Use JWT/OIDC authentication

The jwt auth method can be used to authenticate with Vault using OIDC or by providing a JWT.

The OIDC method allows authentication via a configured OIDC provider using the user's web browser. This method may be initiated from the Vault UI or the command line. Alternatively, a JWT can be provided directly. The JWT is cryptographically verified using locally-provided keys, or, if configured, an OIDC Discovery service can be used to fetch the appropriate keys. The choice of method is configured per role.

Both methods allow additional processing of the claims data in the JWT. Some of the concepts common to both methods will be covered first, followed by specific examples of OIDC and JWT usage.

OIDC authentication

This section covers the setup and use of OIDC roles. If a JWT is to be provided directly, refer to the JWT Authentication section below. Basic familiarity with OIDC concepts is assumed. The Authorization Code flow makes use of the Proof Key for Code Exchange (PKCE) extension.

Vault includes two built-in OIDC login flows: the Vault UI, and the CLI using a vault login.

Redirect URIs

An important part of OIDC role configuration is properly setting redirect URIs. This must be done both in Vault and with the OIDC provider, and these configurations must align. The redirect URIs are specified for a role with the allowed_redirect_uris parameter. There are different redirect URIs to configure the Vault UI and CLI flows, so one or both will need to be set up depending on the installation.

CLI

If you plan to support authentication via vault login -method=oidc, a localhost redirect URI must be set. This can usually be: http://localhost:8250/oidc/callback. Logins via the CLI may specify a different host and/or listening port if needed, and a URI with this host/port must match one of the configured redirected URIs. These same "localhost" URIs must be added to the provider as well.

Vault UI

Logging in via the Vault UI requires a redirect URI of the form:

https://{host:port}/ui/vault/auth/{path}/oidc/callback

The "host:port" must be correct for the Vault server, and "path" must match the path the JWT backend is mounted at (e.g. "oidc" or "jwt").

If the oidc_response_mode is set to form_post, then logging in via the Vault UI requires a redirect URI of the form:

https://{host:port}/v1/auth/{path}/oidc/callback

Prior to Vault 1.6, if namespaces are in use, they must be added as query parameters, for example:

https://vault.example.com:8200/ui/vault/auth/oidc/oidc/callback?namespace=my_ns

For Vault 1.6+, it is no longer necessary to add the namespace as a query parameter in the redirect URI, if namespace_in_state is set to true, which is the default for new configs.

OIDC login (Vault UI)

1. Select the "OIDC" login method.
2. Enter a role name if necessary.
3. Press "Sign In" and complete the authentication with the configured provider.

OIDC login (CLI)

The CLI login defaults to path of /oidc. If this auth method was enabled at a different path, specify -path=/my-path in the CLI.

$ vault login -method=oidc port=8400 role=test

Complete the login via your OIDC provider. Launching browser to:

    https://myco.auth0.com/authorize?redirect_uri=http%3A%2F%2Flocalhost%3A8400%2Foidc%2Fcallback&client_id=r3qXc2bix9eF...

The browser will open to the generated URL to complete the provider's login. The URL may be entered manually if the browser cannot be automatically opened.

• skip_browser (default: "false"). Toggle the automatic launching of the default browser to the login URL.

The callback listener may be customized with the following optional parameters. These are typically not required to be set:

• mount (default: "oidc")
• listenaddress (default: "localhost")
• port (default: 8250)
• callbackhost (default: "localhost")
• callbackmethod (default: "http")
• callbackport (default: value set for port). This value is used in the redirect_uri, whereas port is the localhost port that the listener is using. These two may be different in advanced setups.

OIDC provider configuration

The OIDC authentication flow has been successfully tested with a number of providers. A full guide to configuring OAuth/OIDC applications is beyond the scope of Vault documentation, but a collection of provider configuration steps has been collected to help get started: OIDC Provider Setup

OIDC configuration troubleshooting

This amount of configuration required for OIDC is relatively small, but it can be tricky to debug why things aren't working. Some tips for setting up OIDC:

• If a role parameter (e.g. bound_claims) requires a map value, it can't be set individually using the Vault CLI. In these cases the best approach is to write the entire configuration as a single JSON object:

vault write auth/oidc/role/demo -<<EOF
{
  "user_claim": "sub",
  "bound_audiences": "abc123",
  "role_type": "oidc",
  "policies": "demo",
  "ttl": "1h",
  "bound_claims": { "groups": ["mygroup/mysubgroup"] }
}
EOF

• Monitor Vault's log output. Important information about OIDC validation failures will be emitted.

