337 lines
21 KiB
Plaintext
337 lines
21 KiB
Plaintext
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[[active-directory-realm]]
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=== Active Directory User Authentication
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You can configure {security} to communicate with Active Directory to authenticate
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users. To integrate with Active Directory, you configure an `active_directory`
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realm and map Active Directory users and groups to {security} roles in the
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<<mapping-roles, role mapping file>>.
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To protect passwords, communications between Elasticsearch and the Active Directory
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server should be encrypted using SSL/TLS. Clients and nodes that connect via
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SSL/TLS to the Active Directory server need to have the Active Directory server's
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certificate or the server's root CA certificate installed in their keystore or
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truststore. For more information about installing certificates, see
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<<active-directory-ssl>>.
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==== Configuring an Active Directory Realm
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{security} uses LDAP to communicate with Active Directory, so `active_directory`
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realms are similar to <<ldap-realm, `ldap` realms>>. Like LDAP directories,
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Active Directory stores users and groups hierarchically. The directory's
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hierarchy is built from containers such as the _organizational unit_ (`ou`),
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_organization_ (`o`), and _domain controller_ (`dc`).
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The path to an entry is a _Distinguished Name_ (DN) that uniquely identifies a
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user or group. User and group names typically have attributes such as a
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_common name_ (`cn`) or _unique ID_ (`uid`). A DN is specified as a string, for
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example `"cn=admin,dc=example,dc=com"` (white spaces are ignored).
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{security} only supports Active Directory security groups. You cannot map
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distribution groups to roles.
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NOTE: When you use Active Directory for authentication, the username entered by
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the user is expected to match the `sAMAccountName` or `userPrincipalName`,
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not the common name.
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To configure an `active_directory` realm:
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. Add a realm configuration of type `active_directory` to `elasticsearch.yml`
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under the `xpack.security.authc.realms` namespace. At a minimum, you must set the realm
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`type` to `active_directory` and specify the Active Directory `domain_name`. To
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use SSL/TLS for secured communication with the Active Directory server, you must
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also set the `url` attribute and specify the `ldaps` protocol and secure port
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number. If you are configuring multiple realms, you should also explicitly set
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the `order` attribute to control the order in which the realms are consulted
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during authentication. See <<ad-settings, Active Directory Realm Settings>>
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for all of the options you can set for an `active_directory` realm.
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+
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NOTE: Binding to Active Directory fails if the domain name is not mapped in DNS.
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If DNS is not being provided by a Windows DNS server, add a mapping for
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the domain in the local `/etc/hosts` file.
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+
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For example, the following realm configuration configures {security} to connect
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to `ldaps://example.com:636` to authenticate users through Active Directory.
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+
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[source, yaml]
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------------------------------------------------------------
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xpack:
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security:
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authc:
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realms:
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active_directory:
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type: active_directory
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order: 0 <1>
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domain_name: ad.example.com
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url: ldaps://ad.example.com:636 <2>
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unmapped_groups_as_roles: true <3>
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------------------------------------------------------------
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<1> The realm order controls the order in which the configured realms are checked
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when authenticating a user.
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<2> If you don't specify the URL, it defaults to `ldap:<domain_name>:389`.
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<3> When this option is enabled, Active Directory groups are automatically mapped
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to roles of the same name.
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+
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IMPORTANT: When you configure realms in `elasticsearch.yml`, only the
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realms you specify are used for authentication. If you also want to use the
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`native` or `file` realms, you must include them in the realm chain.
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. Restart Elasticsearch.
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===== Multiple Domain Support
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When authenticating users across multiple domains in a forest, there are a few minor
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differences in the configuration and the way that users will authenticate. The `domain_name`
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setting should be set to the forest root domain name. The `url` setting also needs to
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be set as you will need to authenticate against the Global Catalog, which uses a different
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port and may not be running on every Domain Controller.
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For example, the following realm configuration configures {security} to connect to specific
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Domain Controllers on the Global Catalog port with the domain name set to the forest root.
