Security Events Working Group
Internet Engineering Task Force (IETF) A. Backman, Ed.
Internet-Draft
Request for Comments: 8935 Amazon
Intended status:
Category: Standards Track M. Jones, Ed.
Expires: December 28, 2020
ISSN: 2070-1721 Microsoft
M. Scurtescu
Coinbase
M. Ansari
Cisco
A. Nadalin
Microsoft
June 26,
Independent
November 2020
Push-Based Security Event Token (SET) Delivery Using HTTP
draft-ietf-secevent-http-push-14
Abstract
This specification defines how a Security Event Token (SET) can be
delivered to an intended recipient using HTTP POST over TLS. The SET
is transmitted in the body of an HTTP POST request to an endpoint
operated by the recipient, and the recipient indicates successful or
failed transmission via the HTTP response.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list It represents the consensus of current Internet-
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Internet-Drafts are draft documents valid the IETF community. It has
received public review and has been approved for a maximum publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of six months this document, any errata,
and how to provide feedback on it may be updated, replaced, or obsoleted by other documents obtained at any
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 28, 2020.
https://www.rfc-editor.org/info/rfc8935.
Copyright Notice
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document authors. All rights reserved.
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Table of Contents
1. Introduction and Overview . . . . . . . . . . . . . . . . . . 2
1.1. Notational Conventions . . . . . . . . . . . . . . . . . 3
1.2. Definitions . . . . . . . . . . . . . . . . . . . . . . . 3
2. SET Delivery . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Transmitting a SET . . . . . . . . . . . . . . . . . . . 5
2.2. Success Response . . . . . . . . . . . . . . . . . . . . 6
2.3. Failure Response . . . . . . . . . . . . . . . . . . . . 6
2.4. Security Event Token Delivery Error Codes . . . . . . . . 8
3. Authentication and Authorization . . . . . . . . . . . . . . 9
4. Delivery Reliability . . . . . . . . . . . . . . . . . . . . 9
5. Security Considerations . . . . . . . . . . . . . . . . . . . 10
5.1. Authentication Using Signed SETs . . . . . . . . . . . . 10
5.2. HTTP Considerations . . . . . . . . . . . . . . . . . . . 10
5.3. Confidentiality of SETs . . . . . . . . . . . . . . . . . 10
5.4. Denial of Service . . . . . . . . . . . . . . . . . . . . 11
5.5. Authenticating Persisted SETs . . . . . . . . . . . . . . 11
6. Privacy Considerations . . . . . . . . . . . . . . . . . . . 11
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
7.1. Security Event Token Delivery Error Codes . . . . . . . . 12
7.1.1. Registration Template . . . . . . . . . . . . . . . . 13
7.1.2. Initial Registry Contents . . . . . . . . . . . . . . 13
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
8.1. Normative References . . . . . . . . . . . . . . . . . . 14
8.2. Informative References . . . . . . . . . . . . . . . . . 16
Appendix A. Unencrypted Transport Considerations . . . . . . . . 16
Appendix B. Other Streaming Specifications . . . . . . . . . . . 17
Appendix C.
Acknowledgments . . . . . . . . . . . . . . . . . . 18
Appendix D. Change Log . . . . . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 24
1. Introduction and Overview
This specification defines a mechanism by which a transmitter of a
Security Event Token (SET) [RFC8417] can deliver the SET to an
intended SET Recipient via HTTP POST [RFC7231] over TLS. This is an
alternative SET delivery method to the one defined in
[I-D.ietf-secevent-http-poll]. [RFC8936].
Push-based SET delivery over HTTP POST is intended for scenarios
where all of the following apply:
o
* The transmitter of the SET is capable of making outbound HTTP
requests.
o
* The recipient is capable of hosting a TLS-enabled HTTP endpoint
that is accessible to the transmitter.
o
* The transmitter and recipient are willing to exchange data with
one another.
In some scenarios, either push-based or poll-based delivery could be
used, and in others, only one of them would be applicable.
A mechanism for exchanging configuration metadata such as endpoint
URLs, cryptographic keys, and possible implementation constraints
such as buffer size limitations between the transmitter and recipient
is out of scope for this specification. How SETs are defined and the
process by which security events are identified for SET Recipients
are specified in [RFC8417].
1.1. 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 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
Throughout this document, all figures may contain spaces and extra
line wrapping for readability and due to space limitations.
1.2. Definitions
This specification utilizes the following terms defined in [RFC8417]:
"Security Event Token (SET)", "SET Issuer", "SET Recipient", and
"Event Payload", as well as the term defined below:
SET Transmitter Transmitter: An entity that delivers SETs in its possession to
one or more SET Recipients.
2. SET Delivery
To deliver a SET to a given SET Recipient, the SET Transmitter makes
a SET transmission request Transmission Request to the SET Recipient, with the SET itself
contained within the request. The SET Recipient replies to this
request with a response either acknowledging successful transmission
of the SET or indicating that an error occurred while receiving,
parsing, and/or validating the SET.
