OpenSearch/x-pack/docs/en/security/authentication/saml-guide.asciidoc

[[saml-guide]]

== Configuring SAML Single-Sign-On on the Elastic Stack

The Elastic Stack supports SAML single-sign-on (SSO) into {kib}, using {es} as
a backend service. In SAML terminology, the Elastic Stack is operating as a
_Service Provider_.

The other component that is needed to enable SAML single-sign-on is the
_Identity Provider_, which is a service that handles your credentials and
performs that actual authentication of users.

If you are interested in configuring SSO into {kib}, then you will need to
provide {es} with information about your _Identity Provider_, and you will need
to register the Elastic Stack as a known _Service Provider_ within that
Identity Provider.  There are also a few configuration changes that are
required in {kib} to activate the SAML authentication provider.

NOTE: The SAML support in {kib} is designed on the expectation that it will be
the primary (or sole) authentication method for users of that {kib} instance.
Once you enable SAML authentication in {kib} it will affect all users who try
to login. The <<saml-kibana>> section provides more detail about how this works.

=== The Identity Provider

The Elastic Stack supports the SAML 2.0 _Web Browser SSO_ and the SAML
2.0 _Single Logout_ profiles and can integrate with any Identity Provider (IdP)
that supports at least the SAML 2.0 _Web Browser SSO Profile_.
It has been tested with a number of popular IdP implementations.

This guide assumes that you have an existing IdP and wish to add {kib} as a
Service Provider.

The Elastic Stack uses a standard SAML _metadata_ document, in XML format that
defines the capabilities and features of your IdP. You should be able to
download or generate such a document within your IdP administration interface.

Download the IdP metadata document and store it within the `config` directory on
each {es} node. For the purposes of this guide, we will assume that you are
storing it as `config/saml/idp-metadata.xml`.

The IdP will have been assigned an identifier (_EntityID_ in SAML terminology)
which is most commonly expressed in _Uniform Resource Identifier_ (URI) form.
Your admin interface may tell you what this is, or you might need to
read the metadata document to find it - look for the `entityID` attribute on the
`EntityDescriptor` element.

Most IdPs will provide an appropriate metadata file with all the features that
the Elastic Stack requires, and should only require the  configuration steps
described below. For completeness sake, the minimum requirements that the Elastic
Stack has for the IdP's metadata are:

- An `<EntityDescriptor>` with an `entityID` that matches the {es}
  <<saml-create-realm, configuration>>
- An `<IDPSSODescriptor>` that supports the SAML 2.0 protocol
  (`urn:oasis:names:tc:SAML:2.0:protocol`).
- At least one `<KeyDescriptor>` that is configured for _signing_ (that is, it
  has `use="signing"` or leaves the `use` unspecified)
- A `<SingleSignOnService>` with binding of HTTP-Redirect
  (`urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect`)
- If you wish to support <<saml-logout, Single Logout>>, a `<SingleLogoutService>`
  with binding of HTTP-Redirect
  (`urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect`)

The Elastic Stack requires that all messages from the IdP are signed.
For authentication `<Response>` messages, the signature may be applied to either
the response itself, or to the individual assertions.
For `<LogoutRequest>` messages, the message itself must be signed, and the
signature should be provided as a URL parameter, as required by the HTTP-Redirect
binding.

=== Configure {es} for SAML Authentication

There are five configuration steps to enable SAML authentication in {es}:

. Enable SSL/TLS for HTTP
. Enable the Token Service
. Create one or more SAML realms
. Configure role mappings
. Generate a SAML Metadata file for use by your Identity Provider _(optional)_

==== Enable TLS for HTTP

If your {es} cluster is operating in production mode, then you must
configure the HTTP interface to use SSL/TLS before you can enable SAML
authentication.

For more information, see
{ref}/configuring-tls.html#tls-http[Encrypting HTTP Client Communications].

