Internet Engineering Task Force                            S. Hollenbeck
Internet-Draft                                             Verisign Labs
Intended status: Standards Track                                 N. Kong
Expires: October 06, 31, 2013                                          CNNIC
                                                          April 04, 29, 2013

      Security Services for the Registration Data Access Protocol
                     draft-ietf-weirds-rdap-sec-02
                     draft-ietf-weirds-rdap-sec-03

Abstract

   The Registration Data Access Protocol (RDAP) provides "RESTful" web
   services to retrieve registration metadata from domain name and
   regional internet registries.  This document describes information
   security services, specific requirements for RDAP, services including authentication, authorization,
   availability, data confidentiality, and approaches to
   provide RDAP security services. data integrity for RDAP.

Status of This Memo

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   This Internet-Draft will expire on October 06, 31, 2013.

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   document authors.  All rights reserved.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions Used in This Document . . . . . . . . . . . . . .   2   3
     2.1.  Acronyms and Abbreviations  . . . . . . . . . . . . . . .   3
   3.  Information Security Services and RDAP  . . . . . . . . . . .   3
     3.1.  Authentication  . . . . . . . . . . . . . . . . . . . . .   3
       3.1.1.  Federated Authentication  . . . . . . . . . . . . . .   4
     3.2.  Authorization . . . . . . . . . . . . . . . . . . . . . .   5
     3.3.  Availability  . . . . . . . . . . . . . . . . . . . . . .   5
     3.4.  Data Confidentiality  . . . . . . . . . . . . . . . . . .   6   5
     3.5.  Data Integrity  . . . . . . . . . . . . . . . . . . . . .   6
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7   6
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   8   7
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   8   7
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   8   7
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   9   8
   Appendix A.  Change Log . . . . . . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   The Registration Data Access Protocol (RDAP) core is specified in two
   documents: multiple
   documents, including "Registration Data Access Protocol Lookup
   Format"
   [I-D.ietf-weirds-rdap-query] and [I-D.ietf-weirds-rdap-query], "JSON Responses for the
   Registration Data Access Protocol (RDAP)" [I-D.ietf-weirds-json-response].
   [I-D.ietf-weirds-json-response], and "HTTP usage in the Registration
   Data Access Protocol (RDAP)" [I-D.ietf-weirds-using-http].

   One goal of RDAP is to provide security services that do not exist in
   the WHOIS [RFC3912] protocol, including authentication,
   authorization, availability, data confidentiality, and data
   integrity.  This document describes how each of these security services from the
   perspective of RDAP requirements and applicability. is
   achieved by RDAP.  Where applicable, informational references to
   requirements for a WHOIS replacement service [RFC3707] are noted.

2.  Conventions Used in This Document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

2.1.  Acronyms and Abbreviations

      DNR: Domain Name Registry

      RDAP: Registration Data Access Protocol

      RIR: Regional Internet Registry

3.  Information Security Services and RDAP

   RDAP itself does not include native security services.  Instead, RDAP
   relies on features that are available in other protocol layers to
   provide needed security services including authentication,
   authorization, availability, data confidentiality, and data
   integrity.  A description of each of these security services can be
   found in RFC 4949 "Internet Security Glossary, Version 2" [RFC4949].  No
   requirements have been identified for other security services.

3.1.  Authentication

   WHOIS does not provide features to identify and authenticate clients.
   As noted in section 3.1.4.2 of RFC 3707 "Cross Registry Internet Service
   Protocol (CRISP) Requirements" [RFC3707], there is utility in
   allowing server operators to offer "varying degrees of access
   depending on policy and need".  Clients have to be identified and
   authenticated to provide that utility.

   REQUIREMENT:

   RDAP MUST include an authentication framework that can accommodate
   anonymous access as well as verification of identities using a range
   of authentication methods and credential services.

   REQUIREMENT: The RDAP authentication framework MUST use
   authentication methods  To that are fully specified and available to
   existing HTTP clients and servers.

   REQUIREMENT: The RDAP authentication framework MUST be capable of
   supporting future authentication methods defined for use with HTTP.

   APPROACH: end, RDAP
   clients and servers MUST implement the authentication framework
   specified in RFC 2617 "HTTP Authentication: Basic and Digest Access
   Authentication" [RFC2617].  The "basic" scheme can be used to send a
   client's user name and password to a server in plaintext,
   based64-encoded form.  The "digest" scheme can be used to
   authenticate a client without exposing the client's plaintext
   password.  If the "basic" scheme is used another protocol (such as used, HTTP Over TLS [RFC2818]) [RFC2818]
   MUST be used to protect the client's credentials from disclosure
   while in transit (see Section 3.4).

