knes1/elasticsearch-readonlyrest-plugin

Free Elasticsearch and Kibana security plugin: super-easy Kibana multi-tenancy, Encryption, Authentication, Authorization, Auditing

ReadonlyREST needs your help ⚠️

ReadonlyREST is an GPLv3 open source project. Its ongoing development can only made possible thanks to the support of its backers:

1. @nmaisonneuve
2. @Id57
3. Joseph Bull

If you care this project keeps on existing, read up the ReadonlyREST Patreon campaign.

Readonly REST Elasticsearch Plugin

Expose the high performance HTTP server embedded in Elasticsearch directly to the public, safely blocking any attempt to delete or modify your data.

In other words... no more proxies! Yay Ponies!

Getting started

1. Install the plugin

Download the binary release for your Elasticsearch version from the official website.

2. Configuration

Append either of these snippets to conf/elasticsearch.yml

USE CASE: Secure public searchbox from ransomware

readonlyrest:
    enable: true
    access_control_rules: 
    
    - name: "Accept all requests from localhost"
      type: allow
      hosts: [127.0.0.1]

    - name: "::PUBLIC SEARCHBOX::"
      type: allow
      indices: ["public"]
      actions: ["indices:data/read/*"]

USE CASE: Enable HTTPS globally

Remember to enable SSL whenever you use HTTP basic auth or API keys so your credentials can't be stolen.

http.type: ssl_netty4
readonlyrest:
    enable: true
    
    ssl:
      enable: true
      keystore_file: "/elasticsearch/plugins/readonlyrest/keystore.jks"
      keystore_pass: readonlyrest
      key_pass: readonlyrest

USE CASE: Full access for localhost, RO some indices from elsewhere

readonlyrest:
    enable: true
    response_if_req_forbidden: Sorry, your request is forbidden.
    
    access_control_rules:

    - name: Accept all requests from localhost
      type: allow
      hosts: [127.0.0.1]

    - name: Just certain indices, and read only
      type: allow
      actions: ["indices:data/read/*"]
      indices: ["product_catalogue-*"] # index aliases are taken in account!

USE CASE: Multi-user Kibana + Authenticated Logstash

readonlyrest:
    enable: true
    verbosity: info # log unmatched requests
    
    ssl:
      enable: true
      keystore_file: "/elasticsearch/plugins/readonlyrest/keystore.jks"
      keystore_pass: readonlyrest
      key_pass: readonlyrest

    response_if_req_forbidden: Forbidden by ReadonlyREST ES plugin

    access_control_rules:

    - name: "::LOGSTASH::"
      # auth_key is good for testing, but replace it with `auth_key_sha1`!
      auth_key: logstash:logstash
      type: allow
      actions: ["cluster:monitor/main","indices:admin/types/exists","indices:data/read/*","indices:data/write/*","indices:admin/template/*","indices:admin/create"]
      indices: ["logstash-*"]

    # We trust Kibana's server side process, full access granted via HTTP authentication
    - name: "::KIBANA-SRV::"
      # auth_key is good for testing, but replace it with `auth_key_sha256`!
      auth_key: kibana:kibana
      verbosity: error # don't log successful request
      type: allow

    # Using "Basic HTTP Auth" from browsers, can RW Kibana settings, RO on logstash indices from 2017 .
    - name: "::RW DEVELOPER::"
      auth_key: rw:dev
      type: allow
      kibana_access: rw
      indices: [".kibana", ".kibana-devnull", "logstash-2017*"]

    # Same as above, but cannot change dashboards, visualizations or settings in Kibana
    - name: "::RO DEVELOPER::"
      auth_key: ro:dev
      type: allow
      kibana_access: ro
      indices: [".kibana", ".kibana-devnull", "logstash-2017*"]

Now activate authentication in Kibana server: let the Kibana daemon connect to ElasticSearch in privileged mode.

• edit the kibana configuration file: kibana.yml and add the following:

elasticsearch.username: "kibana"
elasticsearch.password: "kibana"

This is secure because the users connecting from their browsers will be asked to login separately anyways.

Now activate authenticatoin in Logstash: (follow the docs, it's very similar to Kibana!)

USE CASE: Group-based access control

readonlyrest:
    enable: true
    response_if_req_forbidden: Forbidden by ReadonlyREST ES plugin
    
    access_control_rules:

    - name: Accept requests from users in group team1 on index1
      type: allow
      groups: ["team1"]
      indices: ["index1"]

    - name: Accept requests from users in group team2 on index2
      type: allow
      groups: ["team2"]
      indices: ["index2"]

    - name: Accept requests from users in groups team1 or team2 on index3
      type: allow
      groups: ["team1", "team2"]
      indices: ["index3"]
    
    users:
    
    - username: alice
      auth_key: alice:p455phrase
      groups: ["team1"]
      
    - username: bob
      auth_key: bob:s3cr37
      groups: ["team2", "team4"]
      
    - username: claire
      auth_key_sha1: 2bc37a406bd743e2b7a4cb33efc0c52bc2cb03f0 #claire:p455key
      groups: ["team1", "team5"]

