INTERNET-DRAFT                                      Editor: R. Harrison
draft-ietf-ldapbis-authmeth-11.txt
draft-ietf-ldapbis-authmeth-12.txt                         Novell, Inc.
Obsoletes: 2829, 2830                                        July,                                      August, 2004
Intended Category: Draft Standard

                      LDAP: Authentication Methods
                                  and
                  Connection Level Security Mechanisms

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all

   By submitting this Internet-Draft, I accept the provisions of
   Section 10 4 of RFC 3667.  By submitting this Internet-Draft, I certify
   that any applicable patent or other IPR claims of which I am aware
   have been disclosed, and any of RFC2026. which I become aware will be
   disclosed, in accordance with RFC 3668.

   This document is intended to be, after appropriate review and
   revision, submitted to the RFC Editor as a Standard Track document.
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Copyright Notice

   Copyright (C) The Internet Society (2004).  All Rights Reserved.

Abstract
   This document describes authentication methods and connection level
   security mechanisms of the Lightweight Directory Access Protocol
   (LDAP).

   This document details establishment of TLS (Transport Layer
   Security) using the Start TLS StartTLS operation.

   This document details the simple Bind authentication method
   including anonymous, unauthenticated, and plain-text password
   methods
   mechanisms and the SASL (Simple Authentication and Security Layer)
   Bind authentication method including the use of DIGEST-MD5 and EXTERNAL
   mechanisms.

   This document discusses various authentication and authorization
   states through which a connection to an LDAP server may pass and the
   actions that trigger these state changes.

Table of Contents

   1. Introduction.....................................................3
   1.1. Relationship to Other Documents................................5
   1.2. Conventions Used in this Document..............................5 Document..............................6
   1.2.1. Glossary of Terms............................................5 Terms............................................6
   1.2.2. Security Terms and Concepts..................................6
   1.2.3. Keywords.....................................................6
   2. Implementation Requirements......................................6
   3. Start TLS Operation..............................................7 StartTLS Operation...............................................7
   3.1. Sequencing of the Start TLS Operation..........................7 StartTLS Operation...........................7
   3.1.1. Start TLS StartTLS Request ...........................................7 ............................................7
   3.1.2. Start TLS Response...........................................8 StartTLS Response............................................8
   3.1.3. TLS Version Negotiation......................................8
   3.1.4. Client Certificate...........................................8
   3.1.5. Discovery of Resultant Security Level........................8
   3.1.6. Server Identity Check........................................8 Check........................................9
   3.1.7. Refresh of Server Capabilities Information...................9
   3.2. Effects of TLS on a Client's Authorization Identity............9 Identity...........10
   3.2.1. TLS Connection Establishment Effects........................10
   3.2.2. Client Assertion of Authorization Identity..................10
   3.2.3. TLS Connection Closure Effects..............................10
   3.3. TLS Ciphersuites..............................................10
   3.3.1. TLS Ciphersuites Recommendations............................11
   4. LDAP Associations...............................................10 Associations...............................................12
   4.1. Anonymous LDAP Association on Unbound Connections.............10
   4.2 Connections.............12
   4.2. Anonymous LDAP Association After Failed Bind...................10 Bind..................12
   4.3. Invalidated Associations......................................11 Associations......................................12
   5. Bind Operation .................................................11 Operation..................................................12
   5.1. Simple Authentication Choice..................................11 Choice..................................13
   5.2. SASL Authentication Choice....................................11 Choice....................................13
   6. Anonymous Authentication Mechanism of Simple Bind...............12 Bind...............13
   7. Unauthenticated Authentication Mechanism of Simple Bind.........12 Bind.........13
   8. Simple Authentication Mechanism of Simple Bind .................12 .................14
   9. SASL Protocol Profile...........................................13 Profile...........................................14
   9.1. SASL Service Name for LDAP....................................13 LDAP....................................14
   9.2. SASL Authentication Initiation and Protocol Exchange..........13 Exchange..........15
   9.3. Octet Where Negotiated Security Mechanisms Take Effect........14 Effect........16
   9.4. Determination of Supported SASL Mechanisms....................15 Mechanisms....................16
   9.5. Rules for Using SASL Security Layers..........................15 Layers..........................16
   9.6 Support for Multiple Authentications...........................15 Authentications...........................17
   10. SASL EXTERNAL Mechanism........................................15 Mechanism........................................17
   10.1. Implicit Assertion...........................................16 Assertion...........................................17
   10.2. Explicit Assertion...........................................16 Assertion...........................................17
   10.3. SASL Authorization Identity..................................16 Identity..................................17
   10.4. SASL Authorization Identity Syntax...........................16 Syntax...........................18
   11. SASL DIGEST-MD5 Mechanism......................................17 Mechanism......................................19
   12. General Requirements for Password Handling.....................18
   13. TLS Ciphersuites...............................................18
   13.1. TLS Ciphersuites Recommendations.............................19
   14. Security Considerations........................................20
   14.1. Start TLS
   12.1. General LDAP Security Considerations............................20
   15. Considerations.........................20
   12.1.1.Password-related Security Considerations....................21
   12.2. StartTLS Security Considerations.............................22
   12.3. Unauthenticated Mechanism Security Considerations............22
   12.4. Simple Mechanism Security Considerations.....................23
   12.5. SASL DIGEST-MD5 Mechanism Security Considerations............23
   12.6. Related Security Considerations..............................23
   13. IANA Considerations............................................21
   Acknowledgments....................................................21 Considerations............................................23
   Acknowledgments....................................................23
   Normative References...............................................22 References...............................................24
   Informative References.............................................23 References.............................................25
   Author's Address...................................................23 Address...................................................25
   Appendix A. LDAP Association State Transition Tables...............23 Tables...............25
   A.1. LDAP Association States.......................................23 States.......................................25
   A.2. Actions that Affect LDAP Association State....................24 State....................26
   A.3. Decisions Used in Making LDAP Association State Changes.......24 Changes.......26
   A.4. LDAP Association State Transition Table.......................24 Table.......................27
   Appendix B. Example Deployment Scenarios...........................25
   Appendix C. Authentication and Authorization Concepts..............26
   C.1. Concepts..............27
   B.1. Access Control Policy.........................................26
   C.2. Policy.........................................28
   B.2. Access Control Factors........................................26
   C.3. Factors........................................28
   B.3. Authentication, Credentials, Identity.........................26
   C.4. Identity.........................28
   B.4. Authorization Identity........................................27 Identity........................................28
   Appendix D. C. RFC 2829 Change History................................27 History................................29
   Appendix E. D. RFC 2830 Change History................................31 History................................33
   Appendix F. E. RFC 2251 Change History................................32 History................................33
   Appendix G. F. Change History to Combined Document....................32
   Appendix H. Issues to be Resolved..................................43 Document....................33
   Intellectual Property Rights.......................................57 Rights.......................................52

1. Introduction

   The Lightweight Directory Access Protocol (LDAP) [Roadmap] is a
   powerful protocol for accessing directories. It offers means of
   searching, retrieving and manipulating directory content, and ways
   to access a rich set of security functions.

   It is vital that these security functions be interoperable among all
   LDAP clients and servers on the Internet; therefore there has to be
   a minimum subset of security functions that is common to all
   implementations that claim LDAP conformance.

   Basic threats to an LDAP directory service include:

   (1) Unauthorized access to directory data via data-retrieval
       operations,

   (2) Unauthorized access to directory data by monitoring others'
       access,

   (3) Unauthorized access to reusable client authentication
       information by monitoring others' access,

   (4) Unauthorized modification of directory data,

   (5) Unauthorized modification of configuration information,

   (6) Denial of Service: Use of resources (commonly in excess) in a
       manner intended to deny service to others,

   (7) Spoofing: Tricking a user or client into believing that
       information came from the directory when in fact it did not,
       either by modifying data in transit or misdirecting the client's
       connection. Tricking a user or client into sending privileged
       information to a hostile entity that appears to be the directory
       server but is not. Tricking a directory server into believing
       that information came from a particular client when in fact it
       came from a hostile entity, and

   (8) Hijacking: An attacker seizes control of an established protocol
       session.

   Threats (1), (4), (5), (6), (7) are (8) are active attacks. Threats
   (2) and (3) are passive attacks.

   Threats (1), (4), (5) and (6) are due to hostile clients. Threats
   (2), (3), (7) and (8) are due to hostile agents on the path between
   client and server or hostile agents posing as a server, e.g. IP
   spoofing.

   LDAP offers the following security mechanisms:

   (1) Authentication by means of the Bind operation.  The Bind
       operation provides a simple method which supports anonymous,
       unauthenticated, and authenticated with password mechanisms, and
       the Secure Authentication and Security Layer (SASL) method which
       supports a wide variety of authentication mechanisms,

   (2) Mechanisms to support vendor-specific access control facilities
       (LDAP does not offer a standard access control facility)
   (3) Data integrity protection by means of TLS or SASL mechanisms
       with security layers that provide data integrity protection,

   (4) Data confidentiality protection by means of the TLS protocol or
       SASL mechanisms that provide data confidentiality protection,

   (5) Server resource usage limitation by means of administrative
       limits configured on the server, and

   (6) Server authentication by means of the TLS protocol or SASL
       mechanism.

   LDAP may also be protected by means outside the LDAP protocol, e.g.
   with IP-level security [RFC2401].

   At the moment, imposition of access controls is done by means
   outside the scope of LDAP.

   It seems clear that allowing implementations, faced with the above
   requirements, to simply pick and choose among the possible
   alternatives is not a strategy that is likely to lead to
   interoperability. In the absence of mandates, clients will be
   written that do not support any security function supported by the
   server, or worse, they will support only clear text passwords that
   provide inadequate security for most circumstances.

   It is desirable to allow clients to authenticate using a variety of
   mechanisms including mechanisms where identities are represented as
   distinguished names [X.501] [Models] in string form [LDAPDN] or are
   used in different systems (e.g. user name in string form). Because
   these authentication mechanisms transmit credentials in plain text
   form and other authentication mechanisms do not provide data
   security services, it is desirable to ensure secure interopability
   by indentifying a mandatory-to-implement mechanism for establishing
   transport-layer security services.

   The set of security mechanisms provided in LDAP and described in
   this document is intended to meet the security needs for a wide
   range of deployment scenarios and still provide a high degree of
   interoperability among various LDAP implementations and deployments.
   Appendix B contains example deployment scenarios that list the
   mechanisms that might be used to achieve a reasonable level of
   security in various circumstances.

1.1. Relationship to Other Documents

   This document is an integral part of the LDAP Technical
   Specification [Roadmap].

   This document obsoletes RFC 2829.

   Sections 2 and 4 of RFC 2830 are obsoleted by [Protocol].  The
   remainder of RFC 2830 is obsoleted by this document.

1.2. Conventions Used in this Document

1.2.1. Glossary of Terms

   The following terms are used in this document. To aid the reader,
   these terms are defined here.

     - "user" represents any human or application entity which is
       accessing the directory using a directory client.  A directory
       client (or client) is also known as a directory user agent (DUA).

     - "connection" and "LDAP connection" both refer to the underlying
       transport protocol connection between two protocol peers.

     - "TLS connection" refers to a TLS-protected [TLS] an LDAP
       connection. connection with TLS
       protection [TLS].

     - "association" and "LDAP association" both refer to the
       association of the LDAP connection and its current
       authentication and authorization state.

1.2.2. Security Terms and Concepts

   In general, security terms in this document are used consistently
   with the definitions provided in [RFC2828]. In addition, several
   terms and concepts relating to security, authentication, and
   authorization are presented in Appendix C of this document. While
   the formal definition of these terms and concepts is outside the
   scope of this document, an understanding of them is prerequisite to
   understanding much of the material in this document. Readers who are
   unfamiliar with security-related concepts are encouraged to review
   Appendix C before reading the remainder of this document.

1.2.3. Keywords

   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. Implementation Requirements

   LDAP server implementations MUST support the anonymous
   authentication mechanism of simple bind (as discussed in Section 6).

   LDAP implementations that support any authentication mechanism other
   than the anonymous authentication mechanism of simple bind MUST
   support the DIGEST-MD5 [DIGEST-MD5] mechanism of SASL bind (as
   detailed in section 11).  DIGEST-MD5 is a reasonably strong
   authentication mechanism that provides (mandatory-to-implement) data
   security (data integrity and data confidentiality) services.

   LDAP impementations SHOULD support the simple (DN and password)
   authentication mechanism of simple bind (as detailed in section 8).

   Implementations that support this mechanism MUST be capable of
   protecting it by establishment of TLS (as discussed in section 3) or
   other suitable suitable data confidentiality and data integrity
   protection (e.g. IPSec).

   Implementations MAY support additional mechanisms of the simple and
   SASL bind choices.  Some of these mechanisms are discussed below.

   LDAP server implementations SHOULD support client assertion of
   authorization identity via the SASL EXTERNAL mechanism (sections
   3.2.2 and 9).

   LDAP server implementations SHOULD support the StartTLS operation,
   and server implementations that do support the StartTLS operation
   MUST support the TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA ciphersuite.

3. Start TLS StartTLS Operation

   The Start Transport Layer Security (Start TLS) (StartTLS) operation defined in
   section 4.14 of [Protocol] provides the ability to establish TLS
   [TLS] on an LDAP connection.

3.1. Sequencing of the Start TLS StartTLS Operation

   This section describes the overall procedures clients and servers
   must follow for TLS establishment. These procedures take into
   consideration various aspects of the overall security of the LDAP
   association including discovery of resultant security level and
   assertion of the client's authorization identity.

   Note that the precise effects, on a client's authorization identity,
   of establishing TLS on an LDAP connection are described in detail in
   section 3.2.

3.1.1. Start TLS StartTLS Request

   A client may send the Start TLS StartTLS extended request at any time after
   establishing an LDAP connection, except:

      - when TLS is currently established on the connection,
      - when a multi-stage SASL negotiation is in progress on the
        connection, or
      - when it has not yet received responses for all operation
        requests previously issued on the connection.

   As described in [Protocol] Section 4.14.2.2, a (detected) violation
   of any of these requirements results in a return of the
   operationsError resultCode.

   Client implementers should ensure that they strictly follow these
   operation sequencing requirements to prevent interoperability
   issues. Operational experience has shown that violating these
   requirements causes interoperability issues because there are race
   conditions that prevent servers from detecting some violations of
   these requirements due to server hardware speed, network latencies,
   etc.

   There is no general requirement that the client have or have not
   already performed a Bind operation (section 4) before sending a
   Start TLS
   StartTLS operation request.

   If the client did not establish a TLS connection before sending a
   request and the server requires the client to establish a TLS
   connection before performing that request, the server MUST reject
   that request by sending a resultCode of confidentialityRequired.

3.1.2. Start TLS StartTLS Response

   The server will return an extended response with the resultCode of
   success if it is willing and able to negotiate TLS.

   It will return a resultCode other than success (documented in
   [Protocol] section 4.13.2.2) if it is unwilling or unable to do so.
   The client's current association is unaffected if a non-success
   resultCode is returned.

   In the successful case, the client (which has ceased to transfer
   LDAP requests on the connection) MUST either begin a TLS negotiation
   or close the connection. The client will send PDUs in the TLS Record
   Protocol directly over the underlying transport connection to the
   server to initiate [TLS] negotiation.

3.1.3. TLS Version Negotiation

   Negotiating the version of TLS to be used is a part of the TLS
   Handshake Protocol [TLS]. Please refer to that document for details.

3.1.4. Client Certificate

   In an LDAP server requests a client to provide its certificate
   during TLS negotiation and the client does not present a suitablle
   certifcate (e.g. one that can be validated), the server MAY use a
   local security policy to determine whether to successfully complete
   TLS negotiation.

   If the client provides a certificate that can be validated,
   information in the certificate may be used by the server in
   establishing the client's authorization identity by use of the SASL
   external mechanism as discussed in Section 9.

3.1.5. Discovery of Resultant Security Level

   After a TLS connection is established on an LDAP connection, both
   parties must individually decide whether or not to continue based on
   the security level achieved. The procedure for ascertaining the TLS
   connection's security level is implementation dependent.

   If the client or server decides that the security level is not high
   enough for it to continue, it SHOULD gracefully close the TLS
   connection immediately after the TLS negotiation has completed (see
   [Protocol] section 4.13.3.1 and section 3.2.3 below).  The client
   may then close the connection, attempt to Start TLS StartTLS again, send an
   unbind request, or send any other LDAP request.

3.1.6. Server Identity Check

   The client MUST check its understanding of the server's hostname
   against the server's identity as presented in the server's
   Certificate message in order to prevent man-in-the-middle attacks.

   Matching is performed according to these rules:

     - The client MUST use the server name provided by the user (or
       other trusted entity) as the value to compare against the server
       name as expressed in the server's certificate. A hostname
       derived from the user input is to be considered provided by the user
       only if derived in a secure fashion (e.g., DNSSEC).

     - If a subjectAltName extension of type dNSName is present in the
       certificate, it SHOULD be used as the source of the server's
       identity.

     - Matching is case-insensitive. The string values to be compared MUST be prepared according to
       the rules described in [Matching].

     - The "*" wildcard character is allowed.  If present, it applies
       only to the left-most name component.

       For example, *.bar.com would match a.bar.com and b.bar.com, but
       it would not match a.x.bar.com nor would it match bar.com.  If
       more than one identity of a given type is present in the
       certificate (e.g. more than one dNSName name), a match in any
       one of the set is considered acceptable.

