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Elasticsearch Reference [6.3] » Set up Elasticsearch » Configuring security in Elasticsearch » Configuring an LDAP realm
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Configuring an LDAP realmedit

You can configure X-Pack security to communicate with a Lightweight Directory Access Protocol (LDAP) server to authenticate users. To integrate with LDAP, you configure an ldap realm and map LDAP groups to user roles.

For more information about LDAP realms, see LDAP User Authentication.

  1. 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.

  2. To configure an ldap realm with user search:

    1. Add a realm configuration of type ldap to elasticsearch.yml under the xpack.security.authc.realms namespace. At a minimum, you must set the realm type to ldap, specify the url of the LDAP server, and set user_search.base_dn to the container DN where the users are searched for. If you are configuring multiple realms, you should also explicitly set the order attribute to control the order in which the realms are consulted during authentication. See LDAP realm settingsedit for all of the options you can set for an ldap realm.

      For example, the following snippet shows an LDAP realm configured with a user search:

      xpack:
  security:
    authc:
      realms:
        ldap1:
          type: ldap
          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"
            attribute: cn
          group_search:
            base_dn: "dc=example,dc=com"
          files:
            role_mapping: "CONFIG_DIR/role_mapping.yml"
          unmapped_groups_as_roles: false

      The password for the bind_dn user should be configured by adding the appropriate secure_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.ldap1.secure_bind_password
      Important

      When you configure realms in elasticsearch.yml, only the realms you specify are used for authentication. If you also want to use the native or file realms, you must include them in the realm chain.

  3. To configure an ldap realm with user DN templates:

    1. Add a realm configuration of type ldap to elasticsearch.yml in the xpack.security.authc.realms namespace. At a minimum, you must set the realm type to ldap, specify the url of the LDAP server, and specify at least one template with the user_dn_templates option. If you are configuring multiple realms, you should also explicitly set the order attribute to control the order in which the realms are consulted during authentication. See LDAP realm settingsedit for all of the options you can set for an ldap realm.

      For example, the following snippet shows an LDAP realm configured with user DN templates:

      xpack:
  security:
    authc:
      realms:
        ldap1:
          type: ldap
          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
      Important

      The bind_dn setting is not used in template mode. All LDAP operations run as the authenticating user.

  4. (Optional) Configure how X-Pack security should interact with multiple LDAP servers.

    The load_balance.type setting can be used at the realm level. X-Pack security supports both failover and load balancing modes of operation. See LDAP realm settingsedit.

  5. (Optional) To protect passwords, encrypt communications between Elasticsearch and the LDAP server.
  6. Restart Elasticsearch.

  7. Map LDAP groups to roles.

    The ldap realm enables you to map LDAP users to to roles via their LDAP groups, or other metadata. This role mapping can be configured via the 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 the monitoring and user roles, and maps the users group to the user role.

    Configured via the role-mapping API:

    PUT _xpack/security/role_mapping/admins
{
  "roles" : [ "monitoring" , "user" ],
  "rules" : { "field" : {
    "groups" : "cn=admins,dc=example,dc=com" 
  } },
  "enabled": true
}

    The LDAP distinguished name (DN) of the admins group. 

    PUT _xpack/security/role_mapping/basic_users
{
  "roles" : [ "user" ],
  "rules" : { "field" : {
    "groups" : "cn=users,dc=example,dc=com" 
  } },
  "enabled": true
}

    The LDAP distinguished name (DN) of the users group.

    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.

  8. (Optional) Configure the metadata setting on the LDAP realm to include extra fields in the user’s metadata.

    By default, ldap_dn and ldap_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:
        ldap1:
          type: ldap
          metadata: cn
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