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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Internet Engineering Task Force S. Hollenbeck 3 Internet-Draft Verisign Labs 4 Intended status: Standards Track N. Kong 5 Expires: March 26, 2015 CNNIC 6 September 22, 2014 8 Security Services for the Registration Data Access Protocol 9 draft-ietf-weirds-rdap-sec-09 11 Abstract 13 The Registration Data Access Protocol (RDAP) provides "RESTful" web 14 services to retrieve registration metadata from domain name and 15 regional internet registries. This document describes information 16 security services including authentication, authorization, 17 availability, data confidentiality, and data integrity for RDAP. 19 Status of This Memo 21 This Internet-Draft is submitted in full conformance with the 22 provisions of BCP 78 and BCP 79. 24 Internet-Drafts are working documents of the Internet Engineering 25 Task Force (IETF). Note that other groups may also distribute 26 working documents as Internet-Drafts. The list of current Internet- 27 Drafts is at http://datatracker.ietf.org/drafts/current/. 29 Internet-Drafts are draft documents valid for a maximum of six months 30 and may be updated, replaced, or obsoleted by other documents at any 31 time. It is inappropriate to use Internet-Drafts as reference 32 material or to cite them other than as "work in progress." 34 This Internet-Draft will expire on March 26, 2015. 36 Copyright Notice 38 Copyright (c) 2014 IETF Trust and the persons identified as the 39 document authors. All rights reserved. 41 This document is subject to BCP 78 and the IETF Trust's Legal 42 Provisions Relating to IETF Documents 43 (http://trustee.ietf.org/license-info) in effect on the date of 44 publication of this document. Please review these documents 45 carefully, as they describe your rights and restrictions with respect 46 to this document. Code Components extracted from this document must 47 include Simplified BSD License text as described in Section 4.e of 48 the Trust Legal Provisions and are provided without warranty as 49 described in the Simplified BSD License. 51 Table of Contents 53 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 54 2. Conventions Used in This Document . . . . . . . . . . . . . . 2 55 2.1. Acronyms and Abbreviations . . . . . . . . . . . . . . . 3 56 3. Information Security Services and RDAP . . . . . . . . . . . 3 57 3.1. Authentication . . . . . . . . . . . . . . . . . . . . . 3 58 3.1.1. Federated Authentication . . . . . . . . . . . . . . 4 59 3.2. Authorization . . . . . . . . . . . . . . . . . . . . . . 5 60 3.3. Availability . . . . . . . . . . . . . . . . . . . . . . 6 61 3.4. Data Confidentiality . . . . . . . . . . . . . . . . . . 6 62 3.5. Data Integrity . . . . . . . . . . . . . . . . . . . . . 7 63 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 64 5. Security Considerations . . . . . . . . . . . . . . . . . . . 7 65 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8 66 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 67 7.1. Normative References . . . . . . . . . . . . . . . . . . 9 68 7.2. Informative References . . . . . . . . . . . . . . . . . 9 69 Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 10 70 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 72 1. Introduction 74 The Registration Data Access Protocol (RDAP) is specified in multiple 75 documents, including "Registration Data Access Protocol Lookup 76 Format" [I-D.ietf-weirds-rdap-query], "JSON Responses for the 77 Registration Data Access Protocol (RDAP)" 78 [I-D.ietf-weirds-json-response], and "HTTP usage in the Registration 79 Data Access Protocol (RDAP)" [I-D.ietf-weirds-using-http]. 81 One goal of RDAP is to provide security services that do not exist in 82 the WHOIS [RFC3912] protocol, including authentication, 83 authorization, availability, data confidentiality, and data 84 integrity. This document describes how each of these services is 85 achieved by RDAP. Where applicable, informational references to 86 requirements for a WHOIS replacement service [RFC3707] are noted. 88 2. Conventions Used in This Document 90 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 91 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 92 document are to be interpreted as described in RFC 2119 [RFC2119]. 94 2.1. Acronyms and Abbreviations 96 DNR: Domain Name Registry 98 HTTP: Hypertext Transfer Protocol 100 JSON: JavaScript Object Notation 102 RDAP: Registration Data Access Protocol 104 RIR: Regional Internet Registry 106 TLS: Transport Layer Security 108 3. Information Security Services and RDAP 110 RDAP itself does not include native security services. Instead, RDAP 111 relies on features that are available in other protocol layers to 112 provide needed security services including authentication, 113 authorization, availability, data confidentiality, and data 114 integrity. A description of each of these security services can be 115 found in "Internet Security Glossary, Version 2" [RFC4949]. No 116 requirements have been identified for other security services. 