INTERNET-DRAFT                                      Editor: R. Harrison
draft-ietf-ldapbis-authmeth-06.txt
draft-ietf-ldapbis-authmeth-07.txt                              Novell, Inc.
Obsoletes: 2829, 2830                                      28 June                                    7 October 2003
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 provisions of Section 10 of RFC2026.

   This document is intended to be, after appropriate review and
   revision, submitted to the RFC Editor as a Standard Track document.
   Distribution of this memo is unlimited.  Technical discussion of
   this document will take place on the IETF LDAP Extension Working
   Group mailing list <ietf-ldapbis@OpenLDAP.org>.  Please send
   editorial comments directly to the author
   <roger_harrison@novell.com>.

   Internet-Drafts are working documents of the Internet Engineering
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Copyright Notice

   Copyright (C) The Internet Society (2003).  All Rights Reserved.

Abstract

   This document describes LDAPv3 (Lightweight Directory Access
   Protocol v3) authentication methods and connection level security
   mechanisms that are required of all conforming LDAPv3 server
   implementations and makes recommendations for combinations of these
   mechanisms to be used in various deployment circumstances.

   Among the mechanisms described are

     - various forms of authentication including anonymous
       authentication, password-based authentication, and certificate
       based authentication
     - the use of SASL mechanisms with LDAPv3
     - the use of TLS (Transport Layer Security) with LDAPv3

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

1. Introduction

   This document is an integral part of the LDAP Technical
   Specification [ROADMAP]. This document replaces RFC 2829 and
   portions of RFC 2830. Changes to RFC 2829 are summarized in Appendix
   C and changes to RFC 2830 are summarized in Appendix D.

   LDAPv3 is a powerful access protocol for 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 LDAPv3 conformance.

   Basic threats to an LDAP directory service include:

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

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

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

   (4) Unauthorized modification of directory data,

   (5) Unauthorized modification of configuration information,

   (6) Unauthorized or excessive use of resources (denial of service),
       and

   (7) Spoofing of directory: Tricking a 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. Also, tricking a client into sending privileged
       information to a hostile entity that appears to be the directory
       but is not.

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

   The LDAP protocol suite can be protected with the following security
   mechanisms:

   (1) Client authentication by means of the SASL [RFC2222] [SASL] mechanism set,
       possibly backed by the TLS [RFC2246] credentials exchange
       mechanism,

   (2) Client authorization by means of access control based on the
       requestor's authenticated identity,

   (3) Data integrity protection by means of the TLS protocol or SASL
       mechanisms that provide data integrity services,

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

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

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

   At the moment, imposition of access controls is done by means
   outside the scope of the LDAPv3 protocol.

   It seems clear that allowing any implementation, 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 mechanisms like the LDAPv3
   simple bind using clear text passwords that provide inadequate
   security for most circumstances.

   Given the presence of the Directory, there is a strong desire to see
   mechanisms where identities take the form of an LDAP distinguished
   name [LDAPDN] and authentication data can be stored in the
   directory. This means that this data must be updated outside the
   protocol or only updated in sessions well protected against
   snooping. It is also desirable to allow authentication methods to
   carry authorization identities based on existing--non-LDAP DN--forms
   of user identities for backwards compatibility with non-LDAP-based
   authentication services.

   The set of security mechanisms provided in LDAPv3 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 LDAPv3 implementations and
   deployments. Appendix A contains example deployment scenarios that
   list the mechanisms that might be used to achieve a reasonable level
   of security in various circumstances.

2. Conventions Used in this Document

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 application which is an LDAP client using
       the directory to retrieve or store information.

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

     - "TLS connection" refers to a TLS-protected LDAP connection.

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

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 B 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 B before reading the remainder of this document.

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].

3. Bind Operation

   The Bind operation defined in section 4.2 of [PROTOCOL] [Protocol] allows
   authentication information to be exchanged between the client and
   server.

3.1. Unbound Connection Treated as Anonymous ("Implied Anonymous Bind")

   Unlike LDAP version 2, the client need not send a Bind Request in
   the first PDU of the connection. The client may send any operation
   request prior to binding, and the server MUST treat it as if it had
   been performed after an anonymous bind operation. If the server
   requires that the client bind before browsing or modifying the
   directory, the server MAY reject a request other than binding,
   unbinding or an extended request with the "operationsError" result.

3.2. Simple Authentication
   The simple authentication option provides minimal authentication
   facilities, with the contents of the authentication field consisting
   only of a cleartext password. Note that the use of cleartext
   passwords is strongly discouraged over open networks when the
   underlying transport service cannot guarantee confidentiality (see
   section 8).

3.3. SASL Authentication

   The sasl authentication option Profile

   LDAP allows for authentication via any SASL mechanism defined for
   use with [SASL]. As LDAP
   includes native anonymous and plaintext authentication methods, the
   "ANONYMOUS" [ANONYMOUS] and "PLAIN" [PLAIN] SASL [RFC2222] mechanisms are
   typically not specifically prohibited by this document
   (see section 3.3.1).

   Clients sending a bind request used with LDAP.

   Each protocol that utilizes SASL services is required to supply
   certain information profiling the sasl choice selected SHOULD
   NOT send a value in way they are exposed through the
   protocol ([SASL] section 5). This section explains how each of these
   profiling requirements are met by LDAPv3.

3.3.1. SASL Service Name for LDAP

   The SASL service name field. Servers receiving for LDAPv3 is "ldap", which has been
   registered with the IANA as a GSSAPI service name.

3.3.2. SASL authentication initiation and protocol exchange

   SASL authentication is initiated via an LDAP bind request
   ([Protocol] section 4.2) with the sasl choice selected SHALL ignore any value in the name
   field. following parameters:

      - The version is 3.
      - The AuthenticationChoice is sasl.
      - The mechanism field in element of the SaslCredentials sequence contains
        the name value of the desired SASL mechanism.
      - The optional credentials field contains of of the arbitrary data SaslCredentials
        sequence may be used
   for authentication, inside to provide an OCTET STRING wrapper. Note initial client response for
        mechanisms that unlike
   some Internet application protocols where SASL is used, LDAP is not
   text-based, thus no Base64 transformations are performed on the
   credentials.

   If any SASL-based integrity or confidentiality services are enabled,
   they take effect following the transmission by the server and
   reception by defined to have the client of the final BindResponse with send data first
        (see [SASL] sections 5 and 6.1).

   In general, a resultCode SASL authentication protocol exchange consists of success.

   If a SASL security layer is negotiated, the
   series of server challenges and client MUST discard all
   information about responses, the server fetched prior to the initiation contents of
   which are specific to and defined by the SASL negotiation. If the client is configured to support multiple mechanism. Thus for
   some SASL authentication mechanisms, it SHOULD fetch the supportedSASLmechanisms list
   both before and after the SASL security layer is negotiated. This
   allows may be necessary for the
   client to detect active attacks that remove supported
   SASL mechanisms from the supportedSASLMechanisms list and allows the
   client respond to ensure that it is using the best mechanism supported one or more server challenges by
   both client and server. (This requirement is a SHOULD to allow for
   environments where invoking the supportedSASLMechanisms list
   BindRequest multiple times. A challenge is provided to indicated by the client through a different trusted source, e.g. as part of server
   sending a
   digitally signed object.)

   The client can request BindResponse with the resultCode set to
   saslBindInProgress. This indicates that the server use authentication
   information from requires the
   client to send a lower layer protocol by using new bind request, with the SASL EXTERNAL same sasl mechanism (see section 4.2.2.).

3.3.1. Use of ANONYMOUS and PLAIN SASL Mechanisms

   As LDAP includes native anonymous and plaintext to
   continue the authentication
   methods, process.

   To the "ANONYMOUS" encapsulating protocol, these challenges and "PLAIN" SASL mechanisms responses are not used
   with LDAP. If an authorization identity
   opaque binary tokens of a form different from a
   DN is requested by the client, a data confidentiality mechanism that
   protects arbitrary length. LDAP servers use the password
   serverSaslCreds field, an OCTET STRING, in transit should be used.

3.3.2. Use of EXTERNAL SASL Mechanism

   The "EXTERNAL" SASL mechanism can be used a bind response message
   to request the transmit each challenge. LDAP server
   make clients use of security the credentials exchanged by a lower layer. If field,
   an OCTET STRING, in the SaslCredentials sequence of a
   TLS session has not been established between the client and server
   prior bind request
   message to making the transmit each response. Note that unlike some Internet
   application protocols where SASL EXTERNAL Bind request and there is no other
   external source of authentication credentials (e.g. IP-level
   security [RFC2401]), or if during the process of establishing the
   TLS session, the server did used, LDAP is not text-based,
   thus no Base64 transformations are performed on these challenge and
   response values.

   Clients sending a bind request with the client's authentication
   credentials, sasl choice selected SHOULD
   NOT send a value in the SASL EXTERNAL name field. Servers receiving a bind MUST fail request
   with a resultCode of
   inappropriateAuthentication. Any client authentication and
   authorization state of the LDAP association is lost, so the LDAP
   association is sasl choice selected SHALL ignore any value in an anonymous state after the failure (see
   [PROTOCOL] section 4.2.1).

3.3.3. Other SASL Mechanisms

   Other SASL mechanisms name
   field.

   A client may be used abort a SASL bind negotiation by sending a BindRequest
   with LDAP, but their usage is not
   considered a different value in this document.

3.4. SASL Authorization Identity

   The authorization identity is carried as part of the SaslCredentials
   credentials mechanism field in of SaslCredentials, or
   an AuthenticationChoice other than sasl.

   If the Bind request and response.

   When client sends a BindRequest with the "EXTERNAL" SASL sasl mechanism is being negotiated, if the
   credentials field is present, it contains as
   an authorization identity
   of empty string, the authzId form described below.

   Other mechanisms define server MUST return a BindResponse with
   authMethodNotSuppored as the location 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 authorization identity SASL challenge-response
   exchange  by responding with a bind response in which the credentials field.

3.4.1. Authorization Identity Syntax

   The authorization identity resultCode
   is a string either success, or an error indication.

   The serverSaslCreds field in the UTF-8 character set,
   corresponding bind response can be used to the following ABNF grammar [RFC2234]:

   ; Specific predefined authorization (authz) id schemes
   include an optional challenge with a success notification for
   mechanisms which are
   ; defined below -- new schemes may be defined in to have the future.

   authzId = dnAuthzId / uAuthzId

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

   ; distinguished-name-based authz id.
   dnAuthzId = DNCOLON dn
   dn = utf8string    ; server send additional data
   along with syntax defined in [LDAPDN] section 3.

   ; unspecified authorization id, UTF-8 encoded.
   uAuthzId = UCOLON userid
   userid = utf8string    ; syntax unspecified
   The dnAuthzId choice allows client applications to assert
   authorization identities in the form indication of a distinguished name. The
   decision to allow successful completion.

3.3.3. Octet where negotiated security mechanisms take effect

   If any SASL-based integrity or disallow an authentication identity to have
   access to confidentiality services are enabled,
   they take effect following the requested authorization identity is a matter of local
   policy ([SASL] section 4.2). For this reason there is no requirement
   that transmission by the asserted dn be that server and
   reception by the client of an entry in directory.

   The uAuthzId choice allows for compatibility the final BindResponse with client
   applications that wish to assert an authorization identity to a
   local directory but do not have that identity in distinguished name
   form. The format resultCode
   of utf8string is defined as only a sequence success.

3.3.4. Determination of UTF-
   8 encoded ISO 10646 characters, and further interpretation is
   subject to prior agreement between the supported SASL mechanisms

   An LDAP client and server.

   For example, may determine the userid could identify a user of SASL mechanisms a specific
   directory service, or be server supports
   by performing a login name or search request on the local-part root DSE, requesting the
   supportedSASLMechanisms attribute. The values of an RFC
   822 email address. In general, this attribute, if
   any, list the mechanisms the server supports.

3.3.5. Rules for using SASL security layers

   If a uAuthzId SASL security layer is negotiated, the client MUST NOT be assumed discard all
   information about the server fetched prior to be
   globally unique.

   Additional authorization identity schemes MAY be defined in future
   versions the initiation of this document.

3.5. SASL Service Name for LDAP

   For use with the
   SASL [RFC2222], a protocol must specify a service name negotiation. If the client is configured to be used with various support multiple
   SASL mechanisms, such as GSSAPI. For LDAP, it SHOULD fetch the service name supportedSASLmechanisms list
   both before and after the SASL security layer is "ldap", which has been registered with negotiated. This
   allows the IANA
   as a GSSAPI service name.

3.6. client to detect active attacks that remove supported
   SASL Integrity mechanisms from the supportedSASLMechanisms list and Privacy Protections

   Any negotiated SASL integrity allows the
   client to ensure that it is using the best mechanism supported by
   both client and privacy protections SHALL start on server. (This requirement is a SHOULD to allow for
   environments where the first octet of supportedSASLMechanisms list is provided to
   the first LDAP PDU following successful
   completion client through a different trusted source, e.g. as part of the SASL bind operation. a
   digitally signed object.)

   If a lower level security layer (such as TLS) is negotiated, such as TLS, any
   SASL security services SHALL be layered on top of such security
   layers regardless of the order of their negotiation.

4. Start TLS Operation

   The Start Transport Layer Security (StartTLS) operation defined in
   section 4.13

3.3.6. Use of [PROTOCOL] provides EXTERNAL SASL Mechanism

   A client can use the ability "EXTERNAL" SASL mechanism to establish
   Transport Layer Security [RFC2246] on an request the LDAP association.

