For Elasticsearch
ReadonlyREST is a light weight Elasticsearch plugin that adds encryption, authentication, authorization and access control capabilities to Elasticsearch embedded REST API. The core of this plugin is an ACL engine that checks each incoming request through a sequence of rules a bit like a firewall. There are a dozen rules that can be grouped in sequences of blocks and form a powerful representation of a logic chain.
The Elasticsearch plugin known as
ReadonlyREST Free is released under the GPLv3 license, or alternatively, a commercial license (see ReadonlyREST Embedded) and lays the technological foundations for the companion Kibana plugin which is released in two versions: ReadonlyREST PRO and ReadonlyREST Enterprise.Unlike the Elasticsearch plugin, the Kibana plugins are commercial only. But rely on the Elasticsearch plugin in order to work.
In this document we are going to describe how to operate the Elasticsearch plugin in all its features. Once installed, this plugin will greatly extend the Elasticsearch HTTP API (port 9200), adding numerous extra capabilities:
- Encryption: transform the Elasticsearch API from HTTP to HTTPS
- Authentication: require credentials
- Authorization: declare groups of users, permissions and partial access to indices.
- Access control: complex logic can be modeled using an ACL (access control list) written in YAML.
- Audit logs: a trace of the access requests can be logged to file or index (or both).
The following diagram models an instance of Elasticsearch with the ReadonlyREST plugin installed, and configured with SSL encryption and an ACL with at least one "allow" type ACL block.
readonlyrest request processing diagram
- 1.The User Agent (i.e. cURL, Kibana) sends a search request to Elasticsearch using the port 9200 and the HTTPS URL schema.
- 2.The HTTPS filter in ReadonlyREST plugin unwraps the SSL layer and hands over the request to Elasticsearch HTTP stack
- 3.The HTTP stack in Elasticsearch parses the HTTP request
- 4.The HTTP handler in Elasticsearch extracts the indices, action, request type and creates a
SearchRequest(internal Elasticsearch format). - 5.The SearchRequest goes through the ACL (access control list), external systems like LDAP can be asynchronously queried, and an exit result is eventually produced.
- 6.The exit result is used by the audit log serializer, to write a record to index and/or Elasticsearch log file
- 7.If no ACL block was matched, or if a
type: forbidblock was matched, ReadonlyREST does not forward the search request to the search engine, and creates an "unauthorized" HTTP response. - 8.In case the ACL matched an
type: allowblock, the request is forwarded to the search engine - 9.The Elasticsearch code creates a search response containing the results of the query10.The search response is converted to an HTTP response by the Elasticsearch code
- 10.The HTTP response flows back to ReadonlyREST's HTTPS filter and to the User agent
To install ReadonlyREST plugin for Elasticsearch:
From the official download page. Select your Elasticsearch version and send yourself a link to the compatible ReadonlyREST zip file.
bin/elasticsearch-plugin install file:///tmp/readonlyrest-X.Y.Z_esW.Q.U.zip
Notice how we need to type in the format
file:// + absolute path (yes, with three slashes).@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: plugin requires additional permissions @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
When prompted about additional permissions, answer y.
If you are using Elasticsearch 8.0.x or newer, you need an extra post-installation step. Depending on the Elasticsearch version, this command might tweak the main Elasticsearch installation files and/or copy some jars to
plugins/readonlyrest directory.# Patch ES
$ jdk/bin/java -jar plugins/readonlyrest/ror-tools.jar patch
⚠️IMPORTANT: for Elasticsearch 8.3.x or newer, the patching operation requires
root user privileges.You can verify if Elasticsearch was correctly patched using command
verify:$ jdk/bin/java -jar plugins/readonlyrest/ror-tools.jar verify
Please note that the tool assumes that you run it from the root of your ES installation directory or the default installation directory is
/usr/share/elasticsearch. But if you want or need, you can instruct it where your Elasticsearch is installed by executing one of tool's command with --es-path parameter:$ jdk/bin/java -jar plugins/readonlyrest/ror-tools.jar patch --es-path /my/custom/path/to/es/folder
or
$ jdk/bin/java -jar plugins/readonlyrest/ror-tools.jar verify --es-path /my/custom/path/to/es/folder
NB: In case of any problems with the
ror-tools, please call:$ jdk/bin/java -jar plugins/readonlyrest/ror-tools.jar --help
Create and edit the
readonlyrest.yml settings file in the same directory where elasticsearch.yml is found: vim $ES_PATH_CONF/conf/readonlyrest.yml
Now write some basic settings, just to get started. In this example we are going to tell ReadonlyREST to require HTTP Basic Authentication for all the HTTP requests, and return
401 Unauthorized otherwise.readonlyrest:
access_control_rules:
- name: "Require HTTP Basic Auth"
type: allow
auth_key: user:password
(applies to ES 6.4.0 or greater)
ReadonlyREST and X-Pack security module can't run together, so the latter needs to be disabled.
Edit
elasticsearch.yml and append xpack.security.enabled: false. vim $ES_PATH_CONF/conf/elasticsearch.yml
bin/elasticsearch
or:
service start elasticsearch
Depending on your environment.
