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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Security Events Working Group A. Backman, Ed. 3 Internet-Draft Amazon 4 Intended status: Standards Track M. Jones, Ed. 5 Expires: December 17, 2020 Microsoft 6 M. Scurtescu 7 Coinbase 8 M. Ansari 9 Cisco 10 A. Nadalin 11 Microsoft 12 June 15, 2020 14 Push-Based Security Event Token (SET) Delivery Using HTTP 15 draft-ietf-secevent-http-push-12 17 Abstract 19 This specification defines how a Security Event Token (SET) can be 20 delivered to an intended recipient using HTTP POST over TLS. The SET 21 is transmitted in the body of an HTTP POST request to an endpoint 22 operated by the recipient, and the recipient indicates successful or 23 failed transmission via the HTTP response. 25 Status of This Memo 27 This Internet-Draft is submitted in full conformance with the 28 provisions of BCP 78 and BCP 79. 30 Internet-Drafts are working documents of the Internet Engineering 31 Task Force (IETF). Note that other groups may also distribute 32 working documents as Internet-Drafts. The list of current Internet- 33 Drafts is at https://datatracker.ietf.org/drafts/current/. 35 Internet-Drafts are draft documents valid for a maximum of six months 36 and may be updated, replaced, or obsoleted by other documents at any 37 time. It is inappropriate to use Internet-Drafts as reference 38 material or to cite them other than as "work in progress." 40 This Internet-Draft will expire on December 17, 2020. 42 Copyright Notice 44 Copyright (c) 2020 IETF Trust and the persons identified as the 45 document authors. All rights reserved. 47 This document is subject to BCP 78 and the IETF Trust's Legal 48 Provisions Relating to IETF Documents 49 (https://trustee.ietf.org/license-info) in effect on the date of 50 publication of this document. Please review these documents 51 carefully, as they describe your rights and restrictions with respect 52 to this document. Code Components extracted from this document must 53 include Simplified BSD License text as described in Section 4.e of 54 the Trust Legal Provisions and are provided without warranty as 55 described in the Simplified BSD License. 57 Table of Contents 59 1. Introduction and Overview . . . . . . . . . . . . . . . . . . 2 60 1.1. Notational Conventions . . . . . . . . . . . . . . . . . 3 61 1.2. Definitions . . . . . . . . . . . . . . . . . . . . . . . 3 62 2. SET Delivery . . . . . . . . . . . . . . . . . . . . . . . . 3 63 2.1. Transmitting a SET . . . . . . . . . . . . . . . . . . . 5 64 2.2. Success Response . . . . . . . . . . . . . . . . . . . . 6 65 2.3. Failure Response . . . . . . . . . . . . . . . . . . . . 6 66 2.4. Security Event Token Delivery Error Codes . . . . . . . . 8 67 3. Authentication and Authorization . . . . . . . . . . . . . . 8 68 4. Delivery Reliability . . . . . . . . . . . . . . . . . . . . 9 69 5. Security Considerations . . . . . . . . . . . . . . . . . . . 9 70 5.1. Authentication Using Signed SETs . . . . . . . . . . . . 9 71 5.2. HTTP Considerations . . . . . . . . . . . . . . . . . . . 9 72 5.3. Confidentiality of SETs . . . . . . . . . . . . . . . . . 9 73 5.4. Denial of Service . . . . . . . . . . . . . . . . . . . . 10 74 5.5. Authenticating Persisted SETs . . . . . . . . . . . . . . 10 75 6. Privacy Considerations . . . . . . . . . . . . . . . . . . . 10 76 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 77 7.1. Security Event Token Delivery Error Codes . . . . . . . . 11 78 7.1.1. Registration Template . . . . . . . . . . . . . . . . 11 79 7.1.2. Initial Registry Contents . . . . . . . . . . . . . . 12 80 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 81 8.1. Normative References . . . . . . . . . . . . . . . . . . 12 82 8.2. Informative References . . . . . . . . . . . . . . . . . 14 83 Appendix A. Unencrypted Transport Considerations . . . . . . . . 14 84 Appendix B. Other Streaming Specifications . . . . . . . . . . . 15 85 Appendix C. Acknowledgments . . . . . . . . . . . . . . . . . . 16 86 Appendix D. Change Log . . . . . . . . . . . . . . . . . . . . . 17 87 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21 89 1. Introduction and Overview 91 This specification defines a mechanism by which a transmitter of a 92 Security Event Token (SET) [RFC8417] can deliver the SET to an 93 intended SET Recipient via HTTP POST [RFC7231] over TLS. This is an 94 alternative SET delivery method to the one defined in 95 [I-D.ietf-secevent-http-poll]. 97 Push-based SET delivery over HTTP POST is intended for scenarios 98 where all of the following apply: 100 o The transmitter of the SET is capable of making outbound HTTP 101 requests. 103 o The recipient is capable of hosting an HTTP endpoint using TLS 104 that is accessible to the transmitter. 106 o The transmitter and recipient are known to one another. 108 A mechanism for exchanging configuration metadata such as endpoint 109 URLs and cryptographic keys between the transmitter and recipient is 110 out of scope for this specification. How SETs are defined and the 111 process by which security events are identified for SET Recipients 112 are specified in [RFC8417]. 