4.1. Sequencing
   server to make use of the Start security credentials exchanged by a lower
   layer. If a TLS Operation

   This section describes session has not been established between the overall procedures clients client
   and servers
   must follow for TLS establishment. These procedures take into
   consideration various aspects of the overall security of server prior to making the LDAP
   association including discovery SASL EXTERNAL Bind request and there
   is no other external source of resultant security authentication credentials (e.g. IP-
   level and
   assertion security [RFC2401]), or if during the process of establishing
   the TLS session, the server did not request the client's authorization identity.

   Note that
   authentication credentials, the precise effects, on SASL EXTERNAL bind MUST fail with a client's
   resultCode of inappropriateAuthentication. Any client authentication
   and authorization identity, state of establishing TLS on an the LDAP association are described in detail is lost, so the LDAP
   association is in section 4.5.

4.1.1. Requesting to Start TLS on an LDAP Association anonymous state after the failure (see
   [Protocol] section 4.2.1).

3.4. SASL Authorization Identity

   The client MAY send authorization identity is carried as part of the Start TLS extended request at any time after
   establishing an LDAP association, except that SaslCredentials
   credentials field in the following cases Bind request and response.

   When the client MUST NOT send a Start TLS extended request:

        - if TLS "EXTERNAL" SASL mechanism is currently established on being negotiated, if the connection, or
        - during a multi-stage SASL negotiation, or
        - if there
   credentials field is present, it contains an authorization identity
   of the authzId form described below.

   Other mechanisms define the location of the authorization identity
   in the credentials field.

3.4.1. Authorization Identity Syntax

   The authorization identity is a string in the UTF-8 character set,
   corresponding to the following ABNF grammar [RFC2234]:

   ; Specific predefined authorization (authz) id schemes are any LDAP operations outstanding on
   ; defined below -- new schemes may be defined in the
          connection. future.

   authzId = dnAuthzId / uAuthzId

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

   ; distinguished-name-based authz id.
   dnAuthzId = DNCOLON dn
   dn = utf8string    ; with syntax defined in [LDAPDN] section 3.

   ; unspecified authorization id, UTF-8 encoded.

   uAuthzId = UCOLON userid
   userid = utf8string    ; syntax unspecified

   The result of violating any dnAuthzId choice allows client applications to assert
   authorization identities in the form of these requirements a distinguished name. The
   decision to allow or disallow an authentication identity to have
   access to the requested authorization identity is a resultCode matter of
   operationsError, as described above in [PROTOCOL] local
   policy ([SASL] section 14.3.2.2.

   In particular, 4.2). For this reason there is no requirement
   that the client have or have
   not already performed a Bind operation before sending a Start TLS
   operation request. asserted dn be that of an entry in directory.

   The uAuthzId choice allows for compatibility with client may have already performed a Bind
   operation when it sends
   applications that wish to assert an authorization identity to a Start TLS request, or the client might
   have not yet bound.

   If the client did
   local directory but do not establish have that identity in distinguished name
   form. The format of utf8string is defined as only a TLS connection before sending any
   other requests, sequence of UTF-
   8 encoded ISO 10646 characters, and the server requires further interpretation is
   subject to prior agreement between the client to establish a
   TLS connection before performing a particular request, and server.

   For example, the server
   MUST reject that request by sending userid could identify a resultCode user of
   confidentialityRequired a specific
   directory service, or strongAuthRequired. In response, the
   client MAY send be a Start TLS extended request, login name or it MAY choose to
   close the connection.

4.1.2. Starting TLS

   The server will return an extended response with the resultCode local-part of
   success if it is willing and able an RFC
   822 email address. In general, a uAuthzId MUST NOT be assumed to negotiate TLS.  It will return
   other resultCodes (documented be
   globally unique.

   Additional authorization identity schemes MAY be defined in [PROTOCOL] section 4.13.2.2) if it
   is unable to do so.

   In future
   versions of this document.

3.5. SASL Integrity and Privacy Protections

   Any negotiated SASL integrity and privacy protections SHALL start on
   the successful case, first octet of the client (which has ceased to transfer first LDAP requests PDU following successful
   completion of the SASL bind operation. If lower level security layer
   is negotiated, such as TLS, any SASL security services SHALL be
   layered on top of such security layers regardless of the connection) MUST either begin a order of
   their negotiation.

4. Start TLS negotiation
   or close the connection. Operation

   The client will send PDUs Start Transport Layer Security (StartTLS) operation defined in
   section 4.13 of [Protocol] provides the TLS Record
   Protocol directly over the underlying transport connection to the
   server to initiate TLS negotiation [RFC2246].

4.1.3. TLS Version Negotiation

   Negotiating the version of TLS or SSL to be used is a part of the
   TLS Handshake Protocol, as documented in [RFC2246]. Please refer ability to
   that document for details.

4.1.4. Discovery of Resultant establish
   Transport Layer Security Level
   After a TLS connection is established [RFC2246] on an LDAP association, both
   parties MUST individually decide whether or not to continue based on
   the privacy level achieved. Ascertaining association.

4.1. Sequencing of the Start TLS connection's
   privacy level is implementation dependent, Operation

   This section describes the overall procedures clients and accomplished by
   communicating with one's respective local servers
   must follow for TLS implementation.

   If establishment. These procedures take into
   consideration various aspects of the client or server decides that overall security of the LDAP
   association including discovery of resultant security level and
   assertion of authentication or
   privacy is not high enough for it to continue, it SHOULD gracefully
   close the TLS connection immediately after client's authorization identity.

   Note that the precise effects, on a client's authorization identity,
   of establishing TLS negotiation has
   completed (see [PROTOCOL] section 4.13.3.1 and on an LDAP association are described in detail
   in section 4.2.3 below).
   If the client decides to continue, it MAY attempt 4.2.

4.1.1. Requesting to Start TLS
   again, it MAY send on an unbind request, or it MAY send any other LDAP
   request.

4.1.5. Assertion of Client's Authorization Identity Association
   The client MAY, upon receipt of a MAY send the Start TLS response indicating
   success, assert extended request at any time after
   establishing an LDAP association, except that a specific authorization identity be utilized in determining the client's authorization status. The following cases
   the client
   accomplishes this via an LDAP Bind request specifying MUST NOT send a Start TLS extended request:

        - if TLS is currently established on the connection, or
        - during a multi-stage SASL
   mechanism of "EXTERNAL" [RFC2222] (see section 4.5.1.2 below).

4.1.6. Server Identity Check negotiation, or
        - if there are any LDAP operations outstanding on the
          connection.

   The client MUST check its understanding result of the server's hostname
   against the server's identity violating any of these requirements is a resultCode of
   operationsError, as presented in the server's
   Certificate message described in order to prevent man-in-the-middle attacks.

   Matching is performed according to these rules:

     - The client MUST use the server hostname [Protocol] section 4.13.2.2. Client
   implementers should note that it used is possible to open get back a
   resultCode of success in the case where LDAP operations are
   outstanding on the connection as at the value to compare against time a Start TLS operation
   request is sent by the client but they are processed by the server name as
       expressed in
   prior to its receiving the server's certificate.  The client MUST NOT use
       any other derived form of name (including Start TLS request from the client.
   Implementors should ensure that derived by DNS
       canonicalization).

     - If a subjectAltName extension they do not inadvertently depend
   upon this race condition for proper functioning of type dNSName their
   applications.

   In particular, there is present in no requirement that the
       certificate, client have or have
   not already performed a Bind operation before sending a Start TLS
   operation request. The client may have already performed a Bind
   operation when it SHOULD be used as sends a Start TLS request, or the source of client might
   have not yet bound.

   If the server's
       identity.

     - Matching is case-insensitive.

     - 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 client did 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), establish a match in TLS connection before sending 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
   other requests, and the user server requires the opportunity client to
   continue with the establish a
   TLS connection in any case) or terminate before performing a particular request, the
   connection and indicate server
   MUST reject that request by sending a resultCode of
   confidentialityRequired or strongAuthRequired. In response, the server's identity is suspect.
   Automated clients SHOULD
   client MAY send a Start TLS extended request, or it MAY choose to
   close the connection, returning and/or
   logging connection.

4.1.2. Starting TLS

   The server will return an error indicating that extended response with the server's identity resultCode of
   success if it is suspect.

   Beyond the server identity checks described willing and able to negotiate TLS.  It will return
   other resultCodes (documented in this section, clients
   SHOULD be prepared [Protocol] section 4.13.2.2) if it
   is unable to do further checking to ensure that so.

   In the server
   is authorized to provide successful case, the service it is observed to provide. The client MAY need (which has ceased to make use of local policy information.

4.1.7. Refresh of Server Capabilities Information

   Upon TLS session establishment, transfer
   LDAP requests on the client connection) MUST discard all
   information about the server fetched prior to either begin a TLS negotiation
   or close the initiation of connection. The client will send PDUs in the TLS negotiation and MUST refresh any cached server capabilities
   information (e.g. from Record
   Protocol directly over the server's root DSE; see section 3.4 of
   [PROTOCOL]). This is necessary underlying transport connection to protect against active-
   intermediary attacks that may have altered any the
   server capabilities
   information retrieved prior to initiate TLS establishment.

   The server MAY advertise different capabilities after negotiation [RFC2246].

4.1.3. TLS
   establishment. In particular, Version Negotiation

   Negotiating the value version of supportedSASLMechanisms
   MAY be different after TLS has been negotiated (specifically, the
   EXTERNAL mechanism or the proposed PLAIN mechanism are likely SSL to
   only be listed after used is a TLS negotiation has been performed).

4.2. Effects part of TLS on a Client's Authorization Identity

   This section describes the effects on
   TLS Handshake Protocol, as documented in [RFC2246]. Please refer to
   that document for details.

4.1.4. Discovery of Resultant Security Level
   After a client's authorization
   identity brought about by establishing TLS connection is established on an LDAP association.
   The default effects are described first, association, both
   parties MUST individually decide whether or not to continue based on
   the privacy level achieved. Ascertaining the TLS connection's
   privacy level is implementation dependent, and next accomplished by
   communicating with one's respective local TLS implementation.

   If the facilities for client assertion of authorization identity are discussed including
   error conditions. Finally, or server decides that the effects level of closing authentication or
   privacy is not high enough for it to continue, it SHOULD gracefully
   close the TLS connection
   are described.

   Authorization identities and related concepts are described in
   Appendix B.

4.2.1. Default Effects

   Upon establishment of immediately after the TLS session onto the LDAP association, any
   previously established authentication negotiation has
   completed (see [Protocol] section 4.13.3.1 and authorization identities
   MUST remain in force, including anonymous state. This holds even in
   the case where section 4.2.3 below).
   If the server requests client authentication via TLS --
   e.g. requests decides to continue, it MAY gracefully close the client TLS
   connection and attempt to supply its certificate during Start TLS
   negotiation (see [RFC2246]).

4.2.2. Client again, it MAY send an unbind
   request, or it MAY send any other LDAP request.

4.1.5. Assertion of Client's Authorization Identity

   A

   The client MAY either implicitly request that its LDAP authorization
   identity be derived from its authenticated MAY, upon receipt of a Start TLS credentials or it MAY
   explicitly provide an authorization identity and response indicating
   success, assert that it a specific authorization identity be
   used utilized
   in combination with its authenticated TLS credentials. The
   former is known as an implicit assertion, and determining the latter as an
   explicit assertion.

4.2.2.1. Implicit Assertion

   An implicit client's authorization identity assertion is accomplished after
   TLS establishment by invoking a status. The client
   accomplishes this via an LDAP Bind request of the specifying a SASL form using
   the "EXTERNAL"
   mechanism name [RFC2222] [PROTOCOL] that SHALL NOT
   include the optional credentials octet string (found within the
   SaslCredentials sequence in the Bind Request). of "EXTERNAL" [SASL] (see section 4.2.2 below).

4.1.6. Server Identity Check

   The server will
   derive client MUST check its understanding of the client's authorization identity from server's hostname
   against the authentication server's identity supplied as presented in the client's TLS credentials (typically a
   public key certificate) according to local policy. The underlying
   mechanics of how this is accomplished are implementation specific.

4.2.2.2. Explicit Assertion

   An explicit authorization identity assertion server's
   Certificate message in order to prevent man-in-the-middle attacks.

   Matching is accomplished after
   TLS establishment by invoking a Bind request of the SASL form using
   the "EXTERNAL" mechanism name [RFC2222] [PROTOCOL] that SHALL
   include the credentials octet string. This string performed according to these rules:

     - The client MUST be
   constructed as documented in section 3.4.1.

4.2.2.3. Error Conditions

   For either form of assertion, use the server MUST verify that hostname it used to open the
   client's authentication identity LDAP
       connection as supplied in its TLS credentials
   is permitted to be mapped the value to compare against the asserted authorization identity.
   The server MUST reject the Bind operation with an invalidCredentials
   resultCode name as
       expressed in the Bind response if the server's certificate.  The client is not so authorized.

   Additionally, with either MUST NOT use
       any other derived form of assertion, if name (including that derived by DNS
       canonicalization).

     - If a TLS session has
   not been established between subjectAltName extension of type dNSName is present in the client and server prior to making
       certificate, it SHOULD be used as the SASL EXTERNAL Bind request and there is no other external source of authentication credentials (e.g. IP-level security [RFC2401]), or
   if during the process of establishing the TLS session, server's
       identity.

     - Matching is case-insensitive.

