LDAP user authentication
editLDAP user authentication
editYou can configure the Elastic Stack security features to communicate with a Lightweight Directory Access Protocol (LDAP) server to authenticate users. See Configuring an LDAP realm.
LDAP stores users and groups hierarchically, similar to the way folders are
grouped in a file system. An LDAP directory’s hierarchy is built from containers
such as the organizational unit (ou
), organization (o
), and
domain controller (dc
).
The path to an entry is a Distinguished Name (DN) that uniquely identifies a
user or group. User and group names typically have attributes such as a
common name (cn
) or unique ID (uid
). A DN is specified as a string,
for example "cn=admin,dc=example,dc=com"
(white spaces are ignored).
The ldap
realm supports two modes of operation, a user search mode
and a mode with specific templates for user DNs.
Mapping LDAP groups to roles
editAn integral part of a realm authentication process is to resolve the roles associated with the authenticated user. Roles define the privileges a user has in the cluster.
Since with the ldap
realm the users are managed externally in the LDAP server,
the expectation is that their roles are managed there as well. In fact, LDAP
supports the notion of groups, which often represent user roles for different
systems in the organization.
The ldap
realm enables you to map LDAP users to roles via their LDAP
groups or other metadata. This role mapping can be configured via the
add role mapping API or by using a
file stored on each node. When a user authenticates with LDAP, the privileges
for that user are the union of all privileges defined by the roles to which
the user is mapped.
Configuring an LDAP realm
editTo integrate with LDAP, you configure an ldap
realm and map LDAP groups to
user roles.
-
Determine which mode you want to use. The
ldap
realm supports two modes of operation, a user search mode and a mode with specific templates for user DNs.LDAP user search is the most common mode of operation. In this mode, a specific user with permission to search the LDAP directory is used to search for the DN of the authenticating user based on the provided username and an LDAP attribute. Once found, the user is authenticated by attempting to bind to the LDAP server using the found DN and the provided password.
If your LDAP environment uses a few specific standard naming conditions for users, you can use user DN templates to configure the realm. The advantage of this method is that a search does not have to be performed to find the user DN. However, multiple bind operations might be needed to find the correct user DN.
-
To configure an
ldap
realm with user search:-
Add a realm configuration to
elasticsearch.yml
under thexpack.security.authc.realms.ldap
namespace. At a minimum, you must specify theurl
of the LDAP server, and setuser_search.base_dn
to the container DN where the users are searched for. If you are configuring multiple realms, you should also explicitly set theorder
attribute to control the order in which the realms are consulted during authentication. See LDAP realm settings for all of the options you can set for anldap
realm.For example, the following snippet shows an LDAP realm configured with a user search:
xpack: security: authc: realms: ldap: ldap1: order: 0 url: "ldaps://ldap.example.com:636" bind_dn: "cn=ldapuser, ou=users, o=services, dc=example, dc=com" user_search: base_dn: "dc=example,dc=com" filter: "(cn={0})" group_search: base_dn: "dc=example,dc=com" files: role_mapping: "ES_PATH_CONF/role_mapping.yml" unmapped_groups_as_roles: false
The password for the
bind_dn
user should be configured by adding the appropriatesecure_bind_password
setting to the Elasticsearch keystore. For example, the following command adds the password for the example realm above:bin/elasticsearch-keystore add \ xpack.security.authc.realms.ldap.ldap1.secure_bind_password
When you configure realms in
elasticsearch.yml
, only the realms you specify are used for authentication. If you also want to use thenative
orfile
realms, you must include them in the realm chain.
-
-
To configure an
ldap
realm with user DN templates:-
Add a realm configuration to
elasticsearch.yml
in thexpack.security.authc.realms.ldap
namespace. At a minimum, you must specify theurl
of the LDAP server, and specify at least one template with theuser_dn_templates
option. If you are configuring multiple realms, you should also explicitly set theorder
attribute to control the order in which the realms are consulted during authentication. See LDAP realm settings for all of the options you can set for anldap
realm.For example, the following snippet shows an LDAP realm configured with user DN templates:
xpack: security: authc: realms: ldap: ldap1: order: 0 url: "ldaps://ldap.example.com:636" user_dn_templates: - "cn={0}, ou=users, o=marketing, dc=example, dc=com" - "cn={0}, ou=users, o=engineering, dc=example, dc=com" group_search: base_dn: "dc=example,dc=com" files: role_mapping: "/mnt/elasticsearch/group_to_role_mapping.yml" unmapped_groups_as_roles: false
The
bind_dn
setting is not used in template mode. All LDAP operations run as the authenticating user.
-
-
(Optional) Configure how the security features interact with multiple LDAP servers.