Now you should be able to see the logs and ReadonlyREST related lines like the one below:
[2018-09-18T13:56:25,275][INFO ][o.e.p.PluginsService ] [c3RKGFJ] loaded plugin [readonlyrest]
The following command should succeed, and the response should show a status code 200.
curl -vvv -u user:password "http://localhost:9200/_cat/indices"
The following command should not succeed, and the response should show a status code 401
curl -vvv "http://localhost:9200/_cat/indices"
To upgrade ReadonlyREST for Elasticsearch:
Either kill the process manually, or use:
service stop elasticsearch
depending on your environment.
If you are using Elasticsearch 8.0.x or newer, you need an extra pre-uninstallation step. This will remove all previously copied jars from ROR's installation directory.
# Unpatch ES
$ jdk/bin/java -jar plugins/readonlyrest/ror-tools.jar unpatch
You can verify if Elasticsearch was correctly unpatched using command
verify:$ jdk/bin/java -jar plugins/readonlyrest/ror-tools.jar verify
NB: In case of any problems with the
ror-tools, please call:$ jdk/bin/java -jar plugins/readonlyrest/ror-tools.jar --help
bin/elasticsearch-plugin remove readonlyrest
bin/elasticsearch-plugin install file://<download_dir>/readonlyrest-<ROR_VERSION>_es<ES_VERSION>.zip
e.g.
bin/elasticsearch-plugin install file:///tmp/readonlyrest-1.16.15_es6.1.1.zip
If you are using Elasticsearch 8.0.x or newer, you need an extra post-installation step. Depending on the Elasticsearch version, this command might tweak the main Elasticsearch installation files and/or copy some jars to
plugins/readonlyrest directory.# Patch ES
$ jdk/bin/java -jar plugins/readonlyrest/ror-tools.jar patch
⚠️IMPORTANT: for Elasticsearch 8.3.x or newer, the patching operation requires
root user privileges.You can verify if Elasticsearch was correctly patched using command
verify:$ jdk/bin/java -jar plugins/readonlyrest/ror-tools.jar verify
NB: In case of any problems with the
ror-tools, please call:$ jdk/bin/java -jar plugins/readonlyrest/ror-tools.jar --help
bin/elasticsearch
or:
service start elasticsearch
Depending on your environment.
Now you should be able to see the logs and ReadonlyREST related lines like the one below:
[2018-09-18T13:56:25,275][INFO ][o.e.p.PluginsService ] [c3RKGFJ] loaded plugin [readonlyrest]
Either kill the process manually, or use:
service stop elasticsearch
depending on your environment.
If you are using Elasticsearch 8.0.x or newer, you need an extra pre-uninstallation step. This will remove all previously copied jars from ROR's installation directory.
# Unpatch ES
$ jdk/bin/java -jar plugins/readonlyrest/ror-tools.jar unpatch
You can verify if Elasticsearch was correctly unpatched using command
verify:$ jdk/bin/java -jar plugins/readonlyrest/ror-tools.jar verify
NB: In case of any problems with the
ror-tools, please call:$ jdk/bin/java -jar plugins/readonlyrest/ror-tools.jar --help
bin/elasticsearch-plugin remove readonlyrest
bin/elasticsearch
or:
service start elasticsearch
Depending on your environment.
Unless some advanced features are being used (see below),this Elasticsearch plugin operates like a lightweight, stateless filter glued in front of Elasticsearch HTTP API. Therefore it's sufficient to install the plugin only in the nodes that expose the HTTP interface (port 9200).
Installing ReadonlyREST in a dedicated node has numerous advantages:
- No need to restart all nodes, only the one you have installed the plugin into.
- No need to restart all nodes for updating the security settings
- No need to restart all nodes when a security update is out
- Less complexity on the actual cluster nodes.
For example, if we want to move to HTTPS all the traffic coming from Logstash into a 9 nodes Elasticsearch cluster which has been running stable in production for a while, it's not necessary to install ReadonlyREST plugin in all the nodes.
Creating a dedicated, lightweight ES node where to install ReadonlyREST:
- 1.
- 2.Create a new, lightweight, dedicated node without shards, nor master eligibility.
- 3.
- 4.Configure Logstash to connect to the new node directly in HTTPS.
⚠️IMPORTANT By default when
fields rule is used, it's required to install ReadonlyREST plugin in all the data nodes.The core of this plugin is an ACL (access control list). A logic structure very similar to the one found in firewalls. The ACL is part of the plugin configuration, and it's written in YAML.
- The ACL is composed of an ordered sequence of named blocks
- Each block contains some rules, and a policy (forbid or allow)
- HTTP requests run through the blocks, starting from the first,
- The first block that satisfies all the rules decides if to forbid or allow the request (according to its policy).
- If none of the block match, the request is rejected
⚠️IMPORTANT: The ACL blocks are evaluated sequentially, therefore the ordering of the ACL blocks is crucial. The order of the rules inside an ACL block instead, is irrelevant.
readonlyrest:
access_control_rules:
- name: "Block 1 - only Logstash indices are accessible"
type: allow # <-- default policy type is "allow", so this line could be omitted
indices: ["logstash-*"] # <-- This is a rule
- name: "Block 2 - Blocking everything from a network"
type: forbid
hosts: ["10.0.0.0/24"] # <-- this is a rule
An Example of Access Control List (ACL) made of 2 blocks.
The YAML snippet above, like all of this plugin's settings should be saved inside the
readonlyrest.yml file. Create this file on the same path where elasticsearch.yml is found.TIP: If you are a subscriber of the PRO or Enterprise Kibana plugin, you can edit and refresh the settings through a GUI. For more on this, see the documentation for ReadonlyREST plugin for Kibana.
