]> SGNL

atul@sgnl.ai

Microsoft

tim.cappalli@microsoft.com

Coinbase

marius.scurtescu@coinbase.com

Amazon

richanna@amazon.com

Yubico

secevemt@ve7jtb.com

Cisco

smiel@cisco.com

Shared Signals This Shared Signals Framework (SSF) enables sharing of signals and events between cooperating peers. It enables multiple applications such as Risk Incident Sharing and Coordination (RISC) and the Continuous Access Evaluation Profile () This specification defines: A profile for Security Events Tokens Subject principals Subject claims in SSF events Event types Event properties Transmitter Configuration Metadata and its discovery method for Receivers A management API for Event Streams This specification also directly profiles several IETF Security Events specifications: Security Event Token (SET) Subject Identifiers for Security Event Tokens Push-Based SET Token Delivery Using HTTP Poll-Based SET Token Delivery Using HTTP

Introduction

Notational Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 when, and only when, they appear in all capitals, as shown here.

Subject Principals This Shared Signals Framework specification defines a Subject Principal to be the entities about which an event can be sent by Transmitters and received by Receivers using the Shared Signals Framework. Subject Principals are the managed entities in an SSF Transmitter or Receiver. These include human or robotic principals, devices, customer tenants in a multi-tenanted service, organizational units within a tenant, groups of subject principals, or other entities that are managed by Transmitters and Receivers. There may be other actors or resources that can be treated as Subject Principals, and event-type definitions SHOULD specify the range of principals addressed by the event. Subject Principals are identified by Subject Members defined below.

Subject Members in SSF Events

Subject Members A Subject Member of an SSF event describes a subject of the event. A top-level claim named sub_id MUST be used to describe the primary subject of the event.

Existing CAEP and RISC Events Event types already defined in the CAEP () and RISC () specifications MAY use a subject field within the events claim of the SSF event to describe the primary Subject Principal of the event. SSF Transmitters MUST include the top-level sub_id claim even for these existing event types.

New Event Types New event types MUST use the top-level sub_id claim and MUST NOT use the subject field in the events claim to describe the primary Subject Principal.

Additional Subject Members Specific event types MAY define additional Subject Members if required to describe additional subjects of that event type (e.g. a Transferee). These additional subject fields MAY have any field name.

Subject Member Values Each Subject Member MUST refer to exactly one Subject Principal. The value of a Subject Member MAY be a "simple subject" or a "complex subject".

Simple Subject Members A Simple Subject Member has a claim name and a value that is a "Subject Identifier" as defined in the Subject Identifiers for Security Event Tokens . Below is a non-normative example of a Simple Subject Member in an SSF event.

Complex Subject Members A Complex Subject Member has a name and a value that is a JSON object that has a format field, and one or more Simple Subject Members. The name of the format field is "format", and its value is "complex". The name of each Simple Subject Member in this value MAY be one of the following: user

• OPTIONAL. A Subject Identifier that identifies a user.

device

• OPTIONAL. A Subject Identifier that identifies a device.

session

• OPTIONAL. A Subject Identifier that identifies a session.

application

• OPTIONAL. A Subject Identifier that identifies an application.

tenant

• OPTIONAL. A Subject Identifier that identifies a tenant.

org_unit

• OPTIONAL. A Subject Identifier that identifies an organizational unit.

group

• OPTIONAL. A Subject Identifier that identifies a group.

Additional Subject Member names MAY be used in Complex Subjects. Each member name MAY appear at most once in the Complex Subject value. Below is a non-normative example of a Complex Subject claim in an SSF event.

Complex Subject Interpretation All members within a Complex Subject MUST represent attributes of the same Subject Principal. As a whole, the Complex Subject MUST refer to exactly one Subject Principal.

Subject Identifiers in SSF Events A Subject Identifier in an SSF event MUST have an identifier format that is any one of: Defined in the IANA Registry defined in Subject Identifiers for Security Event Tokens An identifier format defined in the Additional Subject Identifier Formats () section below, OR A proprietary subject identifier format that is agreed to between parties. Members within a subject identifier that has a proprietary subject identifier format are agreed to between the parties and such agreement is outside the scope of this specification.

Additional Subject Identifier Formats The following new subject identifier formats are defined:

JWT ID Subject Identifier Format The "JWT ID" Subject Identifier Format specifies a JSON Web Token (JWT) identifier, defined in . Subject Identifiers of this type MUST contain the following members: iss

• REQUIRED. The "iss" (issuer) claim of the JWT being identified, defined in

jti

• REQUIRED. The "jti" (JWT token ID) claim of the JWT being identified, defined in

The "JWT ID" Subject Identifier Format is identified by the name "jwt_id". Below is a non-normative example of Subject Identifier for the "jwt_id" Subject Identifier Format.

SAML Assertion ID Subject Identifier Format The "SAML Assertion ID" Subject Identifier Format specifies a SAML 2.0 assertion identifier. Subject Identifiers of this format MUST contain the following members: issuer

• REQUIRED. The "Issuer" value of the SAML assertion being identified, defined in

assertion_id

• REQUIRED. The "ID" value of the SAML assertion being identified, defined in

The "SAML Assertion ID" Subject Identifier Format is identified by the name "saml_assertion_id". Below is a non-normative example of Subject Identifier for the "saml_assertion_id" Subject Identifier Format.

Receiver Subject Processing A SSF Receiver MUST make a best effort to process all members from a Subject in an SSF event. The Transmitter Configuration Metadata () defined below MAY define certain members within a Complex Subject to be Critical. A SSF Receiver MUST discard any event that contains a Subject with a Critical member that it is unable to process.

