One document matched: draft-zeilenga-ldap-authpasswd-00.txt
INTERNET-DRAFT Kurt D. Zeilenga
Intended Category: Standard Track OpenLDAP Foundation
Expires: 17 June 2000 17 December 1999
LDAP Authentication Password Attribute
<draft-zeilenga-ldap-authpasswd-00.txt>
1. Status of this Memo
This document is an Internet-Draft and is in full conformance with all
provisions of Section 10 of RFC2026.
This draft document will be submitted to the RFC Editor as a Standard
Track document. Distribution of this memo is unlimited. Technical
discussion of this document will take place on the IETF LDAP Extension
Working Group mailing list <ietf-ldapext@netscape.com>. Please send
editorial comments directly to the author <Kurt@OpenLDAP.org>.
Internet-Drafts are working documents of the Internet Engineering Task
Force (IETF), its areas, and its working groups. Note that other
groups may also distribute working documents as Internet-Drafts.
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.''
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html.
Copyright 1999, The Internet Society. All Rights Reserved.
Please see the Copyright section near the end of this document for
more information.
2. Abstract
This document describes schema for storing authentication passwords in
a LDAP [RFC2251] directory. The document provides schema definitions
for authPassword and related schema definitions. The authPassword is
meant to used instead of clear text password storage mechanisms such
as userPassword [RFC2256]. The attribute may be used to store SASL
[RFC2222] authentication passwords in entries of a directory.
The key words ``MUST'', ``MUST NOT'', ``REQUIRED'', ``SHALL'', ``SHALL
Zeilenga [Page 1]
INTERNET-DRAFT LDAP AuthPasswd 17 December 1999
NOT'', ``SHOULD'', ``SHOULD NOT'', ``RECOMMENDED'', and ``MAY'' in
this document are to be interpreted as described in RFC 2119
[RFC2119].
3. Background and Intended Use
userPassword attribute is intended for plain text storage of user
passwords [RFC 2256]. It is inappropriate for userPassword to have
values which are encrypted passwords.
authPassword is intended to be used to store hashed password values
for authentication purposes. The attribute may be used by servers to
implement LDAP simple bind and SASL [RFC 2222] user/password
mechanisms such as DIGEST-MD5 [DIGEST-MD5].
Though values of authPassword are secured by use of a
cryptographically safe one-way hash, they SHOULD be protected as if
the password was stored in plain text. In particular, if the values
used by some SASL mechanisms are compromised for a given user, then
the attacker may falsely authenticate as this user and gain immediate
access to all information to which that user is authorized.
4. Schema Definitions
The following schema definitions are written using the BNF form
described in RFC 2252 [RFC2252].
4.1. authPasswordSyntax
( authPasswordSyntaxOID
DESC 'authentication password syntax' )
Values of this syntax are encoded according to the following BNF:
authPasswordValue = scheme "$" [ info ] "$" hashedValue
scheme = <an IA5 string of letters, numbers, and "-", "_", and "/">
info = <a base64 encoded value>
hashedValue = <a base64 encoded value>
where scheme describes the hash mechanism, info is a scheme specific,
and hashedValue is the hashed value. The info field is often a salt.
4.2. authPasswordMatch
Zeilenga [Page 2]
INTERNET-DRAFT LDAP AuthPasswd 17 December 1999
( authPasswordSyntaxOID
NAME 'authPasswordMatch'
DESC 'authentication password matching rule'
SYNTAX authPasswordSyntaxOID )
This matching rule allows a client to assert that a password matches
the password stored in the directory. The server shall compare the
stored hashedValue with a value derived from the asserted value and
the stored info field according to the scheme of the attribute value.
4.3. supportedAuthSchemes
( supportedAuthPasswordSchemesOID
NAME 'supportedAuthPasswordSchemes'
DESC 'supported password hash schemes'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.26
USAGE dSAOperation )
The values of this attribute are case insensitive names of supported
cryptographic secure hash schemes which the server supports. This
attribute may only be present in the root DSE. If the server does not
support any mechanisms this attribute will not be present.
4.4. authPassword
( authPasswordOID NAME 'authPassword'
EQUALITY authPasswordMatch
SYNTAX authPasswordSyntaxOID )
The values this attribute are encrypted user password(s). The
attribute may be used for authentication purposes.
Transfer of authentication password values is strongly discouraged
where the underlying transport service cannot guarantee
confidentiality and may result in disclosure of the values to
unauthorized parties.
4.5. authPasswordObject
( authPasswordObjectOID NAME 'authPasswordObject'
DESC 'hashed password mixin class'
MUST 'authPassword' AUXILIARY )
Entries of this object class contain authentication passwords.
Zeilenga [Page 3]
INTERNET-DRAFT LDAP AuthPasswd 17 December 1999
5. Schemes
This section describes the "MD5", "SHA1", and "SASL/DIGEST-MD5".
Other schemes may be defined by other documents. Schemes starting
with string "SASL/" indicate association with a SASL mechanism.
Schemes which are not described by standard track documents SHOULD be
named with a leading "X-" or, if associated with a SASL mechanism,
"SASL/X-" to indicate they are a private or implementation specific
extension. Scheme names are case insensitive.