Upon receipt of a SET, the SET Recipient SHALL validate that all of
the following are true:
o
* The SET Recipient can parse the SET.
o
* The SET is authentic (i.e., it was issued by the issuer specified
within the SET, and if signed, was signed by a key belonging to
the issuer).
o
* The SET Recipient is identified as an intended audience of the
SET.
o
* The SET Issuer is recognized as an issuer that the SET Recipient
is willing to receive SETs from (e.g., the issuer is listed as
allowed by the SET Recipient).
o
* The SET Recipient is willing to accept this SET from this SET
Transmitter (e.g., the SET Transmitter is expected to send SETs
with the issuer and subject of the SET in question).
The mechanisms by which the SET Recipient performs this validation
are out of scope for this document. SET parsing, issuer
identification, and audience identification are defined in [RFC8417].
The mechanism for validating the authenticity of a SET is deployment
specific,
specific and may vary depending on the authentication mechanisms in
use,
use and whether the SET is signed and/or encrypted (See Section 3).
SET Transmitters MAY transmit SETs issued by another entity. The SET
Recipient may accept or reject (i.e., return an error response such
as "access_denied") a SET at its own discretion.
The SET Recipient persists the SET in a way that is sufficient to
meet the SET Recipient's own reliability requirements. The level and
method of retention of SETs by SET Recipients is out of scope of this
specification. Once the SET has been validated and persisted, the
SET Recipient SHOULD immediately return a response indicating that
the SET was successfully delivered. The SET Recipient SHOULD NOT
perform further processing of the SET beyond the required validation
steps prior to sending this response. Any additional steps SHOULD be
executed asynchronously from delivery to minimize the time the SET
Transmitter is waiting for a response.
The SET Transmitter MAY transmit the same SET to the SET Recipient
multiple times, regardless of the response from the SET Recipient.
The SET Recipient MUST respond as it would if the SET had not been
previously received by the SET Recipient. The SET Recipient MUST NOT
expect or depend on a SET Transmitter to re-transmit retransmit a SET or
otherwise make a SET available to the SET Recipient once the SET
Recipient acknowledges that it was received successfully.
The SET Transmitter should not re-transmit retransmit a SET unless the SET
Transmitter suspects that previous transmissions may have failed due
to potentially recoverable errors (such as network outage or
temporary service interruption at either the SET Transmitter or SET
Recipient). In all other cases, the SET Transmitter SHOULD NOT re-
transmit
retransmit a SET. The SET Transmitter SHOULD delay retransmission
for an appropriate amount of time to avoid overwhelming the SET
Recipient (see Section 4).
2.1. Transmitting a SET
To transmit a SET to a SET Recipient, the SET Transmitter makes an
HTTP POST request to a TLS-enabled HTTP endpoint provided by the SET
Recipient. The "Content-Type" header field of this request MUST be
"application/secevent+jwt" as defined in Sections 2.3 and 7.2 of
[RFC8417], and the "Accept" header field MUST be "application/json".
The request body MUST consist of the SET itself, represented as a JWT
JSON Web Token (JWT) [RFC7519].
The SET Transmitter MAY include in the request an "Accept-Language"
header field to indicate to the SET Recipient the preferred
language(s) in which to receive error messages.
The mechanisms by which the SET Transmitter determines the HTTP
endpoint to use when transmitting a SET to a given SET Recipient are
not defined by this specification and are deployment specific.
The following is a non-normative example of a SET transmission
request: Transmission
Request:
POST /Events HTTP/1.1
Host: notify.rp.example.com
Accept: application/json
Accept-Language: en-US, en;q=0.5
Content-Type: application/secevent+jwt
eyJ0eXAiOiJzZWNldmVudCtqd3QiLCJhbGciOiJIUzI1NiJ9Cg
.
eyJpc3MiOiJodHRwczovL2lkcC5leGFtcGxlLmNvbS8iLCJqdGkiOiI3NTZFNjk
3MTc1NjUyMDY5NjQ2NTZFNzQ2OTY2Njk2NTcyIiwiaWF0IjoxNTA4MTg0ODQ1LC
JhdWQiOiI2MzZDNjk2NTZFNzQ1RjY5NjQiLCJldmVudHMiOnsiaHR0cHM6Ly9zY
2hlbWFzLm9wZW5pZC5uZXQvc2VjZXZlbnQvcmlzYy9ldmVudC10eXBlL2FjY291
bnQtZGlzYWJsZWQiOnsic3ViamVjdCI6eyJzdWJqZWN0X3R5cGUiOiJpc3Mtc3V
iIiwiaXNzIjoiaHR0cHM6Ly9pZHAuZXhhbXBsZS5jb20vIiwic3ViIjoiNzM3NT
YyNkE2NTYzNzQifSwicmVhc29uIjoiaGlqYWNraW5nIn19fQ
.