Event Properties Additional members about an event may be included in the "events" claim. Some of these members are required and specified as such in the respective event types specs. If a Transmitter determines that it needs to include additional members that are not specified in the event types spec, then the name of such members MUST be a URI. The discoverability of all additional members is specified in the Discovery section ().

Example SETs that conform to the Shared Signals Framework The following are hypothetical examples of SETs that conform to the Shared Signals Framework.

Transmitter Configuration Discovery This section defines a mechanism for Receivers to obtain the Transmitter Configuration Metadata.

Transmitter Configuration Metadata Transmitters have metadata describing their configuration: spec_version

• OPTIONAL. A version identifying the implementer's draft or final specification implemented by the Transmitter. This includes the numerical portion of the spec version as described in the document . If absent, the Transmitter is assumed to conform to "1_0-ID1" version of the specification (this document).

• The following is a non-normative example of a Transmitter that implements the third implementer's draft of the Shared Signals Framework specification 1_0.

• The following is a non-normative example of a Transmitter that implements the final specification of the Shared Signals Framework 1_0.

issuer

• REQUIRED. URL using the https scheme with no query or fragment component that the Transmitter asserts as its Issuer Identifier. This MUST be identical to the iss claim value in Security Event Tokens issued from this Transmitter.

jwks_uri

• OPTIONAL. URL of the Transmitter's JSON Web Key Set document. This contains the signing key(s) the Receiver uses to validate signatures from the Transmitter. This value MUST be specified if the Transmitter intends to generate signed JWTs. If present, this URL MUST use HTTP over TLS .

delivery_methods_supported

• RECOMMENDED. List of supported delivery method URIs.

configuration_endpoint

• OPTIONAL. The URL of the Configuration Endpoint. If present, this URL MUST use HTTP over TLS .

status_endpoint

• OPTIONAL. The URL of the Status Endpoint. If present, this URL MUST use HTTP over TLS .

add_subject_endpoint

• OPTIONAL. The URL of the Add Subject Endpoint. If present, this URL MUST use HTTP over TLS .

remove_subject_endpoint

• OPTIONAL. The URL of the Remove Subject Endpoint. If present, this URL MUST use HTTP over TLS .

verification_endpoint

• OPTIONAL. The URL of the Verification Endpoint. If present, this URL MUST use HTTP over TLS .

critical_subject_members

• OPTIONAL. An array of member names in a Complex Subject which, if present in a Subject Member in an event, MUST be interpreted by a Receiver.

authorization_schemes

• OPTIONAL. An array of JSON objects that specify the supported authorization scheme properties defined in . To enable seamless discovery of configurations, the service provider SHOULD, with the appropriate security considerations, make the authorization_schemes attribute publicly accessible without prior authentication.

default_subjects

• OPTIONAL. A string indicating the default behavior of newly created streams. If present, the value MUST be either "ALL" or "NONE". If not provided, the Transmitter behavior in this regard is unspecified. - "ALL" indicates that any subjects that are appropriate for the stream are added to the stream by default. The Receiver MAY remove subjects from the stream via the remove_subject_endpoint, causing events for those subjects to not be transmitted. The Receiver MAY re-add any subjects removed this way via the add_subject_endpoint. - "NONE" indicates that no subjects are added by default. The Receiver MAY add subjects to the stream via the add_subject_endpoint, causing only events for those subjects to be transmitted. The Receiver MAY remove subjects added this way via the remove_subject_endpoint.

TODO: consider adding a IANA Registry for metadata, similar to Section 7.1.1 of . This would allow other specs to add to the metadata.

Authorization scheme SSF is an HTTP based signals sharing framework and is agnostic to the authentication and authorization schemes used to secure stream configuration APIs. It does not provide any SSF-specific authentication and authorization schemes but relies on the cooperating parties' mutual security considerations. The authorization scheme section of the metadata provides discovery information related to the Transmitter's stream management APIs. spec_urn

• REQUIRED. A URN that describes the specification of the protocol being used.

The Receiver will call the Transmitter APIs by providing appropriate credentials as per the spec_urn. The following is a non-normative example of the spec_urn

In this case, the Receiver may obtain an access token using the Client Credentials Grant , or any other method suitable for the Receiver and the Transmitter.

Obtaining Transmitter Configuration Metadata Using the Issuer URL as documented by the Transmitter, the Transmitter Configuration Metadata can be retrieved. Receivers SHOULD ensure that the Issuer URL comes from a trusted source and uses the https scheme. Transmitters supporting Discovery MUST make a JSON document available at the path formed by inserting the string "/.well-known/ssf-configuration" into the Issuer between the host component and the path component, if any. The syntax and semantics of ".well-known" are defined in . "ssf-configuration" MUST point to a JSON document compliant with this specification, and that document MUST be returned using the "application/json" content type.

Transmitter Configuration Request A Transmitter Configuration Document MUST be queried using an HTTP "GET" request at the previously specified path. The Receiver would make the following request to the Issuer "https://tr.example.com" to obtain its Transmitter Configuration Metadata, since the Issuer contains no path component:

If the Issuer value contains a path component, any terminating "/" MUST be removed before inserting "/.well-known/ssf-configuration" between the host component and the path component. The Receiver would make the following request to the Issuer "https://tr.example.com/issuer1" to obtain its Transmitter Configuration Metadata, since the Issuer contains a path component:

Using path components enables supporting multiple issuers per host. This is required in some multi-tenant hosting configurations. This use of ".well-known" is for supporting multiple issuers per host; unlike its use in , it does not provide general information about the host.