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[source, yaml]
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------------------------------------------------------------
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xpack:
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security:
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authc:
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realms:
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active_directory:
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type: active_directory
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order: 0
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domain_name: example.com <1>
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url: ldaps://dc1.ad.example.com:3269, ldaps://dc2.ad.example.com:3269 <2>
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load_balance:
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type: "round_robin" <3>
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------------------------------------------------------------
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<1> The `domain_name` is set to the name of the root domain in the forest.
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<2> The `url` value used in this example has URLs for two different Domain Controllers,
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which are also Global Catalog servers. Port 3268 is the default port for unencrypted
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communication with the Global Catalog; port 3269 is the default port for SSL connections.
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The servers that are being connected to can be in any domain of the forest as long as
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they are also Global Catalog servers.
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<3> A load balancing setting is provided to indicate the desired behavior when choosing
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the server to connect to.
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In this configuration, users will need to use either their full User Principal
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Name (UPN) or their Down-Level Logon Name. A UPN is typically a concatenation of
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the username with `@<DOMAIN_NAME` such as `johndoe@ad.example.com`. The Down-Level
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Logon Name is the NetBIOS domain name, followed by a `\` and the username, such as
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`AD\johndoe`. Use of Down-Level Logon Name requires a connection to the regular LDAP
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ports (389 or 636) in order to query the configuration container to retrieve the
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domain name from the NetBIOS name.
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[[ad-load-balancing]]
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===== Load Balancing and Failover
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The `load_balance.type` setting can be used at the realm level to configure how
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{security} should interact with multiple Active Directory servers. Two modes of
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operation are supported: failover and load balancing
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.Load Balancing and Failover Types
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|=======================
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| Type | | | Description
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| `failover` | | | The URLs specified are used in the order that they are
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specified. The first server that can be connected to will
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be used for all subsequent connections. If a connection to
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that server fails then the next server that a connection
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can be established to will be used for subsequent connections.
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| `dns_failover` | | | In this mode of operation, only a single URL may be specified.
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This URL must contain a DNS name. The system will be queried
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for all IP addresses that correspond to this DNS name.
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Connections to the Active Directory server will always be
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tried in the order in which they were retrieved. This differs
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from `failover` in that there is no reordering of the list
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and if a server has failed at the beginning of the list, it
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will still be tried for each subsequent connection.
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| `round_robin` | | | Connections will continuously iterate through the list of
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provided URLs. If a server is unavailable, iterating through
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the list of URLs will continue until a successful connection
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is made.
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| `dns_round_robin` | | | In this mode of operation, only a single URL may be specified.
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This URL must contain a DNS name. The system will be queried
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for all IP addresses that correspond to this DNS name.
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Connections will continuously iterate through the list of
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addresses. If a server is unavailable, iterating through the
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list of URLs will continue until a successful connection is
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made.
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|=======================
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[[ad-settings]]
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===== Active Directory Realm Settings
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[cols="4,^3,10"]
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|=======================
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| Setting | Required | Description
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| `type` | yes | Indicates the realm type. Must be set to `active_directory`.
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| `order` | no | Indicates the priority of this realm within the realm chain.
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Realms with a lower order are consulted first. Although not
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required, we recommend explicitly setting this value when
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you configure multiple realms. Defaults to `Integer.MAX_VALUE`.
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| `enabled` | no | Indicates whether this realm is enabled or disabled. Enables
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you to disable a realm without removing its configuration.
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Defaults to `true`.
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| `domain_name` | yes | Specifies the domain name of the Active Directory. {security}
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uses the domain name to derive the LDAP URL and `user_search_dn`
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if those fields are not specified.
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| `url` | no/yes | Specifies an LDAP URL of the form `ldap[s]://<server>:<port>`.
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{security} attempts to authenticate against this URL. If the
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URL is not specified, it is derived from the `domain_name`,
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assuming an unencrypted connection to port 389. For example,
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`ldap://<domain_name>:389`. This settings is required when
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connecting using SSL/TLS or via a custom port.
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| `load_balance.type` | no | The behavior to use when there are multiple LDAP URLs defined.
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For supported values see <<ad-load-balancing>>.
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| `load_balance.cache_ttl` | no | When using `dns_failover` or `dns_round_robin` as the load
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balancing type, this setting controls the amount of time to
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cache DNS lookups. Defaults to `1h`.