Y4rXxMD406P2edv00cr9Wf3_XwNtLjB9n-jTqN1_lLc
Figure 1: Example SET Transmission Request
2.2. Success Response
If the SET is determined to be valid, the SET Recipient SHALL
acknowledge successful transmission by responding with HTTP Response
Status Code 202 (Accepted) (see Section 6.3.3 of [RFC7231]). The
body of the response MUST be empty.
The following is a non-normative example of a successful receipt of a
SET.
HTTP/1.1 202 Accepted
Figure 2: Example Successful Delivery Response
2.3. Failure Response
In the event of a general HTTP error condition, the SET Recipient
responds with the applicable HTTP Status Code, as defined in
Section 6 of [RFC7231].
When the SET Recipient detects an error parsing, validating, or
authenticating a SET transmitted in a SET Transmission Request, the
SET Recipient SHALL respond with an HTTP Response Status Code of 400
(Bad Request). The "Content-Type" header field of this response MUST
be "application/json", and the body MUST be a UTF-8 encoded JSON
[RFC8259] object containing the following name/value pairs:
err
err: A Security Event Token Error Code (see Section 2.4).
description
description: A UTF-8 string containing a human-readable description
of the error that may provide additional diagnostic information.
The exact content of this field is implementation specific.
The response MUST include a "Content-Language" header field, field whose
value indicates the language of the error descriptions included in
the response body. If the SET Recipient can provide error
descriptions in multiple languages, they SHOULD choose the language
to use according to the value of the "Accept-Language" header field
sent by the SET Transmitter in the transmission request, as described
in Section 5.3.5 of [RFC7231]. If the SET Transmitter did not send
an "Accept-Language" header field, or if the SET Recipient does not
support any of the languages included in the header field, the SET
Recipient MUST respond with messages that are understandable by an
English-speaking person, as described in Section 4.5 of [RFC2277].
The following is a non-normative example error response indicating
that the key used to encrypt the SET has been revoked.
HTTP/1.1 400 Bad Request
Content-Language: en-US
Content-Type: application/json
{
"err": "invalid_key",
"description": "Key ID 12345 has been revoked."
}
Figure 3: Example Error Response (invalid_key)
The following is a non-normative example error response indicating
that the access token included in the request is expired.
HTTP/1.1 400 Bad Request
Content-Language: en-US
Content-Type: application/json
{
"err": "authentication_failed",
"description": "Access token has expired."
}
Figure 4: Example Error Response (authentication_failed)
The following is a non-normative example error response indicating
that the SET Receiver is not willing to accept SETs issued by the
specified issuer from this particular SET Transmitter.
HTTP/1.1 400 Bad Request
Content-Language: en-US
Content-Type: application/json
{
"err": "invalid_issuer",
"description": "Not authorized for issuer https://iss.example.com/." https://iss.example.com/"
}
Figure 5: Example Error Response (access_denied)
2.4. Security Event Token Delivery Error Codes
Security Event Token Delivery Error Codes are strings that identify a specific
category of error that may occur when parsing or validating a SET.
Every Security Event Token Delivery Error Code MUST have a unique name
registered in the IANA "Security Event Token Delivery Error Codes" registry
established by Section 7.1.
The following table presents the initial set of Error Codes that are
registered in the IANA "Security Event Token Delivery Error Codes" registry:
+-----------------------+-------------------------------------------+
+=======================+=====================================+
| Error Code | Description |
+-----------------------+-------------------------------------------+
+=======================+=====================================+
| invalid_request | The request body cannot be parsed as a |
| | as a SET, or the Event Payload within the SET |
| | within the SET does not conform to the event's |
| | the event's definition. |
+-----------------------+-------------------------------------+
| invalid_key | One or more keys used to encrypt or sign |
| | sign the SET is invalid or otherwise |
| | otherwise unacceptable to the SET Recipient |
| | Recipient (expired, revoked, failed certificate |
| | certificate validation, etc.). |
+-----------------------+-------------------------------------+
| invalid_issuer | The SET issuer Issuer is invalid for the SET |
| | SET Recipient. |
+-----------------------+-------------------------------------+
| invalid_audience | The SET audience Audience does not correspond to |
| | correspond to the SET Recipient. |
+-----------------------+-------------------------------------+
| authentication_failed | The SET Recipient could not authenticate |
| | authenticate the SET Transmitter. |
+-----------------------+-------------------------------------+
| access_denied | The SET Transmitter is not authorized to |
| | authorized to transmit the SET to |
| | the SET Recipient. |
+-----------------------+-------------------------------------------+
+-----------------------+-------------------------------------+
Table 1: SET Delivery Error Codes
Other Error Codes may also be received, as the set of Error Codes is
extensible via the IANA "Security Event Token Delivery Error Codes" registry
established in Section 7.1.