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

       For example, *.bar.com would match a.bar.com and b.bar.com, but
       it would not request the client's authentication credentials, the SASL
   EXTERNAL bind MUST fail with a result code match a.x.bar.com nor would it match bar.com.  If
       more than one identity of
   inappropriateAuthentication.

   After a given type is present in the above Bind operation failures,
       certificate (e.g. more than one dNSName name), a match in any client authentication
   and authorization state
       one of the LDAP association set is lost (see
   [PROTOCOL] section 4.2.1), so considered acceptable.

   If the LDAP association is 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
   anonymous state after error indicating that the failure.  The TLS session state server's identity is
   unaffected, though a suspect.

   Beyond the server MAY end identity checks described in this section, clients
   SHOULD be prepared to do further checking to ensure that the TLS session, via a TLS
   close_notify message, based on server
   is authorized to provide the Bind failure (as service it is observed to provide. The
   client MAY at any
   time).

4.2.3. TLS Connection Closure Effects

   Closure need to make use of the local policy information.

4.1.7. Refresh of Server Capabilities Information

   Upon TLS session establishment, the client MUST cause discard all
   information about the LDAP association to move server fetched prior to an anonymous authentication and authorization state regardless the initiation of the state established over
   TLS negotiation and regardless of MUST refresh any cached server capabilities
   information (e.g. from the authentication
   and authorization state prior server's root DSE; see [Model] section
   5.1). This is necessary to TLS session establishment.

5. LDAP Association State Transition Tables

   To comprehensively diagram protect against active-intermediary
   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 various authentication and value of supportedSASLMechanisms
   MAY be different after TLS states
   through which an LDAP association may pass, this section provides a
   state transition table has been negotiated (specifically, the
   EXTERNAL and PLAIN [PLAIN] mechanisms are likely to represent be listed only
   after a state diagram for TLS negotiation has been performed).

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

   This section describes the various
   states through which effects on a client's authorization
   identity brought about by establishing TLS on an LDAP association may pass during association.
   The default effects are described first, and next the course facilities for
   client assertion of its existence and authorization identity are discussed including
   error conditions. Finally, the actions that cause these changes effects of closing the TLS connection
   are described.

   Authorization identities and related concepts are described in state.

5.1. LDAP Association States

   The following table lists
   Appendix B.

4.2.1. Default Effects

   Upon establishment of the TLS session onto the valid LDAP association states association, any
   previously established authentication and
   provides a description of each authorization identities
   MUST remain in force, including anonymous state. The ID for each state is used This holds even in
   the state transition table in section 5.4.

   ID State Description case where the server requests client authentication via TLS -- --------------------------------------------------------------
   S1 Anonymous
       no Authentication  ID is associated with
   e.g. requests the LDAP connection
       no client to supply its certificate during TLS
   negotiation (see [RFC2246]).

4.2.2. Client Assertion of Authorization ID Identity

   A client MAY either implicitly request that its LDAP authorization
   identity be derived from its authenticated TLS credentials or it MAY
   explicitly provide an authorization identity and assert that it be
   used in combination with its authenticated TLS credentials. The
   former is known as an implicit assertion, and the latter as an
   explicit assertion.

4.2.2.1. Implicit Assertion

   An implicit authorization identity assertion is accomplished after
   TLS establishment by invoking a Bind request of the SASL form using
   the "EXTERNAL" mechanism name [SASL] [Protocol] that SHALL 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 in the client's TLS credentials (typically a
   public key certificate) according to local policy. The underlying
   mechanics of how this is accomplished are implementation specific.

4.2.2.2. Explicit Assertion

   An explicit authorization identity assertion is accomplished after
   TLS establishment by invoking a Bind request of the SASL form using
   the "EXTERNAL" mechanism name [SASL] [Protocol] that SHALL include
   the credentials octet string. This string MUST be constructed as
   documented in section 3.4.1.

   The server MUST verify that the client's authentication identity as
   supplied in its TLS credentials is permitted to be mapped to 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.

4.2.2.3. Error Conditions

   Additionally, with either form of assertion, if a TLS session has
   not been established between the client and server prior to making
   the SASL EXTERNAL Bind request and there is no other external source
   of authentication credentials (e.g. IP-level security [RFC2401]), or
   if during the process of establishing the TLS session, the server
   did not request the client's authentication credentials, the SASL
   EXTERNAL bind MUST fail with a result code of
   inappropriateAuthentication.

   After the above Bind operation failures, any client authentication
   and authorization state of the LDAP association is lost (see
   [Protocol] section 4.2.1), so the LDAP association is in an
   anonymous state after the failure.  The TLS session state is
   unaffected, though a server MAY end the TLS session, via a TLS
   close_notify message, based on the Bind failure (as it MAY at any
   time).

4.2.3. TLS Connection Closure Effects

   Closure of the TLS session MUST cause the LDAP association to move
   to an anonymous authentication and authorization state regardless of
   the state established over TLS and regardless of the authentication
   and authorization state prior to TLS session establishment.

5. LDAP Association State Transition Tables

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

5.1. 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 5.4.

   ID State Description
   -- --------------------------------------------------------------
   S1 Anonymous
       no Authentication  ID is associated with the LDAP connection
       no Authorization ID is in force
       No security layer is in effect.
       No TLS credentials have been provided
       TLS: no Creds, OFF]
   S2 no Auth ID
       no AuthZ ID
       [TLS: no Creds, ON]
   S3 no Auth ID
       no AuthZ ID
       [TLS: Creds Auth ID "I", ON]
   S4 Auth ID = Xn
       AuthZ ID= Y
       [TLS: no Creds, OFF]
   S5 Auth ID = Xn
       AuthZ ID= Yn
       [TLS: no Creds, ON]
   S6 Auth ID = Xn
       AuthZ ID= Yn
       [TLS: Creds Auth ID "I", ON]
   S7 Auth ID = I
       AuthZ ID= J
       [TLS: Creds Auth ID "I", ON]
   S8 Auth ID = I
       AuthZ ID= K
       [TLS: Creds Auth ID "I", ON]

5.2. Actions that Affect LDAP Association State

   The following table lists the actions that can affect the state of
   an LDAP association. The ID for each action is used in the state
   transition table in section 5.4.

   ID Action
   -- ------------------------------------------------
   A1 Client binds anonymously
   A2 Inappropriate authentication: client attempts an anonymous
       bind or a bind without supplying credentials to a server that
       requires the client to provide some form of credentials.
   A3 Client Start TLS request
       Server: client auth NOT required
   A4 Client: Start TLS request
       Server: client creds requested
       Client: [TLS creds: Auth ID "I"]
   A5 Client or Server: send TLS closure alert ([PROTOCOL] ([Protocol] section
       X)
   A6 Client: Bind w/simple password or SASL mechanism (e.g. DIGEST-
       MD5 password, Kerberos, etc. -- etc., except EXTERNAL [Auth ID "X"
       maps to AuthZ ID "Y"]
   A7 Client Binds SASL EXTERNAL with credentials: AuthZ ID "J"
       [Explicit Assertion (section 4.2.1.2.2)]
   A8 Client Bind SASL EXTERNAL without credentials [Implicit
       Assertion (section 4.2.1.2.1)]
   A9 Client abandons a bind operation or bind operation fails

5.3. Decisions Used in Making LDAP Association State Changes

   Certain changes in the 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 change in the state transition table in section 5.4.

   ID Decision Question
   -- --------------------------------------------------------------
   D1 Can TLS Credentials Auth ID "I" be mapped to AuthZ ID "J"?
   D2 Can a valid AuthZ ID "K" be derived from TLS Credentials Auth
       ID "I"?

5.4. LDAP Association State Transition Table

   The LDAP Association table below lists the valid states for an LDAP
   association and the actions that could affect them. For any given
   row in the table, the Current State column gives the state of an
   LDAP association, the Action column gives an action that could
   affect the state of an LDAP assocation, and the Next State column
   gives the resulting state of an LDAP association after the action
   occurs.

   The initial state for the state machine described in this table is
   S1.

   Current                 Next
    State  Action         State Comment
   ------- -------------  ----- -----------------------------------
      S1    A1              S1
      S1    A2              S1   Error: Inappropriate authentication
      S1    A3              S2
      S1    A4              S3
      S1    A6              S4
      S1    A7               ?   identity could be provided by
                                  another underlying mechanism such
                                  as IPSec.
      S1    A8               ?   identity could be provided by
                                  another underlying mechanism such
                                  as IPSec.
      S2    A1              S2
      S2    A2              S2   Error: Inappropriate authentication
      S2    A5              S1
      S2    A6              S5
      S2    A7               ?   identity could be provided by
                                  another underlying mechanism such
                                  as IPSec.
      S2    A8               ?   identity could be provided by
                                  another underlying mechanism such
                                  as IPSec.
      S3    A1              S3
      S3    A2              S3   Error: Inappropriate authentication
      S3    A5              S1
      S3    A6              S6
      S3    A7 and D1=NO    S3   Error: InvalidCredentials
      S3    A7 and D1=YES   S7
      S3    A8 and D2=NO    S3   Error: InvalidCredentials
      S3    A8 and D2=YES   S8
      S4    A1              S1
      S4    A2              S4              S1   Error: Inappropriate Authentication
      S4    A3              S5
      S4    A4              S6
      S4    A5              S1
      S4    A6              S4
      S4    A7               ?   identity could be provided by
                                  another underlying mechanism such
                                  as IPSec.
      S4    A8               ?   identity could be provided by
                                  another underlying mechanism such
                                  as IPSec.
      S5    A1              S2
      S5    A2              S5              S2   Error: Inappropriate Authentication
      S5    A5              S1
      S5    A6              S5
      S5    A7               ?   identity could be provided by
                                  another underlying mechanism such
                                  as IPSec.
      S5    A8               ?   identity could be provided by
                                  another underlying mechanism such
                                  as IPSec.
      S6    A1              S3
      S6    A2              S6              S2   Error: Inappropriate Authentication
      S6    A5              S1
      S6    A6              S6
      S6    A7 and D1=NO    S6   Error: InvalidCredentials
      S6    A7 and D1=YES   S7
      S6    A8 and D2=NO    S6    S3   Error: InvalidCredentials
      S6    A8 and D2=YES   S8
      S7    A1              S3
      S7    A2              S7              S2   Error: Inappropriate Authentication
      S7    A5              S1
      S7    A6              S6
      S7    A7              S7
      S7    A8 and D2=NO    S3   Error: InvalidCredentials
      S7    A8 and D2=YES   S8
      S8    A1              S3
      S8    A2              S8              S2   Error: Inappropriate Authentication
      S8    A5              S1
      S8    A6              S6
      S8    A7 and D1=NO    S6   Error: InvalidCredentials
      S8    A7 and D1=YES   S7
      S8    A8              S8
     Any   A9              S1   See [Protocol] section 4.2.1.

6. Anonymous Authentication

   Directory operations that modify entries or access protected
   attributes or entries generally require client authentication.
   Clients that do not intend to perform any of these operations
   typically use anonymous authentication. Servers SHOULD NOT allow
   clients with anonymous authentication to modify directory entries or
   access sensitive information in directory entries.

   LDAP implementations MUST support anonymous authentication, as
   defined in section 6.1.

   LDAP implementations MAY support anonymous authentication with TLS,
   as defined in section 6.2.

   While there MAY be access control restrictions to prevent access to
   directory entries, an LDAP server SHOULD allow an anonymously-bound
   client to retrieve the supportedSASLMechanisms attribute of the root
   DSE.

   An LDAP server MAY use other information about the client provided
   by the lower layers or external means to grant or deny access even
   to anonymously authenticated clients.

6.1. Anonymous Authentication Procedure

   An LDAPv3 client that has not successfully completed a bind
   operation on a connection is anonymously authenticated. See section
   3.3.3.
   3.1.

   An LDAP client MAY also choose to explicitly bind anonymously. A
   client that wishes to do so MUST choose the simple authentication
   option in the Bind Request (see section 3.1)    and set the password to be of zero
   length. (This is often done by LDAPv2 clients.) Typically the name
   is also of zero length.

6.2. Anonymous Authentication and TLS

   An LDAP client MAY use the Start TLS operation (section 5) to
   negotiate the use of TLS security [RFC2246]. If the client has not
   bound beforehand, then until the client uses the EXTERNAL SASL
   mechanism to negotiate the recognition of the client's certificate,
   the client is anonymously authenticated.

   Recommendations on TLS ciphersuites are given in section 9.

   An LDAP server which requests that clients provide their certificate
   during TLS negotiation MAY use a local security policy to determine
   whether to successfully complete TLS negotiation if the client did
   not present a certificate which could be validated.

7. Password-based Authentication

   This section discusses various options for performing password-based
   authentication to LDAPv3 compliant servers and the environments
   suitable for their use.

7.1. Simple Authentication

   The LDAP "simple" authentication choice is not suitable for
   authentication in environments where there is no network or
   transport layer confidentiality. 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.

7.2. Digest Authentication

   LDAP servers that implement any authentication method or mechanism
   (other than simple anonymous bind) MUST implement the SASL
   DIGEST-MD5 mechanism.

   An LDAP client MAY determine whether the server supports this
   mechanism by performing a search request on the root DSE, requesting
   the supportedSASLMechanisms attribute, and checking whether the
   string "DIGEST-MD5" is present as a value of this attribute.

   In the first stage of authentication, when the client is performing
   an "initial authentication" as defined in section 2.1 of [RFC2831],
   the client sends a bind request in which the version number is 3,
   the authentication choice is sasl, the sasl mechanism name is
   "DIGEST-MD5", and the credentials are absent. The client then waits
   for a response from the server to this request.