Backward Compatibility for RISC Transmitters Existing RISC Transmitters MAY continue to use the path component "/risc-configuration" instead of the path component "/ssf-configuration" in the path for the Transmitter Configuration Metadata. New services supporting the Shared Signals Framework SHOULD NOT use this location for publishing the Transmitter Configuration Metadata. For example, the Transmitter Configuration Metadata for the Transmitter "https://risc-tr.example.com" MAY be obtained by making the following request:

Transmitter Configuration Response The response is a set of Claims about the Transmitter's configuration, including all necessary endpoints and public key location information. A successful response MUST use the 200 OK HTTP status code and return a JSON object using the "application/json" content type that contains a set of Claims as its members that are a subset of the Metadata values defined in . Other Claims MAY also be returned. Claims that return multiple values are represented as JSON arrays. Claims with zero elements MUST be omitted from the response. An error response uses the applicable HTTP status code value. The following is a non-normative example of a Transmitter Configuration Response

Transmitter Configuration Validation If any of the validation procedures defined in this specification fail, any operations requiring the information that failed to correctly validate MUST be aborted and the information that failed to validate MUST NOT be used. The "issuer" value returned MUST be identical to the Issuer URL that was directly used to retrieve the configuration information. This MUST also be identical to the "iss" Claim value in Security Event Tokens issued from this Transmitter.

Management API for SET Event Streams An Event Stream is an abstraction for how events are communicated from a Transmitter to a Receiver. The Event Stream's configuration, which is jointly managed by the Transmitter and Receiver, holds information about what types of events will be sent from the Transmitter, as well as the mechanism by which the Receiver can expect to receive the events. The Event Stream also keeps track of what Subjects are of interest to the Receiver, and only events with those Subjects are transmitted on the stream. This section defines an HTTP API to be implemented by Event Transmitters which can be used by Event Receivers to create and delete one or more Event Streams. The API can also be used to query and update the Event Stream's configuration and status, add and remove Subjects, and trigger verification for those streams. Unless there exists some other method of establishing trust between a Transmitter and Receiver, all Stream Management API endpoints MUST use standard HTTP authentication and authorization schemes, as per . This authorization MUST associate a Receiver with one or more stream IDs and "aud" values, such that only authorized Receivers are able to access or modify the details of the associated Event Streams.

| | | | | | | Verification | | | <----------------+ | | | | | +------------+ +------------+ ]]>

It is OPTIONAL for Transmitters to implement a Management API, but it is RECOMMENDED that they implement it, especially the endpoints for querying the Stream Status and for triggering Verification.

Event Stream Management Event Receivers manage how they receive events and the subjects about which they want to receive events over an Event Stream by making HTTP requests to endpoints in the Event Stream Management API. A Transmitter and Receiver MAY use the same Event Stream for updates about multiple Subject Principals. The status of the Event Stream MAY be queried and managed independently for each Subject Principal by Transmitters and Receivers. The Event Stream Management API is implemented by the Event Transmitter and consists of the following endpoints: Configuration Endpoint

• An endpoint used to create and delete Event Streams, as well as read and update an Event Stream's current configuration.

Status Endpoint

• An endpoint used to read and update an Event Stream's current status.

Add Subject Endpoint

• An endpoint used to add subjects to an Event Stream.

Remove Subject Endpoint

• An endpoint used to remove subjects from an Event Stream.

Verification Endpoint

• An endpoint used to request the Event Transmitter to transmit a Verification Event over an Event Stream.

An Event Transmitter MAY use the same URLs as endpoints for multiple Event Receivers, provided that the Event Transmitter has some mechanism through which they can identify the applicable set of Event Streams for any given request, e.g. from authentication credentials. The definition of such mechanisms is outside the scope of this specification.

Stream Configuration An Event Stream's configuration is a collection of data, provided by both the Transmitter and the Receiver, that describes the information being sent over the Event Stream. It is represented as a JSON object with the following properties: stream_id

• Transmitter-Supplied, REQUIRED. A string that uniquely identifies the stream. A Transmitter MUST generate a unique ID for each of its non-deleted streams at the time of stream creation.

iss

• Transmitter-Supplied, REQUIRED. A URL using the https scheme with no query or fragment component that the Transmitter asserts as its Issuer Identifier. This MUST be identical to the "iss" Claim value in Security Event Tokens issued from this Transmitter.

aud

• Transmitter-Supplied, REQUIRED. A string or an array of strings containing an audience claim as defined in JSON Web Token (JWT) that identifies the Event Receiver(s) for the Event Stream. This property cannot be updated. If multiple Receivers are specified then the Transmitter SHOULD know that these Receivers are the same entity.

events_supported

• Transmitter-Supplied, OPTIONAL. An array of URIs identifying the set of events supported by the Transmitter for this Receiver. If omitted, Event Transmitters SHOULD make this set available to the Event Receiver via some other means (e.g. publishing it in online documentation).

events_requested

• Receiver-Supplied, OPTIONAL. An array of URIs identifying the set of events that the Receiver requested. A Receiver SHOULD request only the events that it understands and it can act on. This is configurable by the Receiver. A Transmitter MUST ignore any array values that it does not understand. This array SHOULD NOT be empty.

events_delivered

• Transmitter-Supplied, REQUIRED. An array of URIs identifying the set of events that the Transmitter MUST include in the stream. This is a subset (not necessarily a proper subset) of the intersection of "events_supported" and "events_requested". A Receiver MUST rely on the values received in this field to understand which event types it can expect from the Transmitter.

delivery

• REQUIRED. A JSON object containing a set of name/value pairs specifying configuration parameters for the SET delivery method. The actual delivery method is identified by the special key "method" with the value being a URI as defined in . The value of the "delivery" field contains two sub-fields:

• method

• • Receiver-Supplied, REQUIRED. The specific delivery method to be used. This can be any one of "urn:ietf:rfc:8935" (push) or "urn:ietf:rfc:8936" (poll), but not both.