3. Authentication and Authorization
The SET delivery method described in this specification is based upon
HTTP over TLS [RFC2818] and standard HTTP authentication and
authorization schemes, as per [RFC7235]. The TLS server certificate
MUST be validated using DNS-ID [RFC6125] and/or DANE DNS-Based
Authentication of Named Entities (DANE) [RFC6698].
Authorization for the eligibility to provide actionable SETs can be
determined by using the identity of the SET Issuer, the identity of
the SET Transmitter, perhaps using mutual TLS, or via other employed
authentication methods. Because SETs are not commands, SET
Recipients are free to ignore SETs that are not of interest.
4. Delivery Reliability
Delivery reliability requirements may vary depending upon the use
cases. This specification defines the response from the SET
Recipient in such a way as to provide the SET Transmitter with the
information necessary to determine what further action is required,
if any, in order to meet their requirements. SET Transmitters with
high reliability requirements may be tempted to always retry failed
transmissions. However, it should be noted that for many types of
SET delivery errors, a retry is extremely unlikely to be successful.
For example, "invalid_request" indicates a structural error in the
content of the request body that is likely to remain when re-
transmitting
retransmitting the same SET. Others such as "access_denied" may be
transient, for example example, if the SET Transmitter refreshes expired
credentials prior to re-transmission. retransmission.
The SET Transmitter may be unaware of whether or not a SET has been
delivered to a SET Recipient. For example, a network interruption
could prevent the SET Transmitter from receiving the success
response, or a service outage could prevent the SET Transmitter from
recording the fact that the SET was delivered. It is left to the
implementer to decide how to handle such cases, based on their
requirements. For example, it may be appropriate for the SET
Transmitter to re-transmit retransmit the SET to the SET Recipient, erring on the
side of guaranteeing delivery, or it may be appropriate to assume
delivery was successful, erring on the side of not spending resources
re-transmitting
retransmitting previously delivered SETs. Other options, such as
sending the SET to a "dead letter queue" for manual examination may
also be appropriate.
Implementers SHOULD evaluate the reliability requirements of their
use cases and the impact of various retry mechanisms and re-
transmission
retransmission policies on the performance of their systems to
determine an appropriate strategy for handling various error
conditions.
5. Security Considerations
5.1. Authentication Using Signed SETs
JWS signed SETs can be used (see [RFC7515] and Section 5 of
[RFC8417]) to enable the SET Recipient to validate that the SET
Issuer is authorized to provide actionable SETs.
5.2. HTTP Considerations
SET delivery depends on the use of Hypertext Transfer Protocol and is
thus subject to the security considerations of HTTP Section (Section 9 of
[RFC7230]
[RFC7230]) and its related specifications.
5.3. Confidentiality of SETs
SETs may contain sensitive information, including Personally
Identifiable Information (PII), or be distributed through third
parties. In such cases, SET Transmitters and SET Recipients MUST
protect the confidentiality of the SET contents. TLS MUST be used to
secure the transmitted SETs. In some use cases, encrypting the SET
as described in JWE [RFC7516] will also be required. The Event
delivery endpoint MUST support at least TLS version 1.2 [RFC5246] and
SHOULD support the newest version of TLS that meets its security
requirements, which as of the time of this publication is TLS 1.3
[RFC8446]. The client MUST perform a TLS/SSL server certificate
check using DNS-ID [RFC6125] and/or DANE [RFC6698]. How a SET
Transmitter determines the expected service identity to match the SET
Recipient's server certificate against is out of scope for this
document. The implementation security considerations for TLS in
"Recommendations for Secure Use of TLS Transport Layer Security (TLS) and DTLS"
Datagram Transport Layer Security (DTLS)" [RFC7525] MUST be followed.
5.4. Denial of Service
The SET Recipient may be vulnerable to a denial-of-service attack
where a malicious party makes a high volume of requests containing
invalid SETs, causing the endpoint to expend significant resources on
cryptographic operations that are bound to fail. This may be
mitigated by authenticating SET Transmitters with a mechanism such as
mutual TLS. Rate-limiting problematic transmitters is also a
possible means of mitigation.
5.5. Authenticating Persisted SETs
At the time of receipt, the SET Recipient can rely upon TLS
mechanisms, HTTP authentication methods, and/or other context from
the transmission request to authenticate the SET Transmitter and
validate the authenticity of the SET. However, this context is
typically unavailable to systems to which the SET Recipient forwards
the SET, or to systems that retrieve the SET from storage. If the
SET Recipient requires the ability to validate SET authenticity
outside of the context of the transmission request, then the SET
Recipient SHOULD ensure that such SETs have been signed in accordance
with [RFC7515]. Needed context could also be stored with the SET and
retrieved with it.
6. Privacy Considerations
SET Transmitters should attempt to deliver SETs that are targeted to
the specific business and protocol needs of subscribers.
When sharing personally identifiable information or information that
is otherwise considered confidential to affected users, SET
Transmitters and Recipients MUST have the appropriate legal
agreements and user consent or terms of service in place.