==== Enable the Token Service

The {es} SAML implementation makes use of the {es} Token Service.  This service
is automatically enabled if you configure TLS on the HTTP interface, and can be
explicitly configured by including the following in your `elasticsearch.yml` file:

[source, yaml]
------------------------------------------------------------
xpack.security.authc.token.enabled: true
------------------------------------------------------------

[[saml-create-realm]]
==== Create a SAML Realm

SAML authentication is enabled by configuring a SAML realm within the
authentication chain for {es}.

This realm has a few mandatory settings, and a number of optional settings.
The available settings are described in detail in the
<<saml-settings, SAML realm documentation>>, this guide will walk you through
the most common settings.

Create a realm by adding the following to your `elasticsearch.yml`
configuration file. Each configuration value is explained below.

[source, yaml]
------------------------------------------------------------
xpack.security.authc.realms.saml1:
  type: saml
  order: 2
  idp.metadata.path: saml/idp-metadata.xml
  idp.entity_id: "https://sso.example.com/"
  sp.entity_id:  "https://kibana.example.com/"
  sp.acs: "https://kibana.example.com/api/security/v1/saml"
  sp.logout: "https://kibana.example.com/logout"
  attributes.principal: "urn:oid:0.9.2342.19200300.100.1.1"
  attributes.groups: "urn:oid:1.3.6.1.4.1.5923.1.5.1."
------------------------------------------------------------

IMPORTANT: SAML is used when authenticating via {kib}, but it is not an
effective means of authenticating directly to the {es} REST API. For this reason
we recommend that you include at least one additional realm such as the
<<native-realm, native realm>> in your authentication chain for use by API
clients.

The configuration values used in the example above are:

xpack.security.authc.realms.saml::
    This defines a new authentication realm named "saml1".
    See <<how-authc-works>> for more explanation of realms.

type:: The `type` must be `saml`
order::
    You should define a unique order on each realm in your authentication chain.
    It is recommended that the SAML realm be at the bottom of your authentication
    chain (that is, that it has the _highest_ order).

idp.metadata.path::
    This is the path to the metadata file that you saved for your Identity Provider.
    The path that you enter here is relative to your `config/` directory.
    {security} will automatically monitor this file for changes and will
    reload the configuration whenever it is updated.

idp.entity_id::
    This is the identifier (SAML EntityID) that your IdP uses.
    It should match the `entityID` attribute within the metadata file.

sp.entity_id::
    This is a unique identifier for your {kib} instance, expressed as a URI.
    You will use this value when you add {kib} as a service provider within your IdP.
    We recommend that you use the base URL for your {kib} instance as the entity ID.

sp.acs::
    The _Assertion Consumer Service_ (ACS) endpoint is the URL within {kib} that accepts
    authentication messages from the IdP.
    This ACS endpoint supports the SAML HTTP-POST binding only.
    It must be a URL that is accessible from the web browser of the user who is
    attempting to login to {kib}, it does not need to be directly accessible by {es}
    or the IdP.
    The correct value may vary depending on how you have installed {kib} and
    whether there are any proxies involved, but it will typically be
    +$\{kibana-url}/api/security/v1/saml+ where _$\{kibana-url}_ is the base URL for
    your {kib} instance.

sp.logout::
    This is the URL within {kib} that accepts logout messages from the IdP.
    Like the `sp.acs` URL, it must be accessible from the web browser, but does
    not need to be directly accessible by {es} or the IdP. The correct value may
    vary depending on how you have installed {kib} and whether there are any
    proxies involved, but it will typically be +$\{kibana-url}/logout+ where
    _$\{kibana-url}_ is the base URL for your {kib} instance.

attribute.principal:: See <<saml-attribute-mapping>>.
attribute.groups:: See <<saml-attribute-mapping>>.

[[saml-attribute-mapping]]
==== Attribute Mapping

When a user connects to {kib} through your Identity Provider, the Identity
Provider will supply a SAML Assertion about the user. The assertion will contain
an _Authentication Statement_ indicating that the user has successfully
authenticated to the IdP and one ore more _Attribute Statements_ that will
include _Attributes_ for the user.

