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Versions: (draft-reschke-basicauth-enc) 00 01 02 03 04 05 06 07 RFC 7617

HTTPAuth Working Group                                        J. Reschke
Internet-Draft                                                greenbytes
Updates: 2617 (if approved)                           September 13, 2013
Intended status: Standards Track
Expires: March 17, 2014


                 The 'Basic' HTTP Authentication Scheme
                draft-ietf-httpauth-basicauth-update-00

Abstract

   This document defines the "Basic" Hypertext Transfer Protocol (HTTP)
   Authentication Scheme.

Editorial Note (To be removed by RFC Editor before publication)

   Discussion of this draft takes place on the HTTPAuth working group
   mailing list (http-auth@ietf.org), which is archived at <http://
   www.ietf.org/mail-archive/web/http-auth/current/maillist.html>.

   XML versions, latest edits and the issues list for this document are
   available from <http://greenbytes.de/tech/
   webdav/#draft-ietf-httpauth-basicauth-update>.

   The changes in this draft are summarized in Appendix A.1.

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 http://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 March 17, 2014.

Copyright Notice

   Copyright (c) 2013 IETF Trust and the persons identified as the
   document authors.  All rights reserved.



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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
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   include Simplified BSD License text as described in Section 4.e of
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   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
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   Without obtaining an adequate license from the person(s) controlling
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   than English.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Notational Conventions  . . . . . . . . . . . . . . . . . . . . 3
   3.  The 'Basic' Authentication Scheme . . . . . . . . . . . . . . . 3
   4.  Security Considerations . . . . . . . . . . . . . . . . . . . . 4
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 5
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 6
     7.1.  Normative References  . . . . . . . . . . . . . . . . . . . 6
     7.2.  Informative References  . . . . . . . . . . . . . . . . . . 6
   Appendix A.  Change Log (to be removed by RFC Editor before
                publication) . . . . . . . . . . . . . . . . . . . . . 7
     A.1.  Since RFC 2617  . . . . . . . . . . . . . . . . . . . . . . 7
   Appendix B.  Open issues (to be removed by RFC Editor prior to
                publication) . . . . . . . . . . . . . . . . . . . . . 7
     B.1.  edit  . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
     B.2.  upd . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
     B.3.  enc . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
   Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8









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1.  Introduction

   This document defines the "Basic" Hypertext Transfer Protocol (HTTP)
   Authentication Scheme ([draft-ietf-httpbis-p7-auth]).  This scheme is
   not considered to be a secure method of user authentication unless
   used in conjunction with some external secure system such as TLS
   (Transport Layer Security, [RFC5246]), as the user name and password
   are passed over the network as cleartext.

   The "Basic" scheme previously was defined in Section 2 of [RFC2617].
   This document updates the definition, and also addresses
   internationalization issues.

   Other documents updating RFC 2617 are "Hypertext Transfer Protocol
   (HTTP/1.1): Authentication" ([draft-ietf-httpbis-p7-auth], defining
   the authentication framework) and "HTTP Digest Update"
   ([draft-ietf-httpauth-digest-update], updating the definition of the
   '"Digest" authentication scheme).

2.  Notational Conventions

   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 [RFC2119].

3.  The 'Basic' Authentication Scheme

   The "basic" authentication scheme is based on the model that the
   client must authenticate itself with a user-ID and a password for
   each realm.  The realm value should be considered an opaque string
   which can only be compared for equality with other realms on that
   server.  The server will service the request only if it can validate
   the user-ID and password for the protection space of the Request-URI.
   There are no optional authentication parameters.

   For Basic, the framework above is utilized as follows:

      challenge   = "Basic" realm
      credentials = "Basic" basic-credentials

   Upon receipt of an unauthorized request for a URI within the
   protection space, the origin server MAY respond with a challenge like
   the following:

      WWW-Authenticate: Basic realm="WallyWorld"

   where "WallyWorld" is the string assigned by the server to identify
   the protection space of the Request-URI.  A proxy may respond with



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   the same challenge using the Proxy-Authenticate header field.

   To receive authorization, the client sends the userid and password,
   separated by a single colon (":") character, within a base64
   [RFC2396] encoded string in the credentials.

      basic-credentials = base64-user-pass
      base64-user-pass  = <base64 [RFC2045] encoding of user-pass,
                       except not limited to 76 char/line>
      user-pass   = userid ":" password
      userid      = *<TEXT excluding ":">
      password    = *TEXT

   Userids might be case sensitive.

   If the user agent wishes to send the userid "Aladdin" and password
   "open sesame", it would use the following header field:

      Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==

   A client SHOULD assume that all paths at or deeper than the depth of
   the last symbolic element in the path field of the Request-URI also
   are within the protection space specified by the Basic realm value of
   the current challenge.  A client MAY preemptively send the
   corresponding Authorization header with requests for resources in
   that space without receipt of another challenge from the server.
   Similarly, when a client sends a request to a proxy, it may reuse a
   userid and password in the Proxy-Authorization header field without
   receiving another challenge from the proxy server.  See Section 4 for
   security considerations associated with Basic authentication.

4.  Security Considerations

   The Basic authentication scheme is not a secure method of user
   authentication, nor does it in any way protect the entity, which is
   transmitted in cleartext across the physical network used as the
   carrier.  HTTP does not prevent the addition of enhancements (such as
   schemes to use one-time passwords) to Basic authentication.

