FIPS 140-2edit

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. Elasticsearch offers a FIPS 140-2 compliant mode and as such can run in a FIPS 140-2 configured JVM.

The JVM bundled with Elasticsearch is not configured for FIPS 140-2. You must either configure the bundled JVM to run with a FIPS 140-2 certified Java Security Provider or use an external JVM configured for FIPS 140-2.

After configuring your JVM for FIPS 140-2, you can run Elasticsearch in FIPS mode by setting the xpack.security.fips_mode.enabled to true in elasticsearch.yml.

For Elasticsearch, adherence to FIPS 140-2 is ensured by

  • Using FIPS approved / NIST recommended cryptographic algorithms.
  • Delegating the implementation of these cryptographic algorithms to a NIST validated cryptographic module (available via the Java Security Provider in use in the JVM).
  • Allowing the configuration of Elasticsearch in a FIPS 140-2 compliant manner, as documented below.

Upgrade considerationsedit

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 mode. You can then perform a rolling restart of the nodes, starting each node in a FIPS 140-2 JVM. During the restart, Elasticsearch:

  • Upgrades 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 Elasticsearch Keystore.
  • Upgrades self-generated trial licenses to the latest FIPS 140-2 compliant format.

If your 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.

Configuring Elasticsearch for FIPS 140-2edit

Apart from setting xpack.security.fips_mode.enabled, a number of security related settings need to be configured accordingly in order to be compliant and able to run Elasticsearch successfully in a FIPS 140-2 configured JVM.

Elasticsearch Keystoreedit

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 elasticsearch keystore that stores the node’s 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 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.

TLSedit

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

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 Elasticsearch are FIPS 140-2 compliant and as such can be used in a FIPS 140-2 JVM. See ssl.cipher_suites.

TLS keystores and keysedit

Keystores can be used in a number of General 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:

Table 75. 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+

Password Hashingedit

While Elasticsearch offers a number of algorithms for securely hashing credentials in memory and on disk, only the PBKDF2 based family of algorithms is compliant with FIPS 140-2 for password hashing. However, since PBKDF2 is essentially a key derivation function, your JVM security provider may enforce a 112-bit key strength requirement. Although FIPS 140-2 does not mandate user password standards, this requirement may affect password hashing in Elasticsearch. To comply with this requirement, while allowing you to use passwords that satisfy your security policy, Elasticsearch offers pbkdf2_stretch which is the suggested hashing algorithm when running Elasticsearch 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.

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 cache.hash_algo realm settings and the xpack.security.authc.password_hashing.algorithm setting to one of the available pbkdf_stretch_* values. See User cache and password hash algorithms.

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 elasticsearch-user CLI tool for the file realm and the create users and change password APIs for the native and reserved realms. Other types of realms are not affected and do not require any changes.

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 compliant PBKDF2 based algorithm you have selected.

Limitationsedit

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
  • Ingest Attachment Plugin
  • The 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.