Checklist¶
Check-Block-01: Is user/group ownership of config files set to root/cinder?¶
Configuration files contain critical parameters and information required for smooth functioning of the component. If an unprivileged user, either intentionally or accidentally, modifies or deletes any of the parameters or the file itself then it would cause severe availability issues resulting in a denial of service to the other end users. Thus user ownership of such critical configuration files must be set to root and group ownership must be set to cinder. Additionally, the containing directory should have the same ownership to ensure that new files are owned correctly.
Run the following commands:
$ stat -L -c "%U %G" /etc/cinder/cinder.conf | egrep "root cinder"
$ stat -L -c "%U %G" /etc/cinder/api-paste.ini | egrep "root cinder"
$ stat -L -c "%U %G" /etc/cinder/policy.json | egrep "root cinder"
$ stat -L -c "%U %G" /etc/cinder/rootwrap.conf | egrep "root cinder"
$ stat -L -c "%U %G" /etc/cinder | egrep "root cinder"
Pass: If user and group ownership of all these config files is set to root and cinder respectively. The above commands show output of root cinder.
Fail: If the above commands does not return any output as the user and group ownership might have set to any user other than root or any group other than cinder.
Check-Block-02: Are strict permissions set for configuration files?¶
Similar to the previous check, we recommend setting strict access permissions for such configuration files.
Run the following commands:
$ stat -L -c "%a" /etc/cinder/cinder.conf
$ stat -L -c "%a" /etc/cinder/api-paste.ini
$ stat -L -c "%a" /etc/cinder/policy.json
$ stat -L -c "%a" /etc/cinder/rootwrap.conf
$ stat -L -c "%a" /etc/cinder
A broader restriction is also possible: if the containing directory is set to 750, the guarantee is made that newly created files inside this directory would have the desired permissions.
Pass: If permissions are set to 640 or stricter, or the containing directory is set to 750. The permissions of 640/750 translates into owner r/w, group r, and no rights to others i.e. “u=rw,g=r,o=”. Note that with Check-Block-01: Is user/group ownership of config files set to root/cinder? and permissions set to 640, root has read/write access and cinder has read access to these configuration files. The access rights can also be validated using the following command. This command will only be available on your system if it supports ACLs.
$ getfacl --tabular -a /etc/cinder/cinder.conf
getfacl: Removing leading '/' from absolute path names
# file: etc/cinder/cinder.conf
USER root rw-
GROUP cinder r--
mask r--
other ---
Fail: If permissions are not set to at least 640.
Check-Block-03: Is keystone used for authentication?¶
Note
This item only applies to OpenStack releases Rocky and before as
auth_strategy was deprecated in Stein.
OpenStack supports various authentication strategies like noauth, keystone etc. If the ‘noauth’ strategy is used then the users could interact with OpenStack services without any authentication. This could be a potential risk since an attacker might gain unauthorized access to the OpenStack components. Thus we strongly recommend that all services must be authenticated with keystone using their service accounts.
Pass: If value of parameter auth_strategy under [DEFAULT] section
in /etc/cinder/cinder.conf is set to keystone.
Fail: If value of parameter auth_strategy under [DEFAULT] section
is set to noauth.
Check-Block-04: Is TLS enabled for authentication?¶
OpenStack components communicate with each other using various protocols and the communication might involve sensitive / confidential data. An attacker may try to eavesdrop on the channel in order to get access to sensitive information. Thus all the components must communicate with each other using a secured communication protocol.
Pass: If value of parameter www_authenticate_uri under
[keystone_authtoken] section in /etc/cinder/cinder.conf is set to
Identity API endpoint starting with https:// and value of parameter
insecure under the same [keystone_authtoken] section in the same
/etc/cinder/cinder.conf is set to False.
Fail: If value of parameter www_authenticate_uri under
[keystone_authtoken] section in /etc/cinder/cinder.conf is not set to
Identity API endpoint starting with https:// or value of parameter
insecure under the same [keystone_authtoken] section in the same
/etc/cinder/cinder.conf is set to True.
Check-Block-05: Does cinder communicate with nova over TLS?¶
OpenStack components communicate with each other using various protocols and the communication might involve sensitive / confidential data. An attacker may try to eavesdrop on the channel in order to get access to sensitive information. Thus all the components must communicate with each other using a secured communication protocol.
Pass: If value of parameter nova_api_insecure under [DEFAULT]
section in /etc/cinder/cinder.conf is set to False.
Fail: If value of parameter nova_api_insecure under [DEFAULT]
section in /etc/cinder/cinder.conf is set to True.
Check-Block-06: Does cinder communicate with glance over TLS?¶
Similar to previous check (Check-Block-05: Does cinder communicate with nova over TLS?), we recommend that all components communicate with each other using a secured communication protocol.