   The Transport Layer Security Protocol [RFC5246] includes an optional
   feature to identify and authenticate clients who possess and present
   a valid X.509 digital certificate [RFC5280].  Support for this
   feature is OPTIONAL.

   RDAP SHOULD be capable of supporting future authentication methods
   defined for use with HTTP.

3.1.1.  Federated Authentication

   The traditional client-server authentication model requires clients
   to maintain distinct credentials for every RDAP server.  This
   situation can become unwieldy as the number of RDAP servers
   increases.  Federated authentication mechanisms allow clients to use
   one credential to access multiple RDAP servers and reduce client
   credential management complexity.  RDAP MAY include a federated
   authentication mechanism that permits a client to access multiple
   RDAP servers in the same federation with one credential.

   Federated authentication mechanisms used by RDAP are OPTIONAL.  If
   used, they MUST be fully supported by HTTP.

   POSSIBLE APPROACH:  OAuth, OpenID, and CA-
   based mechanisms are three possible approaches to provide federated
   authentication.

   The OAuth authorization framework [RFC6749] describes a method for
   users to access protected web resources without having to hand out
   their credentials.  Instead, clients supply access tokens issued by
   an authorization server with the permission of the resource owner.
   Using OAuth, multiple RDAP servers can form a federation and the
   clients can access any server in the same federation by providing one
   credential registered in any server in that federation.  The OAuth
   authorization framework is designed for use with HTTP and thus can be
   used with RDAP.

   POSSIBLE APPROACH:

   OpenID [OpenID] is a decentralized single sign-on authentication
   system that allows users to log in at web sites with one ID instead
   of having to create multiple unique accounts.  OpenID
   is decentralized.  An end user can freely
   choose which OpenID provider to use, and can preserve their
   Identifier if they switch OpenID providers.  [To be discussed: Is it possible to introduce
   OpenID into RDAP?]

   POSSIBLE APPROACH:

   Section 7.4.6 of the Transport Layer Security Protocol [RFC5246]
   describes the specification of a client certificate.  Clients who
   possess and present a valid X.509 digital certificate, issued by an
   entity called "Certification Authority" (CA), could be identified and
   authenticated by a server who trusts the corresponding CA.  A
   certificate authentication method can be used to achieve federated
   authentication in which multiple RDAP servers all trust the same CAs
   and then any client with a certificate issued by a trusted CA can
   access any RDAP server in the federation.  This certificate-based
   mechanism is supported by HTTPS and can be introduced into RDAP.

3.2.  Authorization

   WHOIS does not provide services to grant different levels of access
   to clients based on a client's authenticated identity.  As noted in
   section 3.1.4.2 of RFC 3707 "Cross Registry Internet Service Protocol (CRISP)
   Requirements" [RFC3707], there is utility in allowing server
   operators to offer "varying degrees of access depending on policy and
   need".  Access control decisions can be made once a client's identity
   has been established and authenticated (see Section 3.1).

   REQUIREMENT:

   RDAP MUST include an authorization framework that is capable of
   providing granular (per registration data object) access controls
   according to the policies of the operator.

   APPROACH:  Server operators will
   offer varying degrees of access depending on policy and need in
   conjunction with the authentication methods described in Section 3.1.
   Some examples:

   -  Clients will be allowed access only to data for which they have a
      relationship.

   -  Unauthenticated or anonymous access status may not yield any
      contact information.

   -  Full access may be granted to a special group of authenticated
      clients.

   The type of access allowed by a server will most likely vary from one
   operator to the next.

3.3.  Availability

   An RDAP service has to be available to be useful.  There are no RDAP-
   unique requirements to provide availability, but as a general
   security consideration a service operator needs to be aware of the
   issues associated with denial of service.  A thorough reading of RFC
   4732
   "Internet Denial-of-Service Considerations" [RFC4732] is RECOMMENDED. advised.

   An RDAP service MAY use a throttling mechanism to limit the number of
   queries that a single client can send in a given period of time.  If
   used, the server SHOULD return a 429 response code as described in
   RFC 6585
   "Additional HTTP Status Codes" [RFC6585].  A client that receives a
   429 response SHOULD decrease its query rate, and honor the Retry-After Retry-
   After header field if one is present.

3.4.  Data Confidentiality

   WHOIS does not provide the ability to encrypt data while in transit
   to protect it data from inadvertent disclosure.
   disclosure while in transit.  Web services such as RDAP commonly use
   HTTP Over TLS [RFC2818] to provide that protection.