   The server will respond with a bind response in which the resultCode
   is saslBindInProgress, and the serverSaslCreds field is present. The
   contents of this field is a string defined by "digest-challenge" in
   section 2.1.1 of [RFC2831]. The server SHOULD include a realm
   indication and MUST indicate support for UTF-8.

   The client will send a bind request with a distinct message id, in
   which the version number is 3, the authentication choice is sasl,
   the sasl mechanism name is "DIGEST-MD5", and the credentials contain
   the string defined by "digest-response" in section 2.1.2 of
   [RFC2831]. The serv-type is "ldap".

   The server will respond 4. LDAP implementations SHOULD NOT support authentication
   with a bind response in which the resultCode
   is either success, or an error indication. If the "simple" authentication is
   successful and the server does not support subsequent
   authentication, then choice unless the credentials field is absent. If data on the
   authentication
   connection is successful protected using TLS or other data confidentiality and
   data integrity protection.

7.2. Digest Authentication

   LDAP servers that implement any authentication method or mechanism
   (other than simple anonymous bind) MUST implement the server supports subsequent
   authentication, then the credentials field contains the string
   defined by "response-auth" in section 2.1.3 of [RFC2831]. SASL
   DIGEST-MD5 mechanism [DigestAuth].

   Support for subsequent authentication is OPTIONAL in clients and
   servers.

   Implementors 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 ([DigestAuth section 2.1) which are
   syntactically simple strings and semsantically 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,
   o=Ace Industry ", are syntactically allowed, however DIGEST-MD5
   treats them as simple strings for comparison purposes. To illustrate
   further, the two DNs "cn=bob, o=Ace Industry" (space between RDNs)
   and "cn=bob,o=Ace Industry" (no space between RDNs) would be
   equivalent when being compared semantically as LDAP DNs, however
   they are not equivalent if they were used to represent username
   values in DIGEST-MD5 because simple octet-wise comparision semantics
   are used by DIGEST-MD5.

7.3. "simple" authentication choice under TLS encryption

   Following the negotiation of an appropriate TLS ciphersuite
   providing connection confidentiality [RFC2246], a client MAY
   authenticate to a directory that supports the simple authentication
   choice by performing a simple bind operation. operation

   Simple authentication with TLS encryption protection is performed as
   follows:

      1. The client will use the Start TLS operation [PROTOCOL] [Protocol] to
        negotiate the use of TLS security [RFC2246] on the connection
        to the LDAP server. The client need not have bound to the
        directory beforehand.

         For this the subsequent authentication procedure to be successful, performed
         securely, the client and server MUST negotiate a ciphersuite
         which contains a bulk encryption algorithm of appropriate
         strength. Recommendations on cipher suites are given in
         section 9.

      2. Following the successful completion of TLS negotiation, the
         client MUST send an LDAP bind request with the version number
         of 3, the name field containing a DN, and the "simple"
         authentication choice, containing a password.

7.3.1. "simple" Authentication Choice

   DSAs 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. If there is a match, the presented password matches any member of that set,
   then the server will respond with resultCode success, otherwise the
   server will respond with resultCode invalidCredentials.

7.4. Other authentication choices with TLS

   It is also possible, following the negotiation of TLS, to perform a
   SASL authentication that does not involve the exchange of plaintext
   reusable passwords. In this case the client and server need not
   negotiate a ciphersuite that provides confidentiality if the only
   service required is data integrity.

8. Certificate-based authentication

   LDAP server implementations SHOULD support authentication via a
   client certificate in TLS, as defined in section 4.2.2. 8.1.

8.1. Certificate-based authentication with TLS

   A user who has a public/private key pair in which the public key has
   been signed by a Certification Authority may use this key pair to
   authenticate to the directory server if the user's certificate is
   requested by the server. The user's certificate subject field SHOULD
   be the name of the user's directory entry, and the Certification
   Authority that issued the user's certificate must be sufficiently
   trusted by the directory server in order for the server to process
   the certificate. The means by which servers validate certificate
   paths is outside the scope of this document.

   A server MAY support mappings for certificates in which the subject
   field name is different from the name of the user's directory entry.
   A server which supports mappings of names MUST be capable of being
   configured to support certificates for which no mapping is required.

   The client will use the Start TLS operation [PROTOCOL] [Protocol] to negotiate
   the use of TLS security [RFC2246] on the connection to the LDAP
   server. The client need not have bound to the directory beforehand.

   In the TLS negotiation, the server MUST request a certificate. The
   client will provide its certificate to the server, and the server
   MUST perform a private key-based encryption, proving it has the
   private key associated with the certificate.

   In deployments that require protection of sensitive data in transit,
   the client and server MUST negotiate a ciphersuite that contains a
   bulk encryption algorithm of appropriate strength. Recommendations
   of cipher suites are given in section 9.

   The server MUST verify that the client's certificate is valid. The
   server will normally check that the certificate is issued by a known
   certification authority (CA), and that none of the certificates on
   the client's certificate chain are invalid or revoked. There are
   several procedures by which the server can perform these checks.

   Following the successful completion of TLS negotiation, the client
   will send an LDAP bind request with the SASL "EXTERNAL" mechanism.

9. TLS Ciphersuites

   A client or server that supports TLS MUST support
   TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA and MAY support other ciphersuites
   offering equivalent or better protection.

   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 to provide adequate confidentiality
       protection for passwords and other data sent over the 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 being cracked using brute force
       methods, especially in light of ever-increasing CPU speeds that
       reduce the time needed to successfully mount such attacks.

       Client and server implementers SHOULD carefully consider the
       value of the password or data being protected versus the level
       of confidentially protection provided by the ciphersuite to
       ensure that the level 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 used to protect passwords or sensitive
       data, unless the network configuration is such that the danger
       of a man-in-the-middle attack is tolerable.

9.1. TLS Ciphersuites Recommendations

   As of the writing 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 [RFC2246] 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 [RFC2246] 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 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

10. Security Considerations

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

   Servers are encouraged to prevent modifications by anonymous users.
   Servers may also wish to minimize denial of service attacks by
   timing out idle connections, and returning the unwillingToPerform
   result code rather than performing computationally expensive
   operations requested by unauthorized clients.

   Operational experience shows that clients can misuse unauthenticated
   access (simple bind with name but no password).  For example, a
   client program might authenticate a user via LDAP and then grant
   access to information not stored in the directory on the basis of
   completing a successful bind. Some implementations will return a
   success response to a simple bind that consists of a user name and
   an empty password thus leaving the impression that the client has
   successfully authenticated the identity represented by the user
   name, when in reality, the directory server has simply performed an
   anonymous bind.  For this reason, servers SHOULD by default reject
   authentication requests that have a DN with an empty password with
   an error of invalidCredentials.

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

   A connection on which the client has not performed the Start TLS
   operation or negotiated a suitable SASL mechanism for connection
   integrity and encryption services is subject to man-in-the-middle
   attacks to view and modify information in transit.

10.1.  Start TLS Security Considerations

   The goals of using the TLS protocol with LDAP are to ensure
   connection confidentiality and integrity, and to optionally provide
   for authentication. TLS expressly provides these capabilities, as
   described in [RFC2246].

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

   Once established, TLS only provides for and ensures confidentiality
   and integrity of the operations and data in transit over the LDAP
   association--and only if the implementations on the client and
   server support and negotiate it. The use of TLS does not provide or
   ensure for confidentiality and/or non-repudiation of the data housed
   by an LDAP-based directory server. Nor does it secure the data from
   inspection by the server administrators.

   The level of security provided though the use of TLS depends
   directly on both the quality of the TLS implementation used and the
   style of usage of that implementation. Additionally, an active-
   intermediary attacker can remove the Start TLS extended operation
   from the supportedExtension attribute of the root DSE. Therefore,
   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 confidentiality and/or integrity protection, or be
   configurable to refuse to proceed without an acceptable level of
   security.

   Client and server implementors SHOULD take measures to ensure proper
   protection of credentials and other confidential data where such
   measures are not otherwise provided by the TLS implementation.

   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.

   Additional security considerations relating to the EXTERNAL
   mechanism to negotiate TLS can be found in [RFC2222] [SASL] and [RFC2246].

11. IANA Considerations

   The following IANA considerations apply to this document:

   [To be completed]

Contributors

   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.

Acknowledgements

   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 of this document is
   greatly appreciated.

Normative References

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

   [RFC2222] Myers, J., "Simple Authentication and Security Layer
       (SASL)", draft-myers-saslrev-xx.txt, a work in progress.
       Requirement Levels", BCP 14, RFC 2119, March 1997.

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

   [RFC2246] Dierks, T. and C. Allen. "The TLS Protocol Version 1.0",
       RFC 2246, January 1999.

    [RFC2831]

   [DigestAuth] Leach, P. and C. Newman, and A. Melnikov, "Using Digest
      Authentication as a SASL Mechanism", RFC 2831, May 2000. draft-ietf-sasl-rfc2831bis-
      xx.txt, a work in progress.

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

   [PROTOCOL]

   [Model] 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.

Informative References

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

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

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

   [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
   +1 801 861 2642
   roger_harrison@novell.com

Full Copyright Statement

   Copyright (C) The Internet Society (2003). All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph
   are included on all such copies and derivative works. However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assigns.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Appendix A. 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 B. Authentication and Authorization: Definitions and 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.

B.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. A common expression of an
   access control policy is an access control list. Security objects
   and mechanisms, such as those described here, enable the expression
   of access control policies and their enforcement. Access control
   policies are typically expressed in terms of access control factors
   as described below.

B.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]).
   [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.

B.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.

B.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 [RFC2222]. [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 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 C. RFC 2829 Change History

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

C.0. General Editorial Changes
   Version -00

     - Changed other instances of the term LDAP to LDAPv3 where v3 of
       the protocol is implied. Also made all references to LDAPv3 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 reflect inclusion of material from RFC 2830 and
       2251.

C.1. Changes to Section 1

   Version -01

     - Moved conventions used in document to a separate section.

C.2. Changes to Section 2

   Version -01

     - Moved section to an appendix.

C.3. Changes to 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 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 (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.

C.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
       2251.

C.1. Changes to Section 1

   Version -01

     - Moved conventions used data integrity
        mechanisms are in document to a separate section.

C.2. Changes to Section 2

   Version -01

     - force.

     2. Moved first paragraph of section 6 (beginning with "LDAP
       implementations MUST support authentication with a password...")
       to an appendix.

C.3. section on Digest Authentication (Now section 6.2).

C.6.1. Changes to Section 3 6.1.

   Version -01

     - Moved -00 Renamed section to an appendix.

C.4 6.2

     - Added sentence from original section 6 indicating that the
       DIGEST-MD5 SASL mechanism is required for all conforming LDAPv3
       implementations

C.6.2. Changes to Section 4 6.2

   Version -00

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

C.5. Changes Renamed section to Section 5

   Version -00 6.3

     - Added 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 sentence: "Servers SHOULD NOT allow clients negotiation of a TLS ciphersuite that supports
       confidentiality.

     - Replaced "the name of the user's entry" with anonymous authentication to modify directory entries or
       access sensitive information in directory entries."

C.5.1. Changes to "a DN" since not
       all bind operations are performed on behalf of a "user."

     - Added Section 5.1

   Version -00 6.3.1 heading just prior to paragraph 5.

     - Replaced Paragraph 5: replaced "The server" with "DSAs that map the text describing DN
       sent in the procedure for performing an
       anonymous bind (protocol) request to a directory entry with a reference
       userPassword attribute."

C.6.3. Changes to section 4.2 of RFC
       2251 (the protocol spec). 6.3.

     Version -01 -00

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

C.6. 6.4.

C.7. Changes to Section 6. section 7.

   none

C.7.1. Changes to section 7.1.

   Version -00

     Reorganized text in section 6.1 as follows:

     1. Added

     - Clarified the entity issuing a new section (6.1) titled "Simple Authentication" and
       moved one of two introductory paragraphs for section 6 into
       section 6.1. Added sentences certificate by moving the phrase
       "to have issued the certificate" immediately after
       "Certification Authority."

C.8. Changes to section 8.

   Version -00

     - Removed the first paragraph indicating:

        a. because 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
       covered explicitly in force.

     2. 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 first paragraph entire section 8 of RFC 2829 into section 6 (beginning with "LDAP
       implementations MUST support authentication with 3.4 (Using SASL
       for Other Security Services) to bring material on SASL
       mechanisms together into one location.

C.9. Changes to section 9.

   Version -00

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

     - Added section 9.1. heading.

     - Modified a password...") 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 on Digest Authentication (Now 9.1.1. heading.

     - Added section 6.2).

C.6.1. Changes to Section 6.1. 9.1.2. heading.

   Version -00 Renamed -01

     - Moved entire section 9 to 6.2

     - Added sentence from original become section 6 indicating 3.5 so that the
       DIGEST-MD5 it would be
       with other SASL mechanism is required for all conforming LDAPv3
       implementations

C.6.2. material.

C.10. Changes to Section 6.2 10.

   Version -00

     - Renamed section to 6.3

     - Reworded first paragraph to remove Updated reference to user and the
       userPassword password attribute Made the first paragraph more
       general by simply saying that if cracking from a directory supports simple
       authentication that the simple bind operation MAY performed
       following negotiation week of CPU time in 1997 to
       be 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 day of a "user." CPU time in 2000.

     - Added Section 6.3.1 heading text: "These ciphersuites are NOT RECOMMENDED for use...
       and server implementers SHOULD" to sentence just prior to paragraph 5. the
       second list of ciphersuites.

