OpenID Connect

The Security plugin can integrate with identify providers that use the OpenID Connect standard. This feature enables the following:

• Automatic configuration

  Point the Security plugin to the metadata of your identity provider (IdP), and the Security plugin uses that data for configuration.

• Automatic key fetching

  The Security plugin automatically retrieves the public key for validating the JSON Web Tokens (JWTs) from the JSON Web Key Set (JWKS) endpoint of your IdP. You don’t have to configure keys or shared secrets in config.yml.

• Key rollover

  You can change the keys used for signing the JWTs directly in your IdP. If the Security plugin detects an unknown key, it tries to retrieve it from the IdP. This rollover is transparent to the user.

• OpenSearch Dashboards as single sign-on or as one option among multiple authentication types in the Dashboards sign-in window.

Configure OpenID Connect integration

To integrate with an OpenID IdP, set up an authentication domain and choose openid as the HTTP authentication type. JWTs already contain all of the information required to verify the request, so set challenge to false and authentication_backend to noop.

This is the minimal configuration:

_meta:
  type: "config"
  config_version: 2

config:
  dynamic:
    authc:
      openid_auth_domain:
        http_enabled: true
        transport_enabled: true
        order: 0
        http_authenticator:
          type: openid
          challenge: false
          config:
            subject_key: preferred_username
            roles_key: roles
            openid_connect_url: https://keycloak.example.com:8080/auth/realms/master/.well-known/openid-configuration
        authentication_backend:
          type: noop

The following table shows the configuration parameters.

OpenID Connect URL

OpenID Connect specifies various endpoints for integration purposes. The most important endpoint is well-known, which lists endpoints and other configuration options for the Security plugin.

The URL differs between IdPs, but usually ends in /.well-known/openid-configuration.

Keycloak example:

http(s)://<server>:<port>/auth/realms/<realm>/.well-known/openid-configuration

The main information that the Security plugin needs is jwks_uri. This URI specifies where the IdP’s public keys in JWKS format can be found. For example:

jwks_uri: "https://keycloak.example.com:8080/auth/realms/master/protocol/openid-connect/certs"

{
   keys:[
      {
         kid:"V-diposfUJIk5jDBFi_QRouiVinG5PowskcSWy5EuCo",
         kty:"RSA",
         alg:"RS256",
         use:"sig",
         n:"rI8aUrAcI_auAdF10KUopDOmEFa4qlUUaNoTER90XXWADtKne6VsYoD3ZnHGFXvPkRAQLM5d65ScBzWungcbLwZGWtWf5T2NzQj0wDyquMRwwIAsFDFtAZWkXRfXeXrFY0irYUS9rIJDafyMRvBbSz1FwWG7RTQkILkwiC4B8W1KdS5d9EZ8JPhrXvPMvW509g0GhLlkBSbPBeRSUlAS2Kk6nY5i3m6fi1H9CP3Y_X-TzOjOTsxQA_1pdP5uubXPUh5YfJihXcgewO9XXiqGDuQn6wZ3hrF6HTlhNWGcSyQPKh1gEcmXWQlRENZMvYET-BuJEE7eKyM5vRhjNoYR3w",
         e:"AQAB"
      }
   ]
}

For more information about IdP endpoints, see the following:

• Okta
• Keycloak
• Auth0
• Connect2ID
• Salesforce
• IBM OpenID Connect

Time disparity compensation for JWT validation

Occasionally you may find that the clock times between the authentication server and the OpenSearch node are not perfectly synchronized. When this is the case, even by a few seconds, the system that either issues or receives a JWT may try to validate nbf (not before) and exp (expiration) claims and fail to authenticate the user due to the time disparity.

By default, Security allows for a window of 30 seconds to compensate for possible misalignment between server clock times. To set a custom value for this feature and override the default, you can add the jwt_clock_skew_tolerance_seconds setting to the config.yml:

http_authenticator:
  type: openid
  challenge: false
  config:
    subject_key: preferred_username
    roles_key: roles
    openid_connect_url: https://keycloak.example.com:8080/auth/realms/master/.well-known/openid-configuration
    jwt_clock_skew_tolerance_seconds: 20

Fetching public keys

When an IdP generates and signs a JWT, it must add the ID of the key to the JWT header. For example:

{
  "alg": "RS256",
  "typ": "JWT",
  "kid": "V-diposfUJIk5jDBFi_QRouiVinG5PowskcSWy5EuCo"
}

As per the OpenID Connect specification, the kid (key ID) is mandatory. Token verification does not work if an IdP fails to add the kid field to the JWT.

If the Security plugin receives a JWT with an unknown kid, it visits the IdP’s jwks_uri and retrieves all available, valid keys. These keys are used and cached until a refresh is triggered by retrieving another unknown key ID.