An SSL encrypted connection is a prerequisite for secure exchange of credentials and data over the network. To make use of it you need to have certificate and private key. Letsencrypt certificates work just fine (see tutorial below). Before ReadonlyREST 1.44.0 both files, certificate and private key, had to be placed inside PKCS#12 or JKS keystore. See the tutorial at the end of this section. ReadonlyREST 1.44.0 or newer supports using PEM files directly, without the need to use a keystore.
ReadonlyREST can be configured to encrypt network traffic on two independent levels:
- 1.HTTP (port 9200)
- 2.Internode communication - transport module (port 9300)
An Elasticsearch node with ReadonlyREST can join an existing cluster based on native SSL fromxpack.securitymodule. This configuration is useful to deploy ReadonlyREST Enterprise for Kibana to an existing large production cluster without disrupting any configuration. More on this in the dedicated paragraph of this section.
It wraps connection between client and exposed REST API in SSL context, hence making it encrypted and secure. ⚠️IMPORTANT: To enable SSL for REST API, open
elasticsearch.yml and append this one line:http.type: ssl_netty4
Now in
readonlyrest.yml add the following settings:readonlyrest:
ssl:
keystore_file: "keystore.jks" # or keystore.p12 for PKCS#12 format
keystore_pass: readonlyrest
key_pass: readonlyrest
The keystore should be stored in the same directory with
elasticsearch.yml and readonlyrest.yml.This option encrypts communication between nodes forming Elasticsearch cluster.
⚠️IMPORTANT: To enable SSL for internode communication open
elasticsearch.yml and append this one line:transport.type: ror_ssl_internode
In
readonlyrest.yml following settings must be added (it's just example configuration presenting most important properties):readonlyrest:
ssl_internode:
keystore_file: "keystore.jks" # or keystore.p12 for PKCS#12 format
keystore_pass: readonlyrest
key_pass: readonlyrest
Similar to
ssl for HTTP, the keystore should be stored in the same directory with elasticsearch.yml and readonlyrest.yml. This config must be added to all nodes taking part in encrypted communication within cluster.Internode communication with XPack nodes
It is possible to set up internode SSL between ROR and XPack nodes. It works only for ES above 6.3.
To set up cluster in such configuration you have to generate certificate for ROR node according to this description https://www.elastic.co/guide/en/elasticsearch/reference/current/security-basic-setup.html#generate-certificates.
Generated
elastic-certificates.p12 could be then used in ROR node with such configurationreadonlyrest:
ssl_internode:
enable: true
keystore_file: "elastic-certificates.p12"
keystore_pass: [ password for generated certificate ]
key_pass: [ password for generated certificate ]
truststore_file: "elastic-certificates.p12"
truststore_pass: [ password for generated certificate ]
client_authentication: true # default: false
certificate_verification: true # certificate verification is enabled by default on XPack nodes
By default certificate verification is disabled. It means that certificate is not validated in any way, so all certificates are accepted. It is useful on local/test environment, where security is not the most important concern. On production environment it is adviced to enable this option. It can be done by means of:
certificate_verification: true
under
ssl_internode section. This option is applicable only for internode SSL.By default the client authentication is disabled. When enabled, the server asks the client about its certificate, so ES is able to verify the client's identity. It can be enabled by means of:
client_authentication: true
under
ssl section. This option is applicable for REST API external SSL and internode SSL.Optionally, it's possible to specify a list allowed SSL protocols and SSL ciphers. Connections from clients that don't support the listed protocols or ciphers will be dropped.
readonlyrest:
ssl:
# put the keystore in the same dir with elasticsearch.yml
keystore_file: "keystore.jks"
keystore_pass: readonlyrest
key_pass: readonlyrest
allowed_protocols: [TLSv1.2]
allowed_ciphers: [TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256]
ReadonlyREST will log a list of available ciphers and protocols supported by the current JVM at startup.
[2018-01-03T10:09:38,683][INFO ][t.b.r.e.SSLTransportNetty4] ROR SSL: Available ciphers: TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,TLS_RSA_WITH_AES_128_GCM_SHA256,TLS_RSA_WITH_AES_128_CBC_SHA
[2018-01-03T10:09:38,684][INFO ][t.b.r.e.SSLTransportNetty4] ROR SSL: Restricting to ciphers: TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
[2018-01-03T10:09:38,684][INFO ][t.b.r.e.SSLTransportNetty4] ROR SSL: Available SSL protocols: TLSv1,TLSv1.1,TLSv1.2
[2018-01-03T10:09:38,685][INFO ][t.b.r.e.SSLTransportNetty4] ROR SSL: Restricting to SSL protocols: TLSv1.2
[2018-0
ReadonlyREST allows using custom truststore, replacing (provided by JRE) default one. Custom truststore can be set with:
truststore_file: "truststore.jks"
truststore_pass: truststorepass
under
ssl or ssl_internode section. This option is applicable for both ssl modes - external ssl and internode ssl. The truststore should be stored in the same directory with elasticsearch.yml and readonlyrest.yml (like keystore). When not specifed, ReadonlyREST uses default truststore.If you are using ReadonlyREST 1.44.0 or newer then you are able to use PEM files directly without the need of placing them inside a keystore or truststore.