• endpoint_url

• • REQUIRED. The location at which the push or poll delivery will take place. If the method value is "urn:ietf:rfc:8935" (push), then this value MUST be supplied by the Receiver. If the method value is "urn:ietf:rfc:8936" (poll), then this value MUST be supplied by the Transmitter.

min_verification_interval

• Transmitter-Supplied, OPTIONAL. An integer indicating the minimum amount of time in seconds that must pass in between verification requests. If an Event Receiver submits verification requests more frequently than this, the Event Transmitter MAY respond with a 429 status code. An Event Transmitter SHOULD NOT respond with a 429 status code if an Event Receiver is not exceeding this frequency.

description

• Receiver-Supplied, OPTIONAL. A string that describes the properties of the stream. This is useful in multi-stream systems to identify the stream for human actors. The transmitter MAY truncate the string beyond an allowed max length.

TODO: consider adding a IANA Registry for stream configuration metadata, similar to Section 7.1.1 of . This would allow other specs to add to the stream configuration.

Creating a Stream In order to communicate events from a Transmitter to a Receiver, a Receiver MUST first create an Event Stream. An Event Receiver creates a stream by making an HTTP POST request to the Configuration Endpoint. On receiving a valid request the Event Transmitter responds with a "201 Created" response containing a JSON representation of the stream's configuration in the body. The Receiver MUST check the response and confirm that the iss value matches the Issuer from which it received the Transmitter Configuration data. If a stream already exists, and the Transmitter allows multiple streams with the same Receiver, the Event Transmitter MUST respond with a new stream ID. If the Transmitter does not allow multiple streams with the same Receiver, it MUST respond respond with HTTP status code "409 Conflict". The Receiver MAY then GET the existing stream configuration and, if desired, use PATCH or PUT to update or replace the existing stream configuration. The HTTP POST request MAY contain the Receiver-Supplied values of the Stream Configuration () object: events_requested delivery : Note that in the case of the poll method, the endpoint_url value is supplied by the Transmitter. If the request does not contain the delivery property, then the Transmitter MUST assume that the method is "urn:ietf:rfc:8936" (poll). The Transmitter MUST include a delivery property in the response with this method property and an endpoint_url property. The following is a non-normative example request to create an Event Stream:

The following is a non-normative example response:

Errors are signaled with HTTP status codes as follows: Code Description 400 if the request cannot be parsed 401 if authorization failed or it is missing 403 if the Event Receiver is not allowed to create a stream 409 if the Transmitter does not support multiple streams per Receiver

Reading a Stream's Configuration An Event Receiver gets the current configuration of a stream by making an HTTP GET request to the Configuration Endpoint. On receiving a valid request, the Event Transmitter responds with a "200 OK" response containing a JSON representation of the stream's configuration in the body. The Receiver MUST check the response and confirm that the iss value matches the Issuer from which it received the Transmitter Configuration data. The GET request MAY include the "stream_id" as a query parameter in order to identify the correct Event Stream. If the "stream_id" parameter is missing, then the Transmitter MUST return a list of the stream configurations available to this Receiver. In the event that there are no Event Streams configured, the Transmitter MUST return an empty list. The following is a non-normative example request to read an Event Stream's configuration:

The following is a non-normative example response:

The following is a non-normative example request to read an Event Stream's configuration, with no "stream_id" indicated:

The following is a non-normative example response to a request with no "stream_id":

The following is a non-normative example response to a request with no "stream_id" when there is only one Event Stream configured:

The following is a non-normative example response to a request with no "stream_id" when there are no Event Streams configured:

Errors are signaled with HTTP status codes as follows: Code Description 401 if authorization failed or it is missing 403 if the Event Receiver is not allowed to read the stream configuration 404 if there is no Event Stream with the given "stream_id" for this Event Receiver

Updating a Stream's Configuration An Event Receiver updates the current configuration of a stream by making an HTTP PATCH request to the Configuration Endpoint. The PATCH body contains a JSON representation of the stream configuration properties to change. On receiving a valid request, the Event Transmitter responds with a "200 OK" response containing a JSON representation of the entire updated stream configuration in the body. The Receiver MUST check the response and confirm that the iss value matches the Issuer from which it received the Transmitter Configuration data. The stream_id property MUST be present in the request. Other properties MAY be present in the request. Any Receiver-Supplied property present in the request MUST be updated by the Transmitter. Any properties missing in the request MUST NOT be changed by the Transmitter. If events_requested property is included in the request, it SHOULD NOT be an empty array. Transmitter-Supplied properties besides the stream_id MAY be present, but they MUST match the expected value. Missing Transmitter-Supplied properties MUST be ignored by the Transmitter. The events_delivered property, if present, MUST match the Transmitter's expected value before any updates are applied. The following is a non-normative example request to replace an Event Stream's configuration:

The following is a non-normative example response:

Pending conditions or errors are signaled with HTTP status codes as follows: Code Description 202 if the update request has been accepted, but not processed. Receiver MAY try the same request later to get processing result. 400 if the request body cannot be parsed, a Transmitter-Supplied property is incorrect, or if the request is otherwise invalid 401 if authorization failed or it is missing 403 if the Event Receiver is not allowed to update the stream configuration 404 if there is no Event Stream with the given "stream_id" for this Event Receiver

Replacing a Stream's Configuration An Event Receiver replaces the current configuration of a stream by making an HTTP PUT request to the Configuration Endpoint. The PUT body contains a JSON representation of the new configuration. On receiving a valid request, the Event Transmitter responds with a "200 OK" response containing a JSON representation of the updated stream configuration in the body. The Receiver MUST check the response and confirm that the iss value matches the Issuer from which it received the Transmitter Configuration data. The stream_id and the full set of Receiver-Supplied properties MUST be present in the PUT body, not only those specifically intended to be changed. Missing Receiver-Supplied properties MUST be interpreted as requested to be deleted. Event Receivers MAY read the configuration first, modify the JSON representation, then make a replacement request. If events_requested property is included in the request, it SHOULD NOT be an empty array. Transmitter-Supplied properties besides the stream_id MAY be present, but they MUST match the expected value. Missing Transmitter-Supplied properties MUST be ignored by the Transmitter. The events_delivered property, if present, MUST match the Transmitter's expected value before any updates are applied. The following is a non-normative example request to replace an Event Stream's configuration:

The following is a non-normative example response:

Pending conditions or errors are signaled with HTTP status codes as follows: Code Description 202 if the replace request has been accepted, but not processed. Receiver MAY try the same request later in order to get processing result. 400 if the request body cannot be parsed, a Transmitter-Supplied property is incorrect, or if the request is otherwise invalid 401 if authorization failed or it is missing 403 if the Event Receiver is not allowed to replace the stream configuration 404 if there is no Event Stream with the given "stream_id" for this Event Receiver

Deleting a Stream An Event Receiver deletes a stream by making an HTTP DELETE request to the Configuration Endpoint. On receiving a request, the Event Transmitter responds with an empty "204 No Content" response if the configuration was successfully removed. The DELETE request MUST include the "stream_id" as a query parameter in order to identify the correct Event Stream. The following is a non-normative example request to delete an Event Stream:

The following is a non-normative example response of a successful request:

Errors are signaled with HTTP status codes as follows: Code Description 401 if authorization failed or it is missing 403 if the Event Receiver is not allowed to delete the stream 404 if there is no Event Stream with the given "stream_id" for this Event Receiver

Stream Status Event Streams are managed independently. A Receiver MAY request that events from a stream be interrupted by Updating the Stream Status (). If a Transmitter decides to enable, pause or disable updates from a stream independently of an update request from a Receiver, it MUST send a Stream Updated Event () to the Receiver.

Reading a Stream's Status An Event Receiver checks the current status of an Event Stream by making an HTTP GET request to the stream's Status Endpoint. The Stream Status method takes the following parameters: stream_id

• REQUIRED. A string identifying the stream whose status is being queried.

On receiving a valid request, the Event Transmitter responds with a 200 OK response containing a JSON object with the following attributes: stream_id

• REQUIRED. A string identifying the stream whose status is being queried.

status

• REQUIRED. A string whose value MUST be one of the values described below.

reason

• An OPTIONAL string whose value SHOULD express why the stream's status is set to the current value.

The allowable "status" values are: enabled

• The Transmitter MUST transmit events over the stream, according to the stream's configured delivery method.

paused

• The Transmitter MUST NOT transmit events over the stream. The Transmitter will hold any events it would have transmitted while paused, and SHOULD transmit them when the stream's status becomes "enabled". If a Transmitter holds successive events that affect the same Subject Principal, then the Transmitter MUST make sure that those events are transmitted in the order of time that they were generated OR the Transmitter MUST send only the last events that do not require the previous events affecting the same Subject Principal to be processed by the Receiver, because the previous events are either cancelled by the later events or the previous events are outdated.

disabled

• The Transmitter MUST NOT transmit events over the stream and will not hold any events for later transmission.

The following is a non-normative example request to check an Event Stream's status:

The following is a non-normative example response:

Errors are signaled with HTTP status codes as follows: Code Description 401 if authorization failed or it is missing 403 if the Event Receiver is not allowed to read the stream status 404 if there is no Event Stream with the given "stream_id" for this Event Receiver Examples: If a Receiver makes an unauthorized request, then the Transmitter MUST respond with a 401 error status. If a Receiver makes an authorized request, but the Transmitter policy does not permit the Receiver from obtaining the status, then the Transmitter MAY respond with a 403 error status. If the Receiver requests the status for a stream that does not exist then the Transmitter MUST respond with a 404 error status.

Updating a Stream's Status An Event Receiver updates the current status of a stream by making an HTTP POST request to the Status Endpoint. The POST body contains a JSON object with the following fields: stream_id

• REQUIRED. A string identifying the stream whose status is being updated.

status

• REQUIRED. The new status of the Event Stream.

reason

• OPTIONAL. A short text description that explains the reason for the change.

On receiving a valid request, the Event Transmitter responds with a "200 OK" response containing a JSON representation of the updated stream status in the body, using the same fields as described in the request. The following is a non-normative example request to update an Event Stream's status:

The following is a non-normative example of an Update Stream Status request with an optional reason:

The following is a non-normative example response:

Errors are signaled with HTTP status codes as follows: Code Description 202 if the update request has been accepted, but not processed. Receiver MAY try the same request later in order to get processing result. 400 if the request body cannot be parsed or if the request is otherwise invalid 401 if authorization failed or it is missing 403 if the Event Receiver is not allowed to update the stream status 404 if there is no Event Stream with the given "stream_id" for this Event Receiver Examples: If a Receiver makes a request to update a stream status, and the Transmitter is unable to decide whether or not to complete the request, then the Transmitter MUST respond with a 202 status code.

Subjects An Event Receiver can indicate to an Event Transmitter whether or not the Receiver wants to receive events about a particular subject by "adding" or "removing" that subject to the Event Stream, respectively. If a Receiver adds a subject to a stream, the Transmitter SHOULD send any events relating to the subject, which have event_types that the Receiver has subscribed to, and both the stream and the subject are enabled. In the case of Simple Subjects, two subjects match if they are exactly identical. For Complex Subjects, two subjects match if, for all fields in the Complex Subject (i.e. user, group, device, etc.), at least one of the following statements is true: Subject 1's field is not defined Subject 2's field is not defined Subject 1's field is identical to Subject 2's field

Adding a Subject to a Stream To add a subject to an Event Stream, the Event Receiver makes an HTTP POST request to the Add Subject Endpoint, containing in the body a JSON object the following claims: stream_id

• REQUIRED. A string identifying the stream to which the subject is being added.

subject

• REQUIRED. A Subject claim identifying the subject to be added.

verified

• OPTIONAL. A boolean value; when true, it indicates that the Event Receiver has verified the Subject claim. When false, it indicates that the Event Receiver has not verified the Subject claim. If omitted, Event Transmitters SHOULD assume that the subject has been verified.