     - Paragraph 5: replaced "The server" with "DSAs that map Added text: "and MAY support other ciphersuites offering
       equivalent or better protection," to the DN
       sent in last paragraph of the bind request
       section.

C.11. Changes to a directory entry Section 11.

   Version -01

     - Moved to section 3.6 to be with a
       userPassword attribute."

C.6.3. other SASL material.

C.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 6.3. 13.

   Version -00 -01

     - Renamed Moved to section 6.4.

C.7. Changes 3.7 to section 7.

   none

C.7.1. be with other SASL material.

C.13. Changes to Section 13 (original section 7.1.

   Version -00 12).

   None

Appendix D. RFC 2830 Change History

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

D.0. General Editorial Changes

     - Clarified Material showing the entity issuing PDUs for the Start TLS response was broken
       out into a certificate by moving new section.

     - The wording of the phrase
       "to have issued definition of the certificate" immediately after
       "Certification Authority."

C.8. Changes Start TLS request and Start
       TLS response was changed to make them parallel. NO changes were
       made to section 8.

   Version -00

     - Removed the first paragraph because simple authentication is
       covered explicitly in section 6. ASN.1 definition or the associated values of the
       parameters.

     - Added A separate section 8.1. heading just prior for graceful TLS closure was added
       for parallelism with section on abrupt TLS closure.

Appendix E. RFC 2251 Change History

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

E.0. General Editorial Changes

     - Added All material from section 8.2. heading just prior to third paragraph. 4.2 of RFC 2251 was moved into this
       document.

     - Added 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 8.3. heading just prior was also
       subdivided to fourth paragraph.

   Version -01 explicitly call out the various effects being
       described within it.

     - Moved entire section 8 of All SASL profile information from RFC 2829 into section 3.4 (Using SASL
       for Other Security Services) was brought within
       the discussion of the Bind operation (primarily sections 4.4 -
       4.7).

Appendix F. Change History to bring material on SASL
       mechanisms together into one location.

C.9. Combined Document

F.1. Changes to section 9.

   Version -00 for draft-ldap-bis-authmeth-02

   General

     - Paragraph 2: changed "EXTERNAL mechanism" Added references to "EXTERNAL SASL
       mechanism." other LDAP standard documents, to sections
       within the document, and fixed broken references.

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

   Section 1.

     - Added section 9.1. heading. glossary of terms and added sub-section headings

   Section 2.

     - Modified a comment Clarified security mechanisms 3, 4, & 5 and brought language in the ABNF from "unspecified userid" to
       "unspecified authz id".
       line with IETF security glossary.

   Section 3.

     - Deleted sentence, "A utf8string is defined Brought language in requirement (3) in line with security
       glossary.

     - Clarified that information fetched prior to initiation of TLS
       negotiation must be the UTF-8
       encoding discarded
     -Clarified that information fetched prior to initiation of one or more ISO 10646 characters," because it is
       redundant. SASL
       negotiation must be discarded

     - Added section 9.1.1. heading. Rewrote paragraph on SASL negotiation requirements to clarify
       intent

   Section 4.4.

     - Added section 9.1.2. heading.

   Version -01

     - Moved entire section 9 to become section 3.5 so stipulation that sasl choice allows for any SASL mechanism
       not prohibited by this document. (Resolved conflict between this
       statement and one that it would be
       with other prohibited use of ANONYMOUS and PLAIN
       SASL material.

C.10. Changes mechanisms.)

   Section 5.3.6

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

   Section 10.

   Version -00 6

     - Updated reference Added LDAP Association State Transition Tables to cracking show the
       various states through which an LDAP association may pass along
       with the actions and decisions required to traverse from a week of CPU time in 1997 state
       to
       be a day of CPU time state.

   Appendix A

     - Brought security terminology in 2000. line with IETF security glossary
       throughout the appendix.

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

   General

     - Added text: "These ciphersuites are NOT RECOMMENDED for use... introductory notes and server implementers SHOULD" changed title of document and
       references to sentence just prior conform to WG chair suggestions for the
       second list of ciphersuites. overall
       technical specification.

     - Added text: "and MAY support other ciphersuites offering
       equivalent or better protection," Several issues--G.13, G.14, G.16, G.17--were resolved without
       requiring changes to the last paragraph of the
       section.

C.11. Changes to document.

   Section 11.

   Version -01 3

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

C.12. Changes Removed reference to /etc/passwd file and associated text.

   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 4

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

C.13. Changes to Section 13 (original Removed sections 4.1, 4.2 and parts of section 12).

   None

Appendix D. RFC 2830 Change History 4.3. This appendix lists
       information was being duplicated in the changes made 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 text of RFC 2830 sasl choice and servers SHALL ignore any value
       received in
   preparing this document.

D.0. General Editorial Changes circumstance.
     - Material showing the PDUs for the Start TLS response was broken
       out into a new section.

   Section 8.3.1

     - The wording of Generalized the definition language of the Start TLS request and Start
       TLS response was changed this section to make them parallel. NO changes were
       made not refer to the ASN.1 definition any
       specific password attribute or to refer to the associated values directory entry
       as a "user" entry.

   Section 11

     - Added security consideration regarding misuse of the
       parameters. unauthenticated
       access.

     - A separate section heading for graceful TLS closure was added 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.

F.3. Changes for parallelism with section on abrupt TLS closure.

Appendix E. RFC 2251 Change History

   This appendix lists the changes made draft-ldap-bis-authmeth-04

   General

     - Changed references to the text of RFC 2251 use [RFCnnnn] format wherever possible.
       (References to works in
   preparing this document.

E.0. General Editorial Changes progress still use [name] format.)
     - All material from section 4.2 of RFC 2251 was moved into this Various edits to correct typos and bring field names, etc. in
       line with specification in [Protocol] draft.

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

   Section 4.4.1.

     - A new section was created for Changed ABNF grammar to use productions that are like those in
       the Bind Request 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 4.2.1 of RFC 2251 (Sequencing Bind Request) was moved
       after the section on the Bind Response 6

     - Reviewed LDAP Association State table for parallelism with the
       presentation of completeness and
       accuracy. Renumbered actions A3, A4, and A5 to be A5, A3, and A4
       respectively. Re-ordered several lines in the Start TLS operations. The section was also
       subdivided table to explicitly call out ensure
       that actions are in ascending order (makes analyzing the various effects being
       described within it.

     - All SASL profile information from RFC 2829 table
       much more logical). Added action A2 to several states where it
       was brought within
       the discussion missing and valid. Added actions A7 and A8 placeholders to
       states S1, S2, S4 and S5 pending resolution of the Bind operation (primarily sections 4.4 issue G.28.

   Section 11

     -
       4.7).

Appendix F. Change History Modified security consideration (originally added in -03)
       requiring access control to Combined Document

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

   General

     - Added references be applied only to other LDAP standard documents, authenticated
       users. This seems nonsensical because anonymous users may have
       access control applied to sections
       within the document, limit permissible actions.
     -
   Section 13

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

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

   General

     - General editorial editory changes
                               --
                                -
                                - to fix punctuation, spelling, formatting, line
       length issues, etc.

   Section 1.
     - Added glossary of terms Verified and added sub-section headings

   Section 2.

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

   Section 3. inter-document references
       throughout.
     - Brought language in requirement (3) in line Document-wide review for proper usage of RFC 2119 keywords with security
       glossary.
       several changes to correct improper usage.

   Abstract
     - Clarified that information fetched prior Updated to initiation match current contents of TLS
       negotiation must be discarded

     -Clarified that information fetched prior documents. This was needed
       due to initiation movement of SASL
       negotiation must be discarded
     - Rewrote paragraph material on SASL negotiation requirements Bind and Start TLS operations to clarify
       intent
       [Protocol] in this revision.

   Section 4.4. 3.

     - Added stipulation that sasl choice allows Renamed section to "Rationale for any SASL mechanism LDAPv3 Security Mechanisms"
       and removed text that did not prohibited by support this document. (Resolved conflict between theme. Part of the
       motivation for this
       statement change was to remove the implication of the
       previous section title, "Required Security Mechanisms", and one
       other text found in the section that prohibited use 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 ANONYMOUS the draft.

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

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

   Section 5.3.6 4.l.

     - Added a.x.bar.com Changed wording of first paragraph to wildcard matching example on hostname
       check. clarify meaning.

   Section 6 4.2.
     - 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 paragraph from state
       to state.

   Appendix A

     - Brought security terminology in line with IETF section 3 of -04 beginning, "If a SASL
       security glossary
       throughout the appendix.

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

   General layer is negotiated..."

   Section 4.3.3.
     - Added introductory notes and changed title of document and
       references to conform Renamed to WG chair suggestions for "Other SASL Mechanisms" and completely rewrote the overall
       technical specification.

     - Several issues--G.13, G.14, G.16, G.17--were resolved without
       requiring changes
       section (one sentence) to generalize the treatment of SASL
       mechanisms not explicitly mentioned in this document.

   Section 3 4.4.1.

     - Removed reference Added paragraph beginning, "The dnAuthzID choice allows client
       applications..." to /etc/passwd file and associated text.

   Section 4

     - Removed sections 4.1, 4.2 and parts of section 4.3. clarify whether DN form authorization
       identities have to also have a corresponding directory entry.
       This
       information change 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 based on ldapbis editor's perception of WG discussion at IETF52 two sentences were
       added indicating that clients SHOULD NOT send a DN value when
       binding with consensus.

     - Made minor clarifying edits in the sasl paragraph beginning, "The
       uAuthzID choice and servers SHALL ignore any value
       received in this circumstance. allows for compatibility..."

   Section 5.1.1.

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

   Section 8.3.1 5.1.7.

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

   Section 5.2.

     - Changed usage of "TLS connection" to not refer to any
       specific password attribute or to refer to the directory entry
       as a "user" entry. "TLS session" throughout.

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

   Section 11 8.

     - Added security consideration regarding misuse introductory paragraph at beginning of unauthenticated
       access. section.

   Section 8.1.

     - Added security consideration requiring access control Changed term  "data privacy" to "data confidentiality" to be
       applied only
       consistent with usage in rest of document.

   Section 8.2.

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

   Section 11.

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

   Appendix A.

     - Began changes to incorporate information or updating directory
       information.

F.3. on deployment scenarios
       removed from section 3.

F.5. Changes for draft-ldap-bis-authmeth-04 draft-ldap-bis-authmeth-06

   General

     - Changed references Combined Section 2 (Introduction) and Section 3 (Motivation) and
       moved Introduction to use [RFCnnnn] format wherever possible.
       (References section 1. All following sections numbers
       were decremented by one as result.

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

     - Opened several new issues in progress still use [name] format.) 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

     - Various edits to correct typos Changed definition of "LDAP association" and added terms,
       "connection" and "TLS connection" to bring field names, etc. usage in line with specification in [PROTOCOL] draft.

     - Several issues--G.13, G.14, G.16, G.17--were resolved without
       requiring changes to the document.
       [Protocol].

   Section 4.4.1. 4.1.6

     - Changed ABNF grammar to use productions Clarified sentence stating that are like those in the model draft. client MUST NOT use derived
       forms of DNS names.

   Section 5 5.1

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

   Section 6

     - Reviewed LDAP Association State state table for completeness and
       accuracy. Renumbered actions A3, A4, to clarify meaning
       of various states and A5 actions.

     - Added action A9 to be A5, A3, cover abandoned bind operation and A4
       respectively. Re-ordered several lines in added
       appropriate transitions to the state transition table to ensure
       accommodate it.

   Section 7.2
     - Replaced first paragraph to clarify that actions are in ascending order (makes analyzing the table
       much more logical). Added action A2 "DIGEST-MD5" SASL
       mechanism is required to several states where it 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 missing and valid. preserved.

   Section 10

     - Added actions A7 a clarifying example to the consideration regarding misuse
       of unauthenticated access.

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

   General

     - Updated external and A8 placeholders 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
       states S1, S2, S4 and S5 pending resolution mee the SASL profile requirements
       of issue G.28. draft-ietf-sasl-rfc2222bis-xx.txt section 5.

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

   Section 11 4

     - Modified security consideration (originally added Note to implementers in -03)
       requiring access control 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 be applied only
       asserted authorization ID to authenticated
       users. This seems nonsensical because anonymous users may have
       access control applied apply only to limit permissible actions.
     - explicit assertion.
       The local policy in place for implicit assertion is adequate.

   Section 13 7

     - Verified all normative references and moved informative
       references to a Removed most of section 7.2 as the information is now covered
       adequately via the new SASL profile in section 14.

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

   General

     - General editory changes 3.3. Added note
       to fix punctuation, spelling, line
       length issues, etc.
     - Verified and updated intra- implementors regarding the treatment of username and inter-document references
       throughout. realm
       values in DIGEST-MD5.

     - Document-wide review for proper usage of RFC 2119 keywords with
       several changes to correct improper usage.

   Abstract Section 7.3. Minor clarifications in wording.

     - Updated to Section 7.3.1. Clarification that a match current contents of documents. This was needed
       due the presented value
       to movement any member of material on Bind the set of stored passwords constitutes a
       successful authentication.

Appendix G. Issues to be Resolved

   This appendix lists open questions and Start TLS operations issues that need to
       [PROTOCOL] in be
   resolved before work on this revision. document is deemed complete.

G.1.

   Section 3.

     - Renamed section to "Rationale for LDAPv3 Security Mechanisms"
       and removed text 1 lists 6 security mechanisms that did can be used by LDAP
   servers. I'm not support this theme. Part sure what mechanism 5, "Resource limitation by
   means of the
       motivation for this change was administrative limits on service controls" means.

