Authentication

Authentication

General recommendations:

  • Do not use simple login and password credentials, as Identity does not enforce policies on password strength, expiration, or failed authentication attempts as recommended by NIST Special Publication 800-118.

  • Use Identity extensions or external authentication. To integrate Identity authentication with an existing directory service, use LDAP. You can map LDAP users into roles and groups within Identity in /etc/keystone/keystone.conf for use by the various OpenStack services.

External authentication

Use an SQL identity backend together with X.509 authentication or Kerberos for Keystone under Apache instead of using the username and password pair. Attributes coming with X.509 certificate could be matched against OpenStack identity data structures such as projects, domains, and groups.

Multi-factor authentication

Multi-factor authentication reduces the risk of passwords being compromised. We recommend using at least two-factor authentication (TFA) for privileged accounts such as admin to comply with NIST 800-53 IA-2(1) guidance.

Implement multi-factor authentication by leveraging the external authentication mechanism . Similar to the Federation scenario Keystone process is executed on Apache HTTPD. Once authenticated with multi-factor authentication mechanisms, Apache web server will pass down an authenticated user to Keystone using the REMOTE_USER environment variable.

Also we recommend that you enable TLS for client authentication to provide an additional factor of authentication. This requires certificates to be issued for OpenStack services, which can be self-signed and issued by internal authority. However, in this case you need to disable the validity check or mark a certificate as trusted.

Tokens

By default a token expiries in one hour. The recommended expiry value should be set to a lower value that allows enough time for internal services to complete tasks.

Fernet tokens are the most preferable to use. Fernet provides a secure messaging protocol specially designed for REST API communication being non-persistent and lightweight to reduce operational overhead. It uses AES-CBC to encrypt data and SHA HMAC to sign.

Domains

The Identity V3 API introduces a multi-tenancy model via using multiple domains where users can be represented with different authentication back ends and even have different attributes. Users of different domains can be mapped to a single set of roles and privileges, that are used in the policy definitions to access the various service resources.

You can enable domain-specific authentication drivers for multiple domains in the [identity] section of the keystone.conf file.

A domain owner can create additional users, groups, and roles to be used within the domain.

Groups

A group is a container representing a collection of users. Rather than assign a role directly to a user/project, a domain owner can assign a role to a group, and then add users to that group.

Note

  • Generally, groups and domains are optional. However, when using Federation (e.g. SAML), roles or policies are mapped to groups.

  • The domain name and role name is globally unique across all domains.

  • The username, project, and group name are only unique to the owning domain.

Brute-force prevention

The Identity service is susceptible to a brute-force attack. By default, the OpenStack Identity service does not provide the way to block accounts after repeated unsuccessful login attempts, which may lead to an OpenStack cluster compromise.

To counteract the brute-force attack:

  • Specify the necessary strength of a user’s password.

  • Detect the attack by reviewing of access control logs to discover unsuccessful attempts to access accounts.

    Note

    Currently, Keystone does not log information whether a particular login attempt was successful or not. There is no way to detect a brute-force attack with standard OpenStack services. To detect and count login failures, install WAF and check for the 401 Unauthorized HTTP response from the OpenStack Identity service.

  • Prevent the attack by blocking a user’s IP after the specified number of unsuccessful login attempts by means of WAF. Find the use case below describing how to prevent the brute-force attack that attacker runs through the OpenStack Dashboard service on the Mirantis OpenStack controller.

    Note

    This approach does not work for authentication via the Keystone public API endpoint, because, as a side effect, WAF may block IP of proxy nodes in the HA cluster when a user reaches the limit of login failures made via the OpenStack Dashboard.Also, the brute-force prevention based on IP blocking is powerless when an attacker sends every new authentication request through a new proxy bot leveraging a botnet resources.

  • Use multi-factor authentication for privileged user accounts.