On a successful response, the Event Transmitter responds with an empty "200 OK" response. The Event Transmitter MAY choose to silently ignore the request, for example if the subject has previously indicated to the Transmitter that they do not want events to be transmitted to the Event Receiver. In this case, the Transmitter MAY return an empty "200 OK" response or an appropriate error code. See Security Considerations (). The following is a non-normative example request to add a subject to a stream, where the subject is identified by an Email Subject Identifier.

The following is a non-normative example response to a successful request:

Errors are signaled with HTTP status codes as follows: Code Description 400 if the request body cannot be parsed or if the request is otherwise invalid 401 if authorization failed or it is missing 403 if the Event Receiver is not allowed to add this particular subject, or not allowed to add in general 404 if there is no Event Stream with the given "stream_id" for this Event Receiver, or if the subject is not recognized by the Event Transmitter. The Event Transmitter may choose to stay silent in this second case and respond with "200" 429 if the Event Receiver is sending too many requests in a given amount of time

Removing a Subject To remove a subject from an Event Stream, the Event Receiver makes an HTTP POST request to the Remove Subject Endpoint, containing in the body a JSON object with the following claims: stream_id

• REQUIRED. A string identifying the stream from which the subject is being removed.

subject

• REQUIRED. A Subject claim identifying the subject to be removed.

On a successful response, the Event Transmitter responds with a "204 No Content" response. The following is a non-normative example request where the subject is identified by a Phone Number Subject Identifier:

The following is a non-normative example response to a successful request:

Errors are signaled with HTTP status codes as follows: Code Description 400 if the request body cannot be parsed or if the request is otherwise invalid 401 if authorization failed or it is missing 403 if the Event Receiver is not allowed to remove this particular subject, or not allowed to remove in general 404 if there is no Event Stream with the given "stream_id" for this Event Receiver, or if the subject is not recognized by the Event Transmitter. The Event Transmitter may choose to stay silent in this second case and respond with "204" 429 if the Event Receiver is sending too many requests in a given amount of time

Verification In some cases, the frequency of event transmission on an Event Stream will be very low, making it difficult for an Event Receiver to tell the difference between expected behavior and event transmission failure due to a misconfigured stream. Event Receivers can request that a Verification Event be transmitted over the Event Stream, allowing the Receiver to confirm that the stream is configured correctly upon successful receipt of the event. The acknowledgment of a Verification Event also confirms to the Event Transmitter that end-to-end delivery is working, including signature verification and encryption. A Transmitter MAY send a Verification Event at any time, even if one was not requested by the Event Receiver. A Transmitter MAY respond to Verification Event requests even if the event is not present in the events_supported, events_requested and / or events_delivered fields in the Stream Configuration ().

Verification Event The Verification Event is an SSF event with the event type: "https://schemas.openid.net/secevent/ssf/event-type/verification". The event contains the following attribute: state

• OPTIONAL An opaque value provided by the Event Receiver when the event is triggered.

As with any SSF event, the Verification Event has a top-level sub_id claim: sub_id

• REQUIRED. The value of the top-level sub_id claim in a Verification Event MUST always be set to have a simple value of type opaque. The id of the value MUST be the stream_id of the stream being verified.

• Note that the subject that identifies a stream itself is always implicitly added to the stream and MAY NOT be removed from the stream.

Upon receiving a Verification Event, the Event Receiver SHALL parse the SET and validate its claims. In particular, the Event Receiver SHALL confirm that the value for "state" is as expected. If the value of "state" does not match, an error response with the "err" field set to "invalid_state" SHOULD be returned (see Section 2.4 of or Section 2.4.4 of ). In many cases, Event Transmitters MAY disable or suspend an Event Stream that fails to successfully verify based on the acknowledgement or lack of acknowledgement by the Event Receiver.

Triggering a Verification Event. To request that a Verification Event be sent over an Event Stream, the Event Receiver makes an HTTP POST request to the Verification Endpoint, with a JSON object containing the parameters of the verification request, if any. On a successful request, the Event Transmitter responds with an empty "204 No Content" response. Verification requests have the following properties: stream_id

• REQUIRED. A string identifying the stream that the Verification Event is being requested on.

state

• OPTIONAL. An arbitrary string that the Event Transmitter MUST echo back to the Event Receiver in the Verification Event's payload. Event Receivers MAY use the value of this parameter to correlate a Verification Event with a verification request. If the Verification Event is initiated by the Transmitter then this parameter MUST not be set.