   REQUIREMENT: RDAP or a protocol layer used protection by RDAP MUST include
   features to protect plaintext client credentials used for encrypting all
   traffic sent on the connection between client
   authentication.

   REQUIREMENT: The data confidentiality methods used by RDAP MUST be
   fully specified and available server.  It is also
   possible to existing HTTP clients encrypt discrete objects (such as command path segments
   and servers.

   REQUIREMENT: RDAP MUST be capable of supporting future JSON-encoded response objects) at one endpoint, send them to the
   other endpoint via an unprotected transport protocol, and decrypt the
   object on receipt.  Encryption algorithms as described in "Internet
   Security Glossary, Version 2" [RFC4949] are commonly used to provide
   data confidentiality methods defined for use with HTTP.

   OPTION: RDAP or a protocol layer used by RDAP MAY include features to
   encrypt client-server at the object level.

   There are no current requirements for object-level data exchanges.

   APPROACH:
   confidentiality using encryption.  Support for this feature could be
   added to RDAP in the future.

   As noted in Section 3.1, the HTTP "basic" authentication scheme can
   be used to authenticate a client.  When this scheme is
   used used, HTTP
   Over TLS [RFC2818] MUST be used to protect the client's credentials from
   disclosure while in transit.  HTTP Over TLS MAY also
   be used to protect client-server data exchanges if  If the policy of the server operator
   requires encryption.  There are no current
   requirements for object-level encryption, but RDAP encryption to protect client-server data exchanges (such as
   to protect non-public data that can not be accessed without client
   identification and authentication), HTTP Over TLS MUST NOT preclude
   support for this feature in the future. be used to
   protect those exchanges.

3.5.  Data Integrity

   WHOIS does not provide the ability to protect data from modification
   while in transit.  Web services such as RDAP commonly use HTTP Over
   TLS [RFC2818] to provide that protection. protection by using a keyed Message
   Authentication Code (MAC) to detect modifications.  It is also
   possible to sign discrete objects (such as command path segments and
   JSON-encoded response objects) at one endpoint, send them to the
   other endpoint via a transport protocol, and validate the signature
   of the object on receipt.  Digital signatures signature algorithms as described
   in RFC
   4949 "Internet Security Glossary, Version 2" [RFC4949] are also commonly
   used to provide data integrity.  Note that
   this security service is often mistakenly associated with policy integrity at the object level.

   There are no current requirements focused on for object-level data accuracy; those requirements are out of
   scope integrity
   using digital signatures.  Support for this protocol. feature could be added to
   RDAP in the future.

   The most specific need for this service is to provide assurance that
   HTTP 30x redirection hints [RFC2616] and response elements returned
   from the server are not
   modified.

   REQUIREMENT: RDAP or a protocol layer used by RDAP MUST include
   features to protect HTTP 30x redirection hints from modification.

   REQUIREMENT: The data integrity methods used by RDAP MUST be fully
   specified and available to existing HTTP clients and servers.

   OPTION: RDAP or a protocol layer used by RDAP MAY include features to
   provide message integrity checks.

   REQUIREMENT: RDAP MUST be capable of supporting future JSON data
   integrity methods defined for use with HTTP.

   OPTION: RDAP or a protocol layer used by RDAP MAY include features to
   provide data integrity by signing JSON-encoded objects.

   APPROACH: HTTP Over TLS MAY be used to protect client-server data
   exchanges if modified while in transit.  If the policy of
   the server operator requires message
   integrity.  There are no current requirements integrity for object-level client-server data
   signing, but RDAP
   exchanges, HTTP Over TLS MUST NOT preclude support for this feature in the
   future. be used to protect those exchanges.

4.  IANA Considerations
   This document does not specify any IANA actions.  This section can be
   removed if this document is published as an RFC.

5.  Security Considerations

   One of the goals of RDAP is to provide security services that do not
   exist in the WHOIS protocol.  This document describes the security
   services provided by RDAP and associated protocol layers, including
   authentication, authorization, availability, data confidentiality,
   and data integrity.  Non-repudiation services were also considered
   and ultimately rejected due to a lack of requirements.  There are,
   however, currently-deployed WHOIS servers that can return signed
   responses that provide non-repudiation with proof of origin.  RDAP
   MUST NOT preclude support for
   might need to be extended to provide this feature service in the future.

