[role="xpack"]
[[fips-140-compliance]]
=== FIPS 140-2

The Federal Information Processing Standard (FIPS) Publication 140-2, (FIPS PUB
140-2), titled "Security Requirements for Cryptographic Modules" is a U.S.
government computer security standard used to approve cryptographic modules.
{es} offers a FIPS 140-2 compliant mode and as such can run in a FIPS 140-2
configured JVM.

IMPORTANT: The JVM bundled with {es} is not configured for FIPS 140-2. You must
configure an external JDK with a FIPS 140-2 certified Java Security Provider.
Refer to the {es}
https://www.elastic.co/support/matrix#matrix_jvm[JVM support matrix] for
supported JVM configurations. See https://www.elastic.co/subscriptions[subscriptions] for required licensing.

Compliance with FIPS 140-2 requires using only FIPS approved / NIST recommended cryptographic algorithms. Generally this can be done by the following:

- Installation and configuration of a FIPS certified Java security provider.
- Ensuring the configuration of {es} is FIPS 140-2 compliant as documented below.
- Setting `xpack.security.fips_mode.enabled` to `true` in `elasticsearch.yml`. Note - this setting alone is not sufficient to be compliant
with FIPS 140-2.

[discrete]
=== Configuring {es} for FIPS 140-2

Detailed instructions for the configuration required for FIPS 140-2 compliance is beyond the scope of this document.  It is the responsibility
of the user to ensure compliance with FIPS 140-2. {es} has been tested with a specific configuration described below. However, there are
other configurations possible to achieve compliance.

The following is a high-level overview of the required configuration:

* Use an externally installed Java installation. The JVM bundled with {es} is not configured for FIPS 140-2.
* Install a FIPS certified security provider .jar file(s) in {es}'s `lib` directory.
* Configure Java to use a FIPS certified security provider (xref:java-security-provider[see below]).
* Configure {es}'s security manager to allow use of the FIPS certified provider (xref:java-security-manager[see below]).
* Ensure the keystore and truststore are configured correctly (xref:keystore-fips-password[see below]).
* Ensure the TLS settings are configured correctly (xref:fips-tls[see below]).
* Ensure the password hashing settings are configured correctly (xref:fips-stored-password-hashing[see below]).
* Ensure the cached password hashing settings are configured correctly (xref:fips-cached-password-hashing[see below]).
* Configure `elasticsearch.yml` to use FIPS 140-2 mode, see (xref:configuring-es-yml[below]).
* Verify the security provider is installed and configured correctly (xref:verify-security-provider[see below]).
* Review the upgrade considerations (xref:fips-upgrade-considerations[see below]) and limitations (xref:fips-limitations[see below]).


[discrete]
[[java-security-provider]]
==== Java security provider

Detailed instructions for installation and configuration of a FIPS certified Java security provider is beyond the scope of this document.
Specifically, a FIPS certified
https://docs.oracle.com/en/java/javase/17/security/java-cryptography-architecture-jca-reference-guide.html[JCA] and
https://docs.oracle.com/en/java/javase/17/security/java-secure-socket-extension-jsse-reference-guide.html[JSSE] implementation is required
so that the JVM uses FIPS validated implementations of NIST recommended cryptographic algorithms.

Elasticsearch has been tested with Bouncy Castle's https://repo1.maven.org/maven2/org/bouncycastle/bc-fips/1.0.2.4/bc-fips-1.0.2.4.jar[bc-fips 1.0.2.4]
and https://repo1.maven.org/maven2/org/bouncycastle/bctls-fips/1.0.17/bctls-fips-1.0.17.jar[bctls-fips 1.0.17].
Please refer to the {es}
https://www.elastic.co/support/matrix#matrix_jvm[JVM support matrix] for details on which combinations of JVM and security provider are supported in FIPS mode. Elasticsearch does not ship with a FIPS certified provider. It is the responsibility of the user
to install and configure the security provider to ensure compliance with FIPS 140-2. Using a FIPS certified provider will ensure that only
approved cryptographic algorithms are used.

To configure {es} to use additional security provider(s) configure {es}'s <<set-jvm-options, JVM property>> `java.security.properties` to point to a file
(https://raw.githubusercontent.com/elastic/elasticsearch/main/build-tools-internal/src/main/resources/fips_java.security[example]) in {es}'s
`config` directory. Ensure the FIPS certified security provider is configured with the lowest order. This file should contain the necessary
configuration to instruct Java to use the FIPS certified security provider.