Furthermore, data that needs confidentiality protection MUST be
encrypted, at least with TLS and sometimes also using JSON Web
Encryption (JWE) [RFC7516].
In some cases, subject identifiers themselves may be considered
sensitive information, such that their inclusion within a SET may be
considered a violation of privacy. SET Issuers and SET Transmitters
should consider the ramifications of sharing a particular subject
identifier with a SET Recipient (e.g., whether doing so could enable
correlation and/or de-anonymization of data) and choose appropriate
subject identifiers for their use cases.
7. IANA Considerations
7.1. Security Event Token Delivery Error Codes
This document defines Security Event Token Delivery Error Codes, for which
IANA is asked to create has created and maintain now maintains a new registry titled "Security
Event Token Delivery Error Codes". Initial values for the
Security "Security Event
Token Delivery Error Codes Codes" registry are defined in Table 1 and registered
below. Future assignments are to be made through the Specification
Required registration policy ([RFC8126]) [RFC8126] and shall follow the template
below.
Error Codes are intended to be interpreted by automated systems, and
therefore systems;
therefore, they SHOULD identify classes of errors to which an
automated system could respond in a meaningfully distinct way (e.g.,
by refreshing authentication credentials and retrying the request).
Error Code names are case sensitive. Names may not match other
registered names in a case-insensitive manner unless the Designated
Experts state that there is a compelling reason to allow an
exception.
Criteria that should be applied by the Designated Experts includes
determining whether the proposed registration duplicates existing
functionality, whether it is likely to be of general applicability or
whether it is useful only for a single application, and whether the
registration description is clear.
It is suggested that multiple Designated Experts be appointed who are
able to represent the perspectives of different applications using
this specification, specification in order to enable broadly informed review of
registration decisions. In cases where a registration decision could
be perceived as creating a conflict of interest for a particular
Expert,
expert, that Expert expert should defer to the judgment of the other
Experts.
experts.
7.1.1. Registration Template
Error Code
The name of the Security Event Token Delivery Error Code, as described in
Section 2.4. The name MUST be a case-sensitive ASCII string
consisting only of letters, digits, and underscore; these are the
characters whose codes fall within the inclusive ranges 0x30-39,
0x41-5A, 0x5F 0x5F, and 0x61-7A.
Description
A brief human-readable description of the Security Event Token
Delivery
Error Code.
Change Controller
For error codes registered by the IETF or its working groups, list
"IETF". For all other error codes, list the name of the party
responsible for the registration. Contact information such as
mailing address, email address, or phone number may also be
provided.
Defining Document(s)
Reference
A reference to the document or documents that define the Security
Event Token Delivery Error Code. The definition MUST specify the name and
description of the error code and explain under what circumstances
the error code may be used. URIs that can be used to retrieve
copies of each document at no cost SHOULD be included.
7.1.2. Initial Registry Contents
Error Code: invalid_request
Description: The request body cannot be parsed as a SET or the
event payload Event
Payload within the SET does not conform to the event's definition.
Change Controller: IETF
Defining Document(s):
Reference: Section 2.4 of [[ this specification ]] RFC 8935
Error Code: invalid_key
Description: One or more keys used to encrypt or sign the SET is
invalid or otherwise unacceptable to the SET Recipient (expired,
revoked, failed certificate validation, etc.).
Change Controller: IETF
Defining Document(s):
Reference: Section 2.4 of [[ this specification ]] RFC 8935
Error Code: invalid_issuer
Description: The SET issuer Issuer is invalid for the SET Recipient.
Change Controller: IETF
Defining Document(s):
Reference: Section 2.4 of [[ this specification ]] RFC 8935
Error Code: invalid_audience
Description: The SET audience Audience does not correspond to the SET
Recipient.
Change Controller: IETF
Defining Document(s):
Reference: Section 2.4 of [[ this specification ]] RFC 8935
Error Code: authentication_failed
Description: The SET Recipient could not authenticate the SET
Transmitter.
Change Controller: IETF
Defining Document(s):
Reference: Section 2.4 of [[ this specification ]] RFC 8935
Error Code: access_denied
Description: The SET Transmitter is not authorized to transmit the
SET to the SET Recipient.
Change Controller: IETF
Defining Document(s):
Reference: Section 2.4 of [[ this specification ]] RFC 8935
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC2277] Alvestrand, H., "IETF Policy on Character Sets and
Languages", BCP 18, RFC 2277, DOI 10.17487/RFC2277,
January 1998, <https://www.rfc-editor.org/info/rfc2277>.
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818,
DOI 10.17487/RFC2818, May 2000,
<https://www.rfc-editor.org/info/rfc2818>.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246,
DOI 10.17487/RFC5246, August 2008,
<https://www.rfc-editor.org/info/rfc5246>.