   As an HTML-based HTTP-based protocol RDAP is susceptible to code injection
   attacks.  Code injection refers to adding code into a computer system
   or program to alter the course of execution.  There are many types of
   code injection, including SQL injection, dynamic variable or function
   injection, include file injection, shell injection, and html-script
   injection among others.  Data confidentiality and integrity services
   provide a measure of defense against man-in-the-middle injection
   attacks, but vulnerabilities in both client- client-side and server-side
   software make it possible for injection attacks to succeed.

   Data integrity services are sometimes mistakenly associated with
   directory service operational policy requirements focused on data
   accuracy.  "Accuracy" refers to the truthful association of data
   elements (such as names, addresses, and telephone numbers) in the
   context of a particular directory object (such as a domain name).
   Accuracy requirements are out of scope for this protocol.

6.  Acknowledgements

   The authors would like to acknowledge the following individuals for
   their contributions to this document: Marc Blanchet, Ernie Dainow,
   Jean-Philippe Dionne, Byron Ellacott, Peter Koch, Murray Kucherawy,
   Andrew Newton, and Linlin Zhou.

7.  References

7.1.  Normative References

   [I-D.ietf-weirds-json-response]
              Newton, A. and S. Hollenbeck, "JSON Responses for the
              Registration Data Access Protocol (RDAP)", draft-ietf-
              weirds-json-response-02
              weirds-json-response-03 (work in progress), January April 2013.

   [I-D.ietf-weirds-rdap-query]
              Newton, A. and S. Hollenbeck, "Registration Data Access
              Protocol Lookup Format", draft-ietf-weirds-rdap-query-03 draft-ietf-weirds-rdap-query-04
              (work in progress), March April 2013.

   [I-D.ietf-weirds-using-http]
              Newton, A., Ellacott, B., and N. Kong, "HTTP usage in the
              Registration Data Access Protocol (RDAP)", draft-ietf-
              weirds-using-http-04 (work in progress), April 2013.

   [OpenID]   OpenID Foundation, "OpenID Authentication 2.0 - Final ",
              December 2007, <http://specs.openid.net/auth/2.0>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2616]  Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
              Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
              Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.

   [RFC2617]  Franks, J., Hallam-Baker, P.M., Hostetler, J.L., Lawrence,
              S.D., Leach, P.J., Luotonen, A., and L. Stewart, "HTTP
              Authentication: Basic and Digest Access Authentication",
              RFC 2617, June 1999.

   [RFC2818]  Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.

   [RFC4732]  Handley, M., Rescorla, E., IAB, "Internet Denial-of-
              Service Considerations", RFC 4732, December 2006.

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246, August 2008.

   [RFC5280]  Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
              Housley, R., and W. Polk, "Internet X.509 Public Key
              Infrastructure Certificate and Certificate Revocation List
              (CRL) Profile", RFC 5280, May 2008.

   [RFC6585]  Nottingham, M. and R. Fielding, "Additional HTTP Status
              Codes", RFC 6585, April 2012.

   [RFC6749]  Hardt, D., "The OAuth 2.0 Authorization Framework", RFC
              6749, October 2012.

7.2.  Informative References

   [RFC3707]  Newton, A., "Cross Registry Internet Service Protocol
              (CRISP) Requirements", RFC 3707, February 2004.

   [RFC3912]  Daigle, L., "WHOIS Protocol Specification", RFC 3912,
              September 2004.

   [RFC4949]  Shirey, R., "Internet Security Glossary, Version 2", RFC
              4949, August 2007.

Appendix A.  Change Log

   Initial -00:  Adopted as working group document.
   -01:  Extensive text additions and revisions based on in-room
      discussion at IETF-85.  Sections for data integrity and non-
      repudiation have been removed due to a lack of requirements, but
      both topics are now addressed in the Security Considerations
      section.
   -02:  Fixed document names in the Introduction.  Modified text in
      Section 3.1.1 to clarify requirement.  Added text to Section 3.3
      to describe rate limiting.  Added new data integrity section.
      Updated security considerations to describe injection attacks.
   -03:  Extensive updates to address WG last call comments: rewrote
      introduction, removed references to draft documents, changed
      "HTML" to "HTTP" in Section 5, eliminated upper case words that
      could be misunderstood to be normative guidance, rewrote
      Section 3.4 and Section 3.5.

Authors' Addresses

   Scott Hollenbeck
   Verisign Labs
   12061 Bluemont Way
   Reston, VA  20190
   US

   Email: shollenbeck@verisign.com
   URI:   http://www.verisignlabs.com/

   Ning Kong
   China Internet Network Information Center
   4 South 4th Street, Zhongguancun, Haidian District
   Beijing  100190
   China

   Phone: +86 10 5881 3147
   Email: nkong@cnnic.cn