These attributes may include such things as:

- the user's username
- the user's email address
- the user's groups or roles

Attributes in SAML are named using a URI such as
`urn:oid:0.9.2342.19200300.100.1.1` or
`http://schemas.xmlsoap.org/ws/2005/05/identity/claims/upn`, and have one or
more values associated with them.

These attribute identifiers vary between IdPs, and most IdPs offer ways to
customise the URIs and their associated value.

{es} uses these attributes to infer information about the user who has
logged in, and they can be used for role mapping (below).

In order for these attributes to be useful, {es} and the IdP need to have a
common via for the names of the attributes. This is done manually, by
configuring the IdP and the {security} SAML realm to use the same URI name for
each logical user attribute.

The recommended steps for configuring these SAML attributes are as follows:

. Consult your IdP to see what user attributes it can provide.
  This varies greatly between providers, but you should be able to obtain a list
  from the documentation, or from your local admin.

. Read through the list of <<saml-user-properties, user properties>> that {es}
  supports, and decide which of them are useful to you, and can be provided by
  your IdP. At a _minimum_, the `principal` attribute is required.

. Configure your IdP to "release" those attributes to your {kib} SAML service
  provider.  This process varies by provider - some will provide a user interface
  for this, while others may require that you edit configuration files.
  Usually the IdP (or your local administrator) will have suggestions about what
  URI to use for each attribute. You can simply accept those suggestions, as the
  {es} service is entirely configurable and does not require that any specific
  URIs are used.

. Configure the SAML realm in {es} to associate the {es} user properties (see
  <<saml-user-properties, the listing>> below), to the URIs that you configured
  in your IdP. In the example above, we have configured the `principal` and
  `groups` attributes.

===== Special Attribute Names

In general, {es} expects that the configured value for an attribute will be a
URI such as `urn:oid:0.9.2342.19200300.100.1.1`, however there are some
additional names that can be used:

`nameid`::
    This uses the SAML `NamedID` value instead of a SAML attribute. SAML
    `NameID` elements are an optional, but frequently provided, field within a
    SAML Assertion that the IdP may use to identify the Subject of that
    Assertion. In some cases the `NameID` will relate to the user's login
    identifier (username) wihin the IdP, but in many cases they will be
    internally generated identifiers that have no obvious meaning outside
    of the IdP.

`nameid:persistent`::
    This uses the SAML `NameID` value, but only if the NameID format is
    `urn:oasis:names:tc:SAML:2.0:nameid-format:persistent`.
    A SAML `NameID` element has an optional `Format` attribute that indicates
    the semantics of the provided name.  It is common for IdPs to be configured
    with "transient" NameIDs that present a new identifier for each session.
    Since it is rarely useful to use a transient NameID as part of an attribute
    mapping, the "nameid:persistent" attribute name can be used as a safety
    mechanism that will cause an error if you attempt to map from a `NameID`
    that does not have a persistent value.

_friendlyName_::
    A SAML attribute may have a _friendlyName_ in addition to its URI based name.
    For example the attribute with a name of `urn:oid:0.9.2342.19200300.100.1.1`
    might also have a friendlyName of `uid`.
    You may use these friendly names within an attribute mapping, but it is
    recommended that you use the URI based names, as friendlyNames are neither
    standardized or mandatory.

The example below configures a realm to use a persistent nameid for the principal,
and the attribute with the friendlyName "roles" for the user's groups.

[source, yaml]
------------------------------------------------------------
xpack.security.authc.realms.saml1:
  type: saml
  order: 2
  idp.metadata.path: saml/idp-metadata.xml
  idp.entity_id: "https://sso.example.com/"
  sp.entity_id:  "https://kibana.example.com/"
  sp.acs: "https://kibana.example.com/api/security/v1/saml"
  attributes.principal: "nameid:persistent"
  attributes.groups: "roles"
------------------------------------------------------------

[[saml-user-properties]]
===== {es} User Properties

The {es} SAML realm can be configured to map SAML `attributes` to the
following properties on the authenticated user:

principal:: _(Required)_
    This is the _username_ that will be applied to a user that authenticates
    against this realm.
    The `principal` appears in places such as the {es} audit logs.

groups:: _(Recommended)_
    If you wish to use your IdP's concept of groups or roles as the basis for a
    user's {es} privileges, you should map them with this attribute.
    The `groups` are passed directly to your
    <<saml-role-mapping, role mapping rules>>

name:: _(Optional)_ The user's full name.
mail:: _(Optional)_ The user's email address.
dn:: _(Optional)_ The user's X.500 _Distinguished Name_.