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| `user_search.base_dn` | no | Specifies the context to search for the user. Defaults to the
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root of the Active Directory domain.
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| `user_search.scope` | no | Specifies whether the user search should be `sub_tree` (default),
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`one_level`, or `base`. `sub_tree` searches all objects contained
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under `base_dn`. `one_level` only searches users directly
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contained within the `base_dn`. `base` specifies that the
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`base_dn` is a user object and that it is the only user considered.
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| `user_search.filter` | no | Specifies a filter to use to lookup a user given a username.
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The default filter looks up `user` objects with either
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`sAMAccountName` or `userPrincipalName`. If specified, this
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must be a valid LDAP user search filter, for example
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`(&(objectClass=user)(sAMAccountName={0}))`. For more
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information, see https://msdn.microsoft.com/en-us/library/aa746475(v=vs.85).aspx[Search Filter Syntax].
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| `group_search.base_dn` | no | Specifies the context to search for groups in which the user
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has membership. Defaults to the root of the Active Directory
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domain.
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| `group_search.scope` | no | Specifies whether the group search should be `sub_tree` (default),
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`one_level` or `base`. `sub_tree` searches all objects contained
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under `base_dn`. `one_level` searches for groups directly
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contained within the `base_dn`. `base` specifies that the
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`base_dn` is a group object and that it is the only group considered.
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| `unmapped_groups_as_roles` | no | Specifies whether the names of any unmapped Active Directory
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groups should be used as role names and assigned to the user.
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Defaults to `false`.
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| `files.role_mapping` | no | Specifies the path and file name of the
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<<ad-role-mapping, YAML role mapping configuration file>>.
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Defaults to `CONF_DIR/x-pack/role_mapping.yml`,
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where `CONF_DIR` is `ES_HOME/config` (zip/tar installations)
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or `/etc/elasticsearch` (package installations).
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| `follow_referrals` | no | Specifies whether {security} should follow referrals returned
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by the Active Directory server. Referrals are URLs returned by
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the server that are to be used to continue the LDAP operation
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(such as `search`). Defaults to `true`.
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| `ssl.key` | no | Specifies the path to the PEM encoded private key to use if the Active Directory
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server requires client authentication. `ssl.key` and `ssl.keystore.path` may not be used at the
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same time.
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| `ssl.key_passphrase` | no | Specifies the passphrase to decrypt the PEM encoded private key if it is encrypted.
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| `ssl.certificate` | no | Specifies the path to the PEM encoded certificate (or certificate chain) that goes with the key
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if the Active Directory server requires client authentication.
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| `ssl.certificate_authorities`| no | Specifies the paths to the PEM encoded certificate authority certificates that
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should be trusted. `ssl.certificate_authorities` and `ssl.trustsore.path` may not be used at
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the same time.
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| `ssl.keystore.path` | no | The path to the Java Keystore file that contains a private key and certificate. `ssl.key` and
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`ssl.keystore.path` may not be used at the same time.
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| `ssl.keystore.password` | no | The password to the keystore.
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| `ssl.keystore.key_password`| no | The password for the key in the keystore. Defaults to the keystore password.
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| `ssl.truststore.path` | no | The path to the Java Keystore file that contains the certificates to trust.
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`ssl.certificate_authorities` and `ssl.trustsore.path` may not be used at the same time.
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| `ssl.truststore.password` | no | The password to the truststore.
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| `ssl.verification_mode` | no | Specifies the type of verification to be performed when
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connecting to an Active Directory server using `ldaps`. When
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set to `full`, the hostname or IP address used in the `url`
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must match one of the names in the certificate or the
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connection will not be allowed. Due to their potential security impact,
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`ssl` settings are not exposed via the
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{ref}/cluster-nodes-info.html#cluster-nodes-info[nodes info API].
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Values are `none`, `certificate`, and `full`. Defaults to `full`.
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| `ssl.supported_protocols` | no | Specifies the supported protocols for TLS/SSL.
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| `ssl.cipher_suites` | no | Specifies the cipher suites that should be supported when communicating
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with the Active Directory server.
