Submitting requests on behalf of other users

ECH ECK ECE Self-Managed

Elasticsearch roles support a run_as privilege that enables an authenticated user to submit requests on behalf of other users. For example, if your external application is trusted to authenticate users, Elasticsearch can authenticate the external application and use the run as mechanism to issue authorized requests as other users without having to re-authenticate each user.

To "run as" (impersonate) another user, the first user (the authenticating user) must be authenticated by a mechanism that supports run-as delegation. The second user (the run_as user) must be authorized by a mechanism that supports delegated run-as lookups by username.

The run_as privilege essentially operates like a secondary form of delegated authorization. Delegated authorization applies to the authenticating user, and the run_as privilege applies to the user who is being impersonated.

For the authenticating user, the following realms (plus API keys) all support run_as delegation: native, file, Active Directory, JWT, Kerberos, LDAP, and PKI.

Service tokens, the Elasticsearch token service, SAML, and OIDC do not support run_as delegation.

Elasticsearch supports run_as for any realm that supports user lookup. Not all realms support user lookup. Refer to the list of supported realms and ensure that the realm you wish to use is configured in a manner that supports user lookup.

The run_as user must be retrieved from a realm - it is not possible to run as a service account, API key or access token.

To submit requests on behalf of other users, you need to have the run_as privilege in your roles. For example, the following request creates a my_director role that grants permission to submit request on behalf of jacknich or redeniro:

 POST /_security/role/my_director?refresh=true { "cluster": ["manage"], "indices": [ { "names": [ "index1", "index2" ], "privileges": [ "manage" ] } ], "run_as": [ "jacknich", "rdeniro" ], "metadata" : { "version" : 1 } } 

To submit a request as another user, you specify the user in the es-security-runas-user request header. For example:

 curl -H "es-security-runas-user: jacknich" -u es-admin -X GET http://localhost:9200/ 

The run_as user passed in through the es-security-runas-user header must be available from a realm that supports delegated authorization lookup by username. Realms that don’t support user lookup can’t be used by run_as delegation from other realms.

For example, JWT realms can authenticate external users specified in JWTs, and execute requests as a run_as user in the native realm. Elasticsearch will retrieve the indicated runas user and execute the request as that user using their roles.

You can apply the run_as privilege when creating roles with the role management API, or using the role management UI in Kibana. Users who are assigned a role that contains the run_as privilege inherit all privileges from their role, and can also submit requests on behalf of the indicated users.

After a user successfully authenticates to Elasticsearch, an authorization process determines whether the user behind an incoming request is allowed to run that request. If the authenticated user has the run_as privilege in their list of permissions and specifies the run-as header, Elasticsearch discards the authenticated user and associated roles. It then looks in each of the configured realms in the realm chain until it finds the username that’s associated with the run_as user, and uses those roles to execute any requests.

Consider an admin role and an analyst role. The admin role has higher privileges, but might also want to submit requests as another user to test and verify their permissions.

This example uses the role management API, but a similar configuration can be set up using the Create users and Users pages in Kibana.

1. Create an admin role named my_admin_role. This role has manage privileges on the entire cluster, and on a subset of indices. This role also contains the run_as privilege, which enables any user with this role to submit requests on behalf of the specified analyst_user.

   You can set up a similar role using the role management UI in Kibana by selecting an analyst_user from the Run As privileges dropdown menu in the Elasticsearch section.

    POST /_security/role/my_admin_role?refresh=true { "cluster": ["manage"], "indices": [ { "names": [ "index1", "index2" ], "privileges": [ "manage" ] } ], "applications": [ { "application": "myapp", "privileges": [ "admin", "read" ], "resources": [ "*" ] } ], "run_as": [ "analyst_user" ], "metadata" : { "version" : 1 } } 

2. Create an analyst role named my_analyst_role, which has more restricted monitor cluster privileges and manage privileges on a subset of indices.

    POST /_security/role/my_analyst_role?refresh=true { "cluster": [ "monitor"], "indices": [ { "names": [ "index1", "index2" ], "privileges": ["manage"] } ], "applications": [ { "application": "myapp", "privileges": [ "read" ], "resources": [ "*" ] } ], "metadata" : { "version" : 1 } } 

3. Create an administrator user and assign them the role named my_admin_role, which allows this user to submit requests as the analyst_user.

    POST /_security/user/admin_user?refresh=true { "password": "l0ng-r4nd0m-p@ssw0rd", "roles": [ "my_admin_role" ], "full_name": "Eirian Zola", "metadata": { "intelligence" : 7} } 

4. Create an analyst user and assign them the role named my_analyst_role.

    POST /_security/user/analyst_user?refresh=true { "password": "l0nger-r4nd0mer-p@ssw0rd", "roles": [ "my_analyst_role" ], "full_name": "Monday Jaffe", "metadata": { "innovation" : 8} } 

5. You can then authenticate to Elasticsearch as the admin_user or analyst_user. However, the admin_user could optionally submit requests on behalf of the analyst_user.

   The following request authenticates to Elasticsearch with a Basic authorization token and submits the request as the analyst_user:

    curl -s -X GET -H "Authorization: Basic YWRtaW5fdXNlcjpsMG5nLXI0bmQwbS1wQHNzdzByZA==" -H "es-security-runas-user: analyst_user" https://localhost:9200/_security/_authenticate 

   The response indicates that the analyst_user submitted this request, using the my_analyst_role that’s assigned to that user. When the admin_user submitted the request, Elasticsearch authenticated that user, discarded their roles, and then used the roles of the run_as user.

    {"username":"analyst_user","roles":["my_analyst_role"],"full_name":"Monday Jaffe","email":null, "metadata":{"innovation":8},"enabled":true,"authentication_realm":{"name":"native", "type":"native"},"lookup_realm":{"name":"native","type":"native"},"authentication_type":"realm"} % 

   The authentication_realm and lookup_realm in the response both specify the native realm because both the admin_user and analyst_user are from that realm. If the two users are in different realms, the values for authentication_realm and lookup_realm are different (such as pki and native).