===== Extracting partial values from SAML Attributes

There are some occasions where the IdP's attribute may contain more information
than you wish to use within {es}. A common example of this is one where the
IdP works exclusively with email addresses, but you would like the user's
`principal` to use the _local-name_ part of the email address.
For example if their email address was `james.wong@staff.example.com`, then you
would like their principal to simply be `james.wong`.

This can be achieved using the `attribute_patterns` setting in the {es}
realm, as demonstrated in the realm configuration below:

[source, yaml]
------------------------------------------------------------
xpack.security.authc.realms.saml1:
  type: saml
  order: 2
  idp.metadata.path: saml/idp-metadata.xml
  idp.entity_id: "https://sso.example.com/"
  sp.entity_id:  "https://kibana.example.com/"
  sp.acs: "https://kibana.example.com/api/security/v1/saml"
  attributes.principal: "http://schemas.xmlsoap.org/ws/2005/05/identity/claims/emailaddress"
  attribute_patterns.principal: "^([^@]+)@staff\\.example\\.com$"
------------------------------------------------------------

In this case, the user's `principal` is mapped from an email attribute, but a
regular expression is applied to the value before it is assigned to the user.
If the regular expression matches, then the result of the first group is used as
effective value. If the regular expression does not match then the attribute
mapping fails.

In this example, the email address must belong to the `staff.example.com` domain,
and then the local-part (anything before the `@`) is used as the principal.
Any users who try to login using a different email domain will fail because the
regular expression will not match against their email address, and thus their
principal attribute - which is mandatory - will not be populated.

IMPORTANT: Small mistakes in these regular expressions can have significant
security consequences. For example, if we accidentally left off the trailing
`$` from the example above, then we would match any email address where the
domain starts with `staff.example.com`, and this would accept an email
address such as `admin@staff.example.com.attacker.net`. It is important that
you make sure your regular expressions are as precise as possible so that
you do not inadvertently open an avenue for user impersonation attacks.

[[saml-logout]]
==== SAML Logout

The SAML protocol supports the concept of Single Logout (SLO).
The level of support for SLO varies between Identity Providers.
You should consult the documentation for your IdP to determine what Logout
services it offers.

By default the Elastic Stack will support SAML SLO if the following are true:

- Your IdP metadata specifies that the IdP offers a SLO service
- You configure `sp.logout`
- The setting `idp.use_single_logout` is not `false`

===== IdP SLO Service

One of the values that {es} reads from the IdP's SAML metadata is the
`<SingleLogoutService>`. In order for Single Logout to work with the Elastic
stack, {es} requires that this exist and support a binding of
`urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect`.

The Elastic Stack will send both `<LogoutRequest>` and `<LogoutResponse>`
messages to this service as appropriate.

===== The sp.logout setting

The {es} realm setting `sp.logout` specifies a URL in {kib} to which the IdP can
send both `<LogoutRequest>` and `<LogoutResponse>` messages. This service uses
the SAML HTTP-Redirect binding.

{es} will process `<LogoutRequest>` messages, and perform a global signout that
invalidates any existing {es} security tokens that are associated with the
provided SAML session.

If you do not configure a value for `sp.logout`, {es} will refuse all
`<LogoutRequest>` messages.

NOTE: It is common for IdPs to require that `LogoutRequest` messages be signed,
so you may need to configure <<saml-enc-sign,signing credentials>>.