   If the hostname does not match the dNSName-based identity in the
   certificate per the above check, user-oriented clients SHOULD either
   notify the user (clients may give the user the opportunity to
   continue with the connection in any case) or terminate the
   connection and indicate that the server's identity is suspect.
   Automated clients SHOULD close the connection, returning and/or
   logging an error indicating that the server's identity is suspect.

   Beyond the server identity checks described in this section, clients
   SHOULD be prepared to do further checking to ensure that the server
   is authorized to provide the service it is observed to provide. The
   client may need to make use of local policy information in making
   this determination.

3.1.7. Refresh of Server Capabilities Information
   Upon TLS session establishment, the client SHOULD discard or refresh
   all information about the server it obtained prior to the initiation
   of the TLS negotiation and not obtained through secure mechanisms.
   This protects against man-in-the-middle attacks that may have
   altered any server capabilities information retrieved prior to TLS
   establishment.

   The server may advertise different capabilities after TLS
   establishment. In particular, the value of supportedSASLMechanisms
   may be different after TLS has been negotiated (specifically, the
   EXTERNAL and PLAIN [PLAIN] mechanisms are likely to be listed only
   after a TLS negotiation has been performed).

3.2. Effects of TLS on a Client's Authorization Identity

   This section describes the effects on a client's authorization
   identity brought about by establishing TLS on an LDAP connection.
   The default effects are described first, and next the facilities for
   client assertion of authorization identity are discussed including
   error conditions. Finally, the effects of closing the TLS connection
   are described.

   Authorization identities and related concepts are described in
   Appendix C.

3.2.1. TLS Connection Establishment Effects

   The decision to keep or invalidate the established LDAP association
   (section 12) after TLS connection establishment is a matter of local
   server policy.

3.2.2. Client Assertion of Authorization Identity

   After successfully establishing a TLS session, a client may request
   that its certificate exchanged during the TLS establishment be
   utilized to determine the authorization identity of the LDAP
   association. The client accomplishes this via an LDAP Bind request
   specifying a SASL mechanism of EXTERNAL [SASL] (section 9).

3.2.3. TLS Connection Closure Effects

   The decision to keep or invalidate the established LDAP association
   after TLS closure is a matter of local server policy.

4. LDAP Associations

   Every LDAP connection has an associated authentication and
   authorization state referred to as

3.3. TLS Ciphersuites

   Several issues should be considered when selecting TLS ciphersuites
   that are appropriate for use in a given circumstance. These issues
   include the "LDAP association". following:

     - The Bind
   operation defined in section 4.2 of [Protocol] and discussed further
   in section 5 below allows authentication information ciphersuite's ability to be exchanged
   between provide adequate confidentiality
       protection for passwords and other data sent over the client LDAP
       connection. Client and server implementers should recognize that
       some TLS ciphersuites provide no confidentiality protection
       while other ciphersuites that do provide confidentiality
       protection may be vulnerable to set being cracked using brute force
       methods, especially in light of ever-increasing CPU speeds that
       reduce the authentication and
   authorization state and thus establish a new LDAP association.

4.1. Anonymous LDAP Association on Unbound Connections

   Prior time needed to the successful completion of a Bind operation successfully mount such attacks.

       Client and during
   any subsequent authentication exchange, server implementers should carefully consider the session has an anonymous
   LDAP association. Among other things this implies that
       value of the client
   need not send a Bind Request in password or data being protected versus the first PDU level
       of confidentially protection provided by the connection. The
   client may send any operation request prior ciphersuite to binding, and
       ensure that the
   server MUST treat it as if it had been performed after an anonymous
   bind operation (section 6). This authentication state on an LDAP
   association is sometimes referred to as an implied anonymous bind.

4.2 Anonymous LDAP Association After Failed Bind

   Upon receipt level of a Bind request, protection afforded by the LDAP association ciphersuite
       is moved appropriate.

     - The ciphersuite's vulnerability (or lack thereof) to an
   anonymous state and only upon successful completion of the
   authentication exchange (and man-in-the-
       middle attacks. Ciphersuites vulnerable to man-in-the-middle
       attacks SHOULD NOT be used to protect passwords or sensitive
       data, unless the Bind operation) network configuration is such that the association
   moved to an authenticated state. Thus, danger
       of a failed Bind operation
   produces an anonymous LDAP association on the session.

4.3. Invalidated Associations

   The server may invalidate the LDAP association at any time, e.g. if
   the established security association between the client and server
   has unexpectedly failed  or been compromised.  The association
   remains invalidated until the next bind request.  While the
   association man-in-the-middle attack is invalidated, the server may reject any operation
   request other than Bind, Unbind, and Start tolerable.

3.3.1. TLS by responding with a
   resultCode of strongAuthRequired to indicate that the client needs
   to bind to reestablish its authentication state before the server Ciphersuites Recommendations

   [[TODO: Kurt will attempt to perform the requested operation. This behavior is
   explained here to help client implementers properly understand and
   react have someone from security to look at this situation.

5. Bind Operation

   The Bind operation ([Protocol] section 4.2) allows authentication
   information to be exchanged between the client and server to
   establish a new LDAP association.

   The Bind request typically specifies the desired authentication
   identity.  Some Bind mechanisms also allow the client
   will propose how to specify handle discussion of specific TLS ciphersuites
   in this draft.]]

   As of the
   authorization identity.  If writing of this document, the authorization identity is following recommendations
   regarding TLS ciphersuites are applicable. Because circumstances are
   constantly changing, this list must not
   specified, the server derives be considered exhaustive,
   but is hoped that it from the authentication identity will serve as a useful starting point for
   implementers.

   The following ciphersuites defined in
   an implementation-specific manner.

   If the authorization identity is specified the server [TLS] MUST verify
   that the client's authentication identity is permitted NOT be used for
   confidentiality protection of passwords or data:

         TLS_NULL_WITH_NULL_NULL
         TLS_RSA_WITH_NULL_MD5
         TLS_RSA_WITH_NULL_SHA

   The following ciphersuites defined in [TLS] can be cracked easily
   (less than a day of CPU time on a standard CPU in 2000) and are NOT
   RECOMMENDED for use in confidentiality protection of passwords or
   data:

         TLS_RSA_EXPORT_WITH_RC4_40_MD5
         TLS_RSA_EXPORT_WITH_RC2_CBC_40_MD5
         TLS_RSA_EXPORT_WITH_DES40_CBC_SHA
         TLS_DH_DSS_EXPORT_WITH_DES40_CBC_SHA
         TLS_DH_RSA_EXPORT_WITH_DES40_CBC_SHA
         TLS_DHE_DSS_EXPORT_WITH_DES40_CBC_SHA
         TLS_DHE_RSA_EXPORT_WITH_DES40_CBC_SHA
         TLS_DH_anon_EXPORT_WITH_RC4_40_MD5
         TLS_DH_anon_EXPORT_WITH_DES40_CBC_SHA

   The following ciphersuites are vulnerable to assume
   (e.g. proxy for) the asserted man-in-the-middle
   attacks:

         TLS_DH_anon_EXPORT_WITH_RC4_40_MD5
         TLS_DH_anon_WITH_RC4_128_MD5
         TLS_DH_anon_EXPORT_WITH_DES40_CBC_SHA
         TLS_DH_anon_WITH_DES_CBC_SHA
         TLS_DH_anon_WITH_3DES_EDE_CBC_SHA

4. LDAP Associations

   Every LDAP connection has an associated authentication and
   authorization identity. The server
   MUST reject state referred to as the "LDAP association". The Bind
   operation with an invalidCredentials resultCode defined in the Bind response if section 4.2 of [Protocol] and discussed further
   in section 5 below allows authentication information to be exchanged
   between the client is not so authorized.

5.1. Simple Authentication Choice

   The simple authentication choice of and server to set the Bind Operation provides
   three authentication mechanisms:

    1. an anonymous authentication mechanism (section 6),

    2. an unauthenticated authentication mechanism (section 7), and

    3.
   authorization state and thus establish a simple authentication mechanism using credentials consisting new LDAP association.

4.1. Anonymous LDAP Association on Unbound Connections

   Prior to the successful completion of a name (in Bind operation and during
   any subsequent authentication exchange, the form of session has an anonymous
   LDAP distinguished name [LDAPDN])
       and association. Among other things this implies that the client
   need not send a password (section X).

5.2. SASL Authentication Choice

   The sasl authentication choice Bind Request in the first PDU of the Bind Operation provides
   facilities for using connection. The
   client may send any SASL mechanism (sections 9-11) including
   authentication mechanisms and other services (e.g. data security
   services).

6. Anonymous Authentication Mechanism of Simple Bind

   An LDAP client may use operation request prior to binding, and the
   server MUST treat it as if it had been performed after an anonymous
   bind operation (section 6). This authentication mechanism of the
   simple Bind choice state on an LDAP
   association is sometimes referred to explicitly establish as an implied anonymous bind.

4.2. Anonymous LDAP
   association by sending a Association After Failed Bind request with a name value

   Upon receipt of zero
   length and with the simple authentication choice containing a
   password value of zero length.

7. Unauthenticated Authentication Mechanism of Simple Bind

   An request, the LDAP client may use association is moved to an
   anonymous state and only upon successful completion of the unauthenticated
   authentication mechanism
   of exchange (and the simple Bind choice operation) is the association
   moved to establish an authenticated state. Thus, a failed Bind operation
   produces an anonymous LDAP association
   by sending a Bind request with a name value, a distinguished name in on the session.

4.3. Invalidated Associations

   The server may invalidate the LDAP string form [LDAPDN], of non-zero length, association at any time, e.g. if
   the established security association between the client and specifying server
   has unexpectedly failed  or been compromised.  The association
   remains invalidated until the next bind request.  While the simple authentication choice containing a password value of zero
   length.

   Unauthenticated binds can have significant security issues (see
   section 14). Servers SHOULD by default
   association is invalidated, the server may reject unauthenticated bind
   requests any operation
   request other than Bind, Unbind, and StartTLS by responding with a
   resultCode of invalidCredentials, and clients may
   need strongAuthRequired to indicate that the client needs
   to actively detect situations where they would unintentionally
   make an unauthenticated bind request.

8. to reestablish its authentication state before the server
   will attempt to perform the requested operation. This behavior is
   explained here to help client implementers properly understand and
   react to this situation.

5. Bind Operation

   The Bind operation ([Protocol] section 4.2) allows authentication
   information to be exchanged between the client and server to
   establish a new LDAP association.

   The Bind request typically specifies the desired authentication
   identity.  Some Bind mechanisms also allow the client to specify the
   authorization identity.  If the authorization identity is not
   specified, the server derives it from the authentication identity in
   an implementation-specific manner.

   If the authorization identity is specified the server MUST verify
   that the client's authentication identity is permitted to assume
   (e.g. proxy for) the asserted authorization identity. The server
   MUST reject the Bind operation with an invalidCredentials resultCode
   in the Bind response if the client is not so authorized.

5.1. Simple Authentication Choice

   The simple authentication choice of the Bind Operation provides
   three authentication mechanisms:

    1. an anonymous authentication mechanism (section 6),

    2. an unauthenticated authentication mechanism (section 7), and

    3. a simple authentication mechanism using credentials consisting
       of a name (in the form of an LDAP distinguished name [LDAPDN])
       and a password (section X).

5.2. SASL Authentication Choice

   The sasl authentication choice of the Bind Operation provides
   facilities for using any SASL mechanism (sections 9-11) including
   authentication mechanisms and other services (e.g. data security
   services).

6. Anonymous Authentication Mechanism of Simple Bind

   An LDAP client may use the simple anonymous authentication mechanism of the
   simple Bind choice to explicitly establish an authenticated anonymous LDAP
   association by sending a Bind request with a name value, a distinguished name in
   LDAP string form [LDAPDN], and value of zero
   length and with the simple authentication choice containing a
   password value of zero length.

7. Unauthenticated Authentication Mechanism of Simple Bind

   An LDAP client may use the unauthenticated authentication mechanism
   of the simple Bind choice to establish an anonymous LDAP association
   by sending a Bind request with a name value, a distinguished name in
   LDAP string form [LDAPDN], of non-zero length, and specifying the
   the simple authentication choice containing a password value of zero
   length.

   Unauthenticated binds can have significant security issues (see
   section 14). Servers SHOULD by default reject unauthenticated bind
   requests with a resultCode of invalidCredentials, and clients may
   need to actively detect situations where they would unintentionally
   make an unauthenticated bind request.

8. Simple Authentication Mechanism of Simple Bind

   An LDAP client may use the simple authentication mechanism of the
   simple Bind choice to establish an authenticated LDAP association by
   sending a Bind request with a name value, a distinguished name in
   LDAP string form [LDAPDN], and specifying the simple authentication
   choice containing an OCTET STRING password value of non-zero length.

   Servers that map the DN sent in the bind request to a directory
   entry with an associated set of one or more passwords, will compare
   the presented password to the set of passwords associated with that
   entry. The presented password is considered valid if it matches any
   member of this set.

   If the DN is not valid, or the password is not valid for the DN, or
   the server otherwise considers the credentials to be invalid, the
   server is to return the invalidCredentials result code.  The server
   is only to return success result code when the credentials are valid
   and the server is willing to provide service to the entity these
   credentials identify.

   Server behavior is undefined for Bind requests with a zero-length
   name value and specifying the simple authentication choice with a
   value of non-zero length.

   The simple authentication mechanism of simple bind is not suitable
   for authentication in environments where there is no network or
   transport layer confidentiality. LDAP implementations MUST be
   capable of protecting it by establishment establish::qment of TLS (as discussed in
   section 3) or other suitable data confidentiality and data integrity
   protection(e.g. IPSec). LDAP implementations
   SHOULD support authentication with the "simple" authentication
   choice when the connection is protected against eavesdropping using
   TLS, as defined in section 4. LDAP implementations SHOULD NOT
   support authentication with the "simple" authentication choice
   unless the data on the connection is protected using TLS or other
   data confidentiality and data integrity protection.

9. SASL Protocol Profile

   LDAP allows authentication via any SASL mechanism [SASL]. As LDAP
   includes native anonymous and simple (plain text) authentication
   methods, the ANONYMOUS [ANONYMOUS] and PLAIN [PLAIN] SASL mechanisms
   are typically not used with LDAP.

   Each protocol that utilizes SASL services is required to supply
   certain information profiling the way they are exposed through the
   protocol ([SASL] section 5). This section explains how each of these
   profiling requirements are met by LDAP.

9.1. SASL Service Name for LDAP
   The SASL service name for LDAP is "ldap", which has been registered
   with the IANA as a GSSAPI service name.

9.2. SASL Authentication Initiation and Protocol Exchange

   SASL authentication is initiated via an LDAP bind request
   ([Protocol] section 4.2) with the following parameters:

      - The version is 3.
      - The AuthenticationChoice is sasl.
      - The mechanism element of the SaslCredentials sequence contains
        the value of the desired SASL mechanism.
      - The optional credentials field of the SaslCredentials sequence
        may be used to provide an initial client response for
        mechanisms that are defined to have the client send data first
        (see [SASL] sections 5 and 5.1).

   In general, a SASL authentication protocol exchange consists of a
   series of server challenges and client responses, the contents of
   which are specific to and defined by the SASL mechanism. Thus for
   some SASL authentication mechanisms, it may be necessary for the
   client to respond to one or more server challenges by invoking the
   BindRequest multiple times. A challenge is indicated by the server
   sending a BindResponse with the resultCode set to
   saslBindInProgress. This indicates that the server requires the
   client to send a new bind request with the same sasl mechanism to
   continue the authentication process.

   To the LDAP protocol, these challenges and responses are opaque
   binary tokens of arbitrary length. LDAP servers use the
   serverSaslCreds field, an OCTET STRING, in a bind response message
   to transmit each challenge. LDAP clients use the credentials field,
   an OCTET STRING, in the SaslCredentials sequence of a bind request
   message to transmit each response. Note that unlike some Internet
   protocols where SASL is used, LDAP is not text-based, thus no Base64
   transformati    ons
   transformations are performed on these challenge and response values.

   Clients sending a bind request with the sasl choice selected SHOULD
   send an zero-length value in the name field. Servers receiving a
   bind request with the sasl choice selected SHALL ignore any value in
   the name field.

   A client may abort a SASL bind negotiation by sending a BindRequest
   with a different value in the mechanism field of SaslCredentials, or
   an AuthenticationChoice other than sasl.

   If the client sends a BindRequest with the sasl mechanism field as
   an empty string, the server MUST return a BindResponse with
   authMethodNotSupported as the resultCode. This will allow clients to
   abort a negotiation if it wishes to try again with the same SASL
   mechanism.

   The server indicates completion of the SASL challenge-response
   exchange by responding with a bind response in which the resultCode
   is either success, or an error indication.

   The serverSaslCreds field in the bind response BindResponse can be used to include
   an optional challenge with a success notification for mechanisms
   which are defined to have the server send additional data along with
   the indication of successful completion.

   [[TODO: Some implementations If a server does not intend
   to send back a challenge value in a BindResponse message, the server
   SHALL omit the serverSaslCreds field with
   zero length rather (rather than just omitting it as part of the final bind
   response. Some clients expect this present/zero-length behavior.
   Need to provide clarification at this point of including the document on what
   behavior is expected and what servers and clients should do to
   promote interoperability when unexpected behavior occurs. This issue
   is being taken up
   field with the SASL WG. Likely outcome: both approaches
   will be declared equivalent, servers will be advised to send back
   present, a zero-length field, clients will be advised to accept
   either.]] value).