Key rollover and multiple public keys

The Security plugin can maintain multiple valid public keys at once. The OpenID specification does not allow for a validity period of public keys, so a key is valid until it has been removed from the list of valid keys in your IdP and the list of valid keys has been refreshed.

If you want to roll over a key in your IdP, follow these best practices:

• Create a new key pair in your IdP, and give the new key a higher priority than the currently used key.

  Your IdP uses this new key over the old key.

• Upon first appearance of the new kid in a JWT, the Security plugin refreshes the key list.

  At this point, both the old key and the new key are valid. Tokens signed with the old key are also still valid.

• The old key can be removed from your IdP when the last JWT signed with this key has timed out.

If you have to immediately change your public key, you can also delete the old key first and then create a new one. In this case, all JWTs signed with the old key become invalid immediately.

TLS settings

To prevent man-in-the-middle attacks, you should secure the connection between the Security plugin and your IdP with TLS.

Enabling TLS

Use the following parameters to enable TLS for connecting to your IdP:

config:
  openid_connect_idp:
    enable_ssl: <true|false>
    verify_hostnames: <true|false>

Certificate validation

To validate the TLS certificate of your IdP, configure either the path to the IdP’s root CA or the root certificate’s content:

config:
  openid_connect_idp:
    enable_ssl: true
    pemtrustedcas_filepath: /full/path/to/trusted_cas.pem

config:
  openid_connect_idp:
    enable_ssl: true
    pemtrustedcas_content: |-
      -----BEGIN CERTIFICATE-----
      MIID/jCCAuagAwIBAgIBATANBgkqhkiG9w0BAQUFADCBjzETMBEGCgmSJomT8ixk
      ARkWA2NvbTEXMBUGCgmSJomT8ixkARkWB2V4YW1wbGUxGTAXBgNVBAoMEEV4YW1w
      bGUgQ29tIEluYy4xITAfBgNVBAsMGEV4YW1wbGUgQ29tIEluYy4gUm9vdCBDQTEh
      ...
      -----END CERTIFICATE-----

TLS client authentication

To use TLS client authentication, configure the PEM certificate and private key the Security plugin should send for TLS client authentication (or its content):

config:
  openid_connect_idp:
    enable_ssl: true
    pemkey_filepath: /full/path/to/private.key.pem
    pemkey_password: private_key_password
    pemcert_filepath: /full/path/to/certificate.pem

config:
  openid_connect_idp:
    enable_ssl: true
    pemkey_content: |-
      -----BEGIN PRIVATE KEY-----
      MIID2jCCAsKgAwIBAgIBBTANBgkqhkiG9w0BAQUFADCBlTETMBEGCgmSJomT8ixk
      ARkWA2NvbTEXMBUGCgmSJomT8ixkARkWB2V4YW1wbGUxGTAXBgNVBAoMEEV4YW1w
      bGUgQ29tIEluYy4xJDAiBgNVBAsMG0V4YW1wbGUgQ29tIEluYy4gU2lnbmluZyBD
      ...
      -----END PRIVATE KEY-----
    pemkey_password: private_key_password
    pemcert_content: |-
      -----BEGIN CERTIFICATE-----
      MIIEvQIBADANBgkqhkiG9w0BAQEFAASCBKcwggSjAgEAAoIBAQCHRZwzwGlP2FvL
      oEzNeDu2XnOF+ram7rWPT6fxI+JJr3SDz1mSzixTeHq82P5A7RLdMULfQFMfQPfr
      WXgB4qfisuDSt+CPocZRfUqqhGlMG2l8LgJMr58tn0AHvauvNTeiGlyXy0ShxHbD
      ...
      -----END CERTIFICATE-----

Enabled ciphers and protocols

You can limit the allowed ciphers and TLS protocols by using the following keys.

(Advanced) DoS protection

To help protect against denial-of-service (DoS) attacks, the Security plugin only allows a maximum number of new key IDs in a certain span of time. If the number of new key IDs exceeds this threshold, the Security plugin returns HTTP status code 503 (Service Unavailable) and refuses to query the IdP. By default, the Security plugin does not allow for more than 10 unknown key IDs within 10 seconds. The following table shows how to modify these settings.

OpenSearch Dashboards single sign-on

Activate OpenID Connect by adding the following to opensearch_dashboards.yml:

opensearch_security.auth.type: "openid"

Configuration

OpenID Connect providers usually publish their configuration in JSON format under the metadata url. Therefore, most settings can be pulled in automatically, so the OpenSearch Dashboards configuration becomes minimal. The most important settings are the following:

• Connect URL

• Client ID

  Every IdP can host multiple clients (sometimes called applications) with different settings and authentication protocols. When enabling OpenID Connect, you should create a new client for OpenSearch Dashboards in your IdP. The client ID uniquely identifies OpenSearch Dashboards.

