issue?
New description:
Currently a user's password stored in database in this format:
> <algorithm>$<iterations>$<salt>$<hash>
The salt is a random generated string per user. Hash (Last column) is the
password hashed with the stored in previous column.
Example, these are two computed passwords, stored on database, for the
same password of two users.
>
pbkdf2_sha256$600000$fb9cUsHWK4EMZ7VWGBAcGD$2uwiVefFwanIhxLrv+/t3sKvP4X6tDKEMw/ysHD5dIc=
>
pbkdf2_sha256$600000$HgWHWrF2qQD9Owj4XeEkjY$rh0qzfo+/ZCzWbL9ZJa8aKhiO5xoEMfT4EtP/+A+LzI=
The password is **123456**.
Imagine I am an attacker, who got the database of different django
project, I want to look up the users who have the chosen the password
123456.
I have the salts of users stored in database.
> make_password('123456', 'fb9cUsHWK4EMZ7VWGBAcGD')
>
pbkdf2_sha256$600000$fb9cUsHWK4EMZ7VWGBAcGD$2uwiVefFwanIhxLrv+/t3sKvP4X6tDKEMw/ysHD5dIc=
> make_password('123456', 'HgWHWrF2qQD9Owj4XeEkjY')
>
pbkdf2_sha256$600000$HgWHWrF2qQD9Owj4XeEkjY$rh0qzfo+/ZCzWbL9ZJa8aKhiO5xoEMfT4EtP/+A+LzI=
These are correct password combinations. I am able to lookup the users who
have their passwords exposed in public.
There is one more element needed for hashing the password, **pepper**,
should be django project specific. Even when a database is exposed, the
attacker will not be able to lookup the known passwords, since they don't
have the secret pepper key.
This causes CWE-760: Use of a One-Way Hash with a Predictable Salt
[https://cwe.mitre.org/data/definitions/760.html].
--
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Ticket URL: <https://code.djangoproject.com/ticket/34661#comment:1>
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