Security Events Working Group A. Backman, Ed.
Internet-Draft Amazon
Intended status: Standards Track M. Jones, Ed.
Expires: December 17, 2020 Microsoft
M. Scurtescu
Coinbase
M. Ansari
Cisco
A. Nadalin
Microsoft
June 15, 2020
Push-Based Security Event Token (SET) Delivery Using HTTP
draft-ietf-secevent-http-push-12
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 of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 17, 2020.
Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
Backman, et al. Expires December 17, 2020 [Page 1]
Internet-Draft draft-ietf-secevent-http-push June 2020
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
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 . . . . . . . . . . . . . . 8
4. Delivery Reliability . . . . . . . . . . . . . . . . . . . . 9
5. Security Considerations . . . . . . . . . . . . . . . . . . . 9
5.1. Authentication Using Signed SETs . . . . . . . . . . . . 9
5.2. HTTP Considerations . . . . . . . . . . . . . . . . . . . 9
5.3. Confidentiality of SETs . . . . . . . . . . . . . . . . . 9
5.4. Denial of Service . . . . . . . . . . . . . . . . . . . . 10
5.5. Authenticating Persisted SETs . . . . . . . . . . . . . . 10
6. Privacy Considerations . . . . . . . . . . . . . . . . . . . 10
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
7.1. Security Event Token Delivery Error Codes . . . . . . . . 11
7.1.1. Registration Template . . . . . . . . . . . . . . . . 11
7.1.2. Initial Registry Contents . . . . . . . . . . . . . . 12
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
8.1. Normative References . . . . . . . . . . . . . . . . . . 12
8.2. Informative References . . . . . . . . . . . . . . . . . 14
Appendix A. Unencrypted Transport Considerations . . . . . . . . 14
Appendix B. Other Streaming Specifications . . . . . . . . . . . 15
Appendix C. Acknowledgments . . . . . . . . . . . . . . . . . . 16
Appendix D. Change Log . . . . . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21
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].
Backman, et al. Expires December 17, 2020 [Page 2]
Internet-Draft draft-ietf-secevent-http-push June 2020
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 an HTTP endpoint using TLS
that is accessible to the transmitter.
o The transmitter and recipient are known to one another.
A mechanism for exchanging configuration metadata such as endpoint
URLs and cryptographic keys 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".
This specification utilizes terminology defined in [RFC8417], as well
as the terms defined below:
SET 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 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.
Backman, et al. Expires December 17, 2020 [Page 3]
Internet-Draft draft-ietf-secevent-http-push June 2020
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 whitelisted
by the SET Recipient).
o The SET Recipient is willing to accept the SET when transmitted by
the SET Transmitter (e.g., the SET Transmitter is expected to send
SETs with the 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 and issuer and
audience identification are defined in [RFC8417]. The mechanism for
validating the authenticity of a SET is deployment specific, and may
vary depending on the authentication mechanisms in 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 SHOULD ensure that the SET is persisted in a way
that is sufficient to meet the SET Recipient's own reliability
requirements, and MUST NOT expect or depend on a SET Transmitter to
re-transmit or otherwise make available to the SET Recipient a SET
once the SET Recipient acknowledges that it was received
successfully.
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
anything beyond the required validation steps prior to sending this
response. Any additional steps SHOULD be executed asynchronously
from delivery, in order to minimize the expense and impact of SET
delivery on the SET Transmitter.
The SET Transmitter MAY re-transmit a SET if the responses from
previous transmissions timed out or indicated potentially recoverable
Backman, et al. Expires December 17, 2020 [Page 4]
Internet-Draft draft-ietf-secevent-http-push June 2020
error (such as server unavailability that may be transient). In all
other cases, the SET Transmitter SHOULD NOT re-transmit 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 an HTTP endpoint using TLS provided by the SET
Recipient. The "Content-Type" header of this request MUST be
"application/secevent+jwt" as defined in Sections 2.3 and 7.2 of
[RFC8417], and the "Accept" header MUST be "application/json". The
request body MUST consist of the SET itself, represented as a JWT
[RFC7519].
The SET Transmitter MAY include in the request an "Accept-Language"
header 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:
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
Backman, et al. Expires December 17, 2020 [Page 5]
Internet-Draft draft-ietf-secevent-http-push June 2020
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
Note that the purpose of the acknowledgement response is to let the
SET Transmitter know that a SET has been delivered and the
information no longer needs to be retained by the SET Transmitter.
Before acknowledgement, SET Recipients SHOULD ensure they have
validated received SETs and retained them in a manner appropriate to
information retention requirements appropriate to the SET event types
signaled. The level and method of retention of SETs by SET
Recipients is out of scope of this specification.
2.3. Failure Response
In the event of a general HTTP error condition, the SET Recipient
SHOULD respond with an appropriate 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 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 A Security Event Token Error Code (see Section 2.4).
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, 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 sent by the
SET Transmitter in the transmission request, as described in
Backman, et al. Expires December 17, 2020 [Page 6]
Internet-Draft draft-ietf-secevent-http-push June 2020
Section 5.3.5 of [RFC7231]. If the SET Transmitter did not send an
"Accept-Language" header, or if the SET Recipient does not support
any of the languages included in the header, 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 an example non-normative 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 an example non-normative 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 an example non-normative 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": "access_denied",
"description": "Not authorized for issuer https://iss.example.com/."