114 1.1. Notational Conventions 116 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 117 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 118 "OPTIONAL" in this document are to be interpreted as described in BCP 119 14 [RFC2119] [RFC8174] when, and only when, they appear in all 120 capitals, as shown here. 122 Throughout this document, all figures may contain spaces and extra 123 line wrapping for readability and due to space limitations. 125 1.2. Definitions 127 This specification utilizes the following terms defined in [RFC8417]: 128 "Security Event Token (SET)", "SET Issuer", "SET Recipient", and 129 "Event Payload". 131 This specification utilizes terminology defined in [RFC8417], as well 132 as the terms defined below: 134 SET Transmitter An entity that delivers SETs in its possession to 135 one or more SET Recipients. 137 2. SET Delivery 139 To deliver a SET to a given SET Recipient, the SET Transmitter makes 140 a SET transmission request to the SET Recipient, with the SET itself 141 contained within the request. The SET Recipient replies to this 142 request with a response either acknowledging successful transmission 143 of the SET or indicating that an error occurred while receiving, 144 parsing, and/or validating the SET. 146 Upon receipt of a SET, the SET Recipient SHALL validate that all of 147 the following are true: 149 o The SET Recipient can parse the SET. 151 o The SET is authentic (i.e., it was issued by the issuer specified 152 within the SET, and if signed, was signed by a key belonging to 153 the issuer). 155 o The SET Recipient is identified as an intended audience of the 156 SET. 158 o The SET Issuer is recognized as an issuer that the SET Recipient 159 is willing to receive SETs from (e.g., the issuer is whitelisted 160 by the SET Recipient). 162 o The SET Recipient is willing to accept the SET when transmitted by 163 the SET Transmitter (e.g., the SET Transmitter is expected to send 164 SETs with the subject of the SET in question). 166 The mechanisms by which the SET Recipient performs this validation 167 are out of scope for this document. SET parsing and issuer and 168 audience identification are defined in [RFC8417]. The mechanism for 169 validating the authenticity of a SET is deployment specific, and may 170 vary depending on the authentication mechanisms in use, and whether 171 the SET is signed and/or encrypted (See Section 3). 173 SET Transmitters MAY transmit SETs issued by another entity. The SET 174 Recipient may accept or reject (i.e., return an error response such 175 as "access_denied") a SET at its own discretion. 177 The SET Recipient SHOULD ensure that the SET is persisted in a way 178 that is sufficient to meet the SET Recipient's own reliability 179 requirements, and MUST NOT expect or depend on a SET Transmitter to 180 re-transmit or otherwise make available to the SET Recipient a SET 181 once the SET Recipient acknowledges that it was received 182 successfully. 184 Once the SET has been validated and persisted, the SET Recipient 185 SHOULD immediately return a response indicating that the SET was 186 successfully delivered. The SET Recipient SHOULD NOT perform 187 anything beyond the required validation steps prior to sending this 188 response. Any additional steps SHOULD be executed asynchronously 189 from delivery, in order to minimize the expense and impact of SET 190 delivery on the SET Transmitter. 192 The SET Transmitter MAY re-transmit a SET if the responses from 193 previous transmissions timed out or indicated potentially recoverable 194 error (such as server unavailability that may be transient). In all 195 other cases, the SET Transmitter SHOULD NOT re-transmit a SET. The 196 SET Transmitter SHOULD delay retransmission for an appropriate amount 197 of time to avoid overwhelming the SET Recipient (see Section 4). 199 2.1. Transmitting a SET 201 To transmit a SET to a SET Recipient, the SET Transmitter makes an 202 HTTP POST request to an HTTP endpoint using TLS provided by the SET 203 Recipient. The "Content-Type" header of this request MUST be 204 "application/secevent+jwt" as defined in Sections 2.3 and 7.2 of 205 [RFC8417], and the "Accept" header MUST be "application/json". The 206 request body MUST consist of the SET itself, represented as a JWT 207 [RFC7519]. 209 The SET Transmitter MAY include in the request an "Accept-Language" 210 header to indicate to the SET Recipient the preferred language(s) in 211 which to receive error messages. 213 The mechanisms by which the SET Transmitter determines the HTTP 214 endpoint to use when transmitting a SET to a given SET Recipient are 215 not defined by this specification and are deployment specific. 217 The following is a non-normative example of a SET transmission 218 request: 220 POST /Events HTTP/1.1 221 Host: notify.rp.example.com 222 Accept: application/json 223 Accept-Language: en-US, en;q=0.5 224 Content-Type: application/secevent+jwt 226 eyJ0eXAiOiJzZWNldmVudCtqd3QiLCJhbGciOiJIUzI1NiJ9Cg 227 . 