===== The idp.use_single_logout setting

If your IdP provides a `<SingleLogoutService>` but you do not wish to use it,
you can configure `idp.use_single_logout: false` in your SAML realm, and {es}
will ignore the SLO service that your IdP provides. In this case, when a user
logs out of {kib} it will invalidate their {es} session (security token), but
will not perform any logout at the IdP.

===== Using {kib} without Single Logout

If your IdP does not support Single Logout, or you choose not to use it, then
{kib} will perform a "local logout" only.

This means that {kib} will invalidate the session token it is using to
communicate with {es}, but will not be able to perform any sort of invalidation
of the Identity Provider session. In most cases this will mean that {kib} users
are still considered to be logged in to the IdP. Consequently, if the user
navigates to the {kib} landing page, they will be automatically reauthenticated,
and will commence a new {kib} session without needing to enter any credentials.

The possible solutions to this problem are:

- Ask your IdP administrator or vendor to provide a Single Logout service
- If your Idp does provide a Single Logout Service, make sure it is included in
  the IdP metadata file, and do _not_ set `idp.use_single_logout` to `false`.
- Advise your users to close their browser after logging out of {kib}
- Enable the `force_authn` setting on your SAML realm. This setting causes the
  Elastic Stack to request fresh authentication from the IdP every time a user
  attempts to log into {kib}.
  This setting defaults to `false` because it can be a more cumbersome user
  experience, but it can also be an effective protection to stop users
  piggy-backing on existing IdP sessions.


[[saml-enc-sign]]
==== Encryption and Signing

The Elastic Stack supports generating signed SAML messages (for authentication
and/or logout), verifying signed SAML messages from the IdP (for both
authentication and logout) and can process encrypted content.

You can configure {es} for signing, encryption or both, with the same
or separate keys used for each of those.

The Elastic Stack uses X.509 certificates with RSA private keys for SAML
cryptography. These keys can be generated using any standard SSL tool, including
the `certutil` tool that ships with X-Pack.

Your IdP may require that the Elastic Stack have a cryptographic key for signing
SAML messages, and that you provide the corresponding signing certificate within
the Service Provider configuration (either within the Elastic Stack SAML
metadata file or manually configured within the IdP administration interface).
While most IdPs do not expected authentication requests to be signed, it is
commonly the case that signatures are required for logout requests. Your IdP
will validate these signatures against the signing certificate that has been
configured for the Elastic Stack Service Provider.

Encryption certificates are rarely needed, but the Elastic Stack supports them
for cases where IdPs or local policies mandate their use.

===== Generating certificates and keys.

{es} supports certificates and keys in either PEM, PKCS#12 or JKS format.
Some Identity Providers are more restrictive in the formats they support, and
will require you to provide the certificates as a file in a particular format.
You should consult the documentation for your IdP to determine what formats they
support. Since PEM format is the most commonly supported format, the examples
below will generate certificates in that format.

Using the {ref}/certutil.html[`certutil`] tool, you can generate a signing
certificate with the following command:

[source, sh]
--------------------------------------------------
bin/x-pack/certutil cert -pem -days 1100 -name saml-sign -out saml-sign.zip
--------------------------------------------------

This will

- generate a certificate and key pair (the `cert` subcommand)
- create the files in PEM format (`-pem` option)
- generate a certificate that is valid for 3 years (`-days 1100`)
- name the certificate `saml-sign` (`-name` option)
- save the certificate and key in the `saml-sign.zip` file (`-out` option)

The generated zip archive will contain 3 files:

- `saml-sign.crt`, the public certificate to be used for signing
- `saml-sign.key`, the private key for the certificate
- `ca.crt`, a CA certificate that is not need, and can be ignored.

Encryption certificates can be generated with the same process.

===== Configuring {es} for Signing

By default, {security} will sign _all_ outgoing SAML messages if a signing
key has been configured.

If you wish to use *PEM formatted* keys and certificates for signing, then
you should configure the following settings on the SAML realm:

`signing.certificate`::
The path to the PEM formatted certificate file. e.g. `saml/saml-sign.crt`

`signing.key`::
The path to the PEM formatted key file. e.g. `saml/saml-sign.key`

`signing.secure_key_passphrase`::
The passphrase for the key, if the file is encypted. This is a
{ref}/secure-settings.html[secure setting] that must be set with the
`elasticsearch-keystore` tool.