9.3. Octet Where Negotiated Security Mechanisms Take Effect

   SASL security layers take effect following the transmission by the
   server and reception by the client of the final successful
   BindResponse in the exchange.

   Once a SASL security layer providing integrity or confidentiality
   services takes effect, the layer remains in effect until a new layer
   is installed (i.e. at the first octet following the final
   BindResponse of the bind operation that caused the new layer to take
   effect).  Thus, an established SASL security layer is not affected
   by a failed or non-SASL Bind.

9.4. Determination of Supported SASL Mechanisms

   Clients may determine the SASL mechanisms a server supports by
   reading the supportedSASLMechanisms attribute from the root DSE
   (DSA-Specific Entry) ([Models] section 5.1).  The values of this
   attribute, if any, list the mechanisms the server supports in the
   current LDAP session state. LDAP servers SHOULD allow an
   anonymously-bound client to retrieve the supportedSASLMechanisms
   attribute of the root DSE.

   Because SASL mechanisms provide critical security functions, clients
   and servers should be configurable to specify what mechanisms are
   acceptable and allow only those mechanisms to be used. Both clients
   and servers must confirm that the negotiated security level meets
   their requirements before proceeding to use the connection.

9.5. Rules for Using SASL Security Layers

   If a SASL security layer is negotiated, the client SHOULD discard
   information about the server it obtained prior to the initiation of
   the SASL negotiation and not obtained through secure mechanisms.

   If a lower level security layer (such as TLS) is negotiated, any
   SASL security services SHALL be layered on top of such security
   layers regardless of the order of their negotiation. In all other
   respects, SASL security services and other security layers act
   independently, e.g. if both TLS and SASL security service are in
   effect then removing the SASL security service does not affect the
   continuing service of TLS and vice versa.

9.6 Support for Multiple Authentications

   LDAP supports multiple SASL authentications as defined in [SASL]
   section 6.3.

10. SASL EXTERNAL Mechanism

   A client can use the EXTERNAL SASL [SASL] mechanism to request the
   LDAP server to authenticate and establish a resulting authorization
   identity using security credentials exchanged by a lower security
   layer (such as by TLS authentication or IP-level security
   [RFC2401]).

   The resulting authentication identity of the LDAP association is
   derived from the security credentials in an implementation-specific
   manner.  If the client's authentication credentials have not been
   established at a lower security layer, the SASL EXTERNAL bind MUST
   fail with a resultCode of inappropriateAuthentication.  Although
   this situation has the effect of leaving the LDAP association in an
   anonymous state (section 5), the state of any established security
   layer is unaffected.

   A client may either implicitly request that its LDAP authorization
   identity be derived from its authentication credentials exchanged at
   a lower security layer or it may explicitly provide an authorization
   identity and assert that it be used in combination with those
   authentication credentials. The former is known as an implicit
   assertion, and the latter as an explicit assertion.

10.1. Implicit Assertion

   An implicit authorization identity assertion is performed by
   invoking a Bind request of the SASL form using the EXTERNAL
   mechanism name that does not include the optional credentials octet
   string (found within the SaslCredentials sequence in the Bind
   Request). The server will derive the client's authorization identity
   from the authentication identity supplied by the security layer
   (e.g., a public key certificate used during TLS establishment)
   according to local policy. The underlying mechanics of how this is
   accomplished are implementation specific.

10.2. Explicit Assertion

   An explicit authorization identity assertion is performed by
   invoking a Bind request of the SASL form using the EXTERNAL
   mechanism name that includes the credentials octet string. This
   string MUST be constructed as documented in section 3.4.1.

10.3. SASL Authorization Identity

   When the EXTERNAL SASL mechanism is being negotiated, if the
   SaslCredentials credentials field is present, it contains an
   authorization identity. Other mechanisms define the location of the
   authorization identity in the credentials field. In either case, the
   authorization identity is represented in the authzId form described
   below.

10.4. SASL Authorization Identity Syntax

   The authorization identity is a string of UTF-8 [RFC3629] encoded
   [Unicode] characters corresponding to the following ABNF [RFC2234]
   grammar:

   authzId = dnAuthzId / uAuthzId

   DNCOLON  = %x64 %x6e %x3a ; "dn:"
   UCOLON = %x75 %x3a ; "u:"

   ; distinguished-name-based authz id.
   dnAuthzId = DNCOLON distinguishedName

   ; unspecified authorization id, UTF-8 encoded.
   uAuthzId = UCOLON userid
   userid = *UTF8    ; syntax unspecified

   where the <distinguishedName> production is defined in section 3 of
   [LDAPDN] and <UTF8> production is defined in section 1.3 of [Models].

   In order to support additional specific authorization identity
   forms, future updates to this specification may add new choices
   supporting other forms of the authzId production.

   The dnAuthzId choice is used to assert authorization identities in
   the form of a distinguished name to be matched in accordance with
   the distinguishedNameMatch matching rule [Syntaxes]. The decision to
   allow or disallow an authentication identity to have access to the
   requested authorization identity is a matter of local policy ([SASL]
   section 4.2). For this reason there is no requirement that the
   asserted dn be that of an entry in the directory.

   The uAuthzId choice allows for compatibility with clients that wish to assert an authorization
   identity to a directory but do not have that identity is not in distinguished name form. The value contained within
   a uAuthzId MUST be prepared using [SASLPrep] before being compared
   octet-wise. The format of
   userid is defined as only a sequence of UTF-8 [RFC3629] encoded
   [Unicode] characters, and any further interpretation is subject to prior agreement between the client a local
   matter.  To compare  uAuthzID values, each uAuthzID value MUST be
   prepared using [SASLPrep] and
   server. then the two values are compared
   octet-wise.

   For example, the userid could identify a user of a specific
   directory service or service, be a login name name, or the local-part of be an RFC 822 email address. A
   uAuthzId SHOULD NOT be assumed to be globally unique.

11. SASL DIGEST-MD5 Mechanism

   LDAP servers that implement any authentication method or mechanism
   other than simple anonymous bind MUST implement the SASL
   DIGEST-MD5 mechanism [DIGEST-MD5].  This provides client
   authentication with protection against passive eavesdropping attacks
   but does not provide protection against man-in-the-middle attacks.
   DIGEST-MD5 also provides data integrity and data confidentiality
   capabilities.

   Support for subsequent authentication ([DIGEST-MD5] section 2.2) is
   OPTIONAL in clients and servers.

   Implementers must take care to ensure that they maintain the
   semantics of the DIGEST-MD5 specification even when handling data
   that has different semantics in the LDAP protocol.
   For example, the SASL DIGEST-MD5 authentication mechanism utilizes
   realm and username values ([DIGEST-MD5] section 2.1) which are
   syntactically simple strings and semantically simple realm and
   username values. These values are not LDAP DNs, and there is no
   requirement that they be represented or treated as such. Username
   and realm values that look like LDAP DNs in form, e.g. <cn=bob,
   dc=example,dc=com>, are syntactically allowed, however DIGEST-MD5
   treats them as simple strings for comparison purposes. To illustrate
   further, the two DNs <cn=Bob,dc=example,dc=com> (upper case "B") and
   <cn=bob,dc=example,dc=com> (lower case "b") are equivalent when
   being compared semantically as LDAP DNs because the cn attribute is
   defined to be case insensitive, however the two values are not
   equivalent if they represent username values in DIGEST-MD5 because
   [SASLPrep] semantics are used by DIGEST-MD5.

12. General Requirements for Password Handling Security Considerations

   Security issues are discussed throughout this document. The transmission
   unsurprising conclusion is that security is an integral and
   necessary part of passwords in the clear--typically for
   authentication or modification--poses LDAP.  This section discusses a significant number of LDAP-
   related security considerations.

12.1. General LDAP Security Considerations

   LDAP itself provides no security risk.
   This risk can be avoided by using SASL authentication [SASL]
   mechanisms that do not transmit passwords in the clear or by
   negotiating transport protection from accessing or session layer confidentiality services
   before transmitting password values.

   To mitigate
   updating the security risks associated with directory by other means than through the use LDAP
   protocol, e.g. from inspection by database administrators. Access
   control SHOULD always be applied when reading sensitive information
   or updating directory information.

   Servers can minimize denial of passwords,
   a server implementation that supports any password-based
   authentication mechanism MUST implement a configuration that at service attacks by timing out idle
   connections, and returning the
   time of authentication or password modification, requires:

     1) unwillingToPerform resultCode rather
   than performing computationally expensive operations requested by
   unauthorized clients.

   A Start TLS encryption layer has been successfully negotiated.

      OR

     2) Some other confidentiality mechanism that protects connection on which the password
        value from snooping client has been provided.

      OR

     3) not established connection
   integrity and privacy services (e.g via StartTLS, IPSec or a
   suitable SASL mechanism) is subject to man-in-the-middle attacks to
   view and modify information in transit. Client and server
   implementors SHOULD take measures to protect confidential data from
   these attacks by using data protection services as discussed in this
   document.

12.1.1.Password-related Security Considerations

   LDAP allows multi-valued password attributes.  In systems where
   entries are expected to have one and only one password,
   administrative controls should be provided to enforce this behavior.

   The use of clear text passwords and other unprotected authentication
   credentials is strongly discouraged over open networks when the
   underlying transport service cannot guarantee confidentiality.

   The transmission of passwords in the clear--typically for
   authentication or modification--poses a significant security risk.
   This risk can be avoided by using SASL authentication [SASL]
   mechanisms that do not transmit passwords in the clear or by
   negotiating transport or session layer confidentiality services
   before transmitting password values.

   To mitigate the security risks associated with the transfer of
   passwords, a server implementation that supports any password-based
   authentication mechanism that transmits passwords in the clear MUST
   support a policy mechanism that at the time of authentication or
   password modification, requires:

        A StartTLS encryption layer has been successfully negotiated.

      OR

        Some other confidentiality mechanism that protects the password
        value from snooping has been provided.

      OR

        The server returns a resultCode of confidentialityRequired for
        the operation (i.e. simple bind with password value, SASL bind
        transmitting a password value in the clear, add or modify
        including a userPassword value, etc.), even if the password
        value is correct.

13. TLS Ciphersuites

   A client or server implementation that supports

12.2. StartTLS Security Considerations

   The goals of using the TLS MUST support
   TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA. Servers SHOULD NOT support weaker
   ciphersuites unless other data integrity and [TLS] protocol with LDAP are to ensure
   connection confidentiality
   protection (such as a SASL security layer) is in place.

   Several issues should be considered when selecting TLS ciphersuites
   that are appropriate for use in a given circumstance. These issues
   include the following:

     - The ciphersuite's ability and integrity, and to optionally provide adequate confidentiality
       protection
   for passwords and other data sent over authentication. TLS expressly provides these capabilities
   (although the LDAP
       connection. Client and server implementers should recognize that
       some authentication services of TLS ciphersuites provide no confidentiality protection
       while other ciphersuites that do provide confidentiality
       protection may be vulnerable are available to being cracked using brute force
       methods, especially LDAP
   only in light of ever-increasing CPU speeds that
       reduce combination with the time needed to successfully mount such attacks.

       Client SASL EXTERNAL authentication method,
   and server implementers SHOULD carefully consider then only if the
       value SASL EXTERNAL implementation chooses to make
   use of the password or data being protected versus TLS credentials).

   All security gained via use of the StartTLS operation is gained by
   the use of TLS itself. The StartTLS operation, on its own, does not
   provide any additional security.

   The level of confidentially protection security provided by though the ciphersuite to
       ensure that use of TLS depends
   directly on both the level quality of protection afforded by the ciphersuite
       is appropriate.

     - The ciphersuite's vulnerability (or lack thereof) to man-in-the-
       middle attacks. Ciphersuites vulnerable to man-in-the-middle
       attacks SHOULD NOT be TLS implementation used to protect passwords or sensitive
       data, unless the network configuration is such that and the danger
   style of a man-in-the-middle attack is tolerable.

13.1. TLS Ciphersuites Recommendations

   As usage of that implementation. Additionally, a man-in-the-
   middle attacker can remove the writing StartTLS extended operation from the
   supportedExtension attribute of this document, the following recommendations
   regarding TLS ciphersuites are applicable. Because circumstances are
   constantly changing, this list must not be considered exhaustive,
   but is hoped that it will serve as a useful starting point for
   implementers.

   The following ciphersuites defined in [TLS] MUST NOT be used for
   confidentiality protection of passwords or data:

         TLS_NULL_WITH_NULL_NULL
         TLS_RSA_WITH_NULL_MD5
         TLS_RSA_WITH_NULL_SHA

   The following ciphersuites defined in [TLS] can be cracked easily
   (less than a day of CPU time on a standard CPU in 2000) root DSE. Both parties SHOULD
   independently ascertain and are NOT
   RECOMMENDED for use in confidentiality protection of passwords or
   data.

         TLS_RSA_EXPORT_WITH_RC4_40_MD5
         TLS_RSA_EXPORT_WITH_RC2_CBC_40_MD5
         TLS_RSA_EXPORT_WITH_DES40_CBC_SHA
         TLS_DH_DSS_EXPORT_WITH_DES40_CBC_SHA
         TLS_DH_RSA_EXPORT_WITH_DES40_CBC_SHA
         TLS_DHE_DSS_EXPORT_WITH_DES40_CBC_SHA
         TLS_DHE_RSA_EXPORT_WITH_DES40_CBC_SHA
         TLS_DH_anon_EXPORT_WITH_RC4_40_MD5
         TLS_DH_anon_EXPORT_WITH_DES40_CBC_SHA

   The following ciphersuites are vulnerable consent to man-in-the-middle
   attacks:

         TLS_DH_anon_EXPORT_WITH_RC4_40_MD5
         TLS_DH_anon_WITH_RC4_128_MD5
         TLS_DH_anon_EXPORT_WITH_DES40_CBC_SHA
         TLS_DH_anon_WITH_DES_CBC_SHA
         TLS_DH_anon_WITH_3DES_EDE_CBC_SHA

14. Security Considerations

   Security issues are discussed throughout this memo; the unsurprising
   conclusion is that mandatory security level achieved
   once TLS is important and that session
   confidentiality protection is required when snooping is a problem.

   Servers can minimize denial of service attacks by timing out idle
   connections, established and returning the unwillingToPerform resultCode rather
   than performing computationally expensive operations requested by
   unauthorized clients.

   The before beginning use of cleartext passwords and other unprotected authentication
   credentials is strongly discouraged over open networks when the
   underlying transport service cannot guarantee confidentiality.

   Operational experience shows that clients can (and frequently do)
   misuse unauthenticated bind (see section 5.1). TLS
   connection. For example, a
   client program might make a decision to grant access to non-
   directory information on the basis security level of completing a successful bind
   operation. Some LDAP server implementations will return a success
   response the TLS connection
   might have been negotiated down to an unauthenticated bind thus leaving plaintext.

    Clients SHOULD either warn the user when the security level
   achieved does not provide data confidentiality and/or integrity
   protection, or be configurable to refuse to proceed without an
   acceptable level of security.

   Server implementors SHOULD allow server administrators to elect
   whether and when data confidentiality and integrity are required, as
   well as elect whether TLS authentication of the client is required.

   Implementers should be aware of and understand TLS security
   considerations as discussed in the TLS specification [TLS].

12.3. Unauthenticated Mechanism Security Considerations

   Operational experience shows that clients can (and frequently do)
   misuse the unauthenticated authentication mechanism of simple bind
   (see section 7).  For example, a client program might make a
   decision to grant access to non-directory information on the basis
   of completing a successful bind operation. LDAP server
   implementations will return a success response to an unauthenticated
   bind request thus leaving the client with the impression that the
   server has successfully authenticated the identity represented by
   the user name, when in effect, an anonymous LDAP association has
   been created. established. Clients that use the results from a simple bind
   operation to make authorization decisions should actively detect
   unauthenticated bind requests (by verifying that the supplied
   password is not empty) and react appropriately.

   Access control SHOULD always be applied when reading sensitive
   information or updating directory information.

   A connection on which

12.4. Simple Mechanism Security Considerations

   The simple authentication mechanism of simple bind discloses the client has
   password to server, which is an inherent security risk. There are
   other mechanisms such as DIGEST-MD5 that do not established connection
   integrity and privacy services (e.g via Start TLS, IPSec or a
   suitable disclose password to
   server.

12.5. SASL mechanism) DIGEST-MD5 Mechanism Security Considerations

   The SASL DIGEST-MD5 mechanism is subject prone to man-in-the-middle attacks to
   view and modify information the qop substitution
   attack, as discussed in transit.

   LDAP itself 6.2 of RFC 2831.  The qop substitution
   attack can be mitigated (as discussed in 6.2 of RFC 2831).

   The SASL DIGEST-MD5 mechanism [DIGEST-MD5] provides no security or client
   authentication with protection from accessing or
   updating the directory by other means than through the LDAP
   protocol, e.g. from inspection by database administrators.

   Client and server implementors SHOULD take measures to protect
   credentials and other confidential data by using data against passive eavesdropping attacks
   but does not provide protection
   services against man-in-the-middle attacks.

   Implementers should be aware of and understand DIGEST-MD5 security
   considerations as discussed in this document. the DIGEST-MD5 specification [DIGEST-
   MD5].

12.6. Related Security Considerations
   Additional security considerations relating to the various
   authentication methods and mechanisms discussed in this document
   apply and can be found in [DIGEST-MD5], [SASL], [SASLPrep],
   [StringPrep], [TLS] [StringPrep] and
   [RFC3629].