228 eyJpc3MiOiJodHRwczovL2lkcC5leGFtcGxlLmNvbS8iLCJqdGkiOiI3NTZFNjk 229 3MTc1NjUyMDY5NjQ2NTZFNzQ2OTY2Njk2NTcyIiwiaWF0IjoxNTA4MTg0ODQ1LC 230 JhdWQiOiI2MzZDNjk2NTZFNzQ1RjY5NjQiLCJldmVudHMiOnsiaHR0cHM6Ly9zY 231 2hlbWFzLm9wZW5pZC5uZXQvc2VjZXZlbnQvcmlzYy9ldmVudC10eXBlL2FjY291 232 bnQtZGlzYWJsZWQiOnsic3ViamVjdCI6eyJzdWJqZWN0X3R5cGUiOiJpc3Mtc3V 233 iIiwiaXNzIjoiaHR0cHM6Ly9pZHAuZXhhbXBsZS5jb20vIiwic3ViIjoiNzM3NT 234 YyNkE2NTYzNzQifSwicmVhc29uIjoiaGlqYWNraW5nIn19fQ 235 . 236 Y4rXxMD406P2edv00cr9Wf3_XwNtLjB9n-jTqN1_lLc 238 Figure 1: Example SET Transmission Request 240 2.2. Success Response 242 If the SET is determined to be valid, the SET Recipient SHALL 243 acknowledge successful transmission by responding with HTTP Response 244 Status Code 202 (Accepted) (see Section 6.3.3 of [RFC7231]). The 245 body of the response MUST be empty. 247 The following is a non-normative example of a successful receipt of a 248 SET. 250 HTTP/1.1 202 Accepted 252 Figure 2: Example Successful Delivery Response 254 Note that the purpose of the acknowledgement response is to let the 255 SET Transmitter know that a SET has been delivered and the 256 information no longer needs to be retained by the SET Transmitter. 257 Before acknowledgement, SET Recipients SHOULD ensure they have 258 validated received SETs and retained them in a manner appropriate to 259 information retention requirements appropriate to the SET event types 260 signaled. The level and method of retention of SETs by SET 261 Recipients is out of scope of this specification. 263 2.3. Failure Response 265 In the event of a general HTTP error condition, the SET Recipient 266 SHOULD respond with an appropriate HTTP Status Code as defined in 267 Section 6 of [RFC7231]. 269 When the SET Recipient detects an error parsing, validating, or 270 authenticating a SET transmitted in a SET Transmission Request, the 271 SET Recipient SHALL respond with an HTTP Response Status Code of 400 272 (Bad Request). The "Content-Type" header of this response MUST be 273 "application/json", and the body MUST be a UTF-8 encoded JSON 274 [RFC8259] object containing the following name/value pairs: 276 err A Security Event Token Error Code (see Section 2.4). 278 description A UTF-8 string containing a human-readable description 279 of the error that MAY provide additional diagnostic information. 280 The exact content of this field is implementation specific. 282 The response MUST include a "Content-Language" header, whose value 283 indicates the language of the error descriptions included in the 284 response body. If the SET Recipient can provide error descriptions 285 in multiple languages, they SHOULD choose the language to use 286 according to the value of the "Accept-Language" header sent by the 287 SET Transmitter in the transmission request, as described in 288 Section 5.3.5 of [RFC7231]. If the SET Transmitter did not send an 289 "Accept-Language" header, or if the SET Recipient does not support 290 any of the languages included in the header, the SET Recipient MUST 291 respond with messages that are understandable by an English-speaking 292 person, as described in Section 4.5 of [RFC2277]. 294 The following is an example non-normative error response indicating 295 that the key used to encrypt the SET has been revoked. 297 HTTP/1.1 400 Bad Request 298 Content-Language: en-US 299 Content-Type: application/json 301 { 302 "err": "invalid_key", 303 "description": "Key ID 12345 has been revoked." 304 } 306 Figure 3: Example Error Response (invalid_key) 308 The following is an example non-normative error response indicating 309 that the access token included in the request is expired. 311 HTTP/1.1 400 Bad Request 312 Content-Language: en-US 313 Content-Type: application/json 315 { 316 "err": "authentication_failed", 317 "description": "Access token has expired." 318 } 320 Figure 4: Example Error Response (authentication_failed) 322 The following is an example non-normative error response indicating 323 that the SET Receiver is not willing to accept SETs issued by the 324 specified issuer from this particular SET Transmitter. 326 HTTP/1.1 400 Bad Request 327 Content-Language: en-US 328 Content-Type: application/json 330 { 331 "err": "access_denied", 332 "description": "Not authorized for issuer https://iss.example.com/." 333 } 335 Figure 5: Example Error Response (access_denied) 337 2.4. Security Event Token Delivery Error Codes 339 Security Event Token Delivery Error Codes are strings that identify a 340 specific category of error that may occur when parsing or validating 341 a SET. Every Security Event Token Delivery Error Code MUST have a 342 unique name registered in the IANA "Security Event Token Delivery 343 Error Codes" registry established by Section 7.1. 