To use PEM files instead of keystore file, use such configuration instead of
keystore_file, keystore_pass, key_pass fields:server_certificate_key_file: private_key.pem
server_certificate_file: cert_chain.pem
To use PEM file instead of truststore file, use such configuration instead of
truststore_file, truststore_pass fields:client_trusted_certificate_file: trusted_certs.pem
We are going to show how to first add all the certificates and private key into PKCS#12 keystore, and then (optionally) converting it to JKS keystore. ReadonlyREST supports both formats.
⚠️IMPORTANT: if you are using ReadonlyREST in version above 1.44.0 then you don't have to create a keystore. You are able to use PEM files directly using the description above.
This tutorial can be a useful example on how to use certificates from other providers.
1. Create keys
./letsencrypt-auto certonly --standalone -d DOMAIN.TLD -d DOMAIN_2.TLD --email [email protected]
Now change to the directory (probably /etc/letsencrypt/live/DOMAIN.tld) where the certificates were created.
2. Create a PKCS12 keystore with the full chain and private key
openssl pkcs12 -export -in fullchain.pem -inkey privkey.pem -out pkcs.p12 -name NAME
3. Convert PKCS12 to JKS Keystore (Optional)
The STORE_PASS is the password which was entered in step 2) as a password for the pkcs12 file.
keytool -importkeystore -deststorepass PASSWORD_STORE -destkeypass PASSWORD_KEYPASS -destkeystore keystore.jks -srckeystore pkcs.p12 -srcstoretype PKCS12 -srcstorepass STORE_PASS -alias NAME
If you happen to get a
java.io.IOException: failed to decrypt safe contents entry: javax.crypto.BadPaddingException: Given final block not properly padded, you have probably forgotten to enter the correct password from step 2.Every block must have at least the
name field, and optionally a type field valued either "allow" or "forbid". If you omit the type, your block will be treated as type: allow by default.Keep in mind that ReadonlyREST ACL is a white list, so by default all request are blocked, unless you specify a block of rules that allowes all or some requests.
namewill appear in logs, so keep it short and distinctive.typecan be eitheralloworforbid. Can be omitted, default isallow.
- name: "Block 1 - Allowing anything from localhost"
type: allow
# In real life now you should increase the specificity by adding rules here (otherwise this block will allow all requests!)
Example: the simplest example of an allow block.
⚠️IMPORTANT: if no blocks are configured, ReadonlyREST rejects all requests.
ReadonlyREST access control rules allow to take decisions on three levels:
- Network level
- HTTP level
- Elasticsearch level
Please refrain from using HTTP level rules to protect certain indices or limit what people can do to an index. The level of control at this level is really coarse, especially because Elasticsearch REST API does not always respect RESTful principles. This makes of HTTP a bad abstraction level to write ACLs in Elasticsearch all together.
The only clean and exhaustive way to implement access control is to reason about requests AFTER ElasticSearch has parsed them. Only then, the list of affected indices and the action will be known for sure. See Elasticsearch level rules.
These are the most basic rules. It is possible to allow/forbid requests originating from a list of IP addresses, host names or IP networks (in slash notation).
hosts: ["10.0.0.0/24"] Match a request whose origin IP address (also called origin address, or OA in logs) matches one of the specified IP addresses or subnets.hosts_local: ["127.0.0.1", "127.0.0.2"] Match a request whose destination IP address (called DA in logs) matches one of the specified IP addresses or subnets. This finds application when Elasticsearch HTTP API is bound to multiple IP addresses.accept_x-forwarded-for_header: false⚠️DEPRECATED (use
x_forwarded_for instead) A modifier for hosts rule: if the origin IP won't match, fallback to check the X-Forwarded-For headerx_forwarded_for: ["192.168.1.0/24"]Behaves exactly like
hosts, but gets the source IP address (a.k.a. origin address, OA in logs) inside the X-Forwarded-For header only (useful replacement to hostsrule when requests come through a load balancer like AWS ELB)Load balancers
This is a nice tip if your Elasticsearch is behind a load balancer. If you want to match all the requests that come through the load balancer, use
x_forwarded_for: ["0.0.0.0/0"]. This will match the requests with a valid IP address as a value of the X-Forwarded-For header.DNS lookup caching
It's worth to note that resolutions of DNS are going to be cached by JVM. By default successfully resolved IPs will be cached forever (until Elasticsearch is restarted) for security reasons. However, this may not always be the desired behaviour, and it can be changed by adding the following JVM options either in the jvm.options file or declaring the ES_JAVA_OPTS environment variable:
sun.net.inetaddr.ttl=TTL_VALUE (or/and sun.net.inetaddr.negative.ttl=TTL_VALUE). More details about the problem can be found here.methods: [GET, DELETE]Match requests with HTTP methods specified in the list. N.B. Elasticsearch HTTP stack does not make any difference between HEAD and GET, so all the HEAD request will appear as GET.
headers: ["h1:x*y","~h2:*xy"]Match if all the HTTP headers in the request match the defined patterns in headers rule. This is useful in conjunction with proxy_auth, to carry authorization information (i.e. headers:
x-usr-group: admins).The
~ sign is a pattern negation, so eg. ~h2:*xy means: match if h2 header's value does not match the pattern *xy, or h2 is not present at all.headers_and: ["hdr1:val_*xyz","~hdr2:xyz_*"]Alias for
headers ruleheaders_or: ["x-myheader:val*","~header2:*xy"]Match if at least one the specified HTTP headers
key:value pairs is matched.uri_re: ["^/secret-index/.*", "^/some-index/.*"]☠️HACKY (try to use indices/actions rule instead)
Match if at least one specifed regular expression matches requested URI.
maxBodyLength: 0Match requests having a request body length less or equal to an integer. Use
0 to match only requests without body.NB: Elasticsearch HTTP API breaks the specifications, nad GET requests might have a body length greater than zero.
api_keys: [123456, abcdefg]A list of api keys expected in the header
X-Api-Keyindices: ["sales", "logstash-*"]Matches if the request involves a set of indices whose name is "sales", or starts with the string "logstash-", or a combination of both.