If you wish to use *PKCS#12 formatted* files or a *Java Keystore* for
signing, then you should configure the following settings on the SAML realm:

`signing.keystore.path`::
The path to the PKCS#12 or JKS keystore. e.g. `saml/saml-sign.p12`

`signing.keystore.alias`::
The alias of the key within the keystore. e.g. `signing-key`

`signing.keystore.secure_password`::
The passphrase for the keystore, if the file is encypted. This is a
{ref}/secure-settings.html[secure setting] that must be set with the
`elasticsearch-keystore` tool.

If you wish to sign some, but not all outgoing *SAML messages*, then you
should configure the following setting on the SAML realm:

`signing.saml_messages`::
A list of message types to sign. A message type is identified by the
_local name_ of the XML element used for the message. Supported values
are: `AuthnRequest`, `LogoutRequest` and `LogoutResponse`.

===== Configuring {es} for Encrypted Messages

{security} supports a single key for message decryption. If a key is
configured, then {security} will attempt to use it to decrypt
`EncryptedAssertion` and `EncryptedAttribute` elements in Authentication
responses, and `EncryptedID` elements in Logout requests.

{security} will reject any SAML message that contains an `EncryptedAssertion`
that cannot be decrypted.

If an `Assertion` contains both encrypted and plain-text attributes, then
failure to decrypt the encrypted attributes will not cause an automatic
rejection. Rather, {security} will process the available plain-text attributes
(and any `EncryptedAttributes` that could be decrypted).

If you wish to use *PEM formatted* keys and certificates for SAML encryption,
then you should configure the following settings on the SAML realm:

`encryption.certificate`::
The path to the PEM formatted certificate file. e.g. `saml/saml-crypt.crt`

`encryption.key`::
The path to the PEM formatted key file. e.g. `saml/saml-crypt.key`

`encryption.secure_key_passphrase`::
The passphrase for the key, if the file is encypted. This is a
{ref}/secure-settings.html[secure setting] that must be set with the
`elasticsearch-keystore` tool.

If you wish to use *PKCS#12 formatted* files or a *Java Keystore* for SAML
encryption, then you should configure the following settings on the SAML realm:

`encryption.keystore.path`::
The path to the PKCS#12 or JKS keystore. e.g. `saml/saml-crypt.p12`

`encryption.keystore.alias`::
The alias of the key within the keystore. e.g. `encryption-key`

`encryption.keystore.secure_password`::
The passphrase for the keystore, if the file is encypted. This is a
{ref}/secure-settings.html[secure setting] that must be set with the
`elasticsearch-keystore` tool.

=== Generating SP metadata

Some Identity Providers support importing a metadata file from the Service
Provider. This will automatically configure many of the integration options
between the IdP and the SP.

The Elastic Stack supports generating such a metadata file using the
`bin/x-pack/saml-metadata` command in your {es} directory.

The {ref}/saml-metadata.html[documentation for the saml-metadata utility]
describes how to run it, and the available command line options.

[[saml-role-mapping]]
=== Configuring Role Mappings

When a user authenticates using SAML, they are identified to the Elastic Stack,
but this does not automatically grant them access to perform any actions or
access any data.

Your SAML users cannot do anything until they are mapped to X-Pack Security
roles. This mapping is performed through the
{ref}/security-api-role-mapping.html[role-mapping API]

This is an example of a simple role mapping that grants the `kibana_user` role
to any user who authenticates against the `saml1` realm:

[source,js]
--------------------------------------------------
PUT /_xpack/security/role_mapping/saml-kibana
{
  "roles": [ "kibana_user" ],
  "enabled": true,
  "rules": {
    "field": { "realm.name": "saml1" }
  }
}
--------------------------------------------------
// CONSOLE
// TEST


The attributes that are mapped via the realm configuration are used to process
role mapping rules, and these rules determine which roles a user is granted.