   Status: resolved. Changed wording to remove the implication of "administrative service limits"
   to clarify meaning.

G.2.

   Section 2 paragraph 1 defines the
       previous section title, "Required Security Mechanisms", term, "sensitive." Do we want to
   bring this term and other text found in the section that everything security-related terms in alignment with
   usage with the section IETF security glossary (RFC 2828)?

   Status: resolved. WG input at IETF 51 was a requirement

     - Information from several removed paragraphs that describe
       deployment scenarios will be added Appendix A in the next
       revision of we should do this, so
   the draft.

     - Paragraph beginning, " If TLS appropriate changes have been made.

G.3.

   Section 2, deployment scenario 2: What is negotiated, meant by the client MUST
       discard all information..." was moved to section 5.1.7 and
       integrated with related material there.

     - Paragraph beginning, "If term "secure
   authentication function?"

   Status: resolved. Based on the idea that a SASL security layer is negotiated..."
       was moved to section 4.2

   Section 4.l.

     - Changed "secure authentication
   function" could be provided by TLS, I changed the wording of first paragraph to clarify meaning. require
   data confidentiality for sensitive authentication information and
   data integrity for all authentication information.

G.4.

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

   Section 4.3.3.
     - Renamed to "Other SASL Mechanisms" and completely rewrote meant by the
       section (one sentence) to generalize phrase,
   "directory data is authenticated by the treatment of SASL
       mechanisms not explicitly mentioned in server?"

   Status: resolved. I interpreted this document.

   Section 4.4.1.

     - Added paragraph beginning, "The dnAuthzID choice allows client
       applications..." to clarify whether DN form authorization
       identities have mean the ability to also have a corresponding directory entry.
       This change was based on editor's perception ensure
   the identity 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 directory server and the last paragraph integrity of the
       section.

   Section 5.1.7.

     - Wording data
   sent 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" that server to "TLS session" throughout.

     - Removed empty section 5.2.1 the client, 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. explictly stated such.

G.5.

   Section 8.2.

     - Changed first 4 paragraph to require implementations 3: What is meant by the phrase, "this means that
       implement *password-based*
   either this data is useless for faking authentication (like the Unix
   "/etc/passwd" file format used to implement and
       support DIGEST-MD5 SASL authentication.

   Section 11.

     - First paragraph: changed "session encryption" to "session
       confidentiality protection" be)?"
   Status: resolved. Discussion at IETF 52 along with discussions with
   the original authors of this material have convinced us that this
   reference is simply too arcane to be consistent with usage left in rest
       of document.

   Appendix A.

     - Began changes place. In -03 the text
   has been modified to incorporate information focus on deployment scenarios
       removed from section 3.

F.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 the need to fix typos, I-D nits, etc.

     - Opened several new issues either update password
   information 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 a protected fashion outside of "LDAP association" and added terms,
       "connection" and "TLS connection" the protocol or to bring usage
   update it in line with
       [Protocol].

   Section 4.1.6

     - Clarified sentence stating that session well protected against snooping, and the client MUST NOT use derived
       forms of DNS names.

   Section 5.1

     - Began edits
   reference to LDAP Association state table /etc/passwd has been removed.

G.6.

   Section 4 paragraph 7 begins: "For a directory needing session
   protection..." Is this referring to clarify meaning
       of various states and actions.

     - Added action A9 data confidentiality or data
   integrity or both?

   Status: resolved. Changed wording to cover abandoned bind operation say, "For a directory needing
   data security (both data integrity and added
       appropriate transitions data confidentiality)..."

G.7.

   Section 4 paragraph 8 indicates that "information about the server
   fetched fetched prior to the TLS negotiation" must be discarded. Do
   we want to explicitly state transition table that this applies to
       accommodate it.

   Section 7.2

     - Replaced first paragraph information fetched
   prior to clarify that the "DIGEST-MD5" SASL
       mechanism *completion* of the TLS negotiation or is required to implement.

   Section 9

     - Rewrote this going
   too far?

   Status: resolved. Based on comments in the section IETF 51 LDAPBIS WG
   meeting, this has been changed to explicitly state, "fetched prior
   to make the advice more applicable over the
       long term, i.e. more "timeless." The intent initiation of content in the
       original section was preserved. TLS negotiation..."

G.8.

   Section 10

     - Added 4 paragraph 9 indicates that clients SHOULD check the
   supportedSASLMechanisms list both before and after a clarifying example SASL security
   layer is negotiated to ensure that they are using the consideration regarding misuse
       of unauthenticated access.

Appendix G. Issues to be Resolved

   This appendix lists open questions best available
   security mechanism supported mutually by the client and issues server. A
   note at the end of the paragraph indicates that need to be
   resolved before work on this document is deemed complete.

G.1.

   Section 1 lists 6 security a SHOULD
   since there are environments where the client might get a list of
   supported SASL mechanisms that can from a different trusted source.

   I wonder if the intent of this could be used by LDAP
   servers. I'm not sure what mechanism 5, "Resource limitation by
   means restated more plainly using
   one of administrative limits on service controls" means.

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

G.2.

   Section 2 paragraph 1 defines these two approaches (I've paraphrased for the term, "sensitive." Do we want to
   bring this term sake of
   brevity):

        Approach 1: Clients SHOULD check the supportedSASLMechanisms
        list both before and other security-related terms in alignment with
   usage with after SASL negotiation or clients SHOULD
        use a different trusted source to determine available supported
        SASL mechanisms.

        Approach 2: Clients MUST check the IETF security glossary (RFC 2828)? 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 we should do this, so Approach 1 was
   probably best. I ended up keeping the appropriate changes have been made.

G.3. basic structure similar to the
   original to meet this intent.

G.9.

   Section 2, deployment scenario 2: What is meant by 6.3.1 states: "DSAs that map the term "secure
   authentication function?"

   Status: resolved. Based on DN sent in the idea that bind request
   to a "secure authentication
   function" could be provided by TLS, I changed directory entry with a userPassword attribute will... compare
   [each value in the wording named user's entry]... with the presented
   password."  This implies that this applies only to require
   data confidentiality for sensitive authentication information and
   data integrity for all authentication information.

G.4.

   Section 3, deployment scenario 3: user entries with
   userPassword attributes.  What is meant by the phrase,
   "directory data is authenticated by about other types of entries that
   might allow passwords and might store in the server?"

   Status: resolved. I interpreted password information in
   other attributes?  Do we want to make this text more general?

   Status: resolved in -03 draft by generalizing section 8.3.1 to mean the ability not
   refer to ensure any specific password attribute and by removing the identity of term
   "user" in referring to the directory server and entry specified by the integrity of DN in
   the data
   sent from bind request.

G.10 userPassword and simple bind

   We need to be sure that server we don't require userPassword to be the client, only
   attribute used for authenticating via simple bind. (See 2251 sec 4.2
   and explictly stated such.

G.5.

   Section 4 paragraph 3: What authmeth 6.3.1. Work with Jim Sermersheim on resolution to this.
   On publication state something like: "This is meant by the phrase, "this means that
   either this data is useless for faking authentication (like specific
   implementation of what we discussed in our general reorg
   conversation on the Unix
   "/etc/passwd" file format used to be)?" list." (Source: Kurt Zeilenga)

   Status: resolved. Discussion at IETF 52 along with discussions with
   the original authors of this material have convinced us that this
   reference is simply too arcane to be left resolved in place. In -03 the text
   has been modified draft by generalizing section 8.3.1 to focus on the need not
   refer to either update any specific password
   information in a protected fashion outside of the protocol or to
   update it in session well protected against snooping, attribute and by removing the
   reference to /etc/passwd has been removed.

G.6.

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

   Status: resolved. Changed wording to say, "For the directory entry specified by the DN in
   the bind request.

G.11. Meaning of LDAP Association

   The original RFC 2830 uses the term "LDAP association" in describing
   a directory needing
   data security (both data integrity connection between an LDAP client and data confidentiality)..."

G.7.

   Section 4 paragraph 8 indicates that "information about the server
   fetched fetched prior to regardless of the TLS negotiation" must be discarded. Do
   we want to explicitly
   state that this applies to information fetched
   prior to the *completion* of the TLS negotiation on that connection. This term needs to be defined or is this going
   too far?
   possibly changed.

   Status: resolved. Based on comments in the at IETF 51 LDAPBIS WG
   meeting, this has been changed to explicitly state, "fetched prior Bob Morgan indicated that the term
   "LDAP association" was intended to distinguish the initiation of LDAP-level
   connection from the TLS negotiation..."

G.8.

   Section 4 paragraph 9 indicates that clients SHOULD check TLS-level connection.  This still needs to be
   clarified somewhere in the
   supportedSASLMechanisms list both before and after draft. Added "LDAP association" to a SASL security
   layer
   glossary in section 1.

G.12. Is DIGEST-MD5 mandatory for all implementations?

   Reading 2829bis I think DIGEST-MD5 is negotiated mandatory ONLY IF your server
   supports password based authentication...but the following makes it
   sound mandatory to ensure that they are provide BOTH password authentication AND DIGEST-
   MD5:

   "6.2. Digest authentication
   LDAP implementations MUST support authentication with a password
   using the best available
   security DIGEST-MD5 SASL mechanism supported mutually by 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 to a
   single "fairly secure" mechanism--if there is no such mandatory
   authentication scheme then you cannot do that. (Source: Rob Byrne)

   Status: resolved. -00 version of the client and server. A
   note draft added a sentence at the end
   beginning of the paragraph indicates section 8.2 stating that LDAP server implementations
   must support this is a SHOULD
   since there are environments where the client might get a list method.

G.13. Ordering of
   supported SASL mechanisms from a different trusted source.

   I wonder if authentication levels requested

   Again on the intent subject of this could authentication level, is it possible to
   define an ordering on authentication levels which defines their
   relative "strengths" ? This would be restated more plainly using
   one of these two approaches (I've paraphrased for useful in acl as you could say
   things like"a given aci grants access to a given subject at this
   authentication level AND ABOVE". David Chadwick raised this before
   in the sake context of
   brevity):

        Approach 1: Clients SHOULD check the supportedSASLMechanisms
        list both before and after SASL negotiation or clients SHOULD
        use a different trusted source denying access to determine available supported
        SASL mechanisms.

        Approach 2: Clients MUST check the supportedSASLMechanisms list
        both before and after SASL negotiation UNLESS they use a
        different trusted source subject at a given
   authentication level, in which case he wanted to determine available supported SASL
        mechanisms.

   Status: resolved. WG input express "deny
   access to this subject at IETF 51 was that Approach 1 was
   probably best. I ended up keeping this authentication level AND TO ALL
   IDENTITIES AUTHENTICATED BELOW THAT LEVEL". (Source: Rob Byrne)

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

G.14. Document vulnerabilities of various mechanisms

   While I'm here...in 2829, I think it would be good to the
   original have some
   comments or explicit reference to meet this intent.

G.9.

   Section 6.3.1 states: "DSAs that map a place where the DN sent in security
   properties of the bind request particular mandatory authentication schemes are
   outlined. When I say "security properties" I mean stuff like "This
   scheme is vulnerable to a directory entry with a userPassword attribute will... compare
   [each value in such and such attacks, is only safe if the named user's entry]... with
   key size is > 50, this hash is widely considered the presented
   password."  This implies best, etc...".
   I think an LDAP implementor is likely to be interested in that this applies only
   information, without having to user entries with
   userPassword attributes.  What about other types wade through the security RFCs.
   (Source: Rob Byrne)

   Status: out of entries that
   might allow passwords and might store in scope. This is outside the password information in
   other attributes?  Do we want to make scope of this text more general? document and
   will not be addressed.

G.15. Include a StartTLS 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 In Process. Table provided in -03 draft by generalizing section 8.3.1 to not
   refer to any specific password attribute and by removing the term
   "user" -03. Review of content for
   accuracy in referring to the directory entry specified by -04. Additional review is needed, plus comments from WG
   members indicate that additional description of each state's meaning
   would be helpful.

G.16. Empty sasl credentials question

   I spent some more time looking microscopically at ldap-auth-methods
   and ldap-ext-tls drafts. The drafts say that the DN in credential must
   have the bind request.

G.10 userPassword and simple bind

   We need to form dn:xxx or u:xxx or be sure that we absent, and although they don't require userPassword
   say what to be do in the only
   attribute used for authenticating via simple bind. (See 2251 sec 4.2
   and authmeth 6.3.1. Work with Jim Sermersheim on resolution to this.
   On publication state something like: "This case of an empty octet string I would say that
   we could send protocolError (claim it is a bad PDU).

   There is still the specific
   implementation question of what we discussed in our general reorg
   conversation on to do if the list." credential is 'dn:'
   (or 'u:') followed by the empty string. (Source: Kurt Zeilenga) ariel@columbia.edu
   via Jeff Hodges)

   Status: resolved resolved. Kurt Zeilenga indicated during ldapbis WG
   discussion at IETF 52 that SASL AuthzID credentials empty and absent
   are equivalent in -03 draft by generalizing section 8.3.1 the latest SASL ID. This resolves the issue.

G.17. Hostname check from MUST to not
   refer SHOULD?

   I am uneasy about the hostname check. My experience from PKI with
   HTTP probably is a contributing factor; we have people using the
   short hostname to any specific password attribute and by removing get to a server which naturally has the term
   "user" FQDN in referring to
   the directory entry specified by certificate, no end of problems. I have a certificate on my
   laptop which has the FQDN for the casse when the system is on our
   Columbia network with a fixed IP; when I dial in however, I have
   some horrible dialup name, and using the DN local https server becomes
   annoying. Issuing a certificate in the bind request.

