Version: 7.x-45.0.0
Enterprise

Active Directory and LDAP Authentication

Activating Authentication

To use Active Directory / LDAP for authentication first configure a respective authentication domain in the authc section of sg_config:

authc:
  ldap:
    http_enabled: true
    order: 1
    http_authenticator:
      type: basic
      challenge: true
    authentication_backend:
      type: ldap
      config:
        ...

Afterwards add the connection settings for your Active Directory / LDAP server to the config section of the authentication domain, e.g.:

config:
  enable_ssl: true
  enable_start_tls: false
  enable_ssl_client_auth: false
  verify_hostnames: true
  hosts:
    - ldap.example.com:8389
  bind_dn: cn=admin,dc=example,dc=com
  password: passw0rd

Configuring Authentication

Authentication works by issuing an LDAP query containing the username against the user subtree of the LDAP directory.

Search Guard first takes the configured LDAP query, and replaces the placeholder {0} with the username from the user’s credentials.

usersearch: '(sAMAccountName={0})'

Search Guard then issues this query against the user subtree (“userbase”). Currently the whole subtree beneath the configured userbase is searched:

userbase: 'ou=people,dc=example,dc=com'

If the query was successful, Search Guard retrieves the username from the LDAP entry. You can specify which attribute from the LDAP entry Search Guard should use as the username:

username_attribute: uid

If this key is not set, or null, then the DN of the LDAP entry is used.

Configuration summary

Name Description
userbase Specifies the subtree in the directory where user information is stored
usersearch The actual LDAP query that Search Guard executes when trying to authenticate a user. The variable {0} is substituted with the username.
username_attribute Search Guard uses this attribute of the directory entry to look for the user name. If set to null, the DN is used (default). If this references a multi-value field it is undefined which value will be used. It’s therefore not recommended to set it to a multi-value field.

Complete authentication example

ldap:
  http_enabled: true
  order: 1
  http_authenticator:
    type: basic
    challenge: true
  authentication_backend:
    type: ldap
    config:
      enable_ssl: true
      enable_start_tls: false
      enable_ssl_client_auth: false
      verify_hostnames: true
      hosts:
        - ldap.example.com:636
      bind_dn: cn=admin,dc=example,dc=com
      password: password
      userbase: 'ou=people,dc=example,dc=com'
      usersearch: '(sAMAccountName={0})'
      username_attribute: uid

Multiple user bases

You can also configure multiple user bases. Search Guard will query the user bases one after the other until the user was authenticated successfully:

users:
  primary-userbase:
    base: 'ou=people,dc=example,dc=com'
    search: '(uid={0})'
  secondary-userbase:
    base: 'ou=otherpeople,dc=example,dc=com'
    search: '(initials={0})'
  tertiary-rolebase:    
    ...

The names of the configuration keys (primary-userbase, secondary-userbase…) are just telling names. You can choose them freely and you can configure as many user bases as you need.

Complete authentication example

ldap:
  http_enabled: false
  order: 1
  http_authenticator:
    type: basic
    challenge: true
  authentication_backend:
    type: ldap
    config:
      enable_ssl: true
      enable_start_tls: false
      enable_ssl_client_auth: false
      verify_hostnames: true
      hosts:
        - ldap.example.com:636
      bind_dn: cn=admin,dc=example,dc=com
      password: password
      users:
        primary-userbase:
          base: 'ou=people,dc=example,dc=com'
          search: '(uid={0})'
        secondary-userbase:
          base: 'ou=otherpeople,dc=example,dc=com'
          search: '(initials={0})'
      username_attribute: uid

Using Further Active Directory Attributes

Search Guard allows to use further user attributes to construct dynamic index patterns and dynamic queries for document and field level security. In order to use these attributes, you need to use the configuration attribute map_ldap_attrs_to_user_attrs to provide a mapping from LDAP attributes to Search Guard user attributes inside the LDAP configuration.

As the other LDAP configuration, the map_ldap_attrs_to_user_attrs attribute needs to be placed in the config section of the LDAP authentication backend configuration. As value, you need to provide a map of the form search_guard_user_attribute: ldap_attribute.

This might look like this:

ldap:
  http_enabled: true
  order: 1
  http_authenticator:
    type: basic
    challenge: true
  authentication_backend:
    type: ldap
    config:
      map_ldap_attrs_to_user_attrs:
        department: departmentNumber
        email_address: mail

This adds the attributes department and email_address to the Search Guard user and sets them to the respective values from LDAP. Multi-value attributes from LDAP are supported. Actually, attributes will be always stored as arrays in the Search Guard user attributes, even if the attribute has only a single value.

In the Search Guard role configuration, the attributes can be then used like this:

my_dls_role:
  index_permissions:
  - index_patterns:
    - "dls_test"
    dls: '{"terms" : {"filter_attr": ${user.attrs.department|toList|toJson}}}'
    allowed_actions:
    - "READ"

Note: Take care that the mapped attributes are of reasonable size. As the attributes need to be internally forwarded over the network for each operation in the Elasticsearch cluster, attributes carrying a big amount of data may cause a performance penalty.

Note: This method of providing attributes supersedes the old way which provided all LDAP attributes as Search Guard user attributes with the prefix attr.ldap. These attributes are still supported, but are now deprecated.

Advanced: Exclude certain users from role lookup

It is possible to exclude users from LDAP authentication by specifying a ‘skip_users’ section inside the domain configuration. Wildcards and regular expressions are exported.

skip_users:
  - kibanaserver
  - 'cn=Michael Jackson,ou*people,o=TEST'
  - '/\S*/'


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