345 The following table presents the initial set of Error Codes that are 346 registered in the IANA "Security Event Token Delivery Error Codes" 347 registry: 349 +-----------------------+-------------------------------------------+ 350 | Error Code | Description | 351 +-----------------------+-------------------------------------------+ 352 | invalid_request | The request body cannot be parsed as a | 353 | | SET, or the Event Payload within the SET | 354 | | does not conform to the event's | 355 | | definition. | 356 | invalid_key | One or more keys used to encrypt or sign | 357 | | the SET is invalid or otherwise | 358 | | unacceptable to the SET Recipient. (e.g., | 359 | | expired, revoked, failed certificate | 360 | | validation, etc.) | 361 | authentication_failed | The SET Recipient could not authenticate | 362 | | the SET Transmitter. | 363 | access_denied | The SET Transmitter is not authorized to | 364 | | transmit the SET to the SET Recipient. | 365 +-----------------------+-------------------------------------------+ 367 Table 1: SET Delivery Error Codes 369 Implementations SHOULD expect that other Error Codes may also be 370 received, as the set of Error Codes is extensible via the IANA 371 "Security Event Token Delivery Error Codes" registry established in 372 Section 7.1. 374 3. Authentication and Authorization 376 The SET delivery method described in this specification is based upon 377 HTTP over TLS [RFC2818] and standard HTTP authentication and 378 authorization schemes, as per [RFC7235]. The TLS server certificate 379 MUST be validated, per [RFC6125]. 381 Authorization for the eligibility to provide actionable SETs can be 382 determined by using the identity of the SET Issuer, the identity of 383 the SET Transmitter, perhaps using mutual TLS, or via other employed 384 authentication methods. Because SETs are not commands, SET 385 Recipients are free to ignore SETs that are not of interest. 387 4. Delivery Reliability 389 Delivery reliability requirements may vary depending upon the use 390 cases. This specification defines the response from the SET 391 Recipient in such a way as to provide the SET Transmitter with the 392 information necessary to determine what further action is required, 393 if any, in order to meet their requirements. SET Transmitters with 394 high reliability requirements may be tempted to always retry failed 395 transmissions, however, it should be noted that for many types of SET 396 delivery errors, a retry is extremely unlikely to be successful. For 397 example, "invalid_request" indicates a structural error in the 398 content of the request body that is likely to remain when re- 399 transmitting the same SET. Others such as "access_denied" may be 400 transient, for example if the SET Transmitter refreshes expired 401 credentials prior to re-transmission. 403 Implementers SHOULD evaluate the reliability requirements of their 404 use cases and the impact of various retry mechanisms on the 405 performance of their systems to determine an appropriate strategy for 406 handling various error conditions. 408 5. Security Considerations 410 5.1. Authentication Using Signed SETs 412 JWS signed SETs can be used (see [RFC7515] and Section 5 of 413 [RFC8417]) to enable the SET Recipient to validate that the SET 414 Issuer is authorized to provide actionable SETs. 416 5.2. HTTP Considerations 418 SET delivery depends on the use of Hypertext Transfer Protocol and is 419 thus subject to the security considerations of HTTP Section 9 of 420 [RFC7230] and its related specifications. 422 5.3. Confidentiality of SETs 424 SETs may contain sensitive information that is considered Personally 425 Identifiable Information (PII). In such cases, SET Transmitters and 426 SET Recipients MUST protect the confidentiality of the SET contents. 427 In some use cases, using TLS to secure the transmitted SETs will be 428 sufficient. In other use cases, encrypting the SET as described in 429 JWE [RFC7516] will also be required. The Event delivery endpoint 430 MUST support at least TLS version 1.2 [RFC5246] and SHOULD support 431 the newest version of TLS that meets its security requirements, which 432 as of the time of this publication is TLS 1.3 [RFC8446]. The client 433 MUST perform a TLS/SSL server certificate check using DNS-ID 434 [RFC6125]. How a SET Transmitter determines the expected service 435 identity to match the SET Recipient's server certificate against is 436 out of scope for this document. Implementation security 437 considerations for TLS can be found in "Recommendations for Secure 438 Use of TLS and DTLS" [RFC7525]. 440 5.4. Denial of Service 442 The SET Recipient may be vulnerable to a denial-of-service attack 443 where a malicious party makes a high volume of requests containing 444 invalid SETs, causing the endpoint to expend significant resources on 445 cryptographic operations that are bound to fail. This may be 446 mitigated by authenticating SET Transmitters with a mechanism such as 447 mutual TLS. 449 5.5. Authenticating Persisted SETs 451 At the time of receipt, the SET Recipient can rely upon transport 452 layer mechanisms, HTTP authentication methods, and/or other context 453 from the transmission request to authenticate the SET Transmitter and 454 validate the authenticity of the SET. However, this context is 455 typically unavailable to systems that the SET Recipient forwards the 456 SET onto, or to systems that retrieve the SET from storage. If the 457 SET Recipient requires the ability to validate SET authenticity 458 outside of the context of the transmission request, then the SET 459 Recipient SHOULD ensure that such SETs have been signed in accordance 460 with [RFC7515]. 