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| `cache.ttl` | no | Specifies the time-to-live for cached user entries. A user's
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credentials are cached for this period of time. Specify the
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time period using the standard Elasticsearch
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{ref}/common-options.html#time-units[time units].
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Defaults to `20m`.
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| `cache.max_users` | no | Specifies the maximum number of user entries that can be
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stored in the cache at one time. Defaults to 100,000.
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| `cache.hash_algo` | no | Specifies the hashing algorithm that is used for the
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cached user credentials.
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See <<cache-hash-algo, Cache hash algorithms>> for the
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possible values. (Expert Setting).
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|=======================
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[[mapping-roles-ad]]
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==== Mapping Active Directory Users and Groups to Roles
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An integral part of a realm authentication process is to resolve the roles
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associated with the authenticated user. Roles define the privileges a user has
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in the cluster.
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Since with the `active_directory` realm the users are managed externally in the
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Active Directory server, the expectation is that their roles are managed there
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as well. In fact, Active Directory supports the notion of groups, which often
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represent user roles for different systems in the organization.
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The `active_directory` realm enables you to map Active Directory users and groups
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to roles in the role mapping file stored on each node. You specify users and
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groups using their distinguished names (DNs). For example, the following mapping
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configuration maps the Active Directory `admins` group to both the `monitoring`
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and `user` roles, maps the `users` group to the `user` role and maps the `John Doe`
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user to the `user` role.
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[source, yaml]
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------------------------------------------------------------
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monitoring: <1>
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- "cn=admins,dc=example,dc=com" <2>
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user:
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- "cn=users,dc=example,dc=com" <3>
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- "cn=admins,dc=example,dc=com"
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- "cn=John Doe,cn=contractors,dc=example,dc=com" <4>
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------------------------------------------------------------
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<1> The name of the role.
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<2> The Active Directory distinguished name (DN) of the `admins` group.
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<3> The Active Directory distinguished name (DN) of the `users` group.
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<4> The Active Directory distinguished name (DN) of the user `John Doe`.
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For more information, see <<mapping-roles, Mapping Users and Groups to Roles>>.
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[[active-directory-ssl]]
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==== Setting up SSL Between Elasticsearch and Active Directory
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To protect the user credentials that are sent for authentication, it's highly
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recommended to encrypt communications between Elasticsearch and your Active
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Directory server. Connecting via SSL/TLS ensures that the identity of the Active
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Directory server is authenticated before {security} transmits the user
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credentials, and the usernames and passwords are encrypted in transit.
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To encrypt communications between Elasticsearch and Active Directory:
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|
|
|
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. Configure each node to trust certificates signed by the CA that signed your
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Active Directory server certificates. The following example demonstrates how to trust a CA certificate,
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`cacert.pem`, located within the {xpack} configuration directory:
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+
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[source,shell]
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||
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|
--------------------------------------------------
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||
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xpack:
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||
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security:
|
||
|
|
authc:
|
||
|
|
realms:
|
||
|
|
active_directory:
|
||
|
|
type: active_directory
|
||
|
|
order: 0
|
||
|
|
domain_name: ad.example.com
|
||
|
|
url: ldaps://ad.example.com:636
|
||
|
|
ssl:
|
||
|
|
certificate_authorities: [ "CONFIG_DIR/x-pack/cacert.pem" ]
|
||
|
|
--------------------------------------------------
|
||
|
|
+
|
||
|
|
The CA cert must be a PEM encoded certificate.
|
||
|
|
|
||
|
|
. Set the `url` attribute in the realm configuration to specify the LDAPS protocol
|
||
|
|
and the secure port number. For example, `url: ldaps://ad.example.com:636`.
|
||
|
|
|
||
|
|
. Restart Elasticsearch.
|
||
|
|
|
||
|
|
NOTE: By default, when you configure {security} to connect to Active Directory
|
||
|
|
using SSL/TLS, {security} 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, {security} does not allow a connection to the
|
||
|
|
Active Directory server. This is done to protect against man-in-the-middle
|
||
|
|
attacks. If necessary, you can disable this behavior by setting the
|
||
|
|
<<ssl-tls-settings, `ssl.verification_mode`>> property to `none`.
|