Pass: If value of parameter glance_api_insecure under [DEFAULT]
section in /etc/cinder/cinder.conf is set to False and value of
parameter glance_api_servers is set to a value starting with https://.
Fail: If value of parameter glance_api_insecure under [DEFAULT]
section in /etc/cinder/cinder.conf is set to True or the value of
parameter glance_api_servers is set to a value that does not start with
https://.
Check-Block-07: Is NAS operating in a secure environment?¶
Cinder supports an NFS driver which works differently than a traditional block storage driver. The NFS driver does not actually allow an instance to access a storage device at the block level. Instead, files are created on an NFS share and mapped to instances, which emulates a block device. Cinder supports secure configuration for such files by controlling the file permissions when cinder volumes are created. Cinder configuration can also control whether file operations are run as the root user or the current OpenStack process user.
Pass: If value of parameter nas_secure_file_permissions under
[DEFAULT] section in /etc/cinder/cinder.conf is set to auto.
When set to auto, a check is done during cinder startup to determine if
there are existing cinder volumes, no volumes will set the option to True,
and use secure file permissions. The detection of existing volumes will set the
option to False, and use the current insecure method of handling file
permissions. If value of parameter nas_secure_file_operations under
[DEFAULT] section in /etc/cinder/cinder.conf is set to auto.
When set to “auto”, a check is done during cinder startup to determine if there
are existing cinder volumes, no volumes will set the option to True, be
secure and do NOT run as the root user. The detection of existing volumes
will set the option to False, and use the current method of running
operations as the root user. For new installations, a “marker file” is
written so that subsequent restarts of cinder will know what the original
determination had been.
Fail: If value of parameter nas_secure_file_permissions under
[DEFAULT] section in /etc/cinder/cinder.conf is set to False
and if value of parameter nas_secure_file_operations under
[DEFAULT] section in /etc/cinder/cinder.conf is set to False.
Check-Block-08: Is max size for the body of a request set to default (114688)?¶
If the maximum body size per request is not defined, the attacker can craft an arbitrary osapi request of large size causing the service to crash and finally resulting in Denial Of Service attack. Assigning the maximum value ensures that any malicious oversized request gets blocked ensuring continued availability of the service.
Pass: If value of parameter osapi_max_request_body_size under
[DEFAULT] section in /etc/cinder/cinder.conf is set to 114688
or if value of parameter max_request_body_size under [oslo_middleware]
section in /etc/cinder/cinder.conf is set to 114688.
Fail: If value of parameter osapi_max_request_body_size under
[DEFAULT] section in /etc/cinder/cinder.conf is not set to
114688 or if value of parameter max_request_body_size under
[oslo_middleware] section in /etc/cinder/cinder.conf is not set to
114688.
Check-Block-09: Is the volume encryption feature enabled?¶
Unencrypted volume data makes volume-hosting platforms especially high-value targets for attackers, as it allows the attacker to read the data for many different VMs. In addition, the physical storage medium could be stolen, remounted, and accessed from a different machine. Encrypting volume data mitigates these risks and provides defense-in-depth to volume-hosting platforms. Block Storage (cinder) is able to encrypt volume data before it is written to disk, and we recommend that the volume encryption feature is enabled. See the Volume Encryption section of the Openstack Cinder Service Configuration documentation for instructions.
Pass: If 1) the value of parameter backend under the [key_manager]
section in /etc/cinder/cinder.conf is set, 2) the value of parameter
backend under [key_manager] in /etc/nova/nova.conf is set,
and 3) if the instructions in the documentation referenced above are properly
followed.
To verify further, perform these steps after completing the volume encryption setup and creating the volume-type for LUKS as described in the documentation referenced above.
Create a VM:
$ openstack server create --image cirros-0.3.1-x86_64-disk --flavor m1.tiny TESTVM
Create an encrypted volume and attach it to your VM:
$ openstack volume create --size 1 --type LUKS 'encrypted volume' $ openstack volume list $ openstack server add volume --device /dev/vdb TESTVM 'encrypted volume'
On the VM, send some text to the newly attached volume and synchronize it:
# echo "Hello, world (encrypted /dev/vdb)" >> /dev/vdb # sync && sleep 2
On the system hosting cinder volume services, synchronize to flush the I/O cache then test to see if your string can be found:
# sync && sleep 2 # strings /dev/stack-volumes/volume-* | grep "Hello"
The search should not return the string written to the encrypted volume.
Fail: If value of parameter backend under [key_manager] section
in /etc/cinder/cinder.conf is not set, or if the value of parameter
backend under [key_manager] section in /etc/nova/nova.conf
is not set, or if the instructions in the documentation referenced above are
not properly followed.
