draft-vchu-ldap-pwd-policy-xx.txt 31.1 KB
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LDAP-EXT Working Group					   Valerie Chu
INTERNET-DRAFT				 Netscape Communications Corp.
Expires	in six months
Intended Category: Informational
							 December 1998


		  Password Policy for LDAP Directories
		  <draft-vchu-ldap-pwd-policy-00.txt>



1.  Status of this Memo

This document is an Internet-Draft. Internet-Drafts  are  working  docu-
ments  of the Internet Engineering Task	Force (IETF), its areas, and its
working	groups.	Note that other	groups may also	distribute working docu-
ments as Internet-Drafts.

Internet-Drafts	are draft documents valid for a	maximum	 of  six  months
and  may  be  updated,	replaced, or obsoleted by other	documents at any
time. It is inappropriate to use Internet- Drafts as reference	material
or to cite them	other than as ``work in	progress.''

To view	the entire list	of current  Internet-Drafts,  please  check  the
"1id-abstracts.txt"  listing  contained	 in  the  Internet-Drafts Shadow
Directories on ftp.is.co.za (Africa), ftp.nordu.net  (Northern	Europe),
ftp.nic.it  (Southern Europe), munnari.oz.au (Pacific Rim), ftp.ietf.org
(US East Coast), or ftp.isi.edu	(US West Coast).

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.

2.  Abstract

This  document	describes  the	implementation	of  password  policy  in
Netscape  LDAP	directories,  and  introduces  two  new	 object	classes,
twenty-three new attribute types, and two new  controls	 in  support  of
password policy.

Password policy	is a set of rules that control how passwords are used in
LDAP  directories.  In order to	improve	the security of	LDAP directories
and make it difficult for  password  cracking  programs	 to  break  into
directories,  it  is  desirable	 to  enforce  a	set of rules on	password
usage. These rules are made to ensure that the users change their  pass-
words  periodically,  the  new password	meets construction requirements,
the re-use of the old password is restricted, and  lock	 out  the  users



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after a	certain	number of bad password attempts.

3.  Overview

LDAP-based directory services currently	are accepted by	 many  organiza-
tions as the access protocol for directories.  The ability to ensure the
secure read, update access to directory	information throughout the  net-
work is	essential to the successful deployment.	 There are several secu-
rity mechanisms	which are used in Netscape LDAP	implementation	to  pro-
tect  the  directory  data.   For example, the access control is used to
prevent	unauthorized access to information stored in  directories;  SASL
is  used to negotiate for integrity and	privacy	services.[RFC-2251]  The
most fundamental security mechanism in Netscape	Directory is the  simple
authentication using password.	In many	systems, in order to improve the
security of the	system,	the simple password-based  authentication  often
is  used  in  conjunction with a set of	password restrictions to control
how passwords are used in the system.  For example, the	 passwd	 program
in  UNIX  systems, or the user account policy in WindowsNT, has	a set of
rules that users need to follow	to use password	authentication.	 At  the
moment,	 LDAP  does not	define a password policy model,	but it is needed
to achieve greater security protection and it is critical  to  the  suc-
cessful	deployment of LDAP directories.

Specifically, the password policy defines:


  -    The maximum length of time that a given password	is valid.

  -    The minimum length of time required between password changes.

  -    The maximum length of time before a user's  password  is	 due  to
       expire that the user will be sent a warning message.

  -    Whether users can reuse passwords.

  -    The minimum number of characters	a password must	contain.

  -    Whether the password syntax is checked before a new  password  is
       saved.

  -    Whether users are allowed to change their own passwords.

  -    Whether passwords must be changed after they  are  reset	 by  the
       administrator.

  -    Whether users will be locked out	of the directory after	a  given
       number of failed	bind attempts.




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  -    How long	users will be locked out of the	directory after	a  given
       number of failed	bind attempts.

  -    The length of time before  the  password	 failure  counter  which
       keeps track of the number of failed password attempts is	reset.

The password policy defined in this document is	applied	to the LDAP sim-
ple  authentication  method [RFC-2251] and userPassword	attribute values
only.

In this	document, the term "user" represents any application which is an
LDAP client using the directory	to retrieve or store information.

Directory administrators are not forced	to comply with any  of	password
policies.

4.  New	Attribute Types	and Object Classes

4.1.  The passwordPolicy Object	Class

The passwordPolicy object class	holds the password policy settings for a
set  of	 user  accounts.  In the Netscape Directory implementation, they
are located in the "cn=config" entry.

The description	of passwordPolicy object class:

   ( 2.16.840.1.113730.3.2.13
     NAME 'passwordPolicy'
     AUXILIARY
     SUP top
     DESC 'Password Policy object class	to hold	password policy	information'
     MAY (
	   passwordMaxAge $ passwordExp	$ passwordMinLength $
	   passwordKeepHistory $ passwordInHistory $ passwordChange $
	   passwordCheckSyntax $ passwordWarning $ passwordLockout $
	   passwordMaxFailure $	passwordUnlock $ passwordLockoutDuration $
	   passwordMustChange $	passwordStorageScheme $	passwordMinAge $
	   passwordResetFailureCount
	 )
   )

4.2.  The new attribute	types used in the passwordPolicy Object	Class:

   ( 2.16.840.1.113730.3.1.97
     NAME 'passwordMaxAge'
     DESC 'the number of seconds after which user passwords will expire'
     EQUALITY 'caseIgnoreMatch'
     SYNTAX '1.3.6.1.4.1.1466.115.121.1.15'



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   )
   ( 2.16.840.1.113730.3.1.98
     NAME 'passwordExp'
     DESC 'a flag which	indicates whether passwords will expire	after a
	   given number	of seconds'
     EQUALITY 'caseIgnoreMatch'
     SYNTAX '1.3.6.1.4.1.1466.115.121.1.15'
   )
   ( 2.16.840.1.113730.3.1.99
     NAME 'passwordMinLength'
     DESC 'the minimum number of characters that must be used in a password'
     EQUALITY 'caseIgnoreMatch'
     SYNTAX '1.3.6.1.4.1.1466.115.121.1.15'
   )
   ( 2.16.840.1.113730.3.1.100
     NAME 'passwordKeepHistory'
     DESC 'a flag which	indicates whether passwords can	be reused"
     EQUALITY 'caseIgnoreMatch