The user fields that are provided to the role
mapping are derived from the SAML attributes as follows:

- `username`: The `principal` attribute
- `dn`: The `dn` attribute
- `groups`: The `groups` attribute
- `metadata`: See <<saml-user-metadata>>

For more information, see <<mapping-roles>> and
{ref}/security-api-role-mapping.html[Role Mapping APIs]. 

If your IdP has the ability to provide groups or roles to Service Providers,
then you should map this SAML attribute to the `attributes.groups` setting in
the {es} realm, and then make use of it in a role mapping as per the example
below.

This mapping grants the {es} `finance_data` role, to any users who authenticate
via the `saml1` realm with the `finance-team` group.

[source,js]
--------------------------------------------------
PUT /_xpack/security/role_mapping/saml-finance
{
  "roles": [ "finance_data" ],
  "enabled": true,
  "rules": { "all": [
        { "field": { "realm.name": "saml1" } },
        { "field": { "groups": "finance-team" } }
  ] }
}
--------------------------------------------------
// CONSOLE
// TEST

[[saml-user-metadata]]
=== User Metadata

By default users who authenticate via SAML will have some additional metadata
fields.

- `saml_nameid` will be set to the value of the `NameID` element in the SAML
  authentication response
- `saml_nameid_format` will be set to the full URI of the NameID's `format`
  attribute
- Every SAML Attribute that is provided in the authentication response
  (regardless of whether it is mapped to an {es} user property), will be added
  as the metadata field `saml(name)` where "name" is the full URI name of the
  attribute. For example `saml(urn:oid:0.9.2342.19200300.100.1.3)`.
- For every SAML Attribute that has a _friendlyName_, will also be added as the
  metadata field `saml_friendlyName` where "name" is the full URI name of the
  attribute. For example `saml_mail`.

This behaviour can be disabled by adding `populate_user_metadata: false` to as
a setting in the saml realm.

[[saml-kibana]]
=== Configuring {kib}

SAML authentication in {kib} requires a small number of additional settings
in addition to the standard {kib} security configuration. The
{kibana-ref}/using-kibana-with-security.html[{kib} security documentation]
provides details on the available configuration options that you can apply.

In particular, since your {es} nodes have been configured to use TLS on the HTTP
interface, you must configure {kib} to use a `https` URL to connect to {es}, and
you may need to configure `elasticsearch.ssl.certificateAuthorities` to trust
the certificates that {es} has been configured to use.

SAML authentication in {kib} is also subject to the
`xpack.security.sessionTimeout` setting that is described in the {kib} security
documentation, and you may wish to adjst this timeout to meet your local needs.

The two additional settings that are required for SAML support are shown below:

[source, yaml]
------------------------------------------------------------
xpack.security.authProviders: [saml]
server.xsrf.whitelist: [/api/security/v1/saml]
------------------------------------------------------------

The configuration values used in the example above are:

`xpack.security.authProviders`::
Set this to `[ saml ]` to instruct {kib} to use SAML SSO as the authentication
method.

`server.xsrf.whitelist`::
{kib} has in-built protection against _Cross Site Request Forgery_ attacks which
are designed to prevent the {kib} server from processing requests that
originated from outside the {kib} application.
In order to support SAML authentication messages that originate from your
Identity Provider, we need to explicitly _whitelist_ the SAML authentication URL
within {kib}, so that the {kib} server will not reject these external messages.

If your {kib} instance is behind a proxy, you may also need to add configuration
to tell {kib} how to form its public URL. This is needed because all SAML
messages are exchanged via the user's web browser, so {kib} needs to know what
URLs are used within the browser. In this case, the following settings should be
added to your `kibana.yml` configuration file:

[source, yaml]
------------------------------------------------------------
xpack.security.public:
  protocol: https
  hostname: kibana.proxy.com
  port: 443
------------------------------------------------------------

`xpack.security.public.protocol`::
This is the protocol that the user's web browser uses to connect to the proxy.
Must be one of `http` or `https`. It is strongly recommended that you use the
`https` protocol for all access to {kib}.