[RFC6125] Saint-Andre, P. and J. Hodges, "Representation and
Verification of Domain-Based Application Service Identity
within Internet Public Key Infrastructure Using X.509
(PKIX) Certificates in the Context of Transport Layer
Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March
2011, <https://www.rfc-editor.org/info/rfc6125>.
[RFC6698] Hoffman, P. and J. Schlyter, "The DNS-Based Authentication
of Named Entities (DANE) Transport Layer Security (TLS)
Protocol: TLSA", RFC 6698, DOI 10.17487/RFC6698, August
2012, <https://www.rfc-editor.org/info/rfc6698>.
[RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Message Syntax and Routing",
RFC 7230, DOI 10.17487/RFC7230, June 2014,
<https://www.rfc-editor.org/info/rfc7230>.
[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
DOI 10.17487/RFC7231, June 2014,
<https://www.rfc-editor.org/info/rfc7231>.
[RFC7515] Jones, M., Bradley, J., and N. Sakimura, "JSON Web
Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
2015, <https://www.rfc-editor.org/info/rfc7515>.
[RFC7516] Jones, M. and J. Hildebrand, "JSON Web Encryption (JWE)",
RFC 7516, DOI 10.17487/RFC7516, May 2015,
<https://www.rfc-editor.org/info/rfc7516>.
[RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
(JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015,
<https://www.rfc-editor.org/info/rfc7519>.
[RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre,
"Recommendations for Secure Use of Transport Layer
Security (TLS) and Datagram Transport Layer Security
(DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May
2015, <https://www.rfc-editor.org/info/rfc7525>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", STD 90, RFC 8259,
DOI 10.17487/RFC8259, December 2017,
<https://www.rfc-editor.org/info/rfc8259>.
[RFC8417] Hunt, P., Ed., Jones, M., Denniss, W., and M. Ansari,
"Security Event Token (SET)", RFC 8417,
DOI 10.17487/RFC8417, July 2018,
<https://www.rfc-editor.org/info/rfc8417>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
8.2. Informative References
[I-D.ietf-secevent-http-poll]
[RFC7235] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Authentication", RFC 7235,
DOI 10.17487/RFC7235, June 2014,
<https://www.rfc-editor.org/info/rfc7235>.
[RFC8936] Backman, A., Ed., Jones, M., Scurtescu, M., Ansari, M.,
and A. Nadalin, "Poll-Based Security Event Token (SET)
Delivery Using HTTP", draft-ietf-secevent-http-poll-12 (work in
progress), June 2020.
[RFC7235] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Authentication", RFC 7235, 8936, DOI 10.17487/RFC7235, June 2014,
<https://www.rfc-editor.org/info/rfc7235>. 10.17487/RFC8936,
October 2020, <https://www.rfc-editor.org/info/rfc8936>.
Appendix A. Unencrypted Transport Considerations
Earlier versions of this specification made the use of TLS optional
and described security and privacy considerations resulting from use
of unencrypted HTTP as the underlying transport. When the working
group decided to mandate usage of HTTP over TLS, it also decided to
preserve the description of these considerations in this non-
normative appendix.
SETs may contain sensitive information that is considered Personally
Identifiable Information (PII). In such cases, SET Transmitters and
SET Recipients MUST protect the confidentiality of the SET contents.
When TLS is not used, this means that the SET MUST be encrypted as
described in JWE [RFC7516].
If SETs were allowed to be transmitted over unencrypted channels,
some privacy-sensitive information about them might leak, even though
the SETs themselves are encrypted. For instance, an attacker may be
able to determine whether or not a SET was accepted and the reason
for its rejection or may be able to derive information from being
able to observe the size of the encrypted SET. (Note that even when
TLS is utilized, some information leakage is still possible; message
padding algorithms to prevent side channels remain an open research
topic.)
Appendix B. Other Streaming Specifications
[[ NOTE TO THE RFC EDITOR: This section to be removed prior to
publication ]]
Acknowledgments
The following pub/sub, queuing, and streaming systems were reviewed
as possible solutions or as input editors would like to thank the current draft:
Poll-Based Security Event Token (SET) Delivery Using HTTP
In addition to this specification, members of the WG is defining a polling-based
SET delivery protocol. That protocol [I-D.ietf-secevent-http-poll]
describes it as:
This specification defines how a series SCIM Working
Group, which began discussions of Security Event Tokens
(SETs) can be delivered provisioning events starting with
draft-hunt-scim-notify-00 in 2015. We would like to an intended recipient using HTTP POST over
TLS initiated as a poll by thank Phil Hunt
and the recipient. The other authors of draft-ietf-secevent-delivery-02, upon which
this specification also
defines how delivery can be assured, subject is based. We would like to thank the SET Recipient's
need participants
in the SecEvents Working Group for assurance.
XMPP Events
The WG considered XMPP Events and their ability contributions to provide a single
messaging solution without this
specification.
Additionally, we would like to thank the need following individuals for both polling and push modes.
