21e9b81f10
Removing extra space after fullstop in both security notes and security guide. Change-Id: I23edcd68b015aa454845a3b9db56106a69bb717a
68 lines
3.1 KiB
Plaintext
68 lines
3.1 KiB
Plaintext
Keystone token disclosure may result in malicious trust creation
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---
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### Summary ###
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Keystone tokens are the foundation of authentication and authorization
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in OpenStack. When a service node is compromised, it is possible that
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an attacker would have access to all tokens passing through that node.
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With a valid token an attacker will be able to issue new tokens that
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may be used to create trusts between the originating user and a new
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user.
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### Affected Services / Software ###
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Keystone, Grizzly, Havana, Icehouse, Juno, Kilo
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### Discussion ###
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If a service node is compromised, an attacker now has access to every
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token that passes through that node. By default, a Keystone token can
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be exchanged for another token, and there is no restriction on scoping
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of the new token. With the trust API, these tokens can be used to
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delegate roles between the original user and a new user.
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Trusts allow a user to set up a long term delegation that permits
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another user to perform operations on their behalf. While tokens
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created through trusts are limited in what they can do, the
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limitations are only on things like changing passwords or creating
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new tokens. This would grant an attacker access to all the operations
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available to the originating user in their projects, and the roles that
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are delegated through the trust.
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There are other ways that a compromised token can be misused beyond the
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methods described here. This note addresses one possible path for
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vulnerabilities based on the unintended access that could be gained
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from trusts created through intercepted tokens.
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This behavior is intrinsic to the bearer token model used within
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Keystone / OpenStack.
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### Recommended Actions ###
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The following steps are recommended to reduce exposure, based on the
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granularity and accepted level of risk in a given environment:
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1. Monitor and audit trust creation events within your environment.
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Keystone emits notifications on trust creation and deletion that are
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accessible through system logs or, if configured, the CADF
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data/security/trust resource extension.
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2. Offer roles that cannot create trusts / delegate permissions /
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assign new roles via Keystone to users. This limits the vector of
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attack to compromising Keystone directly or man-in-the-middle capture
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of a separate token that has the authorization to create
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trusts/delegate/assign roles.
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3. Retain the default token lifespan of 1 hour. Many workloads require
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a single token for the whole workload, and take more than one hour, so
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installations have increased token lifespans back to the old value of
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24 hours - increasing their exposure to this issue.
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### Contacts / References ###
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Author: Michael McCune, Red Hat
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This OSSN : https://wiki.openstack.org/wiki/OSSN/OSSN-0053
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Original LaunchPad Bug : https://bugs.launchpad.net/keystone/+bug/1455582
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OpenStack Security ML : openstack-security@lists.openstack.org
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OpenStack Security Group : https://launchpad.net/~openstack-ossg
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Hierarchical Roles : https://review.openstack.org/#/c/125704
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Policy by URL : https://review.openstack.org/#/c/192422
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Unified policy file : https://review.openstack.org/#/c/134656
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Endpoint_ID from URL : https://review.openstack.org/#/c/199844
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