If a request involves a wildcard (i.e. "logstash-*", "*"), this is first expanded to the list of available indices, and then treated normally as follows:
- Requests that do not involve any indices (cluster admin, etc) result in a "match".
- Requests that involve only allowed indices result in a "match".
- Requests that involve a mix of allowed and prohibited indices, are rewritten to only involve allowed indices, and result in a "match".
- Requests that involve only prohibited indices result in a "no match". And the ACL evaluation moves on to the next block.
The rejection message and HTTP status code returned to the requester are chosen carefully with the main intent to make ES behave like the prohibited indices do not exist at all.
The rule has also an extended version:
indices:
patterns: ["sales", "logstash-*"]`
must_involve_indices: false
The definition above has the same meaning as the shortest version shown at the beginning of this section. By default the rule will be matched when a request doesn't involve indices (eg. /_cat/nodes request). But we can change the behaviour by configuring
must_involve_indices: true - in this case the request above will be rejected by the rule.In detail, with examples
In ReadonlyREST we roughly classify requests as:
- "read": the request will not change the data or the configuration of the cluster
- "write": when allowed, the request changes the internal state of the cluster or the data.
If a read request asks for a some indices they have permissions for and some indices that they do NOT have permission for, the request is rewritten to involve only the subset of indices they have permission for. This is behaviour is very useful in Kibana: different users can see the same dashboards with data from only their own indices.
When the subset of indices is empty, it means that user are not allowed to access requested indices. In multitenancy environment we should consider two options:
- requested indices don't exist
- requested indices exist but logged user is not authorized to access them
For both of these cases ROR is going to return HTTP 404 or HTTP 200 with an empty response. The same behaviour will be observed for ES with ROR disabled (for nonexistent index). If an index does exist, but a user is not authorized to access it, ROR is going to pretend that the index doesn't exist and a response will be the same like the index actually did not exist. See detailed example.
It's also worth mentioning, that when
prompt_for_basic_auth is set to true (that is, the default value), ROR is going to return 401 instead of 404 HTTP status code. It is relevant for users who don't use ROR Kibana's plugin and who would like to take advantage of default Kibana's behaviour which shows the native browser basic auth dialog, when it receives HTTP 401 response.If a write request wants to write to indices they don't have permission for, the write request is rejected.
Requests related to templates
Templates are also connected with indices, but rather indirectly. An index template has index patterns and could also have aliases. During an index template creation or modification, ROR checks if index patterns and aliases, defined in a request body, are allowed. When a user tries to remove or get template by name, ROR checks if the template can be considered as allowed for the user, and based on that information, it allows/forbids to remove or see it. See details.
actions: ["indices:data/read/*"]Match if the request action starts with "indices:data/read/".
In Elasticsearch, each request carries only one action. We extracted from Elasticsearch source code the full list of valid action strings as of all Elasticsearch versions. Please see the dedicated section to find the actions list of your specific Elasticsearch version.
Example actions (see above for the full list):
"cluster:admin/data_frame/delete"
"cluster:admin/data_frame/preview"
...
"cluster:monitor/data_frame/stats/get"
"cluster:monitor/health"
"cluster:monitor/main"
"cluster:monitor/nodes/hot_threads"
"cluster:monitor/nodes/info"
...
"indices:admin/aliases"
"indices:admin/aliases/get"
"indices:admin/analyze"
...
"indices:data/read/get"
"indices:data/read/mget"
"indices:data/read/msearch"
"indices:data/read/msearch/template"
...
"indices:data/write/bulk"
"indices:data/write/bulk_shard_operations[s]"
"indices:data/write/delete"
"indices:data/write/delete/byquery"
"indices:data/write/index"
"indices:data/write/reindex"
...
many more...
kibana_access: roEnables the minimum set of actions necessary for browsers to use Kibana.
This "macro" rule allows the minimum set of actions necessary for a browser to use Kibana. This rule allows a set of actions towards the designated kibana index (see
kibana_index rule - defaults to ".kibana"), plus a stricter subset of read-only actions towards other indices, which are considered "data indices".The idea is that with one single rule we allow the bare minimum set of index+action combinations necessary to support a Kibana browsing session.
Possible access levels:
ro_strict: the browser has a read-only view on Kibana dashboards and settings and all other indices.ro: some write requests can go through to the.kibanaindex so that UI state in discover can be saved and short urls can be created.rw: some more actions will be allowed towards the.kibanaindex only, so Kibana dashboards and settings can be modified.admin: like above, but has additional permissions to use the ReadonlyREST PRO/Enterprise Kibana app.