• Ensure Redirect URIs are correct in Vault and on the provider. They need to match exactly. Check: http/https, 127.0.0.1/localhost, port numbers, whether trailing slashes are present.

• Start simple. The only claim configuration a role requires is user_claim. After authentication is known to work, you can add additional claims bindings and metadata copying.

• bound_audiences is optional for OIDC roles and typically not required. OIDC providers will use the client_id as the audience and OIDC validation expects this.

• Check your provider for what scopes are required in order to receive all of the information you need. The scopes "profile" and "groups" often need to be requested, and can be added by setting oidc_scopes="profile,groups" on the role.

• If you're seeing claim-related errors in logs, review the provider's docs very carefully to see how they're naming and structuring their claims. Depending on the provider, you may be able to construct a simple curl implicit grant request to obtain a JWT that you can inspect. An example of how to decode the JWT (in this case located in the "access_token" field of a JSON response):

  cat jwt.json | jq -r .access_token | cut -d. -f2 | base64 -D

• As of Vault 1.2, the verbose_oidc_logging role option is available which will log the received OIDC token to the server logs if debug-level logging is enabled. This can be helpful when debugging provider setup and verifying that the received claims are what you expect. Since claims data is logged verbatim and may contain sensitive information, this option should not be used in production.

• Azure requires some additional configuration when a user is a member of more than 200 groups, described in Azure-specific handling configuration

JWT authentication

The authentication flow for roles of type "jwt" is simpler than OIDC since Vault only needs to validate the provided JWT.

JWT verification

Vault verifies JWT signatures against public keys from the issuer. You can only configure one JWT signature verification method per mounted backend from the following options:

• Static Keys. A set of public keys is stored directly in the backend configuration. See the jwt_validation_pubkeys configuration option.

• JWKS. A JSON Web Key Set (JWKS) URL and optional certificate chain is configured. Keys will be fetched from this endpoint for authentication. See the jwks_url and jwks_ca_pem configuration options.

• JWKS Pairs. A list of JSON Web Key Set (JWKS) URLs and optional certificate chain for each is configured. Keys will be fetched from each endpoint for authentication, stopping at the first set to successfully verify the JWT signature. See the jwks_pairs configuration option.

• OIDC Discovery. An OIDC Discovery URL and optional certificate chain is configured. Keys will be fetched from this URL during authentication. When OIDC Discovery is used, OIDC validation criteria (e.g. iss, aud, etc.) will be applied. See the oidc_discovery_url and oidc_discovery_ca_pem configuration options.

To configure additional verification methods, you must mount and configure one backend instance per method at different paths.

After verifying the JWT signatures, Vault checks the corresponding aud claim.

If the JWT in the authentication request contains an aud claim, the associated bound_audiences for the role must match at least one of the aud claims declared for the JWT.

Via the CLI

$ vault write auth/<path-to-jwt-backend>/login role=demo jwt=...

The default path for the JWT authentication backend is /jwt, so if you're using the default backend, the command would be:

$ vault write auth/jwt/login role=demo jwt=...

If your JWT auth backend is using a different path, use that path.

Via the API

The default endpoint is auth/jwt/login. If this auth method was enabled at a different path, use that value instead of jwt.

$ curl \
    --request POST \
    --data '{"jwt": "your_jwt", "role": "demo"}' \
    http://127.0.0.1:8200/v1/auth/jwt/login

The response will contain a token at auth.client_token:

{
  "auth": {
    "client_token": "38fe9691-e623-7238-f618-c94d4e7bc674",
    "accessor": "78e87a38-84ed-2692-538f-ca8b9f400ab3",
    "policies": ["default"],
    "metadata": {
      "role": "demo"
    },
    "lease_duration": 2764800,
    "renewable": true
  }
}

Configuration

Auth methods must be configured in advance before users or machines can authenticate. These steps are usually completed by an operator or configuration management tool.