462 6. Privacy Considerations 464 SET Transmitters SHOULD attempt to deliver SETs that are targeted to 465 the specific business and protocol needs of subscribers. 467 When sharing personally identifiable information or information that 468 is otherwise considered confidential to affected users, SET 469 Transmitters and Recipients MUST have the appropriate legal 470 agreements and user consent or terms of service in place. 471 Furthermore, data that needs confidentiality protection MUST be 472 encrypted, at least with TLS and sometimes also using JSON Web 473 Encryption (JWE) [RFC7516]. 475 In some cases, subject identifiers themselves may be considered 476 sensitive information, such that their inclusion within a SET may be 477 considered a violation of privacy. SET Issuers should consider the 478 ramifications of sharing a particular subject identifier with a SET 479 Recipient (e.g., whether doing so could enable correlation and/or de- 480 anonymization of data) and choose appropriate subject identifiers for 481 their use cases. 483 7. IANA Considerations 485 7.1. Security Event Token Delivery Error Codes 487 This document defines Security Event Token Delivery Error Codes, for 488 which IANA is asked to create and maintain a new registry titled 489 "Security Event Token Delivery Error Codes". Initial values for the 490 Security Event Token Delivery Error Codes registry are defined in 491 Table 1 and registered below. Future assignments are to be made 492 through the Specification Required registration policy ([RFC8126]) 493 and shall follow the template presented in Section 7.1.1. 495 Error Codes are intended to be interpreted by automated systems, and 496 therefore SHOULD identify classes of errors to which an automated 497 system could respond in a meaningfully distinct way (e.g., by 498 refreshing authentication credentials and retrying the request). 500 7.1.1. Registration Template 502 Error Code 503 The name of the Security Event Token Delivery Error Code, as 504 described in Section 2.4. The name MUST be a case-sensitive ASCII 505 string consisting only of letters, digits, and underscore; these 506 are the characters whose codes fall within the inclusive ranges 507 0x30-39, 0x41-5A, 0x5F and 0x61-7A. 509 Description 510 A brief human-readable description of the Security Event Token 511 Delivery Error Code. 513 Change Controller 514 For error codes registered by the IETF or its working groups, list 515 "IETF SecEvent Working Group". For all other error codes, list 516 the name of the party responsible for the registration. Contact 517 information such as mailing address, email address, or phone 518 number may also be provided. 520 Defining Document(s) 521 A reference to the document or documents that define the Security 522 Event Token Delivery Error Code. The definition MUST specify the 523 name and description of the error code and explain under what 524 circumstances the error code may be used. URIs that can be used 525 to retrieve copies of each document at no cost SHOULD be included. 527 7.1.2. Initial Registry Contents 529 Error Code: invalid_request 530 Description: The request body cannot be parsed as a SET or the 531 event payload within the SET does not conform to the event's 532 definition. 533 Change Controller: IETF 534 Defining Document(s): Section 2.4 of [[ this specification ]] 536 Error Code: invalid_key 537 Description: One or more keys used to encrypt or sign the SET is 538 invalid or otherwise unacceptable to the SET Recipient. (e.g., 539 expired, revoked, failed certificate validation, etc.) 540 Change Controller: IETF 541 Defining Document(s): Section 2.4 of [[ this specification ]] 543 Error Code: authentication_failed 544 Description: The SET Recipient could not authenticate the SET 545 Transmitter. 546 Change Controller: IETF 547 Defining Document(s): Section 2.4 of [[ this specification ]] 549 Error Code: access_denied 550 Description: The SET Transmitter is not authorized to transmit the 551 SET to the SET Recipient. 552 Change Controller: IETF 553 Defining Document(s): Section 2.4 of [[ this specification ]] 555 8. References 557 8.1. Normative References 559 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 560 Requirement Levels", BCP 14, RFC 2119, 561 DOI 10.17487/RFC2119, March 1997, 562 . 564 [RFC2277] Alvestrand, H., "IETF Policy on Character Sets and 565 Languages", BCP 18, RFC 2277, DOI 10.17487/RFC2277, 566 January 1998, . 568 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, 569 DOI 10.17487/RFC2818, May 2000, 570 . 