• Client secret

  Beyond the ID, each client also has a client secret assigned. The client secret is usually generated when the client is created. Applications can obtain an identity token only when they provide a client secret. You can find this secret in the settings of the client on your IdP.

Configuration settings

Configuration example

# Enable OpenID authentication
opensearch_security.auth.type: "openid"

# The IdP metadata endpoint
opensearch_security.openid.connect_url: "http://keycloak.example.com:8080/auth/realms/master/.well-known/openid-configuration"

# The ID of the OpenID Connect client in your IdP
opensearch_security.openid.client_id: "opensearch-dashboards-sso"

# The client secret of the OpenID Connect client
opensearch_security.openid.client_secret: "a59c51f5-f052-4740-a3b0-e14ba355b520"

# mTLS Options for obtaining endpoints from IdP
opensearch_security.openid.root_ca: /usr/share/opensearch-dashboards/config/certs/ca.pem
opensearch_security.openid.certificate: /usr/share/opensearch-dashboards/config/certs/cert.pem
opensearch_security.openid.private_key: /usr/share/opensearch-dashboards/config/certs/key.pem

# Use HTTPS instead of HTTP
opensearch.url: "https://<hostname>.com:<http port>"

# Configure the OpenSearch Dashboards internal server user
opensearch.username: "kibanaserver"
opensearch.password: "kibanaserver"

# Disable SSL verification when using self-signed demo certificates
opensearch.ssl.verificationMode: none

# allowlist basic headers and multi-tenancy header
opensearch.requestHeadersAllowlist: ["Authorization", "securitytenant"]

To include OpenID Connect with other authentication types in the Dashboards sign-in window, see Configuring sign-in options.

Session management with additional cookies

To improve session management—especially for users who have multiple roles assigned to them—Dashboards provides an option to split cookie payloads into multiple cookies and then recombine the payloads when receiving them. This can help prevent larger OpenID Connect assertions from exceeding size limits for each cookie. The two settings in the following example allow you to set a prefix name for additional cookies and specify the number of them. They are added to the opensearch_dashboards.yml file. The default number of additional cookies is three:

opensearch_security.openid.extra_storage.cookie_prefix: security_authentication_oidc
opensearch_security.openid.extra_storage.additional_cookies: 3

Note that reducing the number of additional cookies can cause some of the cookies that were in use before the change to stop working. We recommend establishing a fixed number of additional cookies and not changing the configuration after that.

If the ID token from the IdP is especially large, OpenSearch may throw a server log authentication error indicating that the HTTP header is too large. In this case, you can increase the value for the http.max_header_size setting in the opensearch.yml file.

OpenSearch security configuration

Because OpenSearch Dashboards requires that the internal OpenSearch Dashboards server user can authenticate through HTTP basic authentication, you must configure two authentication domains. For OpenID Connect, the HTTP basic domain has to be placed first in the chain. Make sure you set the challenge flag to false.

Modify and apply the following example settings in config.yml:

_meta:
  type: "config"
  config_version: 2

config:
  dynamic:
    authc:
      basic_internal_auth_domain:
        http_enabled: true
        transport_enabled: true
        order: 0
        http_authenticator:
          type: basic
          challenge: false
        authentication_backend:
          type: internal
      openid_auth_domain:
        http_enabled: true
        transport_enabled: true
        order: 1
        http_authenticator:
          type: openid
          challenge: false
          config:
            subject_key: preferred_username
            roles_key: roles
            openid_connect_url: https://keycloak.example.com:8080/auth/realms/master/.well-known/openid-configuration
        authentication_backend:
          type: noop

Docker example with Keycloak

The following steps use Docker and Keycloak IdP to set up a basic authentication backend:

1. Download and unzip the example OpenID Connect zip file
2. Update the .env file with a strong password for the admin user.
3. Substitute the {IP} placeholders in config.yml and opensearch_dashboards.yml with the IP of the local machine.
4. Review the following files:
   • docker-compose.yml defines a single OpenSearch node, OpenSearch Dashboards, and Keycloak server.
   • new-realm.json specifies the details of the realm. In this example, the realm is named new.
   • config.yml configures basic_internal_auth_domain and oidc_auth_domain.
   • opensearch_dashboards.yml should point to Keycloak for authentication. Make sure that the opensearch_security.openid.connect_url setting points to the URL of the realm.
5. At the command line, run docker-compose up.
6. Access OpenSearch Dashboards at http://localhost:5601 and log in with username testuser and password testpassword configured in the new-realm.json file.

After logging in, the testuser receives the backend role admin from Keycloak, which is mapped to the all_access OpenSearch role. These backend roles can be managed using the Keycloak Administrative Console at http://localhost:8080, using username admin and password admin.