14.1. Start TLS Security

13. IANA Considerations

   The goals of using following IANA considerations apply to this document:

   Please update the TLS [TLS] protocol with LDAP are GSSAPI service name registry to ensure
   connection confidentiality point to [Roadmap]
   and integrity, this document.

   [[TODO: add any missing IANA Considerations.]]

Acknowledgments

   This document combines information originally contained in RFC 2829
   and to optionally provide
   for authentication. TLS expressly provides these capabilities
   (although RFC 2830. The editor acknowledges the authentication services work of TLS are available to LDAP
   only in combination with the SASL EXTERNAL authentication method, Harald Tveit
   Alvestrand, Jeff Hodges, Tim Howes, Steve Kille, RL "Bob" Morgan ,
   and then only if the SASL EXTERNAL implementation chooses to make
   use Mark Wahl, each of the TLS credentials).

   All security gained via use whom authored one or more of the Start TLS operation these documents.

   This document is gained by
   the use based upon input of TLS itself. the IETF LDAP Revision working
   group. The Start TLS operation, on contributions and suggestions made by its own, does not
   provide any additional security.

   The level of security provided though the use of TLS depends
   directly on both the quality of members in
   shaping the TLS implementation used contents and the
   style of usage of that implementation. Additionally, an man-in-the-
   middle attacker can remove the Start TLS extended operation from the
   supportedExtension attribute of the root DSE. Both parties SHOULD
   independently ascertain and consent to the security level achieved
   once TLS is established and before beginning use of the TLS
   connection. For example, the security level of the TLS connection
   might have been negotiated down to plaintext.

   Clients SHOULD either warn the user when the security level achieved
   does not provide data confidentiality and/or integrity protection,
   or be configurable to refuse to proceed without an acceptable level
   of security.

   Server implementors SHOULD allow for server administrators to elect
   whether and when connection confidentiality and/or integrity is
   required, as well as elect whether and when client authentication
   via TLS is required.

   Implementers should be aware of and understand TLS security
   considerations as discussed in the TLS specification [TLS].

15. IANA Considerations

   The following IANA considerations apply to this document:

   Please update the GSSAPI service name registry to point to [Roadmap]
   and this document.

   [To be completed]

Acknowledgments

   This document combines information originally contained in RFC 2829
   and RFC 2830. The editor acknowledges the work of Harald Tveit
   Alvestrand, Jeff Hodges, Tim Howes, Steve Kille, RL "Bob" Morgan ,
   and Mark Wahl, each of whom authored one or more of these documents.

   This document is based upon input of the IETF LDAP Revision working
   group. The contributions and suggestions made by its members in
   shaping the contents and technical accuracy technical accuracy of this document is
   greatly appreciated.

Normative References

   [[Note to the RFC Editor: please replace the citation tags used in
   referencing Internet-Drafts with tags of the form RFCnnnn.]]

   [RFC2234]    Crocker, D., Ed. and P. Overell, "Augmented BNF for
                Syntax Specifications: ABNF", RFC 2234, November 1997.

   [DIGEST-MD5] Leach, P. C. Newman, and A. Melnikov, "Using Digest
                Authentication as a SASL Mechanism", draft-ietf-sasl-
                rfc2831bis-xx.txt, a work in progress.

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

   [LDAPDN]     Zeilenga, Kurt D. (editor), "LDAP: String
                Representation of Distinguished Names", draft-ietf-
                ldapbis-dn-xx.txt, a work in progress.

   [Matching]   Hoffman, Paul and Steve Hanna, "Matching Text Strings
                in PKIX Certificates", draft-hoffman-pkix-stringmatch-
                xx.txt, a work in progress.

   [Models]     Zeilenga, Kurt D. (editor), "LDAP: Directory
                Information Models", draft-ietf-ldapbis-models-xx.txt,
                a work in progress.

   [Protocol]   Sermersheim, J., "LDAP: The Protocol", draft-ietf-
                ldapbis-protocol-xx.txt, a work in progress.

   [Roadmap]    K. Zeilenga, "LDAP: Technical Specification Road Map",
                draft-ietf-ldapbis-roadmap-xx.txt, a work in progress.

   [SASL]       Melnikov, A. (editor), "Simple Authentication and
                Security Layer (SASL)", draft-ietf-sasl-rfc2222bis-
                xx.txt, a work in progress.

   [SASLPrep]   Zeilenga, K., "Stringprep profile for user names and
                passwords", draft-ietf-sasl-saslprep-xx.txt, (a work in
                progress).

   [StringPrep] Hoffman P. and         M. Blanchet, "Preparation of Internationalized
                Strings ('stringprep')", draft-
                hoffman-rfc3454bis-xx.txt, draft-hoffman-rfc3454bis-
                xx.txt, a work in progress.

   [Syntaxes]   Legg, S. (editor), "LDAP: Syntaxes and Matching Rules",
                draft-ietf-ldapbis-syntaxes-xx.txt, a work in progress.

   [TLS]        Dierks, T. and C. Allen. "The TLS Protocol Version
                1.1", draft-ietf-tls-rfc2246-bis-xx.txt, a work in
                progress.

   [RFC3629]    Yergeau, F., "UTF-8, a transformation format of ISO
                10646", RFC 3629, STD 63, November 2003.

   [Unicode]    The Unicode Consortium, "The Unicode Standard, Version
                3.2.0" is defined by "The Unicode Standard, Version
                3.0" (Reading, MA, Addison-Wesley, 2000. ISBN 0-201-
                61633-5), as amended by the "Unicode Standard Annex
                #27: Unicode 3.1"
                (http://www.unicode.org/reports/tr27/) and by the
                "Unicode Standard Annex #28: Unicode 3.2"
                (http://www.unicode.org/reports/tr28/).

Informative References

   [ANONYMOUS]  Zeilenga, K.,"Anonymous SASL Mechanism", draft-
                zeilenga-sasl-anon-xx.txt, a work in progress.

   [RFC2828]    Shirey, R., "Internet Security Glossary", RFC 2828, May
                2000.

   [PLAIN]      Zeilenga, K.,"Plain SASL Mechanism", draft-zeilenga-
                sasl-plain-xx.txt, a work in progress.

   [RFC2401]    Kent, S. and R. Atkinson, "Security Architecture for
                the Internet Protocol", RFC 2401, November 1998.

Author's Address

   Roger Harrison
   Novell, Inc.
   1800 S. Novell Place
   Provo, UT 84606
   USA
   +1 801 861 2642
   roger_harrison@novell.com

Appendix A. LDAP Association State Transition Tables

   This section provides a state transition table to represent a state
   diagram for the various authentication and TLS states through which
   an LDAP association may pass during the course of its existence and
   the actions that cause these changes in state.

   This section is based entirely on information found in this document
   and other documents that are part of the LDAP Technical
   Specification [Roadmap]. As such, it is strictly informational in
   nature.

A.1. LDAP Association States

   The following table lists the valid LDAP association states and
   provides a description of each state. The ID for each state is used
   in the state transition table in section A.4.

   ID State Description
   -- --------------------------------------------------------------
   S1 Anonymous
          no Authentication ID is associated with the LDAP connection
          no Authorization ID is in force
   S2 Authenticated
          Authentication ID = I
          Authorization ID = X
   S3 Authenticated SASL EXTERNAL, implicit authorization ID
          Authentication ID = J
          Authorization ID = Y
   S4 Authenticated SASL EXTERNAL, explicit authorization ID Z
          Authentication ID = J
          Authorization ID = Z

A.2. Actions that Affect LDAP Association State

   The following table lists the actions that can affect the
   authentication and authorization state of an LDAP association. The
   ID for each action is used in the state transition table in section
   A.4.

   ID  Action
   --  --------------------------------------------------------------
   A1  Client bind request fails
   A2  Client successfully performs anonymous simple bind
   A3  Client successfully performs unauthenticated simple bind
   A4  Client successfully performs simple bind with name and password
        OR SASL bind with any mechanism except EXTERNAL using an
        authentication ID = I that maps to authorization ID X
   A5  Client Binds SASL EXTERNAL with implicit assertion of
        authorization ID (section 9.1)]. The current authentication ID
        maps to authorization ID = Y.
   A6  Client Binds SASL EXTERNAL with explicit assertion of
        authorization ID = Z (section 9.2)]
   A7  Client Start TLS StartTLS request fails
   A8  Client Start TLS StartTLS request succeeds
   A9  Client or Server: graceful TLS removal

A.3. Decisions Used in Making LDAP Association State Changes

   Certain changes in the authentication and authorization state of an
   LDAP association are only allowed if the server can affirmatively
   answer a question. These questions are applied as part of the
   criteria for allowing or disallowing a state transition in the state
   transition table in section A.4.

   ID Decision Question
   -- --------------------------------------------------------------
   D1 Are lower-layer credentials available?
   D2 Can lower-layer credentials for Auth ID "K" be mapped to
       asserted AuthZID "L"?

A.4. LDAP Association State Transition Table
   The LDAP Association table below lists the the actions that could
   affect authentication and authorization state of an LDAP association
   and the resulting state of an LDAP association after a given action
   occurs.

   S1, the initial state for the state machine described in this table,
   is the authentication state when an LDAP connection is initially
   established.

              Next
   Action    State  Comment
   -------   -----  -------------------------------------------------
   A1         S1   Section 4
   A2         S1   Section 6
   A3         S1   Section 7
   A4         S2   Sections 8, 9
   A5,        S1   Failed bind, section 10.1
   D1=no
   A5,        S3
   D1=yes
   A6,        S1   Failed bind, section 10.2
   D1=no
   A6,        S1   Failed bind, section 10.2
   D1=yes,
   D2=no
   A6,        S4
   D1=yes,
   D2=yes
   A7         no   [Protocol] section 4.14.2.2
             change
   A8         no   [Protocol] section 4.14.2.1
             change
   A9         S1   [Protocol] section 4.14.3.1

Appendix B. Example Deployment Scenarios
   The following scenarios are typical for LDAP directories on the
   Internet, and have different security requirements. (In the
   following discussion, "sensitive data" refers to information whose
   disclosure, alteration, destruction, or loss would adversely affect
   the interests or business of its owner or user. Also note that there
   may be data that is protected but not sensitive.) This is not
   intended to be a comprehensive list; other scenarios are possible,
   especially on physically protected networks.

   (1) A read-only directory, containing no sensitive data, accessible
       to "anyone", and TCP connection hijacking or IP spoofing is not
       a problem. Anonymous authentication, described in section 7, is
       suitable for this type of deployment, and requires no additional
       security functions except administrative service limits.

   (2) A read-only directory containing no sensitive data; read access
       is granted based on identity. TCP connection hijacking is not
       currently a problem. This scenario requires data confidentiality
       for sensitive authentication information AND data integrity for
       all authentication information.

   (3) A read-only directory containing no sensitive data; and the
       client needs to ensure the identity of the directory server and
       that the directory data is not modified while being returned
       from the server. A data origin authentication service AND data
       integrity service are required.

   (4) A read-write directory, containing no sensitive data; read
       access is available to "anyone", update access to properly
       authorized persons. TCP connection hijacking is not currently a
       problem. This scenario requires data confidentiality for
       sensitive authentication information AND data integrity for all
       authentication information.

   (5) A directory containing sensitive data. This scenario requires
       data confidentiality protection AND secure authentication.

Appendix C. Authentication and Authorization Concepts

   This appendix defines basic terms, concepts, and interrelationships
   regarding authentication, authorization, credentials, and identity.
   These concepts are used in describing how various security
   approaches are utilized in client authentication and authorization.

C.1. Access Control Policy

   An access control policy is a set of rules defining the protection
   of resources, generally in terms of the capabilities of persons or
   other entities accessing those resources. Security objects and
   mechanisms, such as those described here, enable the expression of
   access control policies and their enforcement.

C.2. Access Control Factors

   A request, when it is being processed by a server, may be associated
   with a wide variety of security-related factors (section 4.2 of
   [Protocol]). The server uses these factors to determine whether and
   how to process the request. These are called access control factors
   (ACFs). They might include source IP address, encryption strength,
   the type of operation being requested, time of day, etc. Some
   factors may be specific to the request itself, others may be
   associated with the connection via which the request is transmitted,
   others (e.g. time of day) may be "environmental".

   Access control policies are expressed in terms of access control
   factors. E.g., a request having ACFs i,j,k can perform operation Y
   on resource Z. The set of ACFs that a server makes available for
   such expressions is implementation-specific.

C.3. Authentication, Credentials, Identity
   Authentication credentials are the evidence supplied by one party to
   another, asserting the identity of the supplying party (e.g. a user)
   who is attempting to establish an association with the other party
   (typically a server). Authentication is the process of generating,
   transmitting, and verifying these credentials and thus the identity
   they assert. An authentication identity is the name presented in a
   credential.

   There are many forms of authentication credentials -- the form used
   depends upon the particular authentication mechanism negotiated by
   the parties. For example: X.509 certificates, Kerberos tickets,
   simple identity and password pairs. Note that an authentication
   mechanism may constrain the form of authentication identities used
   with it.

C.4. Authorization Identity

   An authorization identity is one kind of access control factor. It
   is the name of the user or other entity that requests that
   operations be performed. Access control policies are often expressed
   in terms of authorization identities; e.g., entity X can perform
   operation Y on resource Z.

   The authorization identity bound to an association is often exactly
   the same as the authentication identity presented by the client, but
   it may be different. SASL allows clients to specify an authorization
   identity distinct from the authentication identity asserted by the
   client's credentials. This permits agents such as proxy servers to
   authenticate using their own credentials, yet request the access
   privileges of the identity for which they are proxying [SASL]. Also,
   the form of authentication identity supplied by a service like TLS
   may not correspond to the authorization identities used to express a
   server's access control policy, requiring a server-specific mapping
   to be done. The method by which a server composes and validates an
   authorization identity from the authentication credentials supplied
   by a client is implementation-specific.

Appendix D. RFC 2829 Change History

   This appendix lists the changes made to the text of RFC 2829 in
   preparing this document.

D.0. General Editorial Changes
   Version -00

     - Changed other instances of the term LDAP to LDAP where v3 of the
       protocol is implied. Also made all references to LDAP use the
       same wording.

     - Miscellaneous grammatical changes to improve readability.

     - Made capitalization in section headings consistent.

   Version -01
     - Changed title to reflect inclusion of material from RFC 2830 and
       2251.

D.1. Changes to Section 1

   Version -01

     - Moved conventions used in document to a separate section.

D.2. Changes to Section 2

   Version -01

     - Moved section to an appendix.

D.3. Changes to Section 3

   Version -01

     - Moved section to an appendix.

D.4 Changes to Section 4

   Version -00

     - Changed "Distinguished Name" to "LDAP distinguished name".

D.5. Changes to Section 5

   Version -00

     - Added the following sentence: "Servers SHOULD NOT allow clients
       with anonymous authentication to modify directory entries or
       access sensitive information in directory entries."

D.5.1. Changes to Section 5.1

   Version -00

     - Replaced the text describing the procedure for performing an
       anonymous bind (protocol) with a reference to section 4.2 of RFC
       2251 (the protocol spec).

   Version -01

     - Brought text describing procedure for performing an anonymous
       bind from section 4.2 of RFC 2251 bis.  This text will be
       removed from the draft standard version of that document.

D.6. Changes to Section 6.

   Version -00
     Reorganized text in section 6.1 as follows:

     1. Added a new section (6.1) titled "Simple Authentication" and
       moved one of two introductory paragraphs for section 6 into
       section 6.1. Added sentences to the paragraph indicating:

        a. simple authentication is not suitable for environments where
        confidentiality is not available.

        b. LDAP implementations SHOULD NOT support simple
        authentication unless confidentiality and data integrity
        mechanisms are in force.

     2. Moved first paragraph of section 6 (beginning with "LDAP
       implementations MUST support authentication with a password...")
       to section on Digest Authentication (Now section 6.2).

D.6.1. Changes to Section 6.1.

   Version -00 Renamed section to 6.2

     - Added sentence from original section 6 indicating that the
       DIGEST-MD5 SASL mechanism is required for all conforming LDAP
       implementations

D.6.2. Changes to Section 6.2

   Version -00

     - Renamed section to 6.3

     - Reworded first paragraph to remove reference to user and the
       userPassword password attribute Made the first paragraph more
       general by simply saying that if a directory supports simple
       authentication that the simple bind operation MAY performed
       following negotiation of a TLS ciphersuite that supports
       confidentiality.

     - Replaced "the name of the user's entry" with "a DN" since not
       all bind operations are performed on behalf of a "user."

     - Added Section 6.3.1 heading just prior to paragraph 5.

     - Paragraph 5: replaced "The server" with "DSAs that map the DN
       sent in the bind request to a directory entry with a
       userPassword attribute."

D.6.3. Changes to section 6.3.

     Version -00

     - Renamed to section 6.4.

D.7. Changes to section 7.

   none

D.7.1. Changes to section 7.1.

   Version -00

     - Clarified the entity issuing a certificate by moving the phrase
       "to have issued the certificate" immediately after
       "Certification Authority."

D.8. Changes to section 8.

   Version -00

     - Removed the first paragraph because simple authentication is
       covered explicitly in section 6.

     - Added section 8.1. heading just prior to second paragraph.

     - Added section 8.2. heading just prior to third paragraph.

     - Added section 8.3. heading just prior to fourth paragraph.

   Version -01

     - Moved entire section 8 of RFC 2829 into section 3.4 (Using SASL
       for Other Security Services) to bring material on SASL
       mechanisms together into one location.

D.9. Changes to section 9.

   Version -00

     - Paragraph 2: changed "EXTERNAL mechanism" to "EXTERNAL SASL
       mechanism."