572 [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security 573 (TLS) Protocol Version 1.2", RFC 5246, 574 DOI 10.17487/RFC5246, August 2008, 575 . 577 [RFC6125] Saint-Andre, P. and J. Hodges, "Representation and 578 Verification of Domain-Based Application Service Identity 579 within Internet Public Key Infrastructure Using X.509 580 (PKIX) Certificates in the Context of Transport Layer 581 Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March 582 2011, . 584 [RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer 585 Protocol (HTTP/1.1): Message Syntax and Routing", 586 RFC 7230, DOI 10.17487/RFC7230, June 2014, 587 . 589 [RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer 590 Protocol (HTTP/1.1): Semantics and Content", RFC 7231, 591 DOI 10.17487/RFC7231, June 2014, 592 . 594 [RFC7515] Jones, M., Bradley, J., and N. Sakimura, "JSON Web 595 Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May 596 2015, . 598 [RFC7516] Jones, M. and J. Hildebrand, "JSON Web Encryption (JWE)", 599 RFC 7516, DOI 10.17487/RFC7516, May 2015, 600 . 602 [RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token 603 (JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015, 604 . 606 [RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre, 607 "Recommendations for Secure Use of Transport Layer 608 Security (TLS) and Datagram Transport Layer Security 609 (DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May 610 2015, . 612 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 613 Writing an IANA Considerations Section in RFCs", BCP 26, 614 RFC 8126, DOI 10.17487/RFC8126, June 2017, 615 . 617 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 618 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 619 May 2017, . 621 [RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data 622 Interchange Format", STD 90, RFC 8259, 623 DOI 10.17487/RFC8259, December 2017, 624 . 626 [RFC8417] Hunt, P., Ed., Jones, M., Denniss, W., and M. Ansari, 627 "Security Event Token (SET)", RFC 8417, 628 DOI 10.17487/RFC8417, July 2018, 629 . 631 [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol 632 Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, 633 . 635 8.2. Informative References 637 [I-D.ietf-secevent-http-poll] 638 Backman, A., Jones, M., Scurtescu, M., Ansari, M., and A. 639 Nadalin, "Poll-Based Security Event Token (SET) Delivery 640 Using HTTP", draft-ietf-secevent-http-poll-10 (work in 641 progress), June 2020. 643 [RFC7235] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer 644 Protocol (HTTP/1.1): Authentication", RFC 7235, 645 DOI 10.17487/RFC7235, June 2014, 646 . 648 Appendix A. Unencrypted Transport Considerations 650 Earlier versions of this specification made the use of TLS optional 651 and described security and privacy considerations resulting from use 652 of unencrypted HTTP as the underlying transport. When the working 653 group decided to mandate usage HTTP over TLS, it also decided to 654 preserve the description of these considerations in this non- 655 normative appendix. 657 SETs may contain sensitive information that is considered Personally 658 Identifiable Information (PII). In such cases, SET Transmitters and 659 SET Recipients MUST protect the confidentiality of the SET contents. 660 When TLS is not used, this means that the SET MUST be encrypted as 661 described in JWE [RFC7516]. 663 If SETs are transmitted over unencrypted channels, some privacy- 664 sensitive information about them might leak, even though the SETs 665 themselves are encrypted. For instance, an attacker may be able to 666 determine whether or not a SET was accepted and the reason for its 667 rejection or may be able to derive information from being able to 668 observe the size of the encrypted SET. 670 Appendix B. Other Streaming Specifications 672 [[ NOTE TO THE RFC EDITOR: This section to be removed prior to 673 publication ]] 675 The following pub/sub, queuing, streaming systems were reviewed as 676 possible solutions or as input to the current draft: 678 Poll-Based Security Event Token (SET) Delivery Using HTTP 680 In addition to this specification, the WG is defining a polling-based 681 SET delivery protocol. That protocol [I-D.ietf-secevent-http-poll] 682 describes it as: 684 This specification defines how a series of Security Event Tokens 685 (SETs) can be delivered to an intended recipient using HTTP POST over 686 TLS initiated as a poll by the recipient. The specification also 687 defines how delivery can be assured, subject to the SET Recipient's 688 need for assurance. 690 XMPP Events 692 The WG considered XMPP Events and their ability to provide a single 693 messaging solution without the need for both polling and push modes. 694 The feeling was the size and methodology of XMPP was too far apart 695 from the current capabilities of the SECEVENTs community, which 696 focuses in on HTTP based service delivery and authorization. 