118 3.1. Authentication 120 This section describes security authentication mechanisms and their 121 need for implementation by authorization policies. It describes 122 requirements for the implementations of clients and servers, but does 123 not dictate the policies of server operators. For example, a server 124 operator with no policy regarding differentiated or tiered access to 125 data will have no authorization mechanisms and will have no need for 126 any type of authentication. A server operator with policies on 127 differentiated access will have to construct an authorization scheme 128 and will need to follow the specified authentication requirements. 130 WHOIS does not provide features to identify and authenticate clients. 131 As noted in section 3.1.4.2 of "Cross Registry Internet Service 132 Protocol (CRISP) Requirements" [RFC3707], there is utility in 133 allowing server operators to offer "varying degrees of access 134 depending on policy and need". Clients have to be identified and 135 authenticated to provide that utility. 137 RDAP's authentication framework needs to accommodate anonymous access 138 as well as verification of identities using a range of authentication 139 methods and credential services. To that end, RDAP clients and 140 servers MUST implement the authentication framework specified in 141 "HTTP Authentication: Basic and Digest Access Authentication" 143 [RFC7235]. The "basic" scheme can be used to send a client's user 144 name and password to a server in plaintext, based64-encoded form. 145 The "digest" scheme can be used to authenticate a client without 146 exposing the client's plaintext password. If the "basic" scheme is 147 used, HTTP Over TLS [RFC2818] MUST be used to protect the client's 148 credentials from disclosure while in transit (see Section 3.4). 150 Servers MUST support either Basic or Digest authentication; they are 151 not required to support both. Clients MUST support both to 152 interoperate with servers that support one or the other. 154 The Transport Layer Security Protocol [RFC5246] includes an optional 155 feature to identify and authenticate clients who possess and present 156 a valid X.509 digital certificate [RFC5280]. Support for this 157 feature is OPTIONAL. 159 RDAP does not impose any unique server authentication requirements. 160 The server authentication provided by TLS fully addresses the needs 161 of RDAP. In general, transports for RDAP must either provide a TLS- 162 protected transport (e.g., HTTPS) or a mechanism that provides an 163 equivalent level of server authentication. 165 Work on HTTP authentication methods continues. RDAP ought to be 166 agile enough to support additional methods as they are defined. 168 3.1.1. Federated Authentication 170 The traditional client-server authentication model requires clients 171 to maintain distinct credentials for every RDAP server. This 172 situation can become unwieldy as the number of RDAP servers 173 increases. Federated authentication mechanisms allow clients to use 174 one credential to access multiple RDAP servers and reduce client 175 credential management complexity. RDAP MAY include a federated 176 authentication mechanism that permits a client to access multiple 177 RDAP servers in the same federation with one credential. 179 Federated authentication mechanisms used by RDAP are OPTIONAL. If 180 used, they MUST be fully supported by HTTP. OAuth, OpenID, and CA- 181 based mechanisms are three possible approaches to provide federated 182 authentication. At the time of this document's publication, 183 negotiation or advertisement of federated authentication services is 184 still an undefined mechanism by the noted federated authentication 185 protocols. Developing this mechanism is beyond the scope of this 186 document. 188 The OAuth authorization framework [RFC6749] describes a method for 189 users to access protected web resources without having to hand out 190 their credentials. Instead, clients are issued access tokens by 191 authorization servers with the permission of the resource owners. 192 Using OAuth, multiple RDAP servers can form a federation and the 193 clients can access any server in the same federation by providing one 194 credential registered in any server in that federation. The OAuth 195 authorization framework is designed for use with HTTP and thus can be 196 used with RDAP. 198 OpenID [OpenID] is a decentralized single sign-on authentication 199 system that allows users to log in at multiple web sites with one ID 200 instead of having to create multiple unique accounts. An end user 201 can freely choose which OpenID provider to use, and can preserve 202 their Identifier if they switch OpenID providers. 