### Summary ###
When a tenant is disabled in Keystone, tokens that have been issued to
that tenant are not invalidated. This can result in users having access
to your cloud after you have attempted to revoke them.

### Affected Services / Software ###
Keystone

### Discussion ###
It appears that Keystone does not purge the tokens given out to tenants
when a tenant is disabled. In some scenarios this could be very
important to cloud providers. Take the case where a cloud provider must
a tenant's access because of some legal investigation. Even though the
tenant is disabled it would be possible for them to terminate VMs /
delete Swift files etc. - There are many other abuse-cases...

### Recommended Actions ###
How the tokens are stored depends on your cloud deployment. If you
deploy using Memcache to back Keystone then flushing the cash when
disabling a token would resolve this issue for you, at the cost of other
token lookups which are no longer in the cash requiring Keystone
interaction.

It is of course possible to script something to remove tokens from any
backend DB or cache but there is no 'official' way to do this.

### Contacts / References ###
Proposed Fix : https://review.openstack.org/#/c/39878/
This OSSN : https://bugs.launchpad.net/ossn/+bug/1179955
OpenStack Security ML : openstack-security at lists.openstack.org
OpenStack Security Group : https://launchpad.net/~openstack-ossg

References:
http://lists.openstack.org/pipermail/openstack-security/2013-August/000263.html