NB: The "admin" access level does not mean the user will be allowed to access all indices/actions. It's just like "rw" with settings changes privileges. If you want really unrestricted access for your Kibana user, including ReadonlyREST PRO/Enterprise app, set
kibana_access: unrestricted. You can use this rule with the users rule to restrict access to selected admins.This rule is often used with the
indices rule, to limit the data a user is able to see represented on the dashboards. In that case do not forget to allow the custom kibana index in the indices rule!kibana_index: .kibana-user1Default value is
.kibanaSpecify to what index we expect Kibana to attempt to read/write its settings (use this together with
kibana.index setting in kibana.yml.)This value directly affects how
kibana_access works because at all the access levels (yes, even admin), kibana_access rule will not maatch any write request in indices that are not the designated kibana index.If used in conjunction with ReadonlyREST Enterprise, this rule enables multi tenancy, because in ReadonlyREST, a tenancy is identified with a set of Kibana configurations, which are by design collected inside a kibana index (default:
.kibana).snapshots: ["[email protected]{user}_*"]Restrict what snapshots names can be saved or restored
repositories: ["[email protected]{user}_*"]Restrict what repositories can snapshots be saved into
filter: '{"query_string":{"query":"user:@{user}"}}'This rule enables Document Level Security (DLS). That is: return only the documents that satisfy the boolean query provided as an argument.
This rule lets you filter the results of a read request using a boolean query. You can use dynamic variables i.e.
@{user} (see dedicated paragraph) to inject a user name or some header values in the query, or even environmental variables.Example: per-user index segmentation
In the index "test-dls", each user can only search documents whose field "user" matches their user name. I.e. A user with username "paul" requesting all documents in "test-dls" index, won't see returned a document containing a field
"user": "jeff" .- name: "::PER-USER INDEX SEGMENTATION::"
proxy_auth: "*"
indices: ["test-dls"]
filter: '{"bool": { "must": { "match": { "user": "@{user}" }}}}'
Example 2: Prevent search of "classified" documents.
In this example, we want to avoid that users belonging to group "press" can see any document that has a field "access_level" with the value "CLASSIFIED". And this policy is applied to all indices (no indices rule is specified).
- name: "::Press::"
groups: ["press"]
filter: '{"bool": { "must_not": { "match": { "access_level": "CLASSIFIED" }}}}'
⚠️IMPORTANT The
filterand fields rules will only affect "read" requests, therefore "write" requests will not match because otherwise it would implicitly allow clients to "write" without the filtering restriction. For reference, this behaviour is identical to x-pack and search guard.⚠️IMPORTANT Beginning with version 1.27.0 all ROR internal requests from kibana will not match blocks containing
filter and/or fields rules. There requests are used to perform kibana login and dynamic config reload.If you want to allow write requests (i.e. for Kibana sessions), just duplicate the ACL block, have the first one with
filter and/or fields rule, and the second one without.This rule enables Field Level Security (FLS). That is:
- for responses where fields with values are returned (e.g. Search/Get API) - filter and show only allowed fields
- make not allowed fields unsearchable - used in QueryDSL requests (e.g. Search/MSearch API) do not have impact on search result.
In other words: FLS protects from usage some not allowed fields for a certain user. From user's perspective it seems like such fields are nonexistent.
Definition
Field rule definition consists of two parts:
- A non empty list of fields (blacklisted or whitelisted) names. Supports wildcards and user runtime variables.
⚠️IMPORTANT With default FLS engine it's required to install ReadonlyREST plugin in all the data nodes. Different configurations allowing to avoid such requirement are described in engine details.
Field names
Fields can be defined using two access modes: blacklist and whitelist.
Blacklist mode (recommended)
Specifies which fields should not be allowed prefixed with
~ (other fields from mapping become allowed implicitly). Example:fields: ["~excluded_fields_prefix_*", "~excluded_field", "~another_excluded_field.nested_field"]Return documents but deprived of the fields that:
- start with
excluded_fields_prefix_ - are equal to
excluded_field - are equal to
another_excluded_field.nested_field
Whitelist mode
Specifies which fields should be allowed explicitly (other fields from mapping become not allowed implicitly). Example:
fields: ["allowed_fields_prefix_*", "_*", "allowed_field.nested_field.text"]Return documents deprived of all the fields, except the ones that:
- start with
allowed_fields_prefix_ - start with underscore
- are equal to
allowed_field.nested_field.text
NB: You can only provide a full black list or white list. Grey lists (i.e.
["~a", "b"]) are invalid settings and ROR will refuse to boot up if this condition is detected.Example: hide prices from catalogue indices
- name: "External users - hide prices"
fields: ["~price"]
indices: ["catalogue_*"]
⚠️IMPORTANT Any metadata fields e.g.
_id or _index can not be used in fields rule.⚠️IMPORTANT The
filterand fields rules will only affect "read" requests, therefore "write" requests will not match because otherwise it would implicitly allow clients to "write" without the filtering restriction. For reference, this behaviour is identical to x-pack and search guard.⚠️IMPORTANT Beginning with version 1.27.0 all ROR internal requests from kibana will not match blocks containing
filter and/or fields rules. There requests are used to perform kibana login and dynamic config reload.If you want to allow write requests (i.e. for Kibana sessions), just duplicate the ACL block, have the first one with
filter and/or fields rule, and the second one without.A normal Kibana session interacts with Elasticsearch using a mix of actions which we can roughly group in two macro categories of "read" and "write" actions. However the
fields and filter rules will only match read requests. They will also block ROR internal request used to log in to kibana and reload config. This means that a complete Kibana session cannot anymore be entirely matched by a single ACL block like it normally would.For example, this ACL block would perfectly support a complete Kibana session. That is, 100% of the actions (browser HTTP requests) would be allowed by this ACL block.