G.11. Meaning name 'localhost' is not a
   solution! Wildcard match does not solve this problem. For these
   reasons I am inclined to argue for 'SHOULD' instead of LDAP Association
   'MUST' in paragraph...

   Also, The original RFC 2830 uses hostname check against the term "LDAP association" name in describing the certificate is a connection between an LDAP client and server regardless
   very weak means of preventing man-in-the-middle attacks; the
   state of TLS on that connection. This term needs to be defined proper
   solution is not here yet (SecureDNS or
   possibly changed.

   Status: resolved. at IETF 51 Bob Morgan indicated that the term
   "LDAP association" was intended to distinguish the LDAP-level
   connection from the TLS-level connection.  This still needs to be
   clarified somewhere some equivalent). Faking out
   DNS is not so hard, and we see this sort of thing in the draft. Added "LDAP association" to press on a
   glossary in section 1.

G.12. Is DIGEST-MD5 mandatory
   pretty regular basis, where site A hijacks the DNS server for site B
   and gets 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 to provide BOTH password authentication AND DIGEST-
   MD5:

   "6.2. Digest authentication

   LDAP implementations MUST support authentication with a password
   using their requests. Some mention of this should be made in
   the DIGEST-MD5 SASL mechanism for password protection, draft. (Source: ariel@columbia.edu via Jeff Hodges)

   Status: resolved. Based on discussion at IETF 52 ldapbis WG meeting,
   this text will stand as
   defined in section 6.1." it is. The thing check is for acl it would be nice (though not critical) to be
   able to default a MUST, but the required authentication level for behavior
   afterward is a subject SHOULD. This gives server implementations the room to a
   single "fairly secure" mechanism--if there
   maneuver as needed.

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

   If the 'dn:' form of sasl creds is no such mandatory
   authentication scheme then you cannot do that. (Source: Rob Byrne)

   Status: resolved. -00 version used, is it the intention of the draft added a sentence at
   draft(ers) that this DN must exist in the
   beginning of section 8.2 stating directory and the client
   will have the privileges associated with that LDAP entry, or can the
   server implementations
   must support this method.

G.13. Ordering of authentication levels requested

   Again on map the subject of authentication level, is it possible sasl DN to
   define an ordering on authentication levels which defines their
   relative "strengths" ? This would be useful perhaps some other DN in acl as you could say
   things like"a given aci grants access to a given subject at this
   authentication level AND ABOVE". David Chadwick raised this before the directory,
   in an implementation-dependent fashion?

   We already know that if *no* sasl credentials are presented, the DN
   or altname in the context of denying access client certificate may be mapped to a subject at a given
   authentication level, DN in which case he wanted to express "deny
   access an
   implementation-dependent fashion, or indeed to this subject at this authentication level AND TO ALL
   IDENTITIES AUTHENTICATED BELOW THAT LEVEL". something not in the
   directory at all. (Right?)  (Source: Rob Byrne) ariel@columbia.edu via Jeff
   Hodges)

   Status: out of scope. This is outside resolved. (11/12/02)Based on my research I propose that the scope of this document and
   will not be addressed.

G.14. Document vulnerabilities
   DN MUST exist in the directory when the DN form of various mechanisms

   While I'm here...in 2829, sasl creds is
   used. I think it would be good to have some
   comments or explicit reference made this proposal to a place where the security
   properties 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 of the particular mandatory authentication schemes are
   outlined. When I say "security properties" I mean stuff like "This
   scheme
   asserted authorization identity is vulnerable to such implementation specific and such attacks,
   policy driven [SASL] section 4.2, and (3) keeping this paragraph is only safe if
   not required for interoperability.

G.19. DN used in conjunction with SASL mechanism

   We need to specify whether the
   key size DN field in Bind operation can/cannot
   be used when SASL mechanism is > 50, specified. (source: RL Bob)

   Status: resolved. (-03) Based on ldapbis WG discussion at IETF52 two
   sentences were added to section 4.3 indicating that clients SHOULD
   NOT send a DN value when binding with the sasl choice and servers
   SHALL ignore any value received in this hash circumstance. During edits
   for -04 version of draft it was noted that [Protocol] section 4.2
   conflicts with this draft. The editor of [Protocol] has been
   notified of the discrepancy, and they have been handled.

G.20. Bind states

   Differences between unauthenticated and anonymous. There are four
   states you can get into. One is widely considered the best, etc...".
   I think an LDAP implementor completely undefined (this is likely now
   explicitly called out in [Protocol]).  This text needs to be interested in that
   information, without having moved
   from [Protocol] to wade through the security RFCs.
   (Source: Rob Byrne) 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 of scope. This in [AuthMeth]. State 3 is outside the scope of called out in [Protocol]; this document and
   will not be addressed.

G.15. Include a StartTLS state transition table

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

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

G.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 an empty password with an error of
   invalidCredentials. (Source: Jeff Hodges) Kurt Zeilenga and Chris Newman (Sun))

   Status: In Process. Table provided Resolved. Added to security considerations in -
                                                         -03. Review of content for
   accuracy in -04. Additional review is needed, plus comments from WG
   members indicate that additional description of each state's meaning
   would be helpful.

G.16. Empty sasl credentials question

   I spent some more time looking microscopically at ldap-auth-methods

G.22. Need to move StartTLS protocol information to [Protocol]

   Status: Resolved. Removed Sections 5.1, 5.2, and ldap-ext-tls drafts. The drafts say that the credential must
   have the form dn:xxx or u:xxx or be absent, 5.4 for -04 and although
   they don't
   say what to do are [Protocol] -11.

G.23. Split Normative and Non-normative references into separate
sections.

   Status: Resolved. Changes made in the case of an empty octet string I would say that
   we could send protocolError (claim it -04

G.24. What is the authentication state if a bad PDU).

   There Bind operation is still the question
abandoned?

   Status: Resolved.

   (3/24/03) This following text appears in section 4.2.1 of what [Protocol]
   revision -13 to do cover what happens if the credential a bind operation 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 that SASL AuthzID credentials empty and absent
   are equivalent in the latest SASL ID. This resolves abandoned:

   A failed or abandoned Bind Operation has the issue.

G.17. Hostname check from MUST to SHOULD?

   I am uneasy about effect of leaving the hostname check. My experience from PKI with
   HTTP probably is
   connection in an anonymous state. To arrive at a contributing factor; we have people using the
   short hostname to get to known
   authentication state after abandoning a server which naturally has bind operation, clients may
   unbind, rebind, or make use of the FQDN BindResponse.

   (6/28/03): The state table in
   the certificate, no end section 6 of problems. I have a certificate on my
   laptop which [AuthMeth] has the FQDN for the casse when the system is on our
   Columbia network with a fixed IP; when I dial been
   updated to reflect this wording.

G.25. Difference between checking server hostname and server's
canonical DNS name in however, Server Identity Check?

   Section 4.1.6: I have
   some horrible dialup name, and using now understand the local https server becomes
   annoying. Issuing a certificate in intent of the name 'localhost' check (prevent
   man-in-the-middle attacks).  But what is not a
   solution! Wildcard match does not solve the subtle difference
   between the "server hostname" and the "server's canonical DNS name"?
   (Source: Tim Hahn)

   Status: In Process.

   (11/12/02) Sent suggested wording change to this problem. For these
   reasons I am inclined paragraph to argue the
   ldapbis mail list and also asked for 'SHOULD' instead of
   'MUST' in paragraph...

   Also, The opinion as to whether we should
   discuss the distinction between server DNS hostname check against and server
   canonical DNS hostname in [AuthMeth].

   (11/21/02): RL Bob Morgan will provide wording that allows
   derivations of the name in that are provided securely.

   (6/28/03): posted to the certificate WG list asking Bob or any other WG member
   who is a
   very weak means of preventing man-in-the-middle attacks; knowledgeable about the proper
   solution is not here yet (SecureDNS issues involved to help me with
   wording or some equivalent). Faking out
   DNS is not so hard, and we see other information I can use to make this sort of thing in change and close
   the press work item.

G.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 a
   pretty regular basis, where site A hijacks the DNS "locate" draft/RFC? (Source: Tim Hahn).

   Status: Resolved. Section 5 of draft-ietf-ldapext-locate-08
   specifically calls out how the server for site B
   and gets all their requests. Some mention of this identity should be made in performed
   if the draft. (Source: ariel@columbia.edu via Jeff Hodges)

   Status: resolved. Based on discussion at IETF 52 ldapbis WG meeting,
   this text will stand as it is. The check server is a MUST, but located using the behavior
   afterward is a SHOULD. method defined in that draft.
   This gives server implementations is the room right location for this information, and the coverage
   appears to
   maneuver as needed.

   G.18. Must SASL DN exist be adequate.

G.27 Inconsistency in the directory?

   If the 'dn:' form effect of sasl creds is used, is it the intention TLS closure on LDAP association.

   Section 4.4.1 of the
   draft(ers) authmeth -03 (section 4.1 of RFC2830) states that this DN must exist in the directory and the client
   TLS closure alert will have leave the privileges associated LDAP association intact. Contrast
   this with Section 4.5.2 (section 5.2 of RFC2830) that entry, or can the
   server map the sasl DN to perhaps some other DN in the directory,
   in an implementation-dependent fashion?

   We already know says that if *no* sasl credentials are presented, the DN
   or altname in
   closure of the client certificate may be mapped TLS connection MUST cause the LDAP association to a DN in an
   implementation-dependent fashion, or indeed
   move to something not in the
   directory at all. (Right?)  (Source: ariel@columbia.edu via Jeff
   Hodges) an anonymous authentication.

   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 Resolved. (11/12/02) This is
   used. I actually a [Protocol] issue
   because these sections have made this proposal now been moved to the ldapbis mailing list.

   (11/21/02) Feedback' from mailing list has [Protocol] -11. I have
   proposed removing this
   paragraph entirely because (1) explicit assertion the following text for Section 4.4.1 of authorization
   identity should only be done when proxying (2) mapping [AuthMeth] -03
   (section 4.13.3.1 of [Protocol]) to resolve this apparent
   discrepancy:

   "Either the
   asserted authorization identity 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 of the LDAP connection is implementation specific and
   policy driven [SASL]
   affected (see [AuthMeth] section 4.2, and (3) keeping 4.2.2).

   (11/21/02): resolution to this paragraph is
   not required for interoperability.

G.19. DN used in conjunction with SASL mechanism

   We need to specify whether the DN field expected in Bind operation can/cannot
   be used when SASL mechanism is specified. (source: RL Bob)

   Status: resolved. (-03) Based on ldapbis WG discussion at IETF52 two
   sentences were added to section 4.3 indicating [Protocol] -12

   (06/28/03): [Protocol]-15 clarifies that clients SHOULD
   NOT send a DN value when binding with TLS closure alert
   terminates the sasl choice and servers
   SHALL ignore any value received in this circumstance. During edits
   for -04 version of draft it was noted that [PROTOCOL] section 4.2
   conflicts with this draft. TLS connection while leaving the LDAP connection
   intact. The editor authentication state table in [AuthMeth] specifies the
   effect on the LDAP association.

G.28 Ordering of [PROTOCOL] has been
   notified external sources of the discrepancy, and they have been handled.

G.20. Bind states

   Differences between unauthenticated and anonymous. There authorization identities

   Section 4.3.2 implies that external sources of authorization
   identities other than TLS are four
   states you can get into. One is completely undefined (this permitted. What is now
   explicitly called out in [PROTOCOL]).  This text needs to be moved
   from [PROTOCOL] to this draft. (source: Jim Sermersheim)

   Status: Resolved. There the behavior when
   two external sources of authentication credentials 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, available
   (e.g. TLS and 4 IPsec are
   called out in [AuthMeth]. State 3 is called out in [PROTOCOL]; both present (is this
   seems appropriate based on review of alternatives.

G.21. Misuse of unauthenticated access
   Add possible?)) and a security consideration that operational experience shows that
   clients can misuse unauthenticated access (simple bind with name but
   no password).  Servers SHOULD SASL
   EXTERNAL Bind operation is performed?

   Status: resolved. 11/20/02: Resolved by default reject authentication
   requests Section 4.2 of [SASL] which
   states that have a DN with an empty password with the decision to allow or disallow the asserted identity
   is based on an error implementation defined policy.

G.29 Rewrite of
   invalidCredentials. (Source: Kurt Zeilenga Section 9, TLS Ciphersuites

   This section contains anachronistic references and Chris Newman (Sun))

   Status: Resolved. Added to security considerations in -
                                                         -03.

G.22. Need to move StartTLS protocol information needs to [PROTOCOL]

   Status: Resolved. Removed Sections 5.1, 5.2, and 5.4 for -04 and
   they are [PROTOCOL] -11.

G.23. Split Normative and Non-normative references into separate
sections.

   Status: Resolved. Changes made be
   updated/rewritten in a way that provides useful guidance for future
   readers in -04

G.24. What is the authentication state if a Bind operation is
abandoned? way that will transcend the passage of time.

   Status: Resolved.

   (3/24/03) This following text appears in (6/28/03): Rewrote the 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
   general issues and considerations involved in selecting TLS
   ciphersuites.

G.30 Update to Appendix A, Example Deployment Scenarios

   This section needs to be updated to indicate which security
   mechanisms and/or combinations of leaving security mechanisms described
   elsewhere in the
   connection document can provide the types of protections
   suggested in an anonymous state. To arrive at a known this appendix.