     - Added section 9.1. heading.

     - Modified a comment in the ABNF from "unspecified userid" to
       "unspecified authz id".

     - Deleted sentence, "A utf8string is defined to be the UTF-8
       encoding of one or more ISO 10646 characters," because it is
       redundant.

     - Added section 9.1.1. heading.

     - Added section 9.1.2. heading.

   Version -01

     - Moved entire section 9 to become section 3.5 so that it would be
       with other SASL material.

D.10. Changes to Section 10.

   Version -00

     - Updated reference to cracking from a week of CPU time in 1997 to
       be a day of CPU time in 2000.

     - Added text: "These ciphersuites are NOT RECOMMENDED for use...
       and server implementers SHOULD" to sentence just prior the
       second list of ciphersuites.

     - Added text: "and MAY support other ciphersuites offering
       equivalent or better protection," to the last paragraph of the
       section.

D.11. Changes to Section 11.

   Version -01

     - Moved to section 3.6 to be with other SASL material.

D.12. Changes to Section 12.

   Version -00

     - Inserted new section 12 that specifies when SASL protections
       begin following SASL negotiation, etc. The original section 12
       is renumbered to become section 13.

   Version -01

     - Moved to section 3.7 to be with other SASL material.

D.13. Changes to Section 13 (original section 12).

   None

Appendix E. RFC 2830 Change History

   This appendix lists the changes made to the text of RFC 2830 in
   preparing this document.

E.0. General Editorial Changes

     - Material showing the PDUs for the Start TLS response was broken
       out into a new section.

     - The wording of the definition of the Start TLS request and Start
       TLS response was changed to make them parallel. NO changes were
       made to the ASN.1 definition or the associated values of the
       parameters.

     - A separate section heading for graceful TLS closure was added
       for parallelism with section on abrupt TLS closure.

Appendix F. RFC 2251 Change History

   This appendix lists the changes made to the text of RFC 2251 in
   preparing this document.

F.0. General Editorial Changes

     - All material from section 4.2 of RFC 2251 was moved into this
       document.

     - A new section was created for the Bind Request

     - Section 4.2.1 of RFC 2251 (Sequencing Bind Request) was moved
       after the section on the Bind Response for parallelism with the
       presentation of the Start TLS operations. The section was also
       subdivided to explicitly call out the various effects being
       described within it.

     - All SASL profile information from RFC 2829 was brought within
       the discussion of the Bind operation (primarily sections 4.4 -
       4.7).

Appendix G. Change History to Combined Document

G.1. Changes for draft-ldap-bis-authmeth-02

   General

     - Added references to other LDAP standard documents, to sections
       within the document, and fixed broken references.

     - General editorial changes--punctuation, spelling, formatting,
       etc.

   Section 1.

     - Added glossary of terms and added sub-section headings

   Section 2.

     - Clarified security mechanisms 3, 4, & 5 and brought language in
       line with IETF security glossary.

   Section 3.

     - Brought language in requirement (3) in line with security
       glossary.

     - Clarified that information fetched prior to initiation of TLS
       negotiation must be discarded
     -Clarified that information fetched prior to initiation of SASL
       negotiation must be discarded

     - Rewrote paragraph on SASL negotiation requirements to clarify
       intent

   Section 4.4.

     - Added stipulation that sasl choice allows for any SASL mechanism
       not prohibited by this document. (Resolved conflict between this
       statement and one that prohibited use of ANONYMOUS and PLAIN
       SASL mechanisms.)

   Section 5.3.6

     - Added a.x.bar.com to wildcard matching example on hostname check.

   Section 6

     - Added LDAP Association State Transition Tables to show the
       various states through which an LDAP association may pass along
       with the actions and decisions required to traverse from state
       to state.

   Appendix A

     - Brought security terminology in line with IETF security glossary
       throughout the appendix.

G.2. Changes for draft-ldap-bis-authmeth-03

   General

     - Added introductory notes and changed title of document and
       references to conform to WG chair suggestions for the overall
       technical specification.

     - Several issues--H.13, H.14, H.16, H.17--were resolved without
       requiring changes to the document.

   Section 3

     - Removed reference to /etc/passwd file and associated text.

   Section 4

     - Removed sections 4.1, 4.2 and parts of section 4.3. This
       information was being duplicated in the protocol specification
       and will now reside there permanently.
   Section 4.2

     - changed words, "not recommended" to "strongly discouraged"

   Section 4.3
     - Based on ldapbis WG discussion at IETF52 two sentences were
       added indicating that clients SHOULD NOT send a DN value when
       binding with the sasl choice and servers SHALL ignore any value
       received in this circumstance.
     -

   Section 8.3.1

     - Generalized the language of this section to not refer to any
       specific password attribute or to refer to the directory entry
       as a "user" entry.

   Section 11

     - Added security consideration regarding misuse of unauthenticated
       access.

     - Added security consideration requiring access control to be
       applied only to authenticated users and recommending it be
       applied when reading sensitive information or updating directory
       information.

G.3. Changes for draft-ldap-bis-authmeth-04

   General

     - Changed references to use [RFCnnnn] format wherever possible.
       (References to works in progress still use [name] format.)
     - Various edits to correct typos and bring field names, etc. in
       line with specification in [Protocol] draft.

     - Several issues--H.13, H.14, H.16, H.17--were resolved without
       requiring changes to the document.

   Section 4.4.1.

     - Changed ABNF grammar to use productions that are like those in
       the model draft.

   Section 5

     - Removed sections 5.1, 5.2, and 5.4 that will be added to
       [Protocol]. Renumbered sections to accommodate this change.
     -

   Section 6

     - Reviewed LDAP Association State table for completeness and
       accuracy. Renumbered actions A3, A4, and A5 to be A5, A3, and A4
       respectively. Re-ordered several lines in the table to ensure
       that actions are in ascending order (makes analyzing the table
       much more logical). Added action A2 to several states where it
       was missing and valid. Added actions A7 and A8 placeholders to
       states S1, S2, S4 and S5 pending resolution of issue H.28.

   Section 11

     - Modified security consideration (originally added in -03)
       requiring access control to be applied only to authenticated
       users. This seems nonsensical because anonymous users may have
       access control applied to limit permissible actions.
     -
   Section 13

     - Verified all normative references and moved informative
       references to a new section 14.

G.4. Changes for draft-ldap-bis-authmeth-05

   General

     - General editory changes to fix punctuation, spelling, line
       length issues, etc.
     - Verified and updated intra- and inter-document references
       throughout.
     - Document-wide review for proper usage of RFC 2119 keywords with
       several changes to correct improper usage.

   Abstract
     - Updated to match current contents of documents. This was needed
       due to movement of material on Bind and Start TLS operations to
       [Protocol] in this revision.

   Section 3.

     - Renamed section to "Rationale for LDAP Security Mechanisms" and
       removed text that did not support this theme. Part of the
       motivation for this change was to remove the implication of the
       previous section title, "Required Security Mechanisms", and
       other text found in the section that everything in the section
       was a requirement

     - Information from several removed paragraphs that describe
       deployment scenarios will be added Appendix A in the next
       revision of the draft.

     - Paragraph beginning, " If TLS is negotiated, the client MUST
       discard all information..." was moved to section 5.1.7 and
       integrated with related material there.

     - Paragraph beginning, "If a SASL security layer is negotiated..."
       was moved to section 4.2

   Section 4.l.

     - Changed wording of first paragraph to clarify meaning.

   Section 4.2.
     - Added paragraph from section 3 of -04 beginning, "If a SASL
       security layer is negotiated..."

   Section 4.3.3.
     - Renamed to "Other SASL Mechanisms" and completely rewrote the
       section (one sentence) to generalize the treatment of SASL
       mechanisms not explicitly mentioned in this document.

   Section 4.4.1.

     - Added paragraph beginning, "The dnAuthzID choice allows client
       applications..." to clarify whether DN form authorization
       identities have to also have a corresponding directory entry.
       This change was based on editor's perception of WG consensus.

     - Made minor clarifying edits in the paragraph beginning, "The
       uAuthzID choice allows for compatibility..."

   Section 5.1.1.

     - Made minor clarifying edits in the last paragraph of the
       section.

   Section 5.1.7.

     - Wording from section 3 paragraph beginning " If TLS is
       negotiated, the client MUST discard all information..." was
       moved to this section and integrated with existing text.

   Section 5.2.

     - Changed usage of "TLS connection" to "TLS session" throughout.

     - Removed empty section 5.2.1 and renumbered sections it had
       previously contained.

   Section 8.

     - Added introductory paragraph at beginning of section.

   Section 8.1.

     - Changed term  "data privacy" to "data confidentiality" to be
       consistent with usage in rest of document.

   Section 8.2.

     - Changed first paragraph to require implementations that
       implement *password-based* authentication to implement and
       support DIGEST-MD5 SASL authentication.

   Section 11.

     - First paragraph: changed "session encryption" to "session
       confidentiality protection" to be consistent with usage in rest
       of document.

   Appendix B.

     - Began changes to incorporate information on deployment scenarios
       removed from section 3.

G.5. Changes for draft-ldap-bis-authmeth-06

   General

     - Combined Section 2 (Introduction) and Section 3 (Motivation) and
       moved Introduction to section 1. All following sections numbers
       were decremented by one as result.

     - Edits to fix typos, I-D nits, etc.

     - Opened several new issues in Appendix G based on feedback from
       WG. Some of these have been resolved. Others require further
       discussion.

   Section 1

     - Added additional example of spoofing under threat (7).

   Section 2.1

     - Changed definition of "LDAP association" and added terms,
       "connection" and "TLS connection" to bring usage in line with
       [Protocol].

   Section 4.1.6

     - Clarified sentence stating that the client MUST NOT use derived
       forms of DNS names.

   Section 5.1

     - Began edits to LDAP Association state table to clarify meaning
       of various states and actions.

     - Added action A9 to cover abandoned bind operation and added
       appropriate transitions to the state transition table to
       accommodate it.

   Section 7.2

     - Replaced first paragraph to clarify that the "DIGEST-MD5" SASL
       mechanism is required to implement.

   Section 9

     - Rewrote the section to make the advice more applicable over the
       long term, i.e. more "timeless." The intent of content in the
       original section was preserved.

   Section 10

     - Added a clarifying example to the consideration regarding misuse
       of unauthenticated access.

G.6. Changes for draft-ldap-bis-authmeth-07

   General

     - Updated external and internal references to accommodate changes
       in recent drafts.

     - Opened several new issues in Appendix G based on feedback from
       WG. Some of these have been resolved. Others require further
       discussion.

   Section 3

     - Rewrote much of section 3.3 to meet the SASL profile
       requirements of draft-ietf-sasl-rfc2222bis-xx.txt section 5.

     - Changed treatement of SASL ANONYMOUS and PLAIN mechanisms to
       bring in line with WG consensus.

   Section 4

     - Note to implementers in section 4.1.1 based on operational
       experience.

     - Clarification on client continuing by performing a Start TLS
       with TLS already established in section 4.1.4.

     - Moved verification of mapping of client's authentication ID to
       asserted authorization ID to apply only to explicit assertion.
       The local policy in place for implicit assertion is adequate.

   Section 7

     - Removed most of section 7.2 as the information is now covered
       adequately via the new SASL profile in section 3.3. Added note
       to implementors regarding the treatment of username and realm
       values in DIGEST-MD5.

     - Section 7.3. Minor clarifications in wording.

     - Section 7.3.1. Clarification that a match of the presented value
       to any member of the set of stored passwords constitutes a
       successful authentication.

G.7. Changes for draft-ldap-bis-authmeth-08

   General

     - Changed usage from LDAPv3 to LDAP for usage consistency across
       LDAP technical specification.

     - Fixed a number of usage nits for consistency and to bring doc in
       conformance with publication guidelines.

   Abstract

     - Significant cleanup and rewording of abstract based on WG
       feedback.

   Section 2.1

     - New definition of user.

   Section 3

     - Added 1.5 sentences at end of introductory paragraph indicating
       the effect of the Bind op on the LDAP association.

   Section 3.1

     - Retitled section and clarified wording

   Section 3.2

     - Clarified that simple authentication choice provides three types
       of authentication: anonymous, unauthenticated, and simple
       password.

   Section 3.3.3

     - New wording clarifying when negotiated security mechanisms take
       effect.

   Section 3.3.5

     - Changed requirement to discard information about server fetched
       prior to SASL negotiation from MUST to SHOULD to allow for
       information obtained through secure mechanisms.

   Section 3.3.6

     - Simplified wording of first paragraph based on suggestion from
       WG.

   Section 3.4

     - Minor clarifications in wording.

   Section 3.4.1

     - Minor clarifications in wording in first sentence.
     - Explicitly called out that the DN value in the dnAuthzID form is
       to be matched using DN matching rules.
     - Called out that the uAuthzID MUST be prepared using SASLprep
       rules before being compared.
     - Clarified requirement on assuming global uniqueness by changing
       a "generally... MUST" wording to "SHOULD".

   Section 4.1.1

     - Simplified wording describing conditions when Start TLS cannot
       be sent.
     - Simplified wording in note to implementers regarding race
       condition with outstanding LDAP operations on connection.

   Section 4.1.5

     - Removed section and moved relevant text to section 4.2.2.

   Section 4.1.6

     - Renumbered to 4.1.5.
     - Updated server identity check rules for server's name based on
       WG list discussion.

   Section 4.1.7

     - Renumbered to 4.1.6
     - Changed requirement to discard information about server fetched
       prior to TLS negotion from MUST to SHOULD to allow for
       information obtained through secure mechanisms.

   Section 6.1

     - Clarified wording.
     - Added definition of anonymous and unauthenticated binds.

   Section 10

     - Added security consideration (moved from elsewhere) discouraging
       use of cleartext passwords on unprotected communication
       channels.

   Section 11

     - Added an IANA consideration to update GSSAPI service name
       registry to point to [Roadmap] and [Authmeth]

G.8. Changes for draft-ldap-bis-authmeth-09

   General

     - Updated section references within document
     - Changed reference tags to match other docs in LDAP TS
     - Used non-quoted names for all SASL mechanisms

   Abstract

     - Inspected keyword usage and removed several improper usages.

     - Removed sentence saying DIGEST-MD5 is LDAP's mandatory-to-
       implement mechanism. This is covered elsewhere in document.

     - Moved section 5, authentication state table, of -08 draft to
       section 8 of -09 and completely rewrote it.

   Section 1

     - Reworded sentence beginning, "It is also desirable to allow
       authentication methods to carry identities based on existing¨
       non-LDAP DN-forms..."
     - Clarified relationship of this document to other documents in
       the LDAP TS.

   Section 3.3.5

     - Removed paragraph beginning,"If the client is configured to
       support multiple SASL mechanisms..." because the actions
       specified in the paragraph do not provide the protections
       indicated. Added a new paragraph indicating that clients and
       server should allow specification of acceptable mechanisms and
       only allow those mechanisms to be used.

     - Clarified independent behavior when TLS and SASL security layers
       are both in force (e.g. one being removed doesn't affect the
       other).

   Section 3.3.6

     - Moved most of section 4.2.2, Client Assertion of Authorization
       Identity, to sections 3.3.6, 3.3.6.1, and 3.3.6.2.

   Section 3.3.6.4

     - Moved some normative comments into text body.

   Section 4.1.2

     - Non success resultCode values are valid if server is *unwilling*
       or unable to negotiate TLS.

   Section 4.2.1

     - Rewrote entire section based on WG feedback.

   Section 4.2.2

     - Moved most of this section to 3.3.6 for better document flow.

   Section 4.2.3

     - Rewrote entire section based on WG feedback.

   Section 5.1

     - Moved imperative language regarding unauthenticated access from
       security considerations to here.

   Section 6

     - Added several paragraphs regarding the risks of transmitting
       passwords in the clear and requiring server implementations to
       provide a specific configuration that reduces these risks.

   Section 6.2

     - Added sentence describing protections provided by DIGEST-MD5
       method.
     - Changed DNs in exmple to be dc=example,dc=com.

   Section 10

     - Updated consideration on use of cleartext passwords to include
       other unprotected authentication credentials
     - Substantial rework of consideration on misuse of unauthenticated
       bind.

G.9. Changes for draft-ldap-bis-authmeth-10

   General

     - Many editorial changes throughout to clarify wording and better
       express intent, primarily based on suggestions from WG mail
       list.
     - More standard naming of authentication mechanisms throughout
       document, e.g. "Anonymous Authentication Mechanism of the Simple
       Bind Choice".

   Section 1

     - Editorial changes to add clarity.
     - Moved section 2 of authmeth -09 into section 1

   Section 2
     - New section outlining implementation requirements.

   Section 3.1.1

     - Editorial clarification on need for following operation
       sequencing requirements.

   Section 3.1.4

     - New section added to describe use of client certificates with
       Start TLS. Incorporates material moved from other sections of
       authmeth -09.

   Section 4
     - New section added to discuss LDAP Associations. Related material
       was moved from various other sections of authmeth -09 and
       incorporated into this new section.

   Section 5

     - Added several paragraphs regarding transmission and derivation
       of authentication and authorization identities using the Bind
       operation.

   Section 8

     - Clarified rules applied as part of the
   criteria for determining valid allowing or disallowing a state transition in the state
   transition table in section A.4.

   ID Decision Question
   -- --------------------------------------------------------------
   D1 Are lower-layer credentials and situations
       where invalidCredentials result is to available?
   D2 Can lower-layer credentials for Auth ID "K" be returned.

   Section 14

     - Added three security considerations based on WG feedback.