- name: "::RW_USER::"
auth_key: rw_user:pwd
kibana_access: rw
indices: ["r*", ".kibana"]
However, when we introduce a filter (or fields) rule, this block will be able to match only some of the actions (only the "read" ones).
- name: "::RW_USER::"
auth_key: rw_user:pwd
kibana_access: rw # <-- won't work because of filter present in block
indices: ["r*", ".kibana"]
filter: '{"query_string":{"query":"DestCountry:FR"}}' # <-- will reject all write requests! :(
The solution is to duplicate the block. The first one will intercept (and filter!) the read requests. The second one will intercept the remaining actions. Both ACL blocks together will entirely support a whole Kibana session.
- name: "::RW_USER (filter read requests)::"
auth_key: rw_user:pwd
indices: ["r*"] # <-- DO NOT FILTER THE .kibana INDEX!
filter: '{"query_string":{"query":"DestCountry:FR"}}'
- name: "::RW_USER (allow remaining requests)::"
auth_key: rw_user:pwd
kibana_access: rw
indices: ["r*", ".kibana"]
NB: Look at how we make sure that the requests to ".kibana" won't get filtered by specifying an
indices rule in the first block.Here is another example, a bit more complex. Look at how we can duplicate the "PERSONAL_GRP" ACL block so that the read requests to the "r*" indices can be filtered, and all the other requests can be intercepted by the second rule (which is identical to the one we had before the duplication).
Before adding the
filter rule: - name: "::PERSONAL_GRP::"
groups: ["Personal"]
kibana_access: rw
indices: ["r*", "[email protected]{user}"]
kibana_hide_apps: ["readonlyrest_kbn", "timelion"]
kibana_index: "[email protected]{user}"
After adding the
filter rule (using the block duplication strategy). - name: "::PERSONAL_GRP (FILTERED SEARCH)::"
groups: ["Personal"]
indices: [ "r*" ]
filter: '{"query_string":{"query":"DestCountry:FR"}}'
- name: "::PERSONAL_GRP::"
groups: ["Personal"]
kibana_access: rw
indices: ["r*", "[email protected]{user}"]
kibana_hide_apps: ["readonlyrest_kbn", "timelion"]
kibana_index: "[email protected]{user}"
This rule allows filtering Elasticsearch responses using a list of fields. It works in very similar way to
fields rule. In contrast to fields rule, which filters out document fields, this rule filters out response fields. It doesn't make use of Field Level Security (FLS) and can be applied to every response returned by Elasticsearch.It can be configured in two modes:
- whitelist allowing only the defined fields from the response object
- blacklist filtering out (removing) only the defined fields from the response object
Blacklist mode
Specifies which fields should be filtered out by adding the ~ prefix to the field name. Other fields in the response will be implicitly allowed. For example:
response_fields: ["~excluded_fields_prefix_*", "~excluded_field", "~another_excluded_field.nested_field"]The above will return the usual response object, but deprived (if found) of the fields that:
- start with
excluded_fields_prefix_ - are equal to
excluded_field - are equal to
another_excluded_field.nested_field
Whitelist mode
In this mode rule is configured to filter out each field that isn't defined in the rule.
response_fields: ["allowed_fields_prefix_*", "_*", "allowed_field.nested_field.text"]Return response deprived of all the fields, except the ones that:
- start with
allowed_fields_prefix_ - start with underscore
- are equal to
allowed_field.nested_field.text
NB: You can only provide a full black list or white list. Grey lists (i.e.
["~a", "b"]) are invalid settings and ROR will refuse to boot up if this condition is detected.Example: allow only
cluster_name and status field in cluster health response:Without any filtering response from
/_cluster/health looks more or less like:{
"cluster_name": "ROR_SINGLE",
"status": "yellow",
"timed_out": false,
"number_of_nodes": 1,
"number_of_data_nodes": 1,
"active_primary_shards": 2,
"active_shards": 2,
"relocating_shards": 0,
"initializing_shards": 0,
"unassigned_shards": 2,
"delayed_unassigned_shards": 0,
"number_of_pending_tasks": 0,
"number_of_in_flight_fetch": 0,
"task_max_waiting_in_queue_millis": 0,
"active_shards_percent_as_number": 50.0
}
but after configuring such rule:
- name: "Filter cluster health response"
uri_re: "^/_cluster/health"
response_fields: ["cluster_name", "status"]
response from above will look like:
{
"cluster_name": "ROR_SINGLE",
"status": "yellow"
}
NB: Any response field can be filtered using this rule.
Local ReadonlyREST users are authenticated via HTTP Basic Auth. This authentication method is secure only if SSL is enabled.
auth_key: sales:p455wdAccepts HTTP Basic Auth. Configure this value in clear text. Clients will need to provide the header e.g.