[discrete]
[[java-security-manager]]
==== Java security manager

All code running in {es} is subject to the security restrictions enforced by the Java security manager.
The security provider you have installed and configured may require additional permissions in order to function correctly. You can grant these permissions by providing your own
https://docs.oracle.com/javase/8/docs/technotes/guides/security/PolicyFiles.html#FileSyntax[Java security policy]

To configure {es}'s security manager configure the JVM property `java.security.policy` to point a file
(https://raw.githubusercontent.com/elastic/elasticsearch/main/build-tools-internal/src/main/resources/fips_java.policy[example])in {es}'s
`config` directory with the desired permissions. This file should contain the necessary configuration for the Java security manager
to grant the required permissions needed by the security provider.


[discrete]
[[keystore-fips-password]]
==== {es} Keystore

FIPS 140-2 (via NIST Special Publication 800-132) dictates that encryption keys should at
least have an effective strength of 112 bits.
As such, the {es} keystore that stores the node's <<secure-settings,secure settings>>
needs to be password protected with a password that satisfies this requirement.
This means that the password needs to be 14 bytes long which is equivalent
to a 14 character ASCII encoded password, or a 7 character UTF-8 encoded password.
You can use the <<elasticsearch-keystore, elasticsearch-keystore passwd>> subcommand to change or set the
password of an existing keystore.
Note that when the keystore is password-protected, you must supply the password each time
Elasticsearch starts.

[discrete]
[[fips-tls]]
==== TLS

SSLv2 and SSLv3 are not allowed by FIPS 140-2, so `SSLv2Hello` and `SSLv3` cannot
be used for <<ssl-tls-settings,`ssl.supported_protocols`>>.

NOTE: The use of TLS ciphers is mainly governed by the relevant crypto module
(the FIPS Approved Security Provider that your JVM uses). All the ciphers that
are configured by default in {es} are FIPS 140-2 compliant and as such can be
used in a FIPS 140-2 JVM. See <<ssl-tls-settings,`ssl.cipher_suites`>>.

[discrete]
==== TLS keystores and keys

Keystores can be used in a number of <<ssl-tls-settings>> in order to
conveniently store key and trust material. Neither `JKS`, nor `PKCS#12` keystores
can be used in a FIPS 140-2 configured JVM. Avoid using
these types of keystores. Your FIPS 140-2 provider may provide a compliant keystore
implementation that can be used, or you can use PEM encoded files. To use PEM encoded
key material, you can use the relevant `\*.key` and `*.certificate` configuration
options, and for trust material you can use `*.certificate_authorities`.


FIPS 140-2 compliance dictates that the length of the public keys used for TLS
must correspond to the strength of the symmetric key algorithm in use in TLS.
Depending on the value of `ssl.cipher_suites` that you select to use, the TLS
keys must have corresponding length according to the following table:

[[comparable-key-strength]]
.Comparable key strengths
|=======================
| Symmetric Key Algorithm | RSA key Length | ECC key length
| `3DES`                  | 2048           | 224-255
| `AES-128`               | 3072           | 256-383
| `AES-256`               | 15630          | 512+
|=======================

[discrete]
==== Stored password hashing
[[fips-stored-password-hashing]]

While {es} offers a number of algorithms for securely hashing credentials
on disk, only the `PBKDF2` based family of algorithms is compliant with FIPS
140-2 for stored password hashing. However, since `PBKDF2` is essentially a key derivation
function, your JVM security provider may enforce a
<<keystore-fips-password,112-bit key strength requirement>>. Although FIPS 140-2
does not mandate user password standards, this requirement may affect password
hashing in {es}. To comply with this requirement,
while allowing you to use passwords that satisfy your security policy, {es} offers
<<hashing-settings, pbkdf2_stretch>> which is the suggested hashing algorithm when running
{es} in FIPS 140-2 environments. `pbkdf2_stretch` performs a single round of SHA-512
on the user password before passing it to the `PBKDF2` implementation.

NOTE: You can still use one of the plain `pbkdf2` options instead of `pbkdf2_stretch` if
you have external policies and tools that can ensure all user passwords for the reserved,
native, and file realms are longer than 14 bytes.

You must set the `xpack.security.authc.password_hashing.algorithm` setting to one of the
available `pbkdf_stretch_*` values.
When FIPS-140 mode is enabled, the default value for
`xpack.security.authc.password_hashing.algorithm` is `pbkdf2_stretch`.
See <<hashing-settings>>.

Password hashing configuration changes are not retroactive so the stored hashed
credentials of existing users of the reserved, native, and file realms are not
updated on disk.
To ensure FIPS 140-2 compliance, recreate users or
change their password using the <<users-command, elasticsearch-user>> CLI tool
for the file realm and the <<security-api-put-user,create users>> and
<<security-api-change-password,change password>> APIs for the native and reserved realms.
Other types of realms are not affected and do not require any changes.