   Appendix A

     - Simplfied state tables by removing two unnecessary actions from mapped to
       asserted AuthZID "L"?

A.4. LDAP Association State Transition Table

   The LDAP Association table below lists the the actions table, that could
   affect authentication and authorization state of an LDAP association
   and removing the current resulting state column of an LDAP association after a given action
   occurs.

   S1, the initial state transition table. Updated references to authmeth and
       [Protocol].

Appendix H. Issues to be Resolved

   This appendix lists open questions and issues that need to be
   resolved before work on for the state machine described in this document table,
   is the authentication state when an LDAP connection is deemed complete.

H.1. initially
   established.

              Next
   Action   State  Comment
   -------  -----  -------------------------------------------------
   A1         S1   Section 4
   A2         S1   Section 1 lists 6 security mechanisms that can be used by LDAP
   servers. I'm not sure what mechanism 5, "Resource limitation by
   means of administrative limits on service controls" means.

   Status: resolved. Changed wording to "administrative service limits"
   to clarify meaning.

H.2.
   A3         S1   Section 2 paragraph 1 7
   A4         S2   Sections 8, 9
   A5,        S1   Failed bind, section 10.1
   D1=no
   A5,        S3
   D1=yes
   A6,        S1   Failed bind, section 10.2
   D1=no
   A6,        S1   Failed bind, section 10.2
   D1=yes,
   D2=no
   A6,        S4
   D1=yes,
   D2=yes
   A7         no   [Protocol] section 4.14.2.2
             change
   A8         no   [Protocol] section 4.14.2.1
             change
   A9         S1   [Protocol] section 4.14.3.1

Appendix B. Authentication and Authorization Concepts

   This appendix defines the term, "sensitive." Do we want to
   bring this term basic terms, concepts, and other security-related terms interrelationships
   regarding authentication, authorization, credentials, and identity.
   These concepts are used in alignment with
   usage with the IETF describing how various security glossary (RFC 2828)?

   Status: resolved. WG input at IETF 51 was that we should do this, so
   the appropriate changes have been made.

H.3.

   Section 2, deployment scenario 2: What is meant by the term "secure
   authentication function?"

   Status: resolved. Based on the idea that a "secure authentication
   function" could be provided by TLS, I changed the wording to require
   data confidentiality for sensitive
   approaches are utilized in client authentication information and
   data integrity for all authentication information.

H.4.

   Section 3, deployment scenario 3: What is meant by the phrase,
   "directory data authorization.

B.1. Access Control Policy

   An access control policy is authenticated by the server?"

   Status: resolved. I interpreted this to mean the ability to ensure a set of rules defining the identity protection
   of resources, generally in terms of the directory server capabilities of persons or
   other entities accessing those resources. Security objects and
   mechanisms, such as those described here, enable the integrity expression of the data
   sent from that server to the client,
   access control policies and explictly stated such.

H.5.

   Section 4 paragraph 3: What their enforcement.

B.2. Access Control Factors

   A request, when it is meant being processed by the phrase, "this means that
   either this data is useless for faking authentication (like the Unix
   "/etc/passwd" file format used to be)?"

   Status: resolved. Discussion at IETF 52 along with discussions a server, may be associated
   with a wide variety of security-related factors (section 4.2 of
   [Protocol]). The server uses these factors to determine whether and
   how to process the original authors request. These are called access control factors
   (ACFs). They might include source IP address, encryption strength,
   the type of operation being requested, time of this material have convinced us that this
   reference is simply too arcane day, etc. Some
   factors may be specific to the request itself, others may be left in place. In -03
   associated with the text
   has been modified to focus on connection via which the need to either update password
   information in a protected fashion outside request is transmitted,
   others (e.g. time of the protocol or to
   update it day) may be "environmental".

   Access control policies are expressed in session well protected against snooping, and the
   reference to /etc/passwd has been removed.

H.6.

   Section 4 paragraph 7 begins: "For a directory needing session
   protection..." Is this referring to data confidentiality or data
   integrity or both?

   Status: resolved. Changed wording to say, "For terms of access control
   factors. E.g., a directory needing
   data security (both data integrity and data confidentiality)..."

H.7.

   Section 4 paragraph 8 indicates request having ACFs i,j,k can perform operation Y
   on resource Z. The set of ACFs that "information about the a server
   fetched prior to makes available for
   such expressions is implementation-specific.

B.3. Authentication, Credentials, Identity

   Authentication credentials are the TLS negotiation" must be discarded. Do we want
   to explicitly state that this applies to information fetched prior evidence supplied by one party to
   another, asserting the *completion* identity of the TLS negotiation or supplying party (e.g. a user)
   who is this going too far?

   Status: resolved. Based on comments in the IETF 51 LDAPBIS WG
   meeting, this has been changed to explicitly state, "fetched prior attempting to establish an association with the initiation of the TLS negotiation..."

H.8.

   Section 4 paragraph 9 indicates that clients SHOULD check the
   supportedSASLMechanisms list both before and after other party
   (typically a SASL security
   layer server). Authentication is negotiated to ensure that the process of generating,
   transmitting, and verifying these credentials and thus the identity
   they assert. An authentication identity is the name presented in a
   credential.

   There are using many forms of authentication credentials -- the best available
   security form used
   depends upon the particular authentication mechanism supported mutually negotiated by
   the client parties. For example: X.509 certificates, Kerberos tickets,
   simple identity and server. A
   note at password pairs. Note that an authentication
   mechanism may constrain the end form of the paragraph indicates that this authentication identities used
   with it.

B.4. Authorization Identity

   An authorization identity is a SHOULD
   since there are environments where the client might get a list one kind of
   supported SASL mechanisms from a different trusted source.

   I wonder if access control factor. It
   is the intent name of this could the user or other entity that requests that
   operations be restated more plainly using
   one performed. Access control policies are often expressed
   in terms of these two approaches (I've paraphrased for authorization identities; e.g., entity X can perform
   operation Y on resource Z.

   The authorization identity bound to an association is often exactly
   the sake of
   brevity):

        Approach 1: Clients SHOULD check same as the supportedSASLMechanisms
        list both before and after authentication identity presented by the client, but
   it may be different. SASL negotiation or allows clients SHOULD
        use a different trusted source to determine available supported
        SASL mechanisms.

        Approach 2: Clients MUST check specify an authorization
   identity distinct from the supportedSASLMechanisms list
        both before and after SASL negotiation UNLESS they use a
        different trusted source to determine available supported SASL
        mechanisms.

   Status: resolved. WG input at IETF 51 was that Approach 1 was
   probably best. I ended up keeping authentication identity asserted by the basic structure similar
   client's credentials. This permits agents such as proxy servers to
   authenticate using their own credentials, yet request the
   original to meet this intent.

H.9.

   Section 6.3.1 states: "DSAs that map access
   privileges of the identity for which they are proxying [SASL]. Also,
   the DN sent in form of authentication identity supplied by a service like TLS
   may not correspond to the bind request authorization identities used to express a directory entry with
   server's access control policy, requiring a userPassword attribute will... compare
   [each value in the named user's entry]... with the presented
   password."  This implies that this applies only server-specific mapping
   to user entries with
   userPassword attributes.  What about other types of entries that
   might allow passwords be done. The method by which a server composes and might store in validates an
   authorization identity from the password information in
   other attributes?  Do we want authentication credentials supplied
   by a client is implementation-specific.

Appendix C. RFC 2829 Change History

   This appendix lists the changes made to make this the text more general?

   Status: resolved of RFC 2829 in -03 draft by generalizing section 8.3.1 to not
   refer to any specific password attribute and by removing
   preparing this document.

C.0. General Editorial Changes
   Version -00

     - Changed other instances of the term
   "user" in referring LDAP to LDAP where v3 of the directory entry specified by the DN in
       protocol is implied. Also made all references to LDAP use the bind request.

H.10 userPassword and simple bind
   We need
       same wording.

     - Miscellaneous grammatical changes to be sure that we don't require userPassword improve readability.

     - Made capitalization in section headings consistent.

   Version -01

     - Changed title to be the only
   attribute used for authenticating via simple bind. (See 2251 sec 4.2 reflect inclusion of material from RFC 2830 and authmeth 6.3.1. Work with Jim Sermersheim on resolution
       2251.

C.1. Changes to this.
   On publication state something like: "This is the specific
   implementation of what we discussed in our general reorg
   conversation on the list." (Source: Kurt Zeilenga)

   Status: resolved Section 1
   Version -01

     - Moved conventions used in -03 draft by generalizing document to a separate section.

C.2. Changes to Section 2

   Version -01

     - Moved section 8.3.1 to not
   refer an appendix.

C.3. Changes to any specific password attribute and by removing the term
   "user" in referring Section 3

   Version -01

     - Moved section to an appendix.

C.4 Changes to Section 4

   Version -00

     - Changed "Distinguished Name" to "LDAP distinguished name".

C.5. Changes to Section 5

   Version -00

     - Added the following sentence: "Servers SHOULD NOT allow clients
       with anonymous authentication to modify directory entry specified by the DN entries or
       access sensitive information in directory entries."

C.5.1. Changes to Section 5.1

   Version -00

     - Replaced the text describing the procedure for performing an
       anonymous bind request.

H.11. Meaning (protocol) with a reference to section 4.2 of LDAP Association

   The original RFC 2830 uses the term "LDAP association" in
       2251 (the protocol spec).

   Version -01

     - Brought text describing
   a connection between procedure for performing an LDAP client and server regardless of the
   state anonymous
       bind from section 4.2 of TLS on that connection. RFC 2251 bis.  This term needs to text will be defined or
   possibly changed.

   Status: resolved. at IETF 51 Bob Morgan indicated that the term
   "LDAP association" was intended to distinguish the LDAP-level
   connection
       removed from the TLS-level connection.  This still needs draft standard version of that document.

C.6. Changes to be
   clarified somewhere Section 6.

   Version -00

     Reorganized text in the draft. section 6.1 as follows:

     1. Added "LDAP association" to a
   glossary in new section 1.

H.12. Is DIGEST-MD5 mandatory (6.1) titled "Simple Authentication" and
       moved one of two introductory paragra   phs for all implementations?

   Reading 2829bis I think DIGEST-MD5 is mandatory ONLY IF your server
   supports password based authentication...but the following makes it
   sound mandatory section 6 into
       section 6.1. Added sentences to provide BOTH password the paragraph indicating:

        a. simple authentication AND DIGEST-
   MD5:

   "6.2. Digest is not suitable for environments where
        confidentiality is not available.

        b. LDAP implementations SHOULD NOT support simple
        authentication

   LDAP unless confidentiality and data integrity
        mechanisms are in force.

     2. Moved first paragraph of section 6 (beginning with "LDAP
       implementations MUST support authentication with a password
   using password...")
       to section on Digest Authentication (Now section 6.2).

C.6.1. Changes to Section 6.1.

   Version -00 Renamed section to 6.2

     - Added sentence from original section 6 indicating that the
       DIGEST-MD5 SASL mechanism for password protection, as
   defined in section 6.1."

   The thing is for acl it would be nice (though not critical) to be
   able to default the required authentication level for a subject all conforming LDAP
       implementations

C.6.2. Changes to a
   single "fairly secure" mechanism--if there is no such mandatory
   authentication scheme then you cannot do that. (Source: Rob Byrne)

   Status: resolved. Section 6.2

   Version -00 version of

     - Renamed section to 6.3

     - Reworded first paragraph to remove reference to user and the draft added
       userPassword password attribute Made the first paragraph more
       general by simply saying that if a sentence at directory supports simple
       authentication that the
   beginning simple bind operation MAY performed
       following negotiation of section 8.2 stating a TLS ciphersuite that LDAP server implementations
   must support this method.

H.13. Ordering supports
       confidentiality.

     - Replaced "the name of authentication levels requested

   Again on the subject user's entry" with "a DN" since not
       all bind operations are performed on behalf of authentication level, is it possible a "user."

     - Added Section 6.3.1 heading just prior to
   define an ordering on authentication levels which defines their
   relative "strengths" ? This would be useful paragraph 5.

     - Paragraph 5: replaced "The server" with "DSAs that map the DN
       sent in acl as you could say
   things like"a given aci grants access the bind request to a directory entry with a
       userPassword attribute."

C.6.3. Changes to section 6.3.

     Version -00

     - Renamed to section 6.4.

C.7. Changes to section 7.

   none

C.7.1. Changes to section 7.1.

   Version -00

     - Clarified the entity issuing a given subject at this
   authentication level AND ABOVE". David Chadwick raised this before
   in certificate by moving the context of denying access phrase
       "to have issued the certificate" immediately after
       "Certification Authority."

C.8. Changes to a subject at a given section 8.

   Version -00

     - Removed the first paragraph because simple authentication level, is
       covered explicitly in which case he wanted section 6.

     - Added section 8.1. heading just prior to express "deny
   access second paragraph.

     - Added section 8.2. heading just prior to this subject at this authentication level AND TO ALL
   IDENTITIES AUTHENTICATED BELOW THAT LEVEL". (Source: Rob Byrne)

   Status: out of scope. This is outside the scope of this document and
   will not be addressed.

H.14. Document vulnerabilities third paragraph.

     - Added section 8.3. heading just prior to fourth paragraph.

   Version -01

     - Moved entire section 8 of various RFC 2829 into section 3.4 (Using SASL
       for Other Security Services) to bring material on SASL
       mechanisms

   While I'm here...in 2829, I think it would be good together into one location.

C.9. Changes to have some
   comments or explicit reference section 9.

   Version -00

     - Paragraph 2: changed "EXTERNAL mechanism" to "EXTERNAL SASL
       mechanism."

     - Added section 9.1. heading.

     - Modified a place where the security
   properties of comment in the particular mandatory authentication schemes are
   outlined. When I say "security properties" I mean stuff like "This
   scheme is vulnerable ABNF from "unspecified userid" to such and such attacks, is only safe if the
   key size is > 50, this hash is widely considered the best, etc...".
   I think an LDAP implementor
       "unspecified authz id".

     - Deleted sentence, "A utf8string is likely defined to be interested in that
   information, without having to wade through the security RFCs.
   (Source: Rob Byrne)

   Status: out of scope. This is outside the scope of this document and
   will not be addressed.

H.15. Include a Start TLS state transition table

   The pictoral representation it is nominally based on is here (URL
   possibly folded):

   http://www.stanford.edu/~hodges/doc/LDAPAssociationStateDiagram-
   1999-12-14.html

   (Source: Jeff Hodges)

   Status: Resolved.

   Table provided in -03. Review UTF-8
       encoding of content for accuracy in -04.
   Additional review one or more ISO 10646 characters," because it is needed, plus comments from WG members indicate
       redundant.

     - Added section 9.1.1. heading.

     - Added section 9.1.2. heading.

   Version -01

     - Moved entire section 9 to become section 3.5 so that additional description of each state's meaning it would be helpful.

   Did
       with other SASL material.

C.10. Changes to Section 10.

   Version -00
     - Updated reference to cracking from a significant revision week of state transition table CPU time in -09. Changes
   were based on suggestions from WG and greatly simplified overall
   table.

H.16. Empty sasl credentials question

   I spent some more 1997 to
       be a day of CPU time looking microscopically at ldap-auth-methods in 2000.

     - Added text: "These ciphersuites are NOT RECOMMENDED for use...
       and ldap-ext-tls drafts. The drafts say that the credential must
   have server implementers SHOULD" to sentence just prior the form dn:xxx or u:xxx
       second list of ciphersuites.

     - Added text: "and MAY support other ciphersuites offering
       equivalent or be absent, and although they don't
   say what better protection," to do in the case last paragraph of an empty octet string I would say that
   we could send protocolError (claim it is a bad PDU).

   There is still the question of what
       section.

C.11. Changes to do if the credential is 'dn:'
   (or 'u:') followed by the empty string. (Source: ariel@columbia.edu
   via Jeff Hodges)
   Status: resolved. Kurt Zeilenga indicated during ldapbis WG
   discussion at IETF 52 Section 11.

   Version -01

     - Moved to section 3.6 to be with other SASL material.

C.12. Changes to Section 12.

   Version -00

     - Inserted new section 12 that specifies when SASL AuthzID credentials empty and absent
   are equivalent in the latest protections
       begin following SASL ID. This resolves the issue.

H.17. Hostname check from MUST to SHOULD?

   I am uneasy about the hostname check. My experience from PKI with
   HTTP probably negotiation, etc. The original section 12
       is a contributing factor; we have people using the
   short hostname renumbered to become section 13.

   Version -01

     - Moved to get section 3.7 to a server which naturally has be with other SASL material.

C.13. Changes to Section 13 (original section 12).

   None

Appendix D. RFC 2830 Change History

   This appendix lists the FQDN in changes made to the certificate, no end text of problems. I have a certificate on my
   laptop which has the FQDN for the case when the system is on our
   Columbia network with a fixed IP; when I dial RFC 2830 in however, I have
   some horrible dialup name, and using
   preparing this document.

D.0. General Editorial Changes

     - Material showing the local https server becomes
   annoying. Issuing a certificate in PDUs for the name 'localhost' is not StartTLS response was broken
       out into a
   solution! Wildcard match does not solve this problem. For these
   reasons I am inclined to argue for 'SHOULD' instead of
   'MUST' in paragraph...

   Also, new section.