USE CASE: Authentication via LDAP + Authorization via groups

Simpler: authentication and authorization in one rule

readonlyrest:
    enable: true
    response_if_req_forbidden: Forbidden by ReadonlyREST ES plugin
    
    access_control_rules:

    - name: Accept requests from users in group team1 on index1
      type: allow
      ldap_auth:
          name: "ldap1"                                       # ldap name from below 'ldaps' section
          groups: ["g1", "g2"]                                # group within 'ou=Groups,dc=example,dc=com'
      indices: ["index1"]
      
    - name: Accept requests from users in group team2 on index2
      type: allow
      ldap_auth:
          - name: "ldap2"
            groups: ["g3"]
            cache_ttl_in_sec: 60
      indices: ["index2"]

    ldaps:
    
    - name: ldap1
      host: "ldap1.example.com"
      port: 389                                                 # optional, default 389
      ssl_enabled: false                                        # optional, default true
      ssl_trust_all_certs: true                                 # optional, default false
      bind_dn: "cn=admin,dc=example,dc=com"                     # optional, skip for anonymous bind
      bind_password: "password"                                 # optional, skip for anonymous bind
      search_user_base_DN: "ou=People,dc=example,dc=com"
      user_id_attribute: "uid"                                  # optional, default "uid"
      search_groups_base_DN: "ou=Groups,dc=example,dc=com"
      unique_member_attribute: "uniqueMember"                   # optional, default "uniqueMember"
      connection_pool_size: 10                                  # optional, default 30
      connection_timeout_in_sec: 10                             # optional, default 1
      request_timeout_in_sec: 10                                # optional, default 1
      cache_ttl_in_sec: 60                                      # optional, default 0 - cache disabled
    
    - name: ldap2
      host: "ldap2.example2.com"
      port: 636
      search_user_base_DN: "ou=People,dc=example2,dc=com"
      search_groups_base_DN: "ou=Groups,dc=example2,dc=com"

Advanced: authentication and authorization in separate rules

readonlyrest:
    enable: true
    response_if_req_forbidden: Forbidden by ReadonlyREST ES plugin
    
    access_control_rules:

    - name: Accept requests from users in group team1 on index1
      type: allow
      ldap_authentication: "ldap1"  
      ldap_authorization:
        name: "ldap1"                                       # ldap name from 'ldaps' section
        groups: ["g1", "g2"]                                # group within 'ou=Groups,dc=example,dc=com'
      indices: ["index1"]
      
    - name: Accept requests from users in group team2 on index2
      type: allow
      ldap_authentication:
        name: "ldap2"  
        cache_ttl_in_sec: 60
      ldap_authorization:
        name: "ldap2"
        groups: ["g3"]
        cache_ttl_in_sec: 60
      indices: ["index2"]

    ldaps:
    
    - name: ldap1
      host: "ldap1.example.com"
      port: 389                                                 # default 389
      ssl_enabled: false                                        # default true
      ssl_trust_all_certs: true                                 # default false
      bind_dn: "cn=admin,dc=example,dc=com"                     # skip for anonymous bind
      bind_password: "password"                                 # skip for anonymous bind
      search_user_base_DN: "ou=People,dc=example,dc=com"
      user_id_attribute: "uid"                                  # default "uid"
      search_groups_base_DN: "ou=Groups,dc=example,dc=com"
      unique_member_attribute: "uniqueMember"                   # default "uniqueMember"
      connection_pool_size: 10                                  # default 30
      connection_timeout_in_sec: 10                             # default 1
      request_timeout_in_sec: 10                                # default 1
      cache_ttl_in_sec: 60                                      # default 0 - cache disabled
    
    - name: ldap2
      host: "ldap2.example2.com"
      port: 636
      search_user_base_DN: "ou=People,dc=example2,dc=com"
      search_groups_base_DN: "ou=Groups,dc=example2,dc=com"

LDAP configuration requirements:

• user from search_user_base_DN should have uid attribute (can be overwritten using user_id_attribute)
• groups from search_groups_base_DN should have uniqueMember attribute (can be overwritten using unique_member_attribute)

(An example OpenLDAP configuration file can be found in our tests: /src/test/resources/test_example.ldif)

Caching can be configured per LDAP client (see ldap1) or per rule (see Accept requests from users in group team2 on index2 rule)

USE CASE: External Basic HTTP Authentication

ReadonlyREST will forward the received Authorization header to a website of choice and evaluate the returned HTTP status code to verify the provided credentials. This is useful if you already have a web server with all the credentials configured and the credentials are passed over the Authorization header.

readonlyrest:
    enable: true
    response_if_req_forbidden: Forbidden by ReadonlyREST ES plugin
    
    access_control_rules:
    
    - name: "::Tweets::"
      type: allow
      methods: GET
      indices: ["twitter"]
      external_authentication: "ext1"

    - name: "::Facebook posts::"
      type: allow
      methods: GET
      indices: ["facebook"]
      external_authentication:
        service: "ext2"
        cache_ttl_in_sec: 60

    external_authentication_service_configs:

    - name: "ext1"
      authentication_endpoint: "http://external-website1:8080/auth1"
      success_status_code: 200
      cache_ttl_in_sec: 60

    - name: "ext2"
      authentication_endpoint: "http://external-website2:8080/auth2"
      success_status_code: 204
      cache_ttl_in_sec: 60

To define an external authentication service the user should specify:

• name for service (then this name is used as id in service attribute of external_authentication rule)
• authentication_endpoint (GET request)
• success_status_code - authentication response success status code

Cache can be defined at the service level or/and at the rule level. In the example, both are shown, but you might opt for setting up either.