Authorization: Basic c2FsZXM6cDQ1NXdk where "c2FsZXM6cDQ1NXdk" is Base64 for "sales:p455wd".⚠️IMPORTANT: this rule is handy just for tests, replace it with another rule that hashes credentials, like:
auth_key_sha512, or auth_key_unix.auth_key_sha512: 280ac6f...94bf9Accepts HTTP Basic Auth. The value is a string like
username:password hashed in SHA512. Clients will need to provide the usual Authorization header.There are also available other rules with less secure SHA algorithms
auth_key_sha256 and auth_key_sha1.The rules support also alternative syntax, where only password is hashed, eg:
auth_key_sha512: "admin:280ac6f...94bf9"In the example below
admin is the username and 280ac6f...94bf9 is the hashed secret.auth_key_pbkdf2: "KhIxF5EEYkH5GPX51zTRIR4cHqhpRVALSmTaWE18mZEL2KqCkRMeMU4GR848mGq4SDtNvsybtJ/sZBuX6oFaSg==" # logstash:logstashauth_key_pbkdf2: "logstash:JltDNAoXNtc7MIBs2FYlW0o1f815ucj+bel3drdAk2yOufg2PNfQ51qr0EQ6RSkojw/DzrDLFDeXONumzwKjOA==" # logstash:logstashAccepts HTTP Basic Auth. The value is hashed in the same way as it's done in
auth_key_sha512 rule, but it uses PBKDF2 key derivation function. At the moment there is no way to configure it, so during the hash generation, the user has to take into consideration the following PBKDF2 input parameters values:Input parameter | Value | Comment |
|---|---|---|
Pseudorandom function | HmacSHA512 | |
Salt | use hashed value as a salt | eg. hashed value = logstash:logstash, use logstash:logstash as the salt |
Iterations count | 10000 | |
Derived key length | 512 | bits |
auth_key_unix: test:$6$rounds=65535$d07dnv4N$QeErsDT9Mz.ZoEPXW3dwQGL7tzwRz.eOrTBepIwfGEwdUAYSy/NirGoOaNyPx8lqiR6DYRSsDzVvVbhP4Y9wf0 # Hashed for "test:test"⚠️IMPORTANT this hashing algorithm is very CPU intensive, so we implemented a caching mechanism around it. However, this will not protect Elasticsearch from a DoS attack with a high number of requests with random credentials.
This method is based on
/etc/shadow file syntax.If you configured sha512 encryption with 65535 rounds on your system the hash in /etc/shadow for the account
test:test will be test:$6$rounds=65535$d07dnv4N$QeErsDT9Mz.ZoEPXW3dwQGL7tzwRz.eOrTBepIwfGEwdUAYSy/NirGoOaNyPx8lqiR6DYRSsDzVvVbhP4Y9wf0readonlyrest:
access_control_rules:
- name: Accept requests from users in group team1 on index1
groups: ["team1"]
indices: ["index1"]
users:
- username: test
auth_key_unix: test:$6$rounds=65535$d07dnv4N$QeErsDT9Mz.ZoEPXW3dwQGL7tzwRz.eOrTBepIwfGEwdUAYSy/NirGoOaNyPx8lqiR6DYRSsDzVvVbhP4Y9wf0 #test:test
groups: ["team1"]
You can generate the hash with mkpasswd Linux command, you need whois package
apt-get install whois (or equivalent)mkpasswd -m sha-512 -R 65534Also you can generate the hash with a python script (works on Linux):
#!/usr/bin/python
import crypt
import random
import sys
import string
def sha512_crypt(password, salt=None, rounds=None):
if salt is None:
rand = random.SystemRandom()
salt = ''.join([rand.choice(string.ascii_letters + string.digits)
for _ in range(8)])
prefix = '$6$'
if rounds is not None:
rounds = max(1000, min(999999999, rounds or 5000))
prefix += 'rounds={0}$'.format(rounds)
return crypt.crypt(password, prefix + salt)
if __name__ == '__main__':
if len(sys.argv) > 1:
print sha512_crypt(sys.argv[1], rounds=65635)
else:
print "Argument is missing, <password>"
Finally you have to put your username at the begining of the hash with ":" separator
test:$6$rounds=65535$d07dnv4N$QeErsDT9Mz.ZoEPXW3dwQGL7tzwRz.eOrTBepIwfGEwdUAYSy/NirGoOaNyPx8lqiR6DYRSsDzVvVbhP4Y9wf0For example,
test is the username and $6$rounds=65535$d07dnv4N$QeErsDT9Mz.ZoEPXW3dwQGL7tzwRz.eOrTBepIwfGEwdUAYSy/NirGoOaNyPx8lqiR6DYRSsDzVvVbhP4Y9wf0 is the hash for test (the password is identical to the username in this example).proxy_auth: "*"Delegated authentication. Trust that a reverse proxy has taken care of authenticating the request and has written the resolved user name into the
X-Forwarded-User header. The value "*" in the example, will let this rule match any username value contained in the X-Forwarded-User header.If you are using this technique for authentication using our Kibana plugins, don't forget to add this snippet to
conf/kibana.yml:readonlyrest_kbn.proxy_auth_passthrough: trueSo that Kibana will forward the necessary headers to Elasticsearch.
users: ["root", "*@mydomain.com"]Limit access to of specific users whose username is contained or matches the patterns in the array. This rule is independent from the authentication method chosen, so it will work well in conjunction LDAP, JWT, proxy_auth, and all others.
For example: