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sha512_crypt is insufficient for password hashing


Use of sha512_crypt for password hashing in versions of Keystone prior to Pike, is insufficient and provides limited protection against brute-forcing of password hashes.

Affected Services / Software

OpenStack Identity Service (Keystone). OpenStack Releases Ocata, Newton.


Keystone uses sha512_crypt for password hashing. This provides insufficient and limited protection, since sha512_crypt algorithm has a low computational cost factor, therefore making it easier to crack passwords offline in a short period of time.

The correct mechanism is to use the more secure hashing algorithms with a higher computational cost factor such as bcrypt, scrypt, or pbkdf2_sha512 instead of sha512_crypt.

Recommended Actions

It is recommended that operators upgrade to the Pike release where all future passwords would be bcrypt hashed.

Operators should also force password changes on all users [1], which will result in the users newly generated passwords being bcrypt hashed.

Contacts / References

Author: Luke Hinds, Red Hat

[1]: https://docs.openstack.org/keystone/latest/admin/identity-security-compliance.html#force-users-to-change-password-upon-first-use

[2] http://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-63b.pdf

This OSSN : https://wiki.openstack.org/wiki/OSSN/OSSN-0081

Original LaunchPad Bug : https://bugs.launchpad.net/ossn/+bug/1668503

Mailing List : [Security] tag on openstack-dev@lists.openstack.org

OpenStack Security Project : https://launchpad.net/~openstack-ossg