The
load_balance.type
setting can be used at the realm level. The Elasticsearch security features support both failover and load balancing modes of operation. See LDAP realm settings. - (Optional) To protect passwords, encrypt communications between Elasticsearch and the LDAP server.
- Restart Elasticsearch.
-
Map LDAP groups to roles.
The
ldap
realm enables you to map LDAP users to roles via their LDAP groups, or other metadata. This role mapping can be configured via the add role mapping API or by using a file stored on each node. When a user authenticates with LDAP, the privileges for that user are the union of all privileges defined by the roles to which the user is mapped.Within a mapping definition, you specify groups using their distinguished names. For example, the following mapping configuration maps the LDAP
admins
group to both themonitoring
anduser
roles, and maps theusers
group to theuser
role.Configured via the role-mapping API:
PUT /_security/role_mapping/admins { "roles" : [ "monitoring" , "user" ], "rules" : { "field" : { "groups" : "cn=admins,dc=example,dc=com" } }, "enabled": true }
PUT /_security/role_mapping/basic_users { "roles" : [ "user" ], "rules" : { "field" : { "groups" : "cn=users,dc=example,dc=com" } }, "enabled": true }
Or, alternatively, configured via the role-mapping file:
monitoring: - "cn=admins,dc=example,dc=com" user: - "cn=users,dc=example,dc=com" - "cn=admins,dc=example,dc=com"
The name of the mapped role.
The LDAP distinguished name (DN) of the
admins
group.The LDAP distinguished name (DN) of the
users
group.For more information, see Mapping LDAP groups to roles and Mapping users and groups to roles.
The LDAP realm supports authorization realms as an alternative to role mapping.
-
(Optional) Configure the
metadata
setting on the LDAP realm to include extra fields in the user’s metadata.By default,
ldap_dn
andldap_groups
are populated in the user’s metadata. For more information, see User metadata in LDAP realms.The example below includes the user’s common name (
cn
) as an additional field in their metadata.xpack: security: authc: realms: ldap: ldap1: metadata: cn
- Set up SSL to encrypt communications between Elasticsearch and LDAP. See Encrypting communications between Elasticsearch and LDAP.
User metadata in LDAP realms
editWhen a user is authenticated via an LDAP realm, the following properties are populated in the user’s metadata:
Field |
Description |
|
The distinguished name of the user. |
|
The distinguished name of each of the groups that were resolved for the user (regardless of whether those groups were mapped to a role). |
This metadata is returned in the authenticate API, and can be used with templated queries in roles.
Additional fields can be included in the user’s metadata by configuring
the metadata
setting on the LDAP realm. This metadata is available for use
with the role mapping API or in
templated role queries.
Load balancing and failover
editThe load_balance.type
setting can be used at the realm level to configure how
the security features should interact with multiple LDAP servers. The
security features support both failover and load balancing modes of operation.
Encrypting communications between Elasticsearch and LDAP
editTo protect the user credentials that are sent for authentication in an LDAP realm, it’s highly recommended to encrypt communications between Elasticsearch and your LDAP server. Connecting via SSL/TLS ensures that the identity of the LDAP server is authenticated before Elasticsearch transmits the user credentials and the contents of the connection are encrypted. Clients and nodes that connect via TLS to the LDAP server need to have the LDAP server’s certificate or the server’s root CA certificate installed in their keystore or truststore.
For more information, see LDAP user authentication.
-
Configure the realm’s TLS settings on each node to trust certificates signed by the CA that signed your LDAP server certificates. The following example demonstrates how to trust a CA certificate,
cacert.pem
, located within the Elasticsearch configuration directory:xpack: security: authc: realms: ldap: ldap1: order: 0 url: "ldaps://ldap.example.com:636" ssl: certificate_authorities: [ "cacert.pem" ]
In the example above, the CA certificate must be PEM encoded.
PKCS#12 and JKS files are also supported - see the description of
ssl.truststore.path
in LDAP realm settings.You can also specify the individual server certificates rather than the CA certificate, but this is only recommended if you have a single LDAP server or the certificates are self-signed.
-
Set the
url
attribute in the realm configuration to specify the LDAPS protocol and the secure port number. For example,url: ldaps://ldap.example.com:636
. - Restart Elasticsearch.
By default, when you configure Elasticsearch to connect to an LDAP server
using SSL/TLS, it attempts to verify the hostname or IP address
specified with the url
attribute in the realm configuration with the
values in the certificate. If the values in the certificate and realm
configuration do not match, Elasticsearch does not allow a connection to the
LDAP server. This is done to protect against man-in-the-middle attacks. If
necessary, you can disable this behavior by setting the
ssl.verification_mode
property to certificate
.