698 Amazon Simple Notification Service 700 Simple Notification Service is a pub/sub messaging product from AWS. 701 SNS supports a variety of subscriber types: HTTP/HTTPS endpoints, AWS 702 Lambda functions, email addresses (as JSON or plain text), phone 703 numbers (via SMS), and AWS SQS standard queues. It does not directly 704 support pull, but subscribers can get the pull model by creating an 705 SQS queue and subscribing it to the topic. Note that this puts the 706 cost of pull support back onto the subscriber, just as it is in the 707 push model. It is not clear that one way is strictly better than the 708 other; larger, sophisticated developers may be happy to own message 709 persistence so they can have their own internal delivery guarantees. 710 The long tail of OIDC clients may not care about that or may fail to 711 get it right. Regardless, I think we can learn something from the 712 Delivery Policies supported by SNS, as well as the delivery controls 713 that SQS offers (e.g., Visibility Timeout, Dead-Letter Queues). I am 714 not suggesting that we need all of these things in the spec, but they 715 give an idea of what features people have found useful. 717 Other information: 719 o API Reference: 720 http://docs.aws.amazon.com/AWSSimpleQueueService/latest/ 721 APIReference/Welcome.html 723 o Visibility Timeouts: 724 http://docs.aws.amazon.com/AWSSimpleQueueService/latest/ 725 SQSDeveloperGuide/sqs-visibility-timeout.html 727 Apache Kafka 729 Apache Kafka is an Apache open source project based upon TCP for 730 distributed streaming. It prescribes some interesting general- 731 purpose features that seem to extend far beyond the simpler streaming 732 model that SECEVENTs is after. A comment from MS has been that Kafka 733 does an acknowledge with poll combination event which seems to be a 734 performance advantage. See: https://kafka.apache.org/intro 736 Google Pub/Sub 738 The Google Pub Sub system favors a model whereby polling and 739 acknowledgement of events is done with separate endpoints and as 740 separate functions. 742 Information: 744 o Cloud Overview - https://cloud.google.com/pubsub/ 746 o Subscriber Overview - https://cloud.google.com/pubsub/docs/ 747 subscriber 749 o Subscriber Pull(poll) - https://cloud.google.com/pubsub/docs/pull 751 Appendix C. Acknowledgments 753 The editors would like to thank the members of the SCIM working 754 group, which began discussions of provisioning events starting with 755 draft-hunt-scim-notify-00 in 2015. We would like to thank Phil Hunt 756 and the other authors of draft-ietf-secevent-delivery-02, upon which 757 this specification is based. We would like to thank the participants 758 in the SecEvents working group for their contributions to this 759 specification. 761 Additionally, we would like to thank the following individuals for 762 their reviews of the specification: Joe Clarke, Vijay Gurbani, 763 Benjamin Kaduk, Yaron Sheffer, and Valery Smyslov. 765 Appendix D. Change Log 767 [[ NOTE TO THE RFC EDITOR: This section to be removed prior to 768 publication ]] 770 Draft 00 - AB - Based on draft-ietf-secevent-delivery-02 with the 771 following changes: 773 o Renamed to "Push-Based SET Token Delivery Using HTTP" 775 o Removed references to the HTTP Polling delivery method. 777 o Removed informative reference to RFC6202. 779 Draft 01 - AB: 781 o Fixed area and workgroup to match secevent. 783 o Removed unused definitions and definitions already covered by SET. 785 o Renamed Event Transmitter and Event Receiver to SET Transmitter 786 and SET Receiver, respectively. 788 o Added IANA registry for SET Delivery Error Codes. 790 o Removed enumeration of HTTP authentication methods. 792 o Removed generally applicable guidance for HTTP, authorization 793 tokens, and bearer tokens. 795 o Moved guidance for using authentication methods as DoS protection 796 to Security Considerations. 798 o Removed redundant instruction to use WWW-Authenticate header. 800 o Removed further generally applicable guidance for authorization 801 tokens. 803 o Removed bearer token from example delivery request, and text 804 referencing it. 806 o Broke delivery method description into separate request/response 807 sections. 809 o Added missing empty line between headers and body in example 810 request. 812 o Removed inapplicable notes about example formatting. 814 o Removed text about SET creation and handling. 816 o Removed duplication in protocol description. 818 o Added "non-normative example" text to example transmission 819 request. 821 o Fixed inconsistencies in use of Error Code term. 823 Draft 02 - AB: 825 o Rewrote abstract and introduction. 827 o Rewrote definitions for SET Transmitter, SET Receiver. 829 o Renamed Event Delivery section to SET Delivery. 831 o Readability edits to Success Response and Failure Response 832 sections. 834 o Consolidated definition of error response under Failure Response 835 section. 837 o Removed Event Delivery Process section and moved its content to 838 parent section. 840 o Readability edits to SET Delivery section and its subsections. 842 o Added callout that SET Receiver HTTP endpoint configuration is 843 out-of-scope. 