`xpack.security.public.hostname`::
The fully qualified hostname that your users use to connect to the proxy server.

`xpack.security.public.port`::
The port number that your users use to connect to the proxy server (e.g. `80`
for `http` or `443` for `https`).

These values must be aligned with the URLs used in the {es} configuration for
`sp.acs` and `sp.logout`.

==== Supporting SAML and Basic authentication in {kib}

The SAML support in {kib} is designed on the expectation that it will be the
primary (or sole) authentication method for users of that {kib} instance.
However, it is possible to support both SAML and Basic authentication within a
single {kib} instance by setting `xpack.security.authProviders` as per the
example below:

[source, yaml]
------------------------------------------------------------
xpack.security.authProviders: [saml, basic]
------------------------------------------------------------

The order is important - this will _initiate_ SAML authentication for
unauthenticated users, but will _accept_ basic authentication.

If {kib} is configured in this way, then users who wish to login with a
username and password, can do so by directly accessing the `/login` page in
{kib}. This login will not use SAML credentials, and will rely on one of the
other security realms within {es}. Only users who have a username and password
for a configured {es} authentication realm will be able to login via this page.

Alternatively, when the `basic` authentication provider is enabled, you can
place a reverse proxy in front of {kib}, and configure it to send a basic
authentication header (`Authorization: Basic ....`) for each request.
If this header is present and valid, {kib} will not initiate the SAML
authentication process.

==== Operating multiple {kib} instances

If you wish to have multiple {kib} instances that authenticate against the same
{es} cluster, then each {kib} instance that is configured for SAML authentication,
requires its own SAML realm.

Each SAML realm must have its own unique Entity ID (`sp.entity_id`), and its own
_Assertion Consumer Service_ (`sp.acs`). Each {kib} instance will be mapped to
the correct realm by looking up the matching `sp.acs` value.

These realms may use the same Identity Provider, but are not required to.

The following is example of having 3 difference {kib} instances, 2 of which
use the same internal IdP, and another which uses a different IdP.

[source, yaml]
------------------------------------------------------------
xpack.security.authc.realms.saml_finance:
  type: saml
  order: 2
  idp.metadata.path: saml/idp-metadata.xml
  idp.entity_id: "https://sso.example.com/"
  sp.entity_id:  "https://kibana.finance.example.com/"
  sp.acs: "https://kibana.finance.example.com/api/security/v1/saml"
  sp.logout: "https://kibana.finance.example.com/logout"
  attributes.principal: "urn:oid:0.9.2342.19200300.100.1.1"
  attributes.groups: "urn:oid:1.3.6.1.4.1.5923.1.5.1."
xpack.security.authc.realms.saml_sales:
  type: saml
  order: 3
  idp.metadata.path: saml/idp-metadata.xml
  idp.entity_id: "https://sso.example.com/"
  sp.entity_id:  "https://kibana.sales.example.com/"
  sp.acs: "https://kibana.sales.example.com/api/security/v1/saml"
  sp.logout: "https://kibana.sales.example.com/logout"
  attributes.principal: "urn:oid:0.9.2342.19200300.100.1.1"
  attributes.groups: "urn:oid:1.3.6.1.4.1.5923.1.5.1."
xpack.security.authc.realms.saml_eng:
  type: saml
  order: 4
  idp.metadata.path: saml/idp-external.xml
  idp.entity_id: "https://engineering.sso.example.net/"
  sp.entity_id:  "https://kibana.engineering.example.com/"
  sp.acs: "https://kibana.engineering.example.com/api/security/v1/saml"
  sp.logout: "https://kibana.engineering.example.com/logout"
  attributes.principal: "http://schemas.xmlsoap.org/ws/2005/05/identity/claims/upn"
------------------------------------------------------------

It is possible to have one or more {kib} instances that use SAML, while other
instances use basic authentication against another realm type (e.g.
<<native-realm, Native>> or <<ldap-realm, LDAP>>).