     - The hostname check against the name in wording of the certificate is a
   very weak means definition of preventing man-in-the-middle attacks; the proper
   solution is not here yet (SecureDNS or some equivalent). Faking out
   DNS is not so hard, StartTLS request and we see this sort of thing in
       StartTLS response was changed to make them parallel. NO changes
       were made to the press on a
   pretty regular basis, where site A hijacks ASN.1 definition or the DNS server for site B
   and gets all their requests. Some mention associated values of this should be made in
       the draft. (Source: ariel@columbia.edu via Jeff Hodges)

   Status: resolved. Based parameters.

     - A separate section heading for graceful TLS closure was added
       for parallelism with section on discussion at IETF 52 ldapbis WG meeting,
   this text will stand as it is. The check is a MUST, but the behavior
   afterward is a SHOULD. abrupt TLS closure.

Appendix E. RFC 2251 Change History
   This gives server implementations appendix lists the room changes made to
   maneuver as needed.

H.18. Must SASL DN exist in the directory?

   If the 'dn:' form text of sasl creds is used, is it the intention RFC 2251 in
   preparing this document.

E.0. General Editorial Changes

     - All material from section 4.2 of the
   draft(ers) that RFC 2251 was moved into this DN must exist in
       document.

     - A new section was created for the directory and Bind Request

     - Section 4.2.1 of RFC 2251 (Sequencing Bind Request) was moved
       after the client
   will have section on the privileges associated Bind Response for parallelism with that entry, or can the
   server map
       presentation of the sasl DN StartTLS operations. The section was also
       subdivided to perhaps some other DN in explicitly call out the directory,
   in an implementation-dependent fashion?

   We already know that if *no* sasl credentials are presented, various effects being
       described within it.

     - All SASL profile information from RFC 2829 was brought within
       the DN
   or altname in discussion of the client certificate may be mapped Bind operation (primarily sections 4.4 -
       4.7).

Appendix F. Change History to a DN in an
   implementation-dependent fashion, or indeed Combined Document

F.1. Changes for draft-ldap-bis-authmeth-02

   General

     - Added references to something not in the
   directory at all. (Right?)  (Source: ariel@columbia.edu via Jeff
   Hodges)

   Status: resolved. (11/12/02)Based on my research I propose that the
   DN MUST exist in the directory when the DN form of sasl creds is
   used. I have made this proposal other LDAP standard documents, to sections
       within the ldapbis mailing list.

   (11/21/02) Feedback from mailing list has proposed removing this
   paragraph entirely because (1) explicit assertion of authorization
   identity should only be done when proxying (2) mapping document, and fixed broken references.

     - General editorial changes--punctuation, spelling, formatting,
       etc.

   Section 1.

     - Added glossary of the
   asserted authorization identity is implementation specific terms and
   policy driven [SASL] section 4.2, added sub-section headings

   Section 2.

     - Clarified security mechanisms 3, 4, & 5 and (3) keeping this paragraph is
   not required for interoperability.

H.19. DN used brought language in
       line with IETF security glossary.

   Section 3.

     - Brought language in requirement (3) in conjunction line with SASL mechanism

   We need security
       glossary.

     - Clarified that information fetched prior to specify whether the DN field in Bind operation can/cannot initiation of TLS
       negotiation must be used when discarded

     -Clarified that information fetched prior to initiation of SASL mechanism is specified. (source: RL Bob)

   Status: resolved. (-03) Based
       negotiation must be discarded

     - Rewrote paragraph on ldapbis WG discussion at IETF52 two
   sentences were added SASL negotiation requirements to section 4.3 indicating clarify
       intent
   Section 4.4.

     - Added stipulation that clients SHOULD
   NOT send a DN value when binding with the sasl choice and servers
   SHALL ignore allows for any value received in SASL mechanism
       not prohibited by this circumstance. During edits
   for -04 version of draft it was noted that [Protocol] section 4.2
   conflicts with document. (Resolved conflict between this draft. The editor of [Protocol] has been
   notified of the discrepancy,
       statement and they have been handled.

H.20. Bind states

   Differences between unauthenticated one that prohibited use of ANONYMOUS and anonymous. There are four
   states you can get into. One is completely undefined (this is now
   explicitly called out in [Protocol]).  This text needs to be moved
   from [Protocol] PLAIN
       SASL mechanisms.)

   Section 5.3.6

     - Added a.x.bar.com to this draft. (source: Jim Sermersheim)

   Status: Resolved. There are four states: (1) no name, no password
   (anon); (2) name, no password (anon); (3) no name, password
   (invalid); (4) name, password (simple bind).  States 1, 2, and 4 are
   called out in [AuthMeth]. State 3 is called out in [Protocol]; this
   seems appropriate based wildcard matching example on review of alternatives.

H.21. Misuse of unauthenticated access

   Add a security consideration that operational experience shows that
   clients can misuse unauthenticated access (simple bind with name but
   no password).  Servers SHOULD by default reject authentication
   requests that have a DN with hostname check.

   Section 6

     - Added LDAP Association State Transition Tables to show the
       various states through which an empty password LDAP association may pass along
       with an error of
   invalidCredentials. (Source: Kurt Zeilenga the actions and Chris Newman (Sun))

   Status: Resolved. Added decisions required to traverse from state
       to state.

   Appendix A

     - Brought security considerations terminology in -03.

H.22. Need to move Start TLS protocol information to [Protocol]

   Status: Resolved. Removed Sections 5.1, 5.2, and 5.4 line with IETF security glossary
       throughout the appendix.

F.2. Changes for -04 draft-ldapbis-authmeth-03

   General

     - Added introductory notes and
   they are [Protocol] -11.

H.23. Split Normative changed title of document and Non-normative
       references into separate
sections.

   Status: Resolved. Changes made in -04

H.24. What is the authentication state if a Bind operation is abandoned?

   Status: Resolved.

   (3/24/03) This following text appears in section 4.2.1 of [Protocol]
   revision -13 to cover what happens if a bind operation is abandoned:

   A failed or abandoned Bind Operation has the effect of leaving conform to WG chair suggestions for the
   connection in an anonymous state. To arrive at a known
   authentication state after abandoning a bind operation, clients may
   unbind, rebind, or make use of overall
       technical specification.

     - Several issues--H.13, H.14, H.16, H.17--were resolved without
       requiring changes to the BindResponse.

   (6/28/03): The state table in section 6 of [AuthMeth] has been
   updated document.

   Section 3

     - Removed reference to reflect this wording.

H.25. Difference between checking server hostname /etc/passwd file and server's
canonical DNS name in Server Identity Check? associated text.

   Section 4.1.6: I now understand the intent 4

     - Removed sections 4.1, 4.2 and parts of section 4.3. This
       information was being duplicated in the check (prevent
   man-in-the-middle attacks).  But what is the subtle difference
   between the "server hostname" protocol specification
       and the "server's canonical DNS name"?
   (Source: Tim Hahn)

   Status: Resolved.

   (11/12/02) Sent suggested wording change to this paragraph will now reside there permanently.
   Section 4.2

     - changed words, "not recommended" to the "strongly discouraged"

   Section 4.3

     - Based on ldapbis mail list and also asked for opinion as to whether we should
   discuss WG discussion at IETF52 two sentences were
       added indicating that clients SHOULD NOT send a DN value when
       binding with the distinction between server DNS hostname sasl choice and server
   canonical DNS hostname servers SHALL ignore any value
       received in [AuthMeth].

   (11/21/02): RL Bob Morgan will provide wording that allows
   derivations of this circumstance.

     -

   Section 8.3.1

     - Generalized the name that are provided securely.

   (6/28/03): posted language of this section to the WG list asking Bob or any other WG member
   who is knowledgeable about the issues involved not refer to help me with
   wording any
       specific password attribute or other information I can use to make this change and close refer to the work item.

   (10/08/03): Based on WG list feedback, I've updated this text directory entry
       as a "user" entry.

   Section 11

     - Added security consideration regarding misuse of unauthenticated
       access.

     - Added security consideration requiring access control to
   read what I judge be
       applied only to authenticated users and recommending it be the WG consensus, "The client MUST
       applied when reading sensitive information or updating directory
       information.

F.3. Changes for draft-ldapbis-authmeth-04

   General

     - Changed references to use the
   server provided by the user (or other trusted entity) as the value [RFCnnnn] format wherever possible.
       (References to compare against the server name as expressed works in the server's
   certificate. A hostname derived from the user input is progress still use [name] format.)
     - Various edits to be
   considered provided by the user only if derived in a secure fashion
   (e.g., DNSSEC)."

H.26. Server Identity Check using servers located via SRV records

   Section 4.1.6: What should be done if the server was found using SRV
   records based on the "locate" draft/RFC? (Source: Tim Hahn).

   Status: Resolved. Section 5 of draft-ietf-ldapext-locate-08
   specifically calls out how the server identity should be performed
   if the server is located using the method defined correct typos and bring field names, etc. in that
       line with specification in [Protocol] draft.
   This is the right location for this information, and

     - Several issues--H.13, H.14, H.16, H.17--were resolved without
       requiring changes to the coverage
   appears document.

   Section 4.4.1.

     - Changed ABNF grammar to be adequate.

H.27 Inconsistency use productions that are like those in effect of TLS closure on LDAP association.
       the model draft.

   Section 4.4.1 of authmeth -03 (section 4.1 of RFC2830) states 5

     - Removed sections 5.1, 5.2, and 5.4 that
   TLS closure alert will leave the LDAP association intact. Contrast be added to
       [Protocol]. Renumbered sections to accommodate this with change.
     -

   Section 4.5.2 (section 5.2 of RFC2830) that says 6

     - Reviewed LDAP Association State table for completeness and
       accuracy. Renumbered actions A3, A4, and A5 to be A5, A3, and A4
       respectively. Re-ordered several lines in the table to ensure
       that actions are in ascending order (makes analyzing the
   closure table
       much more logical). Added action A2 to several states where it
       was missing and valid. Added actions A7 and A8 placeholders to
       states S1, S2, S4 and S5 pending resolution of the TLS connection MUST cause the LDAP association issue H.28.

   Section 11
     - Modified security consideration (originally added in -03)
       requiring access control to
   move be applied only to an anonymous authentication.

   Status: Resolved. (11/12/02) authenticated
       users. This is actually a [Protocol] issue seems nonsensical because these sections anonymous users may have now been
       access control applied to limit permissible actions.
     -
   Section 13

     - Verified all normative references and moved informative
       references to [Protocol] -11. I have
   proposed the following text a new section 14.

F.4. Changes for draft-ldapbis-authmeth-05

   General

     - General editory changes to fix punctuation, spelling, line
       length issues, etc.
     - Verified and updated intra- and inter-document references
       throughout.
     - Document-wide review for Section 4.4.1 proper usage of [AuthMeth] -03
   (section 4.13.3.1 RFC 2119 keywords with
       several changes to correct improper usage.

   Abstract
     - Updated to match current contents of [Protocol]) documents. This was needed
       due to resolve this apparent
   discrepancy:

   "
   Either the client or server MAY terminate the TLS connection on an
   LDAP association by sending a TLS closure alert.  The LDAP
   connection remains open for further communication after TLS closure
   occurs although the authentication state movement of the LDAP connection is
   affected (see [AuthMeth] section 4.2.2).

   (11/21/02): resolution material on Bind and StartTLS operations to this is expected in
       [Protocol] -12

   (06/28/03): [Protocol]-15 clarifies that a TLS closure alert
   terminates the TLS connection while leaving the LDAP connection
   intact. The authentication state table in [AuthMeth] specifies the
   effect on the LDAP association.

H.28 Ordering of external sources of authorization identities this revision.

   Section 4.3.2 implies that external sources of authorization
   identities other than TLS are permitted. What is the behavior when
   two external sources of authentication credentials are available
   (e.g. TLS 3.

     - Renamed section to "Rationale for LDAP Security Mechanisms" and IPsec are both present (is
       removed text that did not support this possible?)) and a SASL
   EXTERNAL Bind operation is performed?

   Status: resolved. 11/20/02: Resolved by Section 4.2 theme. Part of [SASL] which
   states that the decision
       motivation for this change was to allow or disallow remove the asserted identity
   is based on an implementation defined policy.

H.29 Rewrite implication of Section 9, TLS Ciphersuites

   This the
       previous section contains anachronistic references title, "Required Security Mechanisms", and needs to be
   updated/rewritten
       other text found in a way the section that provides useful guidance for future
   readers everything in the section
       was a way requirement

     - Information from several removed paragraphs that describe
       deployment scenarios will transcend be added Appendix A in the passage next
       revision of time.

   Status: Resolved. (6/28/03): Rewrote the section to cover the
   general issues and considerations involved in selecting draft.

     - Paragraph beginning, " If TLS
   ciphersuites.

H.30 Update is negotiated, the client MUST
       discard all information..." was moved to Appendix A, Example Deployment Scenarios

   This section needs 5.1.7 and
       integrated with related material there.

     - Paragraph beginning, "If a SASL security layer is negotiated..."
       was moved to be updated section 4.2

   Section 4.l.

     - Changed wording of first paragraph to indicate which security
   mechanisms and/or combinations clarify meaning.

   Section 4.2.
     - Added paragraph from section 3 of -04 beginning, "If a SASL
       security mechanisms described
   elsewhere in layer is negotiated..."
   Section 4.3.3.
     - Renamed to "Other SASL Mechanisms" and completely rewrote the document can provide
       section (one sentence) to generalize the types of protections
   suggested in this appendix.

H.31 Use treatment of PLAIN SASL Mechanism

   At least one LDAP server implementer has found the SASL "PLAIN"
   mechanism useful
       mechanisms not explicitly mentioned in authenticating this document.

   Section 4.4.1.

     - Added paragraph beginning, "The dnAuthzID choice allows client
       applications..." to legacy systems that do not
   represent authentication clarify whether DN form authorization
       identities as DNs. Section 3.3.1 appears have to
   implicitly disallow the use also have a corresponding directory entry.
       This change was based on editor's perception of WG consensus.

     - Made minor clarifying edits in the SASL "PLAIN" mechanism with LDAP.
   Should we allow paragraph beginning, "The
       uAuthzID choice allows for compatibility..."

   Section 5.1.1.

     - Made minor clarifying edits in the use last paragraph of this mechanism? I.e. is this "SASL"
   "PLAIN" MUST NOT be used with LDAP, or is it simply that LDAP
   doesn't define bindings for these mechanism. the
       section.

   Section 5.1.7.

     - Wording from section 3 paragraph beginning " If SASL "PLAIN" TLS is
   allowed,
       negotiated, the following adjustments will be needed client MUST discard all information..." was
       moved to this section and integrated with existing text.

   Section 5.2.

     - Changed usage of "TLS connection" to "TLS session" throughout.

     - Removed empty section 3.3.1:
   (a) change section heading, (b) remove reference to "PLAIN" in the
   section, (c) ensure wording of last sentence regarding non-DN
   AuthZIDs is consistent with rest 5.2.1 and renumbered sections it had
       previously contained.

   Section 8.

     - Added introductory paragraph at beginning of the section.

   Status: Resolved.

   (6/28/03): email

   Section 8.1.

     - Changed term  "data privacy" to WG list stating issue and asking if we should
   remove the reference "data confidentiality" to SASL "PLAIN".

   For -07 draft I've generalized the SASL profile be
       consistent with usage in section 3.3 to
   allow any SASL mechanism.

H.32 Clarification on use rest of SASL mechanisms document.

   Section 3.3.1: BTW, what _are_ the "ANONYMOUS" 8.2.

     - Changed first paragraph to require implementations that
       implement *password-based* authentication to implement and "PLAIN"
       support DIGEST-MD5 SASL
   mechanisms?  They are not defined in RFC2222.  If you refer authentication.

   Section 11.

     - First paragraph: changed "session encryption" to other
   SASL mechanisms than those "session
       confidentiality protection" to be consistent with usage in rfc2222, Maybe you should only list
   which mechanisms _are_used, instead rest
       of which ones are _not. (Source:
   Hallvard Furuseth)

   I (Kurt Zeilenga) note[s] as well that the ANONYMOUS/PLAIN document.

   Appendix B.

     - Began changes to incorporate information on deployment scenarios
       removed from section
   (4.2) should
   be deleted.  ANONYMOUS 3.

F.5. Changes for draft-ldapbis-authmeth-06

   General

     - Combined Section 2 (Introduction) and PLAIN, like in other mechanism,
   can be used in LDAP if a) supported Section 3 (Motivation) and b) enabled.  I note
   that they each offer capabilities not found in their simple
   bind equivalents (and hence are used in some deployments).
   For example, PLAIN (over TLS) is quite useful when interacting
   with legacy authentication subsystems.  (Source: Kurt Zeilenga)

   Status: Resolved.

   For -07 draft I've generalized the SASL profile in
       moved Introduction to section 3.3 1. All following sections numbers
       were decremented by one as result.

     - Edits to
   allow any SASL mechanism.

H.33 Clarification on use of password protection fix typos, I-D nits, etc.

     - Opened several new issues in Appendix G based on AuthZID form feedback from
       WG. Some of these have been resolved. Others require further
       discussion.

   Section 3.3.1: "If an authorization identity 1

     - Added additional example of a form different
   from a DN is requested by the client, a mechanism that protects the
   password in transit SHOULD be used." What has that spoofing under threat (7).

   Section 2.1

     - Changed definition of "LDAP association" and added terms,
       "connection" and "TLS connection" to do bring usage in line with DNs?
   A mechanism
       [Protocol].

   Section 4.1.6

     - Clarified sentence stating that protects the password in transit should be used in
   any case, shouldn't it?

   Status: Resolved.

   In -08 draft this text was removed. There is already a general
   security consideration that covers this issue.