   The most serious flaw in Basic authentication is that it results in
   the essentially cleartext transmission of the user's password over
   the physical network.  Many other authentication schemes address this
   problem.

   Because Basic authentication involves the cleartext transmission of
   passwords it SHOULD NOT be used (without enhancements) to protect
   sensitive or valuable information.




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   A common use of Basic authentication is for identification purposes
   -- requiring the user to provide a user name and password as a means
   of identification, for example, for purposes of gathering accurate
   usage statistics on a server.  When used in this way it is tempting
   to think that there is no danger in its use if illicit access to the
   protected documents is not a major concern.  This is only correct if
   the server issues both user name and password to the users and in
   particular does not allow the user to choose his or her own password.
   The danger arises because naive users frequently reuse a single
   password to avoid the task of maintaining multiple passwords.

   If a server permits users to select their own passwords, then the
   threat is not only unauthorized access to documents on the server but
   also unauthorized access to any other resources on other systems that
   the user protects with the same password.  Furthermore, in the
   server's password database, many of the passwords may also be users'
   passwords for other sites.  The owner or administrator of such a
   system could therefore expose all users of the system to the risk of
   unauthorized access to all those sites if this information is not
   maintained in a secure fashion.

   Basic Authentication is also vulnerable to spoofing by counterfeit
   servers.  If a user can be led to believe that he is connecting to a
   host containing information protected by Basic authentication when,
   in fact, he is connecting to a hostile server or gateway, then the
   attacker can request a password, store it for later use, and feign an
   error.  This type of attack is not possible with Digest
   Authentication.  Server implementers SHOULD guard against the
   possibility of this sort of counterfeiting by gateways or CGI
   scripts.  In particular it is very dangerous for a server to simply
   turn over a connection to a gateway.  That gateway can then use the
   persistent connection mechanism to engage in multiple transactions
   with the client while impersonating the original server in a way that
   is not detectable by the client.

5.  IANA Considerations

   IANA maintains the registry of HTTP Authentication Schemes
   ([draft-ietf-httpbis-p7-auth]) at
   <http://www.iana.org/assignments/http-authschemes>.

   The entry for the "Basic" Authentication Scheme shall be updated with
   a pointer to this specification.

6.  Acknowledgements

   This specification takes over the definition of the "Basic" HTTP
   Authentication Scheme, previously defined in RFC 2617.  We thank John



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   Franks, Phillip M. Hallam-Baker, Jeffery L. Hostetler, Scott D.
   Lawrence, Paul J. Leach, Ari Luotonen, and Lawrence C. Stewart for
   their work on that specification, from which significant amounts of
   text was borrowed.  See Section 6 of [RFC2617] for further
   acknowledgements.

7.  References

7.1.  Normative References

   [RFC2045]                            Freed, N. and N. Borenstein,
                                        "Multipurpose Internet Mail
                                        Extensions (MIME) Part One:
                                        Format of Internet Message
                                        Bodies", RFC 2045,
                                        November 1996.

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

   [RFC2396]                            Berners-Lee, T., Fielding, R.,
                                        and L. Masinter, "Uniform
                                        Resource Identifiers (URI):
                                        Generic Syntax", RFC 2396,
                                        August 1998.

   [draft-ietf-httpbis-p7-auth]         Fielding, R., Ed. and J.
                                        Reschke, Ed., "Hypertext
                                        Transfer Protocol (HTTP/1.1):
                                        Authentication",
                                        draft-ietf-httpbis-p7-auth-23
                                        (work in progress), July 2013.

7.2.  Informative References

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

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



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                                        August 2008.

   [draft-ietf-httpauth-digest-update]  Shekh-Yusef, R. and D. Ahrens,
                                        "HTTP Digest Update", draft-
                                        ietf-httpauth-digest-update-05
                                        (work in progress),
                                        September 2013.

Appendix A.  Change Log (to be removed by RFC Editor before publication)

A.1.  Since RFC 2617

   This draft acts as a baseline for tracking subsequent changes to the
   specification.  As such, it extracts the definition of "Basic", plus
   the related Security Considerations, and also adds the IANA
   registration of the scheme.  Changes to the actual definition will be
   made in subsequent drafts.

Appendix B.  Open issues (to be removed by RFC Editor prior to
             publication)

B.1.  edit

   Type: edit

   julian.reschke@greenbytes.de (2013-09-11): Umbrella issue for
   editorial fixes/enhancements.

B.2.  upd

   In Section 3:

   Type: change

   julian.reschke@greenbytes.de (2013-09-12): Update the definition to
   reflect underlying changes (RFC2616->httpbis, RFC2396->2616, other
   references).

B.3.  enc

   In Section 3:

   Type: change

   julian.reschke@greenbytes.de (2013-09-12): Fix the encoding issue, by
   pulling in draft-ietf-httpauth-basicauth-enc.





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Index

   B
      base64-user-pass  4
      basic-credentials  4

   C
      challenge  3
      credentials  3

   P
      password  4

   U
      user-pass  4
      userid  4

Author's Address

   Julian F. Reschke
   greenbytes GmbH
   Hafenweg 16
   Muenster, NW  48155
   Germany

   EMail: julian.reschke@greenbytes.de
   URI:   http://greenbytes.de/tech/webdav/
























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