}
Figure 5: Example Error Response (access_denied)
Backman, et al. Expires December 17, 2020 [Page 7]
Internet-Draft draft-ietf-secevent-http-push June 2020
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 |
| | SET, or the Event Payload within the SET |
| | does not conform to the event's |
| | definition. |
| invalid_key | One or more keys used to encrypt or sign |
| | the SET is invalid or otherwise |
| | unacceptable to the SET Recipient. (e.g., |
| | expired, revoked, failed certificate |
| | validation, etc.) |
| authentication_failed | The SET Recipient could not authenticate |
| | the SET Transmitter. |
| access_denied | The SET Transmitter is not authorized to |
| | transmit the SET to the SET Recipient. |
+-----------------------+-------------------------------------------+
Table 1: SET Delivery Error Codes
Implementations SHOULD expect that 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, per [RFC6125].
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
Backman, et al. Expires December 17, 2020 [Page 8]
Internet-Draft draft-ietf-secevent-http-push June 2020
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 the same SET. Others such as "access_denied" may be
transient, for example if the SET Transmitter refreshes expired
credentials prior to re-transmission.
Implementers SHOULD evaluate the reliability requirements of their
use cases and the impact of various retry mechanisms 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 9 of
[RFC7230] and its related specifications.
5.3. Confidentiality of SETs
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.
In some use cases, using TLS to secure the transmitted SETs will be
sufficient. In other 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
Backman, et al. Expires December 17, 2020 [Page 9]
Internet-Draft draft-ietf-secevent-http-push June 2020
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]. 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. Implementation security
considerations for TLS can be found in "Recommendations for Secure
Use of TLS and DTLS" [RFC7525].
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.
5.5. Authenticating Persisted SETs
At the time of receipt, the SET Recipient can rely upon transport
layer 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 that the SET Recipient forwards the
SET onto, 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].
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 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-
Backman, et al. Expires December 17, 2020 [Page 10]
Internet-Draft draft-ietf-secevent-http-push June 2020
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 and maintain a new registry titled
"Security Event Token Delivery Error Codes". Initial values for the
Security Event Token Delivery Error Codes registry are defined in
Table 1 and registered below. Future assignments are to be made
through the Specification Required registration policy ([RFC8126])
and shall follow the template presented in Section 7.1.1.
Error Codes are intended to be interpreted by automated systems, and
therefore 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).
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 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 SecEvent Working Group". 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)
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.
Backman, et al. Expires December 17, 2020 [Page 11]
Internet-Draft draft-ietf-secevent-http-push June 2020
7.1.2. Initial Registry Contents
Error Code: invalid_request
Description: The request body cannot be parsed as a SET or the
event payload within the SET does not conform to the event's
definition.
Change Controller: IETF
Defining Document(s): Section 2.4 of [[ this specification ]]
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. (e.g.,
expired, revoked, failed certificate validation, etc.)
Change Controller: IETF
Defining Document(s): Section 2.4 of [[ this specification ]]
Error Code: authentication_failed
Description: The SET Recipient could not authenticate the SET
Transmitter.
Change Controller: IETF
Defining Document(s): Section 2.4 of [[ this specification ]]
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): Section 2.4 of [[ this specification ]]
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>.
Backman, et al. Expires December 17, 2020 [Page 12]
Internet-Draft draft-ietf-secevent-http-push June 2020
[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>.
[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>.
Backman, et al. Expires December 17, 2020 [Page 13]
Internet-Draft draft-ietf-secevent-http-push June 2020
[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]
Backman, A., Jones, M., Scurtescu, M., Ansari, M., and A.
Nadalin, "Poll-Based Security Event Token (SET) Delivery
Using HTTP", draft-ietf-secevent-http-poll-10 (work in
progress), June 2020.
[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>.
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 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 are 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.
Backman, et al. Expires December 17, 2020 [Page 14]
Internet-Draft draft-ietf-secevent-http-push June 2020
Appendix B. Other Streaming Specifications
[[ NOTE TO THE RFC EDITOR: This section to be removed prior to
publication ]]
The following pub/sub, queuing, streaming systems were reviewed as
possible solutions or as input to the current draft:
Poll-Based Security Event Token (SET) Delivery Using HTTP
In addition to this specification, 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 of Security Event Tokens
(SETs) can be delivered to an intended recipient using HTTP POST over
TLS initiated as a poll by the recipient. The specification also
defines how delivery can be assured, subject to the SET Recipient's
need for assurance.
XMPP Events
The WG considered XMPP Events and their ability to provide a single
messaging solution without the need for both polling and push modes.
The feeling was the size and methodology of XMPP was too far apart
from the current capabilities of the SECEVENTs community, which
focuses in on HTTP based service delivery 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:
Backman, et al. Expires December 17, 2020 [Page 15]
Internet-Draft draft-ietf-secevent-http-push June 2020
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, Vijay Gurbani,
Benjamin Kaduk, Yaron Sheffer, and Valery Smyslov.
Backman, et al. Expires December 17, 2020 [Page 16]
Internet-Draft draft-ietf-secevent-http-push June 2020
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.
Backman, et al. Expires December 17, 2020 [Page 17]
Internet-Draft draft-ietf-secevent-http-push June 2020
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.
Backman, et al. Expires December 17, 2020 [Page 18]
Internet-Draft draft-ietf-secevent-http-push June 2020
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.
Backman, et al. Expires December 17, 2020 [Page 19]
Internet-Draft draft-ietf-secevent-http-push June 2020
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:
Backman, et al. Expires December 17, 2020 [Page 20]
Internet-Draft draft-ietf-secevent-http-push June 2020
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.
Authors' Addresses
Annabelle Backman (editor)
Amazon
Email: richanna@amazon.com
Backman, et al. Expires December 17, 2020 [Page 21]
Internet-Draft draft-ietf-secevent-http-push June 2020
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
Email: morteza.ansari@cisco.com
Anthony Nadalin
Microsoft
Email: tonynad@microsoft.com
Backman, et al. Expires December 17, 2020 [Page 22]