5.1. MD5 scheme
The MD5 [RFC1321] scheme name is "MD5".
The hashedValue is the base64 encoding of an MD5 Digest of the
concatenation the user password and optional salt. The salt is
provided in the info field. Implementations of this scheme must
support salts up to 128-bit in length. Use with a 64-bit or larger
salt is RECOMMENDED.
Example:
Given a user "joe" who's password is "mary" and a salt of
"salt", the info field would be the base64 encoding of "salt"
and the hashValue field would be the base64 encoding of the
MD5 digest of "marysalt".
Values of this scheme SHOULD only be used to implement simple
user/password authentication.
It is RECOMMENDED that values of this scheme be protected as if they
were plaintext passwords.
5.2. SHA1 scheme
The SHA1 [SHA1] scheme name is "SHA1".
The hashedValue is the base64 encoding of an SHA1 Digest of the
concatenation the user password and the optional salt. The salt is
provided in the info field. Implementations of this scheme must
support salts up to 128-bit in length. Use with a 64-bit or larger
salt is RECOMMENDED.
Example:
Given a user "joe" who's password is "mary" and a salt of
"salt", the info field would be the base64 encoding of "salt"
and the hashValue field would be the base64 encoding of the
SHA1 digest of "marysalt".
Zeilenga [Page 4]
INTERNET-DRAFT LDAP AuthPasswd 17 December 1999
Values of this scheme SHOULD only be used to implement simple
user/password authentication.
It is RECOMMENDED that values of this scheme be protected as if they
were plaintext passwords.
5.3. DIGEST-MD5 scheme
The DIGEST-MD5 [DIGEST-MD5] scheme name is "SASL/DIGEST-MD5".
The hashedValue is the base64 encoding of
H( { username-value, ":", realm-value, ":", passwd } )
and info is the base64 encoding of
{ username-value, ":", realm-value }
as defined by the DIGEST-MD5 specfication.
Example:
Given a user "joe" within the realm "localhost" who's password
is "mary", the info field would be the base64 encoding of
"joe:localhost" and the hashValue field would be the base64
encoding of the MD5 digest of "joe:localhost:mary".
Values of this scheme SHOULD only be used to implement the
SASL/DIGEST-MD5 as described by the AuthMeth [AuthMeth] specification.
Values of this scheme MUST be protected as if it the values were
plaintext passwords per reasons detailed in DIGEST-MD5, Section 3.9,
"Storing Passwords."
6. Recommended schemes
For implementations of this specification:
Servers that support the simple bind method MUST support the
MD5 scheme and SHOULD support the SHA1 scheme.
Clients SHOULD not initiate operations which provide or assert
values of authPassword unless confidentiality protection is
in place.
Servers SHOULD not provide values of authPassword unless
confidentiality protection is in place.
Zeilenga [Page 5]
INTERNET-DRAFT LDAP AuthPasswd 17 December 1999
7. Security Considerations
This document describes how information which may be used for
authentication purposes may be stored. The values stored SHOULD be
protected as if they were plaintext passwords.
8. Copyright
Copyright 1999, The Internet Society. All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published and
distributed, in whole or in part, without restriction of any kind,
provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be followed,
or as required to translate it into languages other than English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE AUTHORS, THE INTERNET SOCIETY, AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
9. Bibliography
[RFC1321] R. Rivest, "The MD5 Message-Digest Algorithm",
RFC 1321, April 1992
[RFC2219] S. Bradner, "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997.
[RFC2222] J. Myers, "Simple Authentication and Security
Layer (SASL)", RFC 2222, October 1997.
[RFC2251] M. Wahl, T. Howes, S. Kille, "Lightweight
Zeilenga [Page 6]
INTERNET-DRAFT LDAP AuthPasswd 17 December 1999
Directory Access Protocol (v3)", RFC 2251,
December 1997.
[RFC2252] M. Wahl, A. Coulbeck, T. Howes, S. Kille,
"Lightweight Directory Access Protocol (v3):
Attribute Syntax Definitions", RFC 2252,
December 1997.
[RFC2256] M. Wahl, "A Summary of the X.500(96) User Schema
for use with LDAPv3", RFC 2256, December 1997.
[RFC2307] L. Howard, "An Approach for Using LDAP as a
Network Information Service", RFC 2307, March
1998.
[AUTHMETH] M. Wahl, H. Alvestrand, J. Hodges, RL "Bob"
Morgan, "Authentication Methods for LDAP",
draft-ietf-ldapext-authmeth-04.txt, June 1999.
[DIGEST-MD5] P. Leach, C. Newman, "Using Digest Authentication
as a SASL Mechanism",
draft-leach-digest-sasl-05.txt, October 1999.
[SHA1] NIST, FIPS PUB 180-1: Secure Hash Standard,
April 1995.
10. Acknowledgement
This document borrows from a number of IETF documents and is based
upon input from the IETF LDAPext working group.
11. Author's Address
Kurt D. Zeilenga
OpenLDAP Foundation
<Kurt@OpenLDAP.org>
Zeilenga [Page 7]
| PAFTECH AB 2003-2026 | 2026-04-23 04:07:22 |