The feeling was the size and methodology of XMPP was too far apart
from the current capabilities
their reviews of the SECEVENTs community, which
focuses in on HTTP based service delivery specification: Joe Clarke, Roman Danyliw, Vijay
Gurbani, Benjamin Kaduk, Erik Kline, Murray Kucherawy, Barry Leiba,
Yaron Sheffer, Robert Sparks, Valery Smyslov, Éric Vyncke, and authorization.
Amazon Simple Notification Service
Simple Notification Service is a pub/sub messaging product from AWS.
SNS supports a variety of subscriber types: HTTP/HTTPS endpoints, AWS
Lambda functions, email addresses (as JSON or plain text), phone
numbers (via SMS), and AWS SQS standard queues. It does not directly
support pull, but subscribers can get the pull model by creating an
SQS queue and subscribing it to the topic. Note that this puts the
cost of pull support back onto the subscriber, just as it is in the
push model. It is not clear that one way is strictly better than the
other; larger, sophisticated developers may be happy to own message
persistence so they can have their own internal delivery guarantees.
The long tail of OIDC clients may not care about that or may fail to
get it right. Regardless, I think we can learn something from the
Delivery Policies supported by SNS, as well as the delivery controls
that SQS offers (e.g., Visibility Timeout, Dead-Letter Queues). I am
not suggesting that we need all of these things in the spec, but they
give an idea of what features people have found useful.
Other information:
o API Reference:
http://docs.aws.amazon.com/AWSSimpleQueueService/latest/
APIReference/Welcome.html
o Visibility Timeouts:
http://docs.aws.amazon.com/AWSSimpleQueueService/latest/
SQSDeveloperGuide/sqs-visibility-timeout.html
Apache Kafka
Apache Kafka is an Apache open source project based upon TCP for
distributed streaming. It prescribes some interesting general-
purpose features that seem to extend far beyond the simpler streaming
model that SECEVENTs is after. A comment from MS has been that Kafka
does an acknowledge with poll combination event which seems to be a
performance advantage. See: https://kafka.apache.org/intro
Google Pub/Sub
The Google Pub Sub system favors a model whereby polling and
acknowledgement of events is done with separate endpoints and as
separate functions.
Information:
o Cloud Overview - https://cloud.google.com/pubsub/
o Subscriber Overview - https://cloud.google.com/pubsub/docs/
subscriber
o Subscriber Pull(poll) - https://cloud.google.com/pubsub/docs/pull
Appendix C. Acknowledgments
The editors would like to thank the members of the SCIM working
group, which began discussions of provisioning events starting with
draft-hunt-scim-notify-00 in 2015. We would like to thank Phil Hunt
and the other authors of draft-ietf-secevent-delivery-02, upon which
this specification is based. We would like to thank the participants
in the SecEvents working group for their contributions to this
specification.
Additionally, we would like to thank the following individuals for
their reviews of the specification: Joe Clarke, Roman Danyliw, Vijay
Gurbani, Benjamin Kaduk, Erik Kline, Murray Kucherawy, Barry Leiba,
Yaron Sheffer, Robert Sparks, Valery Smyslov, Eric Vyncke, and Robert
Wilton.
Appendix D. Change Log
[[ NOTE TO THE RFC EDITOR: This section to be removed prior to
publication ]]
Draft 00 - AB - Based on draft-ietf-secevent-delivery-02 with the
following changes:
o Renamed to "Push-Based SET Token Delivery Using HTTP"
o Removed references to the HTTP Polling delivery method.
o Removed informative reference to RFC6202.
Draft 01 - AB:
o Fixed area and workgroup to match secevent.
o Removed unused definitions and definitions already covered by SET.
o Renamed Event Transmitter and Event Receiver to SET Transmitter
and SET Receiver, respectively.
o Added IANA registry for SET Delivery Error Codes.
o Removed enumeration of HTTP authentication methods.
o Removed generally applicable guidance for HTTP, authorization
tokens, and bearer tokens.
o Moved guidance for using authentication methods as DoS protection
to Security Considerations.
o Removed redundant instruction to use WWW-Authenticate header.
o Removed further generally applicable guidance for authorization
tokens.
o Removed bearer token from example delivery request, and text
referencing it.
o Broke delivery method description into separate request/response
sections.
o Added missing empty line between headers and body in example
request.
o Removed inapplicable notes about example formatting.
o Removed text about SET creation and handling.
o Removed duplication in protocol description.
o Added "non-normative example" text to example transmission
request.
o Fixed inconsistencies in use of Error Code term.
Draft 02 - AB:
o Rewrote abstract and introduction.
o Rewrote definitions for SET Transmitter, SET Receiver.
o Renamed Event Delivery section to SET Delivery.
o Readability edits to Success Response and Failure Response
sections.
o Consolidated definition of error response under Failure Response
section.
o Removed Event Delivery Process section and moved its content to
parent section.
o Readability edits to SET Delivery section and its subsections.
o Added callout that SET Receiver HTTP endpoint configuration is
out-of-scope.
o Added callout that SET verification mechanisms are out-of-scope.
o Added retry guidance, notes regarding delivery reliability
requirements.
o Added guidance around using JWS and/or JWE to authenticate
persisted SETs.