A successful response from a POST to the Verification Endpoint does not indicate that the Verification Event was transmitted successfully, only that the Event Transmitter has transmitted the event or will do so at some point in the future. Event Transmitters MAY transmit the event via an asynchronous process, and SHOULD publish an SLA for Verification Event transmission times. Event Receivers MUST NOT depend on the Verification Event being transmitted synchronously or in any particular order relative to the current queue of events. Errors are signaled with HTTP status codes as follows: Code Description 400 if the request body cannot be parsed or if the request is otherwise invalid 401 if authorization failed or it is missing 404 if there is no Event Stream with the given "stream_id" for this Event Receiver 429 if the Event Receiver is sending too many requests in a given amount of time; see related "min_verification_interval" in The following is a non-normative example request to trigger a Verification Event:

The following is a non-normative example response to a successful request:

And the following is a non-normative example of a Verification Event sent to the Event Receiver as a result of the above request:

Stream Updated Event A Transmitter MAY change the stream status without a request from a Receiver. The Transmitter sends an event of type "https://schemas.openid.net/secevent/ssf/event-type/stream-updated" to indicate that it has changed the status of the Event Stream. If a Transmitter decides to change the status of an Event Stream from "enabled" to either "paused" or "disabled", then the Transmitter MUST send this event to the Receiver before stopping the stream. If the Transmitter changes the status of the stream from either "paused" or "disabled" to "enabled", then it MUST send this event to the Receiver upon re-enabling the stream. A Transmitter MAY send a Stream Updated event even if the event is not present in the events_supported, events_requested and / or events_delivered fields in the Stream Configuration (). The "stream-updated" event contains the following claims: status

• REQUIRED. Defines the new status of the stream.

reason

• OPTIONAL. Provides a short description of why the Transmitter has updated the status.

As with any SSF event, this event has a top-level sub_id claim: sub_id

• REQUIRED. The top-level sub_id claim specifies the Stream Id for which the status has been updated. The value of the sub_id field MUST be of format opaque, and its id value MUST be the unique ID of the stream.

• Note that the subject that identifies a stream itself is always implicitly added to the stream and MAY NOT be removed from the stream.

• Below is a non-normative example of a Stream Updated event.

Security Considerations

Subject Probing It may be possible for an Event Transmitter to leak information about subjects through their responses to add subject requests. A "404" response may indicate to the Event Receiver that the subject does not exist, which may inadvertently reveal information about the subject (e.g. that a particular individual does or does not use the Event Transmitter service). Event Transmitters SHOULD carefully evaluate the conditions under which they will return error responses to add subject requests. Event Transmitters MAY return a "204" response even if they will not actually send any events related to the subject, and Event Receivers MUST NOT assume that a 204 response means that they will receive events related to the subject.

Information Harvesting SETs may contain personally identifiable information (PII) or other non-public information about the Event Transmitter, the subject (of an event in the SET), or the relationship between the two. It is important for Event Transmitters to understand what information they are revealing to Event Receivers when transmitting events to them, lest the Event Stream become a vector for unauthorized access to private information. Event Transmitters SHOULD interpret add subject requests as statements of interest in a subject by an Event Receiver, and ARE NOT obligated to transmit events related to every subject an Event Receiver adds to the stream. Event Transmitters MAY choose to transmit some, all, or no events related to any given subject and SHOULD validate that they are permitted to share the information contained within an event with the Event Receiver before transmitting the event. The mechanisms by which such validation is performed are outside the scope of this specification.

Malicious Subject Removal A malicious party may find it advantageous to remove a particular subject from a stream, in order to reduce the Event Receiver's ability to detect malicious activity related to the subject, inconvenience the subject, or for other reasons. Consequently it may be in the best interests of the subject for the Event Transmitter to continue to send events related to the subject for some time after the subject has been removed from a stream. Event Transmitters MAY continue sending events related to a subject for some amount of time after that subject has been removed from the stream. Event Receivers MUST tolerate receiving events for subjects that have been removed from the stream, and MUST NOT report these events as errors to the Event Transmitter.

Privacy Considerations

Subject Information Leakage Event Transmitters and Receivers SHOULD take precautions to ensure that they do not leak information about subjects via Subject Identifiers, and choose appropriate Subject Identifier Types accordingly. Parties SHOULD NOT identify a subject using a given Subject Identifier Type if doing so will allow the recipient to correlate different claims about the subject that they are not known to already have knowledge of. Transmitters and Receivers SHOULD always use the same Subject Identifier Type and the same claim values to identify a given subject when communicating with a given party in order to reduce the possibility of information leakage.

Previously Consented Data If SSF events contain new values for attributes of Subject Principals that were previously exchanged between the Transmitter and Receiver, then there are no additional privacy considerations introduced by providing the updated values in the SSF events, unless the attribute was exchanged under a one-time consent obtained from the user.

New Data Data that was not previously exchanged between the Transmitter and the Receiver, or data whose consent to exchange has expired has the following considerations:

Organizational Data If a user has previously agreed with a Transmitter that they allow the release of certain data to third-parties, then the Transmitter MAY send such data in SSF events without additional consent of the user. Such data MAY include organizational data about the Subject Principal that was generated by the Transmitter.

Consentable Data If a Transmitter intends to include data in SSF events that is not previously consented to be released by the user, then the Transmitter MUST obtain consent to release such data from the user in accordance with the Transmitter's privacy policy.

Profiles This section is a profile of the following IETF Security Event specifications: Security Event Token (SET) Push-Based SET Token Delivery Using HTTP Poll-Based SET Token Delivery Using HTTP The RISC use cases that set the requirements are described in Security Events RISC Use Cases . The CAEP use cases that set the requirements are described in CAEP Use Cases (TODO: Add reference when file is added to repository.)

Security Event Token Profile This section provides SSF profiling specifications for the Security Event Token (SET) spec.

Signature Key Resolution The signature key can be obtained through "jwks_uri", see .

SSF Event Subject The primary Subject Member of SSF events is described in the "Subject Members" section (). The JWT "sub" claim MUST NOT be present in any SET containing an SSF event.

SSF Event Properties The SSF event MAY contain additional claims within the event payload that are specific to the event type.

Explicit Typing of SETs SSF events MUST use explicit typing as defined in Section 2.3 of .

The purpose is defense against confusion with other JWTs, as described in Sections 4.5, 4.6 and 4.7 of . While current Id Token validators may not be using the "typ" header parameter, requiring it for SSF SETs guarantees a distinct value for future validators.