204 Note that OAuth and OpenID do not consistently require data 205 confidentiality services to protect interactions between providers 206 and consumers. HTTP Over TLS [RFC2818] can be used as needed to 207 provide protection against man-in-the-middle attacks. 209 The Transport Layer Security Protocol [RFC5246], Section 7.4.6, 210 describes the specification of a client certificate. Clients who 211 possess and present a valid X.509 digital certificate, issued by an 212 entity called a "Certification Authority" (CA), could be identified 213 and authenticated by a server who trusts the corresponding CA. A 214 certificate authentication method can be used to achieve federated 215 authentication in which multiple RDAP servers all trust the same CAs 216 and then any client with a certificate issued by a trusted CA can 217 access any RDAP server in the federation. This certificate-based 218 mechanism is supported by HTTPS and can be used with RDAP. 220 3.2. Authorization 222 WHOIS does not provide services to grant different levels of access 223 to clients based on a client's authenticated identity. As noted in 224 section 3.1.4.2 of "Cross Registry Internet Service Protocol (CRISP) 225 Requirements" [RFC3707], there is utility in allowing server 226 operators to offer "varying degrees of access depending on policy and 227 need". Access control decisions can be made once a client's identity 228 has been established and authenticated (see Section 3.1). 230 Server operators MAY offer varying degrees of access depending on 231 policy and need in conjunction with the authentication methods 232 described in Section 3.1. If such varying degrees of access are 233 supported, an RDAP server MUST provide granular access controls (that 234 is, on a per registration data object basis) in order to implement 235 authorization policies. Some examples: 237 - Clients will be allowed access only to data for which they have a 238 relationship. 240 - Unauthenticated or anonymous access status may not yield any 241 contact information. 243 - Full access may be granted to a special group of authenticated 244 clients. 246 The type of access allowed by a server will most likely vary from one 247 operator to the next. 249 3.3. Availability 251 An RDAP service has to be available to be useful. There are no RDAP- 252 unique requirements to provide availability, but as a general 253 security consideration a service operator needs to be aware of the 254 issues associated with denial of service. A thorough reading of 255 "Internet Denial-of-Service Considerations" [RFC4732] is advised. 257 An RDAP service MAY use a throttling mechanism to limit the number of 258 queries that a single client can send in a given period of time. If 259 used, the server SHOULD return a 429 response code as described in 260 "Additional HTTP Status Codes" [RFC6585]. A client that receives a 261 429 response SHOULD decrease its query rate, and honor the Retry- 262 After header field if one is present. Note that this is not a 263 defense against denial-of-service attacks, since a malicious client 264 could ignore the code and continue to send queries at a high rate. A 265 server might use another response code if it did not wish to reveal 266 to a client that rate limiting is the reason for the denial of a 267 reply. 269 3.4. Data Confidentiality 271 WHOIS does not provide the ability to protect data from inadvertent 272 disclosure while in transit. Web services such as RDAP commonly use 273 HTTP Over TLS [RFC2818] to provide that protection by encrypting all 274 traffic sent on the connection between client and server. It is also 275 possible to encrypt discrete objects (such as command path segments 276 and JSON-encoded response objects) at one endpoint, send them to the 277 other endpoint via an unprotected transport protocol, and decrypt the 278 object on receipt. Encryption algorithms as described in "Internet 279 Security Glossary, Version 2" [RFC4949] are commonly used to provide 280 data confidentiality at the object level. 282 There are no current requirements for object-level data 283 confidentiality using encryption. Support for this feature could be 284 added to RDAP in the future. 286 As noted in Section 3.1, the HTTP "basic" authentication scheme can 287 be used to authenticate a client. When this scheme is used, HTTP 288 Over TLS MUST be used to protect the client's credentials from 289 disclosure while in transit. If the policy of the server operator 290 requires encryption to protect client-server data exchanges (such as 291 to protect non-public data that can not be accessed without client 292 identification and authentication), HTTP Over TLS MUST be used to 293 protect those exchanges. 