Draft 03 - mbj:
o Addressed problems identified in my 18-Jul-18 review message
titled "Issues for both the Push and Poll Specs".
o Changes to align terminology with RFC 8417, for instance, by using
the already defined term SET Recipient rather than SET Receiver.
o Applied editorial and minor normative corrections.
o Updated Marius' contact information.
Draft 04 - AB:
o Replaced Error Codes with smaller set of meaningfully
differentiated codes.
o Added more error response examples.
o Removed un-referenced normative references.
o Added normative reference to JSON in error response definition.
o Added text clarifying that the value of the "description"
attribute in error responses is implementation specific.
o Added requirement that error descriptions and responses are UTF-8
encoded.
o Added error description language preferences and specification via
"Accept-Language" and "Content-Language" headers.
o Added "recognized issuer" validation requirement in section 2.
o Added timeouts as an acceptable reason to resend a SET in section
2.
o Edited text in section 1 to clarify that configuration is out of
scope.
o Made minor editorial corrections.
Draft 05 - AB:
o Made minor editorial corrections.
o Updated example request with a correct SET header and signature.
o Revised TLS guidance to allow implementers to provide
confidentiality protection via JWE.
o Revised TLS guidance to require *at least* TLS 1.2.
o Revised TLS guidance to recommend supporting the newest version of
TLS that meets security requirements.
o Revised SET Delivery Error Code format to allow the same set of
characters as is allowed in error codes in RFC6749.
o Added mention of HTTP Poll spec to list of other streaming specs
in appendix.
o Added validation step requiring SET Recipient to verify that the
SET is one which the SET Transmitter is expected to send to the
SET Recipient.
o Changed responding to errors with an appropriate HTTP status code
from optional to recommended.
o Changed Error Codes registry change policy from Expert Review to
First Come First Served; added guidance that error codes are meant
to be consumed by automated systems.
o Added text making clear that it is up to SET Recipients whether or
not they will accept SETs where the SET Issuer is different from
the SET Transmitter.
o Reworded guidance around signing and/or encrypting SETs for
integrity protection.
o Renamed TLS "Support Considerations" section to "Confidentiality
of SETs".
o Reworded guidance around subject identifier selection and privacy
concerns.
Draft 06 - mbj, MS:
o Made minor editorial corrections.
o Updated to indicate that failure response should be returned if
errors occur in authenticating the SET.
o Updated reference for JSON from RFC 7159 to RFC 8259.
o Fixed Authentication Using Signed SETs to indicate the SET
Transmitter must be authorized to deliver the SET, not the SET
Issuer.
o Fixed Authenticating Persisted SETs to put the responsibility for
ensuring the SET is signed on the SET Recipient.
o Fixed error code format definition to match error codes defined in
doc.
Draft 07 - AB:
o Made minor editorial corrections.
o Removed "SET Recipient" definition and added explicit list of
terms used from RFC8417.
Draft 08 - mbj
o Addressed area director review comments by Benjamin Kaduk.
Draft 09 - mbj + AB
o Corrected editorial nits.
Draft 10 - AB
o Addressed area director review comments by Benjamin Kaduk:
* Added reference to 8417 as definition document for SETs.
* Added text clarifying that determining the SET Recipient's
service identity is out of scope.
* Added normative recommendation for transmitters to target SETs
to specific business needs of subscribers.
* Minor editorial corrections.
Draft 11 - mbj
o Addressed SecDir review comments by Valery Smyslov.
o Addressed OpsDir review comments by Joe Clarke.
o Addressed GenArt review comments by Vijay Gurbani.
Draft 12 - mbj
o Revised to unambiguously require the use of TLS, while preserving
descriptions of precautions needed for non-TLS use in an appendix.
Draft 13 - mbj
o Addressed IESG comments.
Draft 14 - AB
o Revised normative requirements for SET re-transmission to clarify
"at least once" delivery expectiations.
o Added non-normative text to Section 4 - Delivery Reliability
describing conditions where re-transmission of successfully
delivered SETs may occur.
Authors' Addresses
Annabelle Backman (editor) Robert
Wilton.
Authors' Addresses
Annabelle Backman (editor)
Amazon
Email: richanna@amazon.com
Michael B. Jones (editor)
Microsoft
Email: mbj@microsoft.com
URI: https://self-issued.info/
Marius Scurtescu
Coinbase
Email: marius.scurtescu@coinbase.com
Morteza Ansari
Cisco
Independent
Email: morteza.ansari@cisco.com morteza@sharppics.com
Anthony Nadalin
Microsoft
Independent
Email: tonynad@microsoft.com nadalin@prodigy.net