G.31 Use of PLAIN SASL Mechanism

   At least one LDAP server implementer has found the SASL "PLAIN"
   mechanism useful in authenticating to legacy systems that do not
   represent authentication state after abandoning a bind operation, clients may
   unbind, rebind, or make identities as DNs. Section 3.3.1 appears to
   implicitly disallow the use of the BindResponse.

   (6/28/03): The state table in section 6 SASL "PLAIN" mechanism with LDAP.
   Should we allow the use of [AuthMeth] has been
   updated to reflect this wording.

G.25. Difference between checking server hostname and server's
canonical DNS name 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. If SASL "PLAIN" is
   allowed, the following adjustments will be needed to section 3.3.1:
   (a) change section heading, (b) remove reference to "PLAIN" in Server Identity Check?

   Section 4.1.6: I now understand the intent
   section, (c) ensure wording of the check (prevent
   man-in-the-middle attacks).  But what last sentence regarding non-DN
   AuthZIDs is consistent with rest of the subtle difference
   between the "server hostname" and the "server's canonical DNS name"?
   (Source: Tim Hahn) section.

   Status: In Process.

   (11/12/02) Sent suggested wording change to this paragraph Resolved.

   (6/28/03): email to the
   ldapbis mail WG list stating issue and also asked for opinion as to whether asking if we should
   discuss
   remove the distinction between server DNS hostname reference to SASL "PLAIN".

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

G.32 Clarification on use of SASL mechanisms

   Section 3.3.1: BTW, what _are_ the "ANONYMOUS" and server
   canonical DNS hostname "PLAIN" SASL
   mechanisms?  They are not defined in [AuthMeth].

   (11/21/02): RL Bob Morgan will provide wording that allows
   derivations RFC2222.  If you refer to other
   SASL mechanisms than those in rfc2222, Maybe you should only list
   which mechanisms _are_used, instead of which ones are _not. (Source:
   Hallvard Furuseth)

   I (Kurt Zeilenga) note[s] as well that the name ANONYMOUS/PLAIN section
   (4.2) should
   be deleted.  ANONYMOUS and PLAIN, like in other mechanism,
   can be used in LDAP if a) supported and b) enabled.  I note
   that they each offer capabilities not found in their simple
   bind equivalents (and hence are provided securely.

   (6/28/03): posted to 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 WG list asking Bob or SASL profile in section 3.3 to
   allow any other WG member
   who SASL mechanism.

G.33 Clarification on use of password protection based on AuthZID form

   Section 3.3.1: "If an authorization identity of a form different
   from a DN is knowledgeable about requested by the issues involved client, a mechanism that protects the
   password in transit SHOULD be used." What has that to help me do with
   wording or other information I can use to make this change and close DNs?
   A mechanism that protects the work item.

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

   Section 4.1.6: What password in transit should be done if the server was found using SRV
   records based used in
   any case, shouldn't it?

G.34 Clarification on the "locate" draft/RFC? (Source: Tim Hahn).

   Status: Resolved. Section 5 use of draft-ietf-ldapext-locate-08
   specifically calls out how the server identity matching rules in Server Identity Check

   The text in section 4.1.6 isn't explicit on whether all rules apply
   to both CN and dNSName values.  The text should be performed
   if clear as to which
   rules apply to which values....  in particular, the server is located using wildcard
   rules. (Source: Kurt Zeilenga)

G.35 Requested Additions to Security Considerations

   Requested to mention hostile servers which the method defined in user might have been
   fooled to into contacting. Which mechanisms that draft.
   This is are standardized by
   the right location for this information, and LDAP standard do/do not disclose the coverage
   appears user's password to be adequate.

G.27 Inconsistency in effect of TLS closure on LDAP association.

   Section 4.4.1 the
   server? (Or to servers doing man-in-the-middle attack? Or is that a
   stupid question?)

   Requested to mention denial of authmeth -03 (section 4.1 service attacks.

   Requested list of RFC2830) states methods that
   TLS closure alert will leave need/don't need the LDAP association intact. Contrast
   this with Section 4.5.2 (section 5.2 of RFC2830) that says that server to know
   the
   closure user's plaintext password. (I say 'know' instead of 'store'
   because it could still store the TLS connection MUST cause the LDAP association password encrypted, but in a way
   which it knows how to
   move decrypt.)

   (Source: Hallvard Furuseth)

G.36 Add reference to an anonymous authentication.

   Status: Resolved. (11/12/02) This is actually definition of DIGEST-MD5

   Need a [PROTOCOL] issue
   because these sections have now been moved reference to [PROTOCOL] -11. I have
   proposed the following text for Section 4.4.1 of [AuthMeth] -03
   (section 4.13.3.1 definition of [PROTOCOL]) DIGEST-MD5 SASL mechanism in
   section 7.2 (Source: Hallvard Furuseth)

   Status: Resolved. A reference to to resolve this apparent
   discrepancy:

   "Either the client or server MAY terminate DIGEST-MD5 SASL mechanism,
   [DigestAuth], is included in the TLS connection -07 revision.

G.37 Clarification on an
   LDAP association by sending a TLS closure alert.  The LDAP
   connection remains open procedure for further communication after certificate-based authentication

   8.1. Certificate-based authentication with TLS closure
   occurs although states: "Following
   the authentication state successful completion of TLS negotiation, the client will send
   an LDAP connection is
   affected (see [AuthMeth] section 4.2.2).

   (11/21/02): resolution to bind request with the SASL "EXTERNAL" mechanism." Is this
   immediately following, or just some time later? Should the wording,
   "the client will send..." actually read, "the client MUST send..."?

G.38 Effect of StartTLS on authentication state

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

G.39 Be sure that there is expected a consideration in [PROTOCOL] -12

   (06/28/03): [PROTOCOL]-15 clarifies [SCHEMA] that discusses
multiple password values in userPassword

   Allowing multiple values obviously does raise a TLS closure alert
   terminates number of security
   considerations and these need to be discussed in the TLS connection while leaving document.

   Certainly applications which intend to replace the LDAP connection
   intact. The userPassword with
   new value(s) should use modify/replaceValues (or
   modify/deleteAttribute+addAttribute). Additionally, server
   implementations should be encouraged to provide administrative
   controls which, if enabled, restrict userPassword to one value.

G.40. Clarify need to verify mapping between authentication state table in [AuthMeth] specifies the
   effect identity
and resulting authorization identity on the LDAP association.

G.28 Ordering implicit assertion of external sources AuthZID.

   4.2.2.3. Error Conditions

   "For either form of authorization identities

   Section 4.3.2 implies assertion, the server MUST verify that external sources of authorization
   identities other than the
   client's authentication identity as supplied in its TLS are permitted. What credentials
   is permitted to be mapped to the behavior when asserted authorization identity."

   This makes sense for the explicit assertion case, but seems to be
   ambiguous for the implicit case.
   IMHO, the mapping can be done as two external sources of steps:
   a). deriving LDAP authentication credentials are available
   (e.g. identity from TLS and IPsec are both present (is credentials; If t
   this possible?)) and a SASL steps fails, EXTERNAL Bind operation mechanism returns failure.
   b). verify that the authorization identity is performed? allowed for the
   derived authentication identity. This is always "noop" for the
   implicit case.
   I am not sure that the text is saying this.
   (Source: Alexey Melnikov email 8/1/2003 5:30:43 PM)

   Status: resolved. 11/20/02: Resolved by Section 4.2 in -07. After reading the comments and the text of [SASL] which
   states
   the draft, I believe that this should be clarified. The local policy
   used to map the decision AuthNID to allow or disallow the asserted identity AuthZID in the implicit case is based on an implementation defined policy.

G.29 Rewrite of Section 9, TLS Ciphersuites
   sufficient and that no additional verification is useful or needed.
   This section text has been moved to apply only to the explicit assertion
   case.

G.41. Section 7.2 contains anachronistic references  unnecessary and needs to be
   updated/rewritten misleading detail.

   " I am not sure why this section is required in the document.
   DIGEST-MD5 is defined in a way that provides useful guidance separate document and there should be
   nothing magical about its usage in LDAP. If DIGEST-MD5 description
   creates confusion for future
   readers in a way that will transcend the passage of time.

   Status: Resolved. (6/28/03): Rewrote LDAP implementors, let's fix the DIGEST-MD5
   document! Also, this section tries to cover redefine DIGEST-MD5 behavior,
   which is explicitly prohibited by the
   general issues SASL specification."
   (Source: Alexey Melnikov: email 8/1/2003 5:30:43 PM)

   Status: Resolved.

   After reading the comments and considerations involved the text of the draft plus the
   related text in selecting TLS
   ciphersuites.

G.30 Update draft-ietf-sasl-rfc2831bis-02.txt plus
   http://www.ietf.org/internet-drafts/draft-ietf-sasl-rfc2222bis-
   02.txt, I am inclined to Appendix A, Example Deployment Scenarios

   This agree with Alexey. In -07 I rewrote section needs to be updated
   3.3 (SASL mechanisms) to indicate which security
   mechanisms and/or combinations of security mechanisms described
   elsewhere in match the document can provide profiling requirements
   rfc2831bis. I then dramatically reduced the types of protections
   suggested material in this appendix.

G.31 Use of PLAIN section 7.2
   to a bare minimum and let the SASL Mechanism

   At least profile stand on its own.

G.42. Does change for G.41 cause interoperability issue?

   There is one LDAP server implementer has found issue with the SASL "PLAIN"
   mechanism useful in authenticating to legacy systems that do not
   represent authentication identities as DNs. Section 3.3.1 appears to
   implicitly disallow way the use of authmeth draft is currently
   written that changes the SASL "PLAIN" mechanism DIGEST-MD5 behavior on the way the
   server responds with LDAP.
   Should we allow the use of subsequent authentication information .
   This has been documented in this mechanism? I.e. is fashion since RFC 2829 (section
   6.1) was originally published and may cause an interoperability
   issue at this "SASL"
   "PLAIN" MUST NOT point if it changed to follow the DIGEST-MD5 spec (as
   it was in -07 of AuthMeth). Take this issue to the list.

G.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 with LDAP, or is it simply in the protocol and MAY further restrict
   its syntax and protocol-specific semantics."

   I don't believe that any such guidance exists within the LDAP
   doesn't define bindings TS.
   The most likely place for these mechanism. If SASL "PLAIN" is
   allowed, the following adjustments will be needed to section 3.3.1:
   (a) change section heading, (b) remove reference this to "PLAIN" reside is in the
   section, (c) ensure wording of last sentence regarding non-DN
   AuthZIDs is consistent authmeth draft.

   Related email from Alexey Melnikov (8/4/2003 1:08:40 PM):

   "The problem I have with rest of the section.

   Status: In process.

   (6/28/03): email to WG list stating issue and asking if we document is that it references realm
   without explaining what it is (or at least some examples of valid
   values). For LDAP, some recommendations should
   remove be given. For
   example:
   1). Use a hardcoded string as the reference to SASL "PLAIN".

G.32 Clarification on use realm (one of SASL mechanisms

   Section 3.3.1: BTW, what _are_ the "ANONYMOUS" and "PLAIN" SASL
   mechanisms?  They are not defined in RFC2222.  If you refer to other
   SASL mechanisms than those in rfc2222, Maybe you should only list
   which mechanisms _are_used, instead of which ones are _not. (Source:
   Hallvard Furuseth)

G.33 Clarification on use of password protection based implementations
   I worked on AuthZID form

   Section 3.3.1: "If an authorization identity of a form different
   from a DN is requested by the client, was doing that)
   2). Use hostname (realm==host) or domain/cluster name (realm
   includes multiple hosts).
   3). Use a mechanism that protects the
   password node in transit SHOULD 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 used." What has that
   "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 to do define a realm name for use with DNs?
   A mechanism
   Digest-MD5 that protects the password in transit should corresponds to LDAP DNs known to this server.
   Authzid is okay, but perhaps could be used in
   any case, shouldn't it?

G.34 Clarification on use better put into context.

   John  McMeeking (5/12/2003)

G.44. Use of matching rules DNs in Server Identity Check

   The text usernames and realms in section 4.1.6 isn't explicit DIGEST-MD5

   In reading the discussion on whether all rules apply
   to both CN the mailing list, I reach the following
   conclusions:

   DIGEST-MD5 username and dNSName values. realm are simple strings. The text should be clear syntax of
   these strings allows strings that look like DNs in form, however,
   DIGEST-MD5 treats them a simple strings for comparision purposes.
   For example, the DNs cn=roger, o=US 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 which
   rules apply to which values....
   compare username values in particular, the wildcard
   rules. (Source: Kurt Zeilenga)

G.35 Requested Additions DIGEST-MD5. Ditto for realm values.

   Status: Resolved.

   In -07 revision I added notes to Security Considerations

   Requested implementors expressing this issue
   in section 7.2.

G.45: Open Issue: Is Simple+TLS mandatory to mention hostile servers which the user might have been
   fooled implement?

   Going forward, it would be much better to into contacting. Which mechanisms clarify that are standardized by simple
   +TLS 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 LDAP standard do/do time RFC 2829 was
   debated, a large number on the WG wanted this. They did not disclose get
   their way because of the user's password to complexity of the
   server? (Or to servers doing man-in-the-middle attack? Or is solution. It was argued
   that a
   stupid question?)

   Requested to mention denial 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 the use of service attacks. (Source: Hallvard
   Furuseth) DN values as the
   username for DIGEST-MD5.