295 3.5. Data Integrity 297 WHOIS does not provide the ability to protect data from modification 298 while in transit. Web services such as RDAP commonly use HTTP Over 299 TLS [RFC2818] to provide that protection by using a keyed Message 300 Authentication Code (MAC) to detect modifications. It is also 301 possible to sign discrete objects (such as command path segments and 302 JSON-encoded response objects) at one endpoint, send them to the 303 other endpoint via a transport protocol, and validate the signature 304 of the object on receipt. Digital signature algorithms as described 305 in "Internet Security Glossary, Version 2" [RFC4949] are commonly 306 used to provide data integrity at the object level. 308 There are no current requirements for object-level data integrity 309 using digital signatures. Support for this feature could be added to 310 RDAP in the future. 312 The most specific need for this service is to provide assurance that 313 HTTP 30x redirection hints [RFC7231] and response elements returned 314 from the server are not modified while in transit. If the policy of 315 the server operator requires message integrity for client-server data 316 exchanges, HTTP Over TLS MUST be used to protect those exchanges. 318 4. IANA Considerations 320 This document does not specify any IANA actions. This section can be 321 removed if this document is published as an RFC. 323 5. Security Considerations 325 One of the goals of RDAP is to provide security services that do not 326 exist in the WHOIS protocol. This document describes the security 327 services provided by RDAP and associated protocol layers, including 328 authentication, authorization, availability, data confidentiality, 329 and data integrity. Non-repudiation services were also considered 330 and ultimately rejected due to a lack of requirements. There are, 331 however, currently-deployed WHOIS servers that can return signed 332 responses that provide non-repudiation with proof of origin. RDAP 333 might need to be extended to provide this service in the future. 335 As an HTTP-based protocol RDAP is susceptible to code injection 336 attacks. Code injection refers to adding code into a computer system 337 or program to alter the course of execution. There are many types of 338 code injection, including SQL injection, dynamic variable or function 339 injection, include file injection, shell injection, and HTML-script 340 injection among others. Data confidentiality and integrity services 341 provide a measure of defense against man-in-the-middle injection 342 attacks, but vulnerabilities in both client-side and server-side 343 software make it possible for injection attacks to succeed. 344 Consistently checking and validating server credentials can help 345 detect man-in-the-middle attacks. 347 As noted in Section 3.1.1, digital certificates can be used to 348 implement federated authentication. There is a risk of too- 349 promiscuous, or even rogue, CAs being included in the list of 350 acceptable CAs that the TLS server sends the client as part of the 351 TLS client-authentication handshake and lending the appearance of 352 trust to certificates signed by those CAs. Periodic monitoring of 353 the list of CAs that RDAP servers trust for client authentication can 354 help reduce this risk. 356 The Transport Layer Security Protocol [RFC5246] includes a null 357 cipher suite that does not encrypt data and thus does not provide 358 data confidentiality. This option must not be used when data 359 confidentiality services are needed. 361 Data integrity services are sometimes mistakenly associated with 362 directory service operational policy requirements focused on data 363 accuracy. "Accuracy" refers to the truthful association of data 364 elements (such as names, addresses, and telephone numbers) in the 365 context of a particular directory object (such as a domain name). 366 Accuracy requirements are out of scope for this protocol. 368 Additional security considerations are described in the 369 specifications for HTTP [RFC7231], HTTP basic and digest access 370 authentication [RFC7235], HTTP Over TLS [RFC2818], and additional 371 HTTP status codes [RFC6585]. Security considerations for federated 372 authentication systems can be found in the OAuth [RFC6749] and OpenID 373 [OpenID] specifications. 