1. Enable the JWT auth method. Either the "jwt" or "oidc" name may be used. The backend will be mounted at the chosen name.

   $ vault auth enable jwt
     or
   $ vault auth enable oidc
   

2. Use the /config endpoint to configure Vault. To support JWT roles, either local keys, JWKS URL(s), or an OIDC Discovery URL must be present. For OIDC roles, OIDC Discovery URL, OIDC Client ID and OIDC Client Secret are required. For the list of available configuration options, please see the API documentation.

   $ vault write auth/jwt/config \
       oidc_discovery_url="https://myco.auth0.com/" \
       oidc_client_id="m5i8bj3iofytj" \
       oidc_client_secret="f4ubv72nfiu23hnsj" \
       default_role="demo"
   

   If you need to perform JWT verification with JWT token validation, then leave the oidc_client_id and oidc_client_secret blank.

   $ vault write auth/jwt/config \
      oidc_discovery_url="https://MYDOMAIN.eu.auth0.com/" \
      oidc_client_id="" \
      oidc_client_secret="" \
   

3. Create a named role:

   vault write auth/jwt/role/demo \
       allowed_redirect_uris="http://localhost:8250/oidc/callback" \
       bound_subject="r3qX9DljwFIWhsiqwFiu38209F10atW6@clients" \
       bound_audiences="https://vault.plugin.auth.jwt.test" \
       user_claim="https://vault/user" \
       groups_claim="https://vault/groups" \
       policies=webapps \
       ttl=1h
   

   This role authorizes JWTs with the given subject and audience claims, gives it the webapps policy, and uses the given user/groups claims to set up Identity aliases.

   For the complete list of configuration options, please see the API documentation.

Bound claims

Once a JWT has been validated as being properly signed and not expired, the authorization flow will validate that any configured "bound" parameters match. In some cases there are dedicated parameters, for example bound_subject, that must match the provided sub claim. For roles of type "jwt":

1. the bound_audiences parameter is required when an aud claim is set.
2. the bound_audiences parameter must match at least one of provided aud claims.

You can also configure roles to check an arbitrary set of claims and required values with the bound_claims map. For example, assume bound_claims is set to:

{
  "division": "Europe",
  "department": "Engineering"
}

Only JWTs containing both the "division" and "department" claims, and respective matching values of "Europe" and "Engineering", would be authorized. If the expected value is a list, the claim must match one of the items in the list. To limit authorization to a set of email addresses:

{
  "email": ["fred@example.com", "julie@example.com"]
}

Bound claims can optionally be configured with globs. See the API documentation for more details.

Claims as metadata

Data from claims can be copied into the resulting auth token and alias metadata by configuring claim_mappings. This role parameter is a map of items to copy. The map elements are of the form: "<JWT claim>":"<metadata key>". Assume claim_mappings is set to:

{
  "division": "organization",
  "department": "department"
}

This specifies that the value in the JWT claim "division" should be copied to the metadata key "organization". The JWT "department" claim value will also be copied into metadata but will retain the key name. If a claim is configured in claim_mappings, it must existing in the JWT or else the authentication will fail.

Note: the metadata key name "role" is reserved and may not be used for claim mappings. Since Vault 1.16 the role name is available by the key role in the alias metadata of the entity after a successful login.

Claim specifications and JSON pointer

Some parameters (e.g. bound_claims, groups_claim, claim_mappings, user_claim) are used to point to data within the JWT. If the desired key is at the top of level of the JWT, the name can be provided directly. If it is nested at a lower level, a JSON Pointer may be used.

Assume the following JSON data to be referenced:

{
  "division": "North America",
  "groups": {
    "primary": "Engineering",
    "secondary": "Software"
  }
}

A parameter of "division" will reference "North America", as this is a top level key. A parameter "/groups/primary" uses JSON Pointer syntax to reference "Engineering" at a lower level. Any valid JSON Pointer can be used as a selector. Refer to the JSON Pointer RFC for a full description of the syntax.

Tutorial

Refer to the following tutorials for OIDC auth method usage examples:

• OIDC Auth Method
• Azure Active Directory with OIDC Auth Method and External Groups
• OIDC Authentication with Okta
• OIDC Authentication with Google Workspace

API

The JWT Auth Plugin has a full HTTP API. Please see the API docs for more details.