USE CASE: External groups provider: XML/JSON service (external authorization)

This external authorization connector makes it possible to resolve to what groups a users belong, using an external JSON or XML service.

readonlyrest:
    enable: true
    response_if_req_forbidden: Forbidden by ReadonlyREST ES plugin
    
    access_control_rules:

    - name: "::Tweets::"
      type: allow
      methods: GET
      indices: ["twitter"]
      proxy_auth:
        proxy_auth_config: "proxy1"
        users: ["*"]
      groups_provider_authorization:
        user_groups_provider: "GroupsService"
        groups: ["group3"]

    - name: "::Facebook posts::"
      type: allow
      methods: GET
      indices: ["facebook"]
      proxy_auth:
        proxy_auth_config: "proxy1"
        users: ["*"]
      groups_provider_authorization:
        user_groups_provider: "GroupsService"
        groups: ["group1"]
        cache_ttl_in_sec: 60

    proxy_auth_configs:

    - name: "proxy1"
      user_id_header: "X-Auth-Token"                           # default X-Forwarded-User

    user_groups_providers:

    - name: GroupsService
      groups_endpoint: "http://localhost:8080/groups"
      auth_token_name: "token"
      auth_token_passed_as: QUERY_PARAM                        # HEADER OR QUERY_PARAM
      response_groups_json_path: "$..groups[?(@.name)].name"   # see: https://github.com/json-path/JsonPath
      cache_ttl_in_sec: 60

In example above, a user is authenticated by reverse proxy and then external service is asked for groups for that user. If groups returned by the service contain any group declared in groups list, user is authorized and rule matches.

To define user groups provider you should specify:

• name for service (then this name is used as id in user_groups_provider attribute of groups_provider_authorization rule)
• groups_endpoint - service with groups endpoint (GET request)
• auth_token_name - user identifier will be passed with this name
• auth_token_passed_as - user identifier can be send using HEADER or QUERY_PARAM
• response_groups_json_path - response can be unrestricted, but you have to specify JSON Path for groups name list (see example in tests)

As usual, the cache behaviour can be defined at service level or/and at rule level.

3. Restart Elasticsearch

For other use cases and finer access control have a look at the official documentation to see the full list of supported rules

Important!

Before going to production, read this.

disallow explicit indices

When you want to restrict access to certain indices, in order to prevent the user from overriding the index which has been specified in the URL, add this setting to the config.yml file:

rest.action.multi.allow_explicit_index: false

The default value is true, but when set to false, Elasticsearch will reject requests that have an explicit index specified in the request body.

Use hashed credentials

Plain text auth_key is is great for testing, but remember to replace it with auth_key_sha256!

Key Features

Tiny memory overhead, blazing fast networking 🚀

Other security plugins are replacing the high performance, Netty based, embedded REST API of Elasticsearch with Tomcat, Jetty or other cumbersome XML based JEE madness.

This plugin instead is just a lightweight pure-Java filtering layer. Even the SSL layer is provided as an extra Netty transport handler.

Less moving parts

Some suggest to spin up a new HTTP proxy (Varnish, NGNix, HAProxy) between ES and clients to filter out malicious access with regular expressions on HTTP methods and paths. This is a bad idea for two reasons:

• You're introducing more complexity in your architecture.
• Reasoning about security at HTTP level is risky, flaky and less granular than controlling access at the internal ElasticSearch protocol level.

The only clean way to do the access control is AFTER ElasticSearch has parsed the queries.

Just set a few rules with this plugin and confidently open it up to the external world.

An easy, flexible access control list

Build your ACL from simple building blocks (rules) i.e.:

IP level Rules

• hosts a list of origin IP addresses or subnets

HTTP level rules

• api_keys a list of api keys passed in via header X-Api-Key
• methods a list of HTTP methods
• accept_x-forwarded-for_header interpret the X-Forwarded-For header as origin host (useful for AWS ELB and other reverse proxies)
• auth_key_sha1 HTTP Basic auth (credentials stored as hashed strings).
• uri_re Match the URI path as a regex.

ElasticSearch internal protocol level rules

• indices indices (aliases and wildcards work)
• actions list of ES actions (e.g. "cluster:" , "indices:data/write/", "indices:data/read*")

ElasticSearh level macro-rules

• kibana_access captures the read-only, read-only + new visualizations/dashboards, read-write use cases of Kibana.

All the available rules in detail

• Official website detailed documentation

History

This project was incepted in this StackOverflow thread.

Credits

Thanks Ivan Brusic for publishing this guide