H.34 Clarification on client MUST NOT use derived
       forms of matching rules in Server Identity Check

   The text in section 4.1.6 isn't explicit on whether all rules apply DNS names.

   Section 5.1

     - Began edits to both CN LDAP Association state table to clarify meaning
       of various states and dNSName values.  The text should be clear as actions.

     - Added action A9 to which
   rules apply cover abandoned bind operation and added
       appropriate transitions to which values....  in particular, the wildcard
   rules. (Source: Kurt Zeilenga)

H.35 Requested Additions to Security Considerations

   Requested state transition table to mention hostile servers which the user might have been
   fooled
       accommodate it.

   Section 7.2

     - Replaced first paragraph to into contacting. Which mechanisms clarify that are standardized by the LDAP standard do/do not disclose the user's password to the
   server? (Or to servers doing man-in-the-middle attack? Or "DIGEST-MD5" SASL
       mechanism is that a
   stupid question?)

   Requested required to mention denial of service attacks.

   Requested list of methods that need/don't need implement.

   Section 9

     - Rewrote the server section to know make the user's plaintext password. (I say 'know' instead advice more applicable over the
       long term, i.e. more "timeless." The intent of 'store'
   because it could still store the password encrypted, but content in the
       original section was preserved.

   Section 10

     - Added a way
   which it knows how clarifying example to decrypt.)

   (Source: Hallvard Furuseth)

H.36 Add reference the consideration regarding misuse
       of unauthenticated access.

F.6. Changes for draft-ldapbis-authmeth-07

   General

     - Updated external and internal references to definition accommodate changes
       in recent drafts.

     - Opened several new issues in Appendix G based on feedback from
       WG. Some of DIGEST-MD5

   Need a reference these have been resolved. Others require further
       discussion.

   Section 3

     - Rewrote much of section 3.3 to meet the definition of DIGEST-MD5 SASL mechanism in profile
       requirements of draft-ietf-sasl-rfc2222bis-xx.txt section 7.2 (Source: Hallvard Furuseth)

   Status: Resolved. A reference 5.

     - Changed treatement of SASL ANONYMOUS and PLAIN mechanisms to
       bring in line with WG consensus.

   Section 4

     - Note to the DIGEST-MD5 SASL mechanism,
   [DigestAuth], is included implementers in the -07 revision.

H.37 section 4.1.1 based on operational
       experience.

     - Clarification on procedure for certificate-based authentication

   8.1. Certificate-based authentication client continuing by performing a StartTLS with
       TLS states: "Following
   the successful completion already established in section 4.1.4.

     - Moved verification of TLS negotiation, mapping of client's authentication ID to
       asserted authorization ID to apply only to explicit assertion.
       The local policy in place for implicit assertion is adequate.

   Section 7

     - Removed most of section 7.2 as the client will send
   an LDAP bind request with information is now covered
       adequately via the new SASL "EXTERNAL" mechanism." Is this
   immediately following, or just some time later? Should profile in section 3.3. Added note
       to implementors regarding the wording,
   "the client will send..." actually read, "the client MUST send..."?

   Status: Resolved. In -10 this text has been absorbed into treatment of username and realm
       values in DIGEST-MD5.

     - Section 7.3. Minor clarifications in wording.

     - Section 7.3.1. Clarification that a match of the SASL
   EXTERNAL mechanism section.

H.38 Effect presented value
       to any member of Start TLS on authentication state

   Should the server drop all knowledge set of connection, i.e. return to
   anonymous state, if it gets a Start TLS request on stored passwords constitutes a connection that
   has successfully bound using the simple method?

   Status: Resolved. In -09 the effect on an
       successful authentication.

F.7. Changes for draft-ldapbis-authmeth-08

   General
     - Changed usage from LDAPv3 to LDAP association by a
   Start TLS operation is made for usage consistency across
       LDAP technical specification.

     - Fixed a matter number of local policy. This is usage nits for consistency and to bring doc in
       conformance with publication guidelines.

   Abstract

     - Significant cleanup and rewording of abstract based on editorĂs perception of WG consensus gaged by conversations
       feedback.

   Section 2.1

     - New definition of user.

   Section 3

     - Added 1.5 sentences at
   IETF 58 and subsequent discussion end of introductory paragraph indicating
       the effect of the Bind op on the WG  mail list.

H.39 Be sure LDAP association.

   Section 3.1

     - Retitled section and clarified wording

   Section 3.2

     - Clarified that there is a consideration simple authentication choice provides three types
       of authentication: anonymous, unauthenticated, and simple
       password.

   Section 3.3.3

     - New wording clarifying when negotiated security mechanisms take
       effect.

   Section 3.3.5

     - Changed requirement to discard information about server fetched
       prior to SASL negotiation from MUST to SHOULD to allow for
       information obtained through secure mechanisms.

   Section 3.3.6

     - Simplified wording of first paragraph based on suggestion from
       WG.

   Section 3.4

     - Minor clarifications in wording.

   Section 3.4.1

     - Minor clarifications in wording in [SCHEMA] first sentence.

     - Explicitly called out that discusses
multiple password values the DN value in userPassword

   Allowing multiple values obviously does raise a number of security
   considerations and these need the dnAuthzID form is
       to be discussed in matched using DN matching rules.
     - Called out that the document.

   Certainly applications which intend uAuthzID MUST be prepared using SASLprep
       rules before being compared.
     - Clarified requirement on assuming global uniqueness by changing
       a "generally... MUST" wording to replace the userPassword with
   new value(s) should use modify/replaceValues (or
   modify/deleteAttribute+addAttribute). Additionally, server
   implementations should "SHOULD".

   Section 4.1.1

     - Simplified wording describing conditions when StartTLS cannot be encouraged
       sent.
     - Simplified wording in note to provide administrative
   controls which, if enabled, restrict userPassword implementers regarding race
       condition with outstanding LDAP operations on connection.

   Section 4.1.5

     - Removed section and moved relevant text to one value.

H.40. Clarify need section 4.2.2.

   Section 4.1.6

     - Renumbered to verify mapping between authentication identity
and resulting authorization 4.1.5.
     - Updated server identity check rules for server's name based on implicit assertion of AuthZID.

   4.2.2.3. Error Conditions

   "For either form of assertion, the
       WG list discussion.

   Section 4.1.7

     - Renumbered to 4.1.6
     - Changed requirement to discard information about server MUST verify that the
   client's authentication identity as supplied in its fetched
       prior to TLS credentials
   is permitted negotion from MUST to be mapped SHOULD to the asserted authorization identity."

   This makes sense allow for the explicit assertion case, but seems
       information obtained through secure mechanisms.

   Section 6.1

     - Clarified wording.
     - Added definition of anonymous and unauthenticated binds.

   Section 10

     - Added security consideration (moved from elsewhere) discouraging
       use of cleartext passwords on unprotected communication
       channels.

   Section 11

     - Added an IANA consideration to be
   ambiguous update GSSAPI service name
       registry to point to [Roadmap] and [Authmeth]

F.8. Changes for the implicit case.
   IMHO, the mapping can be done as two steps:
   a). deriving draft-ldapbis-authmeth-09

   General

     - Updated section references within document
     - Changed reference tags to match other docs in LDAP authentication identity from TLS credentials; If t
   this steps fails, EXTERNAL mechanism returns failure.
   b). verify that the authorization identity is allowed TS
     - Used non-quoted names for the
   derived authentication identity. This all SASL mechanisms
   Abstract

     - Inspected keyword usage and removed several improper usages.

     - Removed sentence saying DIGEST-MD5 is always "noop" for the
   implicit case.
   I am not sure that the text LDAP's mandatory-to-
       implement mechanism. This is saying this.
   (Source: Alexey Melnikov email 8/1/2003 5:30:43 PM)

   Status: Resolved covered elsewhere in -07. After reading the comments and the text document.

     - Moved section 5, authentication state table, of
   the draft, I believe that this should be clarified. The local policy
   used to map the AuthNID -08 draft to the AuthZID in the implicit case is
   sufficient
       section 8 of -09 and that no additional verification completely rewrote it.

   Section 1

     - Reworded sentence beginning, "It is useful or needed.
   This text has been moved also desirable to apply only allow
       authentication methods to the explicit assertion
   case.

H.41. Section 7.2 contains unnecessary and misleading detail.

   " I am not sure why carry identities based on existing¨
       non-LDAP DN-forms..."
     - Clarified relationship of this section is required document to other documents in
       the document.
   DIGEST-MD5 LDAP TS.

   Section 3.3.5

     - Removed paragraph beginning,"If the client is defined configured to
       support multiple SASL mechanisms..." because the actions
       specified in the paragraph do not provide the protections
       indicated. Added a separate document new paragraph indicating that clients and there
       server should allow specification of acceptable mechanisms and
       only allow those mechanisms to be
   nothing magical about its usage used.

     - Clarified independent behavior when TLS and SASL security layers
       are both in LDAP. If DIGEST-MD5 description
   creates confusion for LDAP implementors, let's fix force (e.g. one being removed doesn't affect the DIGEST-MD5
   document! Also, this
       other).

   Section 3.3.6

     - Moved most of section tries 4.2.2, Client Assertion of Authorization
       Identity, to redefine DIGEST-MD5 behavior,
   which is explicitly prohibited by the SASL specification."
   (Source: Alexey Melnikov: email 8/1/2003 5:30:43 PM)

   Status: Resolved.

   After reading the comments sections 3.3.6, 3.3.6.1, and the text of the draft plus the
   related 3.3.6.2.

   Section 3.3.6.4

     - Moved some normative comments into text in draft-ietf-sasl-rfc2831bis-02.txt plus
   http://www.ietf.org/internet-drafts/draft-ietf-sasl-rfc2222bis-
   02.txt, I am inclined body.

   Section 4.1.2

     - Non success resultCode values are valid if server is *unwilling*
       or unable to agree with Alexey. In -07 I rewrote negotiate TLS.

   Section 4.2.1

     - Rewrote entire section
   3.3 (SASL mechanisms) to match the profiling requirements
   rfc2831bis. I then dramatically reduced the material in based on WG feedback.

   Section 4.2.2

     - Moved most of this section 7.2 to a bare minimum and let the SASL profile stand on its own.

H.42. Does change 3.3.6 for H.41 cause interoperability issue?

   There is one issue with the way the authmeth draft is currently
   written that changes the SASL DIGEST-MD5 behavior better document flow.

   Section 4.2.3

     - Rewrote entire section based on WG feedback.

   Section 5.1

     - Moved imperative language regarding unauthenticated access from
       security considerations to here.

   Section 6

     - Added several paragraphs regarding the way the
   server responds with the subsequent authentication information .
   This has been documented risks of transmitting
       passwords in this fashion since RFC 2829 (section
   6.1) was originally published the clear and may cause an interoperability
   issue at this point if it changed requiring server implementations to follow the
       provide a specific configuration that reduces these risks.

   Section 6.2

     - Added sentence describing protections provided by DIGEST-MD5 spec (as
   it was
       method.
     - Changed DNs in -07 exmple to be dc=example,dc=com.

   Section 10

     - Updated consideration on use of cleartext passwords to include
       other unprotected authentication credentials
     - Substantial rework of consideration on misuse of unauthenticated
       bind.

F.9. Changes for draft-ldapbis-authmeth-10

     - Reorganized content of AuthMeth). Take this issue sections 3-9 to the list.

   Status: improve document flow and
       reduce redundancy.
     - Resolved

   (10/08/03) This item was discussed issue of effect of Start TLS and TLS closure on LDAP
       association state.
     - Made numerous minor wording changes based on the WG feedback.
     - Updated list between 5/2/03 and
   5/9/03. Consensus apppears to support the notion that RFC 2829 was
   in error and that the semantics of RFC 2831 are correct and threats for Section 1.
     - Recommendation that servers should
   be reflected in authmeth. This not support weaker TLS
       ciphersuites unless other protection is already the case as of the -07
   draft.

H.43. DIGEST-MD5 Realms recommendations for LDAP

   From http://www.ietf.org/internet-drafts/draft-ietf-sasl-rfc2222bis-
   02.txt: A protocol profile SHOULD provide a guidance how realms are
   to be constructed and used in the protocol and MAY further restrict
   its syntax place.
     - Moved authentication state table to appendix and protocol-specific semantics."

   I don't believe that any such guidance exists within the LDAP TS.
   The most likely place relettered
       appendices.

F.10. Changes for this draft-ldapbis-authmeth-11

   General

     - Many editorial changes throughout to reside is in the authmeth draft.

   Related email clarify wording and better
       express intent, primarily based on suggestions from Alexey Melnikov (8/4/2003 1:08:40 PM):

   "The problem I have with the document is that it references realm
   without explaining what it is (or at least some examples WG mail
       list.
     - More standard naming of valid
   values). For LDAP, some recommendations should be given. For example:
   1). Use a hardcoded string as the realm (one authentication mechanisms throughout
       document, e.g. "Anonymous Authentication Mechanism of the implementations
   I worked on was doing that)
   2). Use hostname (realm==host) or domain/cluster name (realm
   includes multiple hosts).
   3). Use a node in DIT above user entry, for example for "cn=Barbara
   Jensen, ou=Accounting, o=Ace Industry, c=US"
    and "cn=John Doe, ou=Accounting, o=Ace Industry, c=US" realm can be
   "ou=Accounting, o=Ace Industry, c=US"
   (or "o=Ace Industry, c=US"); for "cn=Gern Jensen, ou=Product
   Testing,o=Ace Industry, c=US" realm can be "ou=Product Testing,
   o=Ace Industry, c=US".

   Of course other choices are possible.

   Alexey

   To summarize:  I'd like authmeth Simple
       Bind Choice".

   Section 1
     - Editorial changes to define a realm name add clarity.
     - Moved section 2 of authmeth -09 into section 1

   Section 2

     - New section outlining implementation requirements.

   Section 3.1.1

     - Editorial clarification on need for following operation
       sequencing requirements.

   Section 3.1.4

     - New section added to describe use of client certificates with
   Digest-MD5 that corresponds
       StartTLS. Incorporates material moved from other sections of
       authmeth -09.

   Section 4
     - New section added to discuss LDAP DNs known to this server.
   Authzid is okay, but perhaps could be better put Associations. Related material
       was moved from various other sections of authmeth -09 and
       incorporated into context.

   John  McMeeking (5/12/2003)

   Status: Resolved.

   draft-ietf-sasl-rfc2222bis-03.txt no longer requires this
   information in a SASL protocol. In addition, the ldapbis WG chairs
   have ruled this work out of scope. Individuals are welcome to make
   submissions to provide guidance on the use of realm new section.

   Section 5

     - Added several paragraphs regarding transmission and realm values
   in LDAP.

H.44. Use derivation
       of DNs in usernames authentication and realms in DIGEST-MD5

   In reading the discussion on the mailing list, I reach authorization identities using the following
   conclusions:

   DIGEST-MD5 username and realm are simple strings. The syntax of
   these strings allows strings that look like DNs in form, however,
   DIGEST-MD5 treats them a simple strings Bind
       operation.

   Section 8

     - Clarified rules for comparision purposes.
   For example, the DNs cn=roger, o=US determining valid credentials and cn=roger,o=us are equivalent
   when being compared semantically as DNs, however, these would be
   considered two different username values in DIGEST-MD5 because
   simple octet-wise semantics (rather than DN semantics) are used to
   compare username values in DIGEST-MD5. Ditto for realm values.

   Status: Resolved.

   In -07 revision I added notes to implementors expressing this issue
   in section 7.2.

H.45: Open Issue: Is Simple+TLS mandatory to implement?

   Going forward, it would be much better to clarify that simple
   +TLS situations
       where invalidCredentials result is to be used for DN/password credentials and DIGEST-MD5
   (or PLAIN+TLS) be used for username/password credentials. (Kurt
   Zeilenga, 5/12/2003)
   I don't believe you can mandate simple/TLS! At the time RFC 2829 was
   debated, a large number returned.

   Section 14

     - Added three security considerations based on the WG wanted this. They did not get
   their way because of feedback.

   Appendix A

     - Simplfied state tables by removing two unnecessary actions from
       the actions table, and removing the complexity current state column of the solution. It was argued
       state transition table. Updated references to authmeth and
       [Protocol].

F.11. Changes for draft-ldapbis-authmeth-12

   General

     - Changed refererences from Start TLS to StartTLS.
     - Removed Appendix B: Example Deployment Scenarios
     - Removed Appendix H as all issues listed in the appendix are now
       resolved.

   Section 2

     - Added implementation requirement that server implementations
       that SUPPORT StartTLS MUST support the
       TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA ciphersuite.

   Section 3.1.2

     - Added wording clarifying that a password-based method would be better. I think they believed
   it would still be DN/password, though. (Ron Ramsay, 5/12/2003)

   This was officially opened as an issue by WG co-chair Kurt Zeilenga
   on 5/12/03. Little direct discussion has occurred since, however
   there has been significant discussion on client's association is
       unaffected if a non-success resultCode is returned in the use
       StartTLS response.

   Section 9.2

     - Final paragraph of DN values as the
   username this section details requirements for DIGEST-MD5.

   Status: Resolved.

   Based
       serverSaslCreds field when no challenge value is sent.

   Section 10

     - Clarified language on uAuthzID usage.

   Section 12

     - Moved entire section into security considerations. New section
       number is 12.1.1.
     - Reorganized security considerations by topic.
     - Added several security considerations based on WG list discussion, Kurt Zeilenga has gaged a lack of WG
   consensus that Simple+TLS should be mandatory feedback.

   Section 13

     - Moved section to implement. No
   further discussion is necessary. become section 3.3.

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