[discrete]
==== Cached password hashing
[[fips-cached-password-hashing]]

`ssha256` (salted `sha256`) is recommended for cache hashing. Though
`PBKDF2` is compliant with FIPS-140-2, it is -- by design -- slow, and
thus not generally suitable as a cache hashing algorithm. Cached
credentials are never stored on disk, and salted `sha256` provides an
adequate level of security for in-memory credential hashing, without
imposing prohibitive performance overhead. You _may_ use `PBKDF2`,
however you should carefully assess performance impact first. Depending
on your deployment, the overhead of `PBKDF2` could undo most of the
performance gain of using a cache.

Either set all `cache.hash_algo` settings to `ssha256` or leave
them undefined, since `ssha256` is the default value for all
`cache.hash_algo` settings. See <<hashing-settings>>.

The user cache will be emptied upon node restart, so any existing
hashes using non-compliant algorithms will be discarded and the new
ones will be created using the algorithm you have selected.

[discrete]
[[configuring-es-yml]]
==== Configure {es} elasticsearch.yml

* Set `xpack.security.fips_mode.enabled` to `true` in `elasticsearch.yml`. This setting is used to ensure to configure some internal
configuration to be FIPS 140-2 compliant and provides some additional verification.

* Set `xpack.security.autoconfiguration.enabled` to `false`. This will disable the automatic configuration of the security settings.
Users must ensure that the security settings are configured correctly for FIPS-140-2 compliance. This is only applicable for new installations.

* Set `xpack.security.authc.password_hashing.algorithm` appropriately see xref:fips-stored-password-hashing[above].

* Other relevant security settings. For example, TLS for the transport and HTTP interfaces. (not explicitly covered here or in the example below)

* Optional: Set `xpack.security.fips_mode.required_providers` in `elasticsearch.yml` to ensure the required security providers (8.13+).
see xref:verify-security-provider[below].

[source,yaml]
--------------------------------------------------
xpack.security.fips_mode.enabled: true
xpack.security.autoconfiguration.enabled: false
xpack.security.fips_mode.required_providers: ["BCFIPS", "BCJSSE"]
xpack.security.authc.password_hashing.algorithm: "pbkdf2_stretch"
--------------------------------------------------

[discrete]
[[verify-security-provider]]
==== Verify the security provider is installed

To verify that the security provider is installed and in use, you can use any of the following steps:

* Verify the required security providers are configured with the lowest order in the file pointed to by `java.security.properties`.
For example, `security.provider.1` is a lower order than `security.provider.2`

* Set `xpack.security.fips_mode.required_providers` in `elasticsearch.yml` to the list of required security providers.
This setting is used to ensure that the correct security provider is installed and configured. (8.13+)
If the security provider is not installed correctly, {es} will fail to start. `["BCFIPS", "BCJSSE"]` are the values to
use for Bouncy Castle's FIPS JCE and JSSE certified provider.

[discrete]
[[fips-upgrade-considerations]]
=== Upgrade considerations
include::fips-java17.asciidoc[]

[IMPORTANT]
====
Some encryption algorithms may no longer be available by default in updated FIPS 140-2 security providers.
Notably, Triple DES and PKCS1.5 RSA are now discouraged and https://www.bouncycastle.org/fips-java[Bouncy Castle] now
requires explicit configuration to continue using these algorithms.
====

If you plan to upgrade your existing cluster to a version that can be run in
a FIPS 140-2 configured JVM, we recommend to first perform a rolling
upgrade to the new version in your existing JVM and perform all necessary
configuration changes in preparation for running in FIPS 140-2 mode. You can then
perform a rolling restart of the nodes, starting each node in a FIPS 140-2 JVM.
During the restart, {es}:

- Upgrades <<secure-settings,secure settings>> to the latest, compliant format.
A FIPS 140-2 JVM cannot load previous format versions. If your keystore is
not password-protected, you must manually set a password. See
<<keystore-fips-password>>.
- Upgrades self-generated trial licenses to the latest FIPS 140-2 compliant format.

If your {subscriptions}[subscription] already supports FIPS 140-2 mode, you
can elect to perform a rolling upgrade while at the same time running each
upgraded node in a FIPS 140-2 JVM. In this case, you would need to also manually
regenerate your `elasticsearch.keystore` and migrate all secure settings to it,
in addition to the necessary configuration changes outlined below, before
starting each node.

[discrete]
[[fips-limitations]]
=== Limitations

Due to the limitations that FIPS 140-2 compliance enforces, a small number of
features are not available while running in FIPS 140-2 mode. The list is as follows:

* Azure Classic Discovery Plugin
* The <<certutil,`elasticsearch-certutil`>> tool. However,
 `elasticsearch-certutil` can very well be used in a non FIPS 140-2
  configured JVM (pointing `ES_JAVA_HOME` environment variable to a different
  java installation) in order to generate the keys and certificates that
  can be later used in the FIPS 140-2 configured JVM.
* The SQL CLI client cannot run in a FIPS 140-2 configured JVM while using
  TLS for transport security or PKI for client authentication.
