You can configure Elasticsearch to use Public Key Infrastructure (PKI) certificates to authenticate users. This requires clients to present X.509 certificates.
You cannot use PKI certificates to authenticate users in Kibana.
To use PKI in Elasticsearch, you configure a PKI realm, enable client authentication on the desired network layers (transport or http), and map the Distinguished Names (DNs) from the user certificates to roles in the role-mapping API or role-mapping file.
You can also use a combination of PKI and username/password authentication. For
example, you can enable SSL/TLS on the transport layer and define a PKI realm to
require transport clients to authenticate with X.509 certificates, while still
authenticating HTTP traffic using username and password credentials. You can
also set xpack.security.transport.ssl.client_authentication
to optional
to
allow clients without certificates to authenticate with other credentials.
You must enable SSL/TLS and enable client authentication to use PKI.
For more information, see PKI User Authentication.
Add a realm configuration for a pki
realm to elasticsearch.yml
under the
xpack.security.authc.realms.pki
namespace.
If you are configuring multiple realms, you should
explicitly set the order
attribute. See PKI realm settings for all of the
options you can set for a pki
realm.
For example, the following snippet shows the most basic pki
realm configuration:
xpack: security: authc: realms: pki: pki1: order: 1
With this configuration, any certificate trusted by the SSL/TLS layer is accepted for authentication. The username is the common name (CN) extracted from the DN of the certificate.
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.
If you want to use something other than the CN of the DN as the username, you can specify a regex to extract the desired username. For example, the regex in the following configuration extracts the email address from the DN:
xpack: security: authc: realms: pki: pki1: username_pattern: "EMAILADDRESS=(.*?)(?:,|$)"
Enable client authentication on the desired network layers (transport or http).
The PKI realm relies on the TLS settings of the node’s network interface. The realm can be configured to be more restrictive than the underlying network connection - that is, it is possible to configure the node such that some connections are accepted by the network interface but then fail to be authenticated by the PKI realm. However, the reverse is not possible. The PKI realm cannot authenticate a connection that has been refused by the network interface.
In particular this means:
client_authentication
to optional
or required
.
truststore
or certificate_authorities
paths,
or by setting verification_mode
to none
. See
ssl.verification_mode
for an explanation of this
setting.
The relevant network interface (transport or http) must be configured to trust any certificate that is to be used within the PKI realm. However, it possible to configure the PKI realm to trust only a subset of the certificates accepted by the network interface. This is useful when the SSL/TLS layer trusts clients with certificates that are signed by a different CA than the one that signs your users' certificates.
To configure the PKI realm with its own truststore, specify the truststore.path
option. For example:
xpack: security: authc: realms: pki: pki1: truststore: path: "/path/to/pki_truststore.jks" password: "x-pack-test-password"
The certificate_authorities
option can be used as an alternative to the
truststore.path
setting.
Map roles for PKI users.
You map roles for PKI users through the role mapping APIs or by using a file stored on each node. When a user authenticates against a PKI realm, the privileges for that user are the union of all privileges defined by the roles to which the user is mapped.
You identify a user by the distinguished name in their certificate.
For example, the following mapping configuration maps John Doe
to the
user
role:
Using the role-mapping API:
PUT /_security/role_mapping/users { "roles" : [ "user" ], "rules" : { "field" : { "dn" : "cn=John Doe,ou=example,o=com" } }, "enabled": true }
Or, alternatively, configured in a role-mapping file:
The distinguished name for a PKI user follows X.500 naming conventions which
place the most specific fields (like cn
or uid
) at the beginning of the
name, and the most general fields (like o
or dc
) at the end of the name.
Some tools, such as openssl, may print out the subject name in a different
format.
One way that you can determine the correct DN for a certificate is to use the
authenticate API (use the relevant PKI
certificate as the means of authentication) and inspect the metadata field in
the result. The user’s distinguished name will be populated under the pki_dn
key. You can also use the authenticate API to validate your role mapping.
For more information, see Mapping Users and Groups to Roles.
The PKI realm supports authorization realms as an alternative to role mapping.