375 6. Acknowledgements 377 The authors would like to acknowledge the following individuals for 378 their contributions to this document: Richard Barnes, Marc Blanchet, 379 Ernie Dainow, Spencer Dawkins, Jean-Philippe Dionne, Byron Ellacott, 380 Stephen Farrell, Tony Hansen, Peter Koch, Murray Kucherawy, Barry 381 Leiba, Andrew Newton, and Linlin Zhou. 383 7. References 385 7.1. Normative References 387 [I-D.ietf-weirds-json-response] 388 Newton, A. and S. Hollenbeck, "JSON Responses for the 389 Registration Data Access Protocol (RDAP)", draft-ietf- 390 weirds-json-response-08 (work in progress), August 2014. 392 [I-D.ietf-weirds-rdap-query] 393 Newton, A. and S. Hollenbeck, "Registration Data Access 394 Protocol Query Format", draft-ietf-weirds-rdap-query-13 395 (work in progress), August 2014. 397 [I-D.ietf-weirds-using-http] 398 Newton, A., Ellacott, B., and N. Kong, "HTTP usage in the 399 Registration Data Access Protocol (RDAP)", draft-ietf- 400 weirds-using-http-11 (work in progress), September 2014. 402 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 403 Requirement Levels", BCP 14, RFC 2119, March 1997. 405 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000. 407 [RFC6585] Nottingham, M. and R. Fielding, "Additional HTTP Status 408 Codes", RFC 6585, April 2012. 410 [RFC7231] Fielding, R. and J. Reschke, "Hypertext Transfer Protocol 411 (HTTP/1.1): Semantics and Content", RFC 7231, June 2014. 413 [RFC7235] Fielding, R. and J. Reschke, "Hypertext Transfer Protocol 414 (HTTP/1.1): Authentication", RFC 7235, June 2014. 416 7.2. Informative References 418 [OpenID] OpenID Foundation, "OpenID Authentication 2.0 - Final", 419 December 2007, . 421 [RFC3707] Newton, A., "Cross Registry Internet Service Protocol 422 (CRISP) Requirements", RFC 3707, February 2004. 424 [RFC3912] Daigle, L., "WHOIS Protocol Specification", RFC 3912, 425 September 2004. 427 [RFC4732] Handley, M., Rescorla, E., and IAB, "Internet Denial-of- 428 Service Considerations", RFC 4732, December 2006. 430 [RFC4949] Shirey, R., "Internet Security Glossary, Version 2", RFC 431 4949, August 2007. 433 [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security 434 (TLS) Protocol Version 1.2", RFC 5246, August 2008. 436 [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., 437 Housley, R., and W. Polk, "Internet X.509 Public Key 438 Infrastructure Certificate and Certificate Revocation List 439 (CRL) Profile", RFC 5280, May 2008. 441 [RFC6749] Hardt, D., "The OAuth 2.0 Authorization Framework", RFC 442 6749, October 2012. 444 Appendix A. Change Log 446 Initial -00: Adopted as working group document. 447 -01: Extensive text additions and revisions based on in-room 448 discussion at IETF-85. Sections for data integrity and non- 449 repudiation have been removed due to a lack of requirements, but 450 both topics are now addressed in the Security Considerations 451 section. 452 -02: Fixed document names in the Introduction. Modified text in 453 Section 3.1.1 to clarify requirement. Added text to Section 3.3 454 to describe rate limiting. Added new data integrity section. 455 Updated security considerations to describe injection attacks. 456 -03: Extensive updates to address WG last call comments: rewrote 457 introduction, removed references to draft documents, changed 458 "HTML" to "HTTP" in Section 5, eliminated upper case words that 459 could be misunderstood to be normative guidance, rewrote 460 Section 3.4 and Section 3.5. 461 -04: Address AD evaluation comments: In Section 3.1 change "RDAP 462 MUST include an authentication framework that can accommodate" to 463 "RDAP's authentication framework needs to accommodate"; in 464 Section 3.2 change "RDAP MUST include an authorization framework 465 that is capable of providing granular (per registration data 466 object) access controls according to the policies of the operator" 467 to "An RDAP server MUST provide granular access controls (that is, 468 on a per registration data object basis) in order to implement 469 authorization policies"; move RFCs 4732, 5280, and 6749 from 470 normative to informative subsection. 471 -05: Address IETF last call comments: Added text to Section 3.1.1 to 472 recommend the use of HTTP over TLS. Modified Section 3.2 to 473 clarify granular access control text. Added additional Security 474 Considerations. Made references to RFC 5246 and OpenID 475 informative. Minor typo fixes. 476 -06: Keepalive refresh. No content updates. 477 -07: Keepalive refresh. No content updates. 479 -08: Updated HTTP references. 2616 -> 7231, 2617 -> 7235. 480 -09: Address WG last call comments. 482 Authors' Addresses 484 Scott Hollenbeck 485 Verisign Labs 486 12061 Bluemont Way 487 Reston, VA 20190 488 US 490 Email: shollenbeck@verisign.com 491 URI: http://www.verisignlabs.com/ 493 Ning Kong 494 China Internet Network Information Center 495 4 South 4th Street, Zhongguancun, Haidian District 496 Beijing 100190 497 China 499 Phone: +86 10 5881 3147 500 Email: nkong@cnnic.cn