52 lines
2.2 KiB
Plaintext
52 lines
2.2 KiB
Plaintext
Glance configuration option can lead to privilege escalation
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---
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### Summary ###
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Glance exposes a configuration option called `use_user_token` in the
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configuration file `glance-api.conf`. It should be noted that the
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default setting (`True`) is secure. If, however, the setting is
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changed to `False` and valid admin credentials are supplied in the
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following section (`admin_user` and `admin_password`), Glance API
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commands will be executed with admin privileges regardless of the
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intended privilege level of the calling user.
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### Affected Services / Software ###
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Glance, Juno, Kilo, Liberty
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### Discussion ###
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The `use_user_token` configuration option was created to enable
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automatic re-authentication for tokens whch are close to expiration,
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thus preventing the tokens from expiring in the middle of
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longer-lasting Glance commands. Unfortunately the implementation
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enables privilege escalation attacks by automatically executing API
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commands as an administrator level user.
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By default `use_user_token` is set to `True` which is secure. If the
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option is disabled (set to `False`) and valid admin credentials are
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specified in the `glance-api.conf` file, API commands will be executed
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as the supplied admin user regardless of the intended privileges of the
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calling user. Glance API v2 configurations which don't enable the
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registry service (`data_api = glance.db.registry.api`) aren't affected.
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Enabling unauthenticated and lower privileged users to execute Glance
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commands with administrator privileges is very dangerous and may
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expose risks including:
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- tampering with images
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- deleting images
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- denial of service attacks
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### Recommended Actions ###
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A comprehensive fix will be included in the Mitaka release. Meanwhile
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it is recommended that all users ensure that `use_user_token` is left
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at the default setting (`True`) or commented out.
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### Contacts / References ###
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Author: Travis McPeak, HPE
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This OSSN : https://wiki.openstack.org/wiki/OSSN/OSSN-0060
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Original LaunchPad Bug : https://bugs.launchpad.net/glance/+bug/1493448
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OpenStack Security Documentation : https://security.openstack.org
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OpenStack Security Project : https://wiki.openstack.org/wiki/Security
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Bug Introduction : https://review.openstack.org/#/c/29967/
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