845 o Added callout that SET verification mechanisms are out-of-scope. 847 o Added retry guidance, notes regarding delivery reliability 848 requirements. 850 o Added guidance around using JWS and/or JWE to authenticate 851 persisted SETs. 853 Draft 03 - mbj: 855 o Addressed problems identified in my 18-Jul-18 review message 856 titled "Issues for both the Push and Poll Specs". 858 o Changes to align terminology with RFC 8417, for instance, by using 859 the already defined term SET Recipient rather than SET Receiver. 861 o Applied editorial and minor normative corrections. 863 o Updated Marius' contact information. 865 Draft 04 - AB: 867 o Replaced Error Codes with smaller set of meaningfully 868 differentiated codes. 870 o Added more error response examples. 872 o Removed un-referenced normative references. 874 o Added normative reference to JSON in error response definition. 876 o Added text clarifying that the value of the "description" 877 attribute in error responses is implementation specific. 879 o Added requirement that error descriptions and responses are UTF-8 880 encoded. 882 o Added error description language preferences and specification via 883 "Accept-Language" and "Content-Language" headers. 885 o Added "recognized issuer" validation requirement in section 2. 887 o Added timeouts as an acceptable reason to resend a SET in section 888 2. 890 o Edited text in section 1 to clarify that configuration is out of 891 scope. 893 o Made minor editorial corrections. 895 Draft 05 - AB: 897 o Made minor editorial corrections. 899 o Updated example request with a correct SET header and signature. 901 o Revised TLS guidance to allow implementers to provide 902 confidentiality protection via JWE. 904 o Revised TLS guidance to require *at least* TLS 1.2. 906 o Revised TLS guidance to recommend supporting the newest version of 907 TLS that meets security requirements. 909 o Revised SET Delivery Error Code format to allow the same set of 910 characters as is allowed in error codes in RFC6749. 912 o Added mention of HTTP Poll spec to list of other streaming specs 913 in appendix. 915 o Added validation step requiring SET Recipient to verify that the 916 SET is one which the SET Transmitter is expected to send to the 917 SET Recipient. 919 o Changed responding to errors with an appropriate HTTP status code 920 from optional to recommended. 922 o Changed Error Codes registry change policy from Expert Review to 923 First Come First Served; added guidance that error codes are meant 924 to be consumed by automated systems. 926 o Added text making clear that it is up to SET Recipients whether or 927 not they will accept SETs where the SET Issuer is different from 928 the SET Transmitter. 930 o Reworded guidance around signing and/or encrypting SETs for 931 integrity protection. 933 o Renamed TLS "Support Considerations" section to "Confidentiality 934 of SETs". 936 o Reworded guidance around subject identifier selection and privacy 937 concerns. 939 Draft 06 - mbj, MS: 941 o Made minor editorial corrections. 943 o Updated to indicate that failure response should be returned if 944 errors occur in authenticating the SET. 946 o Updated reference for JSON from RFC 7159 to RFC 8259. 948 o Fixed Authentication Using Signed SETs to indicate the SET 949 Transmitter must be authorized to deliver the SET, not the SET 950 Issuer. 952 o Fixed Authenticating Persisted SETs to put the responsibility for 953 ensuring the SET is signed on the SET Recipient. 955 o Fixed error code format definition to match error codes defined in 956 doc. 958 Draft 07 - AB: 960 o Made minor editorial corrections. 962 o Removed "SET Recipient" definition and added explicit list of 963 terms used from RFC8417. 965 Draft 08 - mbj 967 o Addressed area director review comments by Benjamin Kaduk. 969 Draft 09 - mbj + AB 971 o Corrected editorial nits. 973 Draft 10 - AB 975 o Addressed area director review comments by Benjamin Kaduk: 977 * Added reference to 8417 as definition document for SETs. 979 * Added text clarifying that determining the SET Recipient's 980 service identity is out of scope. 982 * Added normative recommendation for transmitters to target SETs 983 to specific business needs of subscribers. 985 * Minor editorial corrections. 987 Draft 11 - mbj 989 o Addressed SecDir review comments by Valery Smyslov. 991 o Addressed OpsDir review comments by Joe Clarke. 993 o Addressed GenArt review comments by Vijay Gurbani. 995 Draft 12 - mbj 997 o Revised to unambiguously require the use of TLS, while preserving 998 descriptions of precautions needed for non-TLS use in an appendix. 1000 Authors' Addresses 1002 Annabelle Backman (editor) 1003 Amazon 1005 Email: richanna@amazon.com 1006 Michael B. Jones (editor) 1007 Microsoft 1009 Email: mbj@microsoft.com 1010 URI: https://self-issued.info/ 1012 Marius Scurtescu 1013 Coinbase 1015 Email: marius.scurtescu@coinbase.com 1017 Morteza Ansari 1018 Cisco 1020 Email: morteza.ansari@cisco.com 1022 Anthony Nadalin 1023 Microsoft 1025 Email: tonynad@microsoft.com