The "iss" Claim The "iss" claim MUST match the "iss" value in the Stream Configuration data for the stream that the event is sent on. Receivers MUST validate that this claim matches the "iss" in the Stream Configuration data, as well as the Issuer from which the Receiver requested the Transmitter Configuration data.

The "exp" Claim The "exp" claim MUST NOT be used in SSF SETs. The purpose is defense in depth against confusion with other JWTs, as described in Sections 4.5 and 4.6 of .

The "aud" Claim The "aud" claim can be a single string or an array of strings. Values that uniquely identify the Receiver to the Transmitter MAY be used, if the two parties have agreement on the format. More than one value can be present if the corresponding Receivers are known to the Transmitter to be the same entity, for example a web client and a mobile client of the same application. All the Receivers in this case MUST use the exact same delivery method. If multiple Receivers have the exact same delivery configuration but the Transmitter does not know if they belong to the same entity then the Transmitter SHOULD issue distinct SETs for each Receiver and deliver them separately. In this case the multiple Receivers might use the same service to process SETs, and this service might reroute SETs to respective Receivers, an "aud" claim with multiple Receivers would lead to unintended data disclosure.

The "txn" claim Transmitters SHOULD set the "txn" claim value in Security Event Tokens (SETs). If the value is present, it MUST be unique to the underlying event that caused the Transmitter to generate the Security Event Token (SET). The Transmitter, however, may use the same value in the "txn" claim across different Security Events Tokens (SETs), such as session revoked and credential change, to indicate that the SETs originated from the same underlying cause or reason.

The "events" claim The "events" claim SHOULD contain only one event. Multiple event type URIs are permitted only if they are alternative URIs defining the exact same event type.

Security Considerations

Distinguishing SETs from other Kinds of JWTs Of particular concern is the possibility that SETs are confused for other kinds of JWTs. The Security Considerations section of has several sub-sections on this subject. The Shared Signals Framework requires further restrictions: The "sub" claim MUST NOT be present, as described in . SSF SETs MUST use explicit typing, as described in . The "exp" claim MUST NOT be present, as described in .

SET Token Delivery Using HTTP Profile This section provides SSF profiling specifications for the and specs.

Stream Configuration Metadata Each delivery method is identified by a URI, specified below by the "method" metadata.

Push Delivery using HTTP This section provides SSF profiling specifications for the spec. method

• "urn:ietf:rfc:8935"

endpoint_url

• The URL where events are pushed through HTTP POST. This is set by the Receiver. If a Receiver is using multiple streams from a single Transmitter and needs to keep the SETs separated, it is RECOMMENDED that the URL for each stream be unique.

authorization_header

• The HTTP Authorization header that the Transmitter MUST set with each event delivery, if the configuration is present. The value is optional and it is set by the Receiver.

Polling Delivery using HTTP This section provides SSF profiling specifications for the spec. method

• "urn:ietf:rfc:8936"

endpoint_url

• The URL where events can be retrieved from. This is specified by the Transmitter. These URLs MAY be reused across Receivers, but MUST be unique per stream for a given Receiver.

IANA Considerations Subject Identifiers defined in this document will be added to the "Security Events Subject Identifier Types" registry. This registry is defined in the Subject Identifiers for Security Event Tokens specification. The ssf-configuration well-known endpoint is registered in IANA's Well-Known URIs registry, as defined by . IANA is asked to assign the error code "invalid_state", as defined in , to the Security Event Token Error Codes section of the Security Event Token registry, as defined in Section 7.1 of . The following information is provided as required by the registration template: Error Code

• invalid_state

Description

• Indicates that a Verification event contained a "state" claim that does not match the value expected by the Receiver.

Change Controller

• OpenID - Shared Signals Working Group

&OASIS.saml-core-2.0-os; &RFC2119; &RFC6749; &RFC6750; &RFC7159; &RFC7517; &RFC7519; &RFC8174; &RFC8414; &RFC8417; &RFC8615; &RFC8935; &RFC8936; &RFC9110; &RFC9493;

Acknowledgements The authors wish to thank all members of the OpenID Foundation SSF Working Group who contributed to the development of this specification.

Notices Copyright (c) 2024 The OpenID Foundation. The OpenID Foundation (OIDF) grants to any Contributor, developer, implementer, or other interested party a non-exclusive, royalty free, worldwide copyright license to reproduce, prepare derivative works from, distribute, perform and display, this Implementers Draft or Final Specification solely for the purposes of (i) developing specifications, and (ii) implementing Implementers Drafts and Final Specifications based on such documents, provided that attribution be made to the OIDF as the source of the material, but that such attribution does not indicate an endorsement by the OIDF. The technology described in this specification was made available from contributions from various sources, including members of the OpenID Foundation and others. Although the OpenID Foundation has taken steps to help ensure that the technology is available for distribution, it takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this specification or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any independent effort to identify any such rights. The OpenID Foundation and the contributors to this specification make no (and hereby expressly disclaim any) warranties (express, implied, or otherwise), including implied warranties of merchantability, non-infringement, fitness for a particular purpose, or title, related to this specification, and the entire risk as to implementing this specification is assumed by the implementer. The OpenID Intellectual Property Rights policy requires contributors to offer a patent promise not to assert certain patent claims against other contributors and against implementers. The OpenID Foundation invites any interested party to bring to its attention any copyrights, patents, patent applications, or other proprietary rights that may cover technology that may be required to practice this specification.

Document History [[ To be removed from the final specification ]] -03

-02

Contributors ForgeRock

steve.venema@forgerock.com

Steve defined the format field of Complex Subjects Okta

apoorva.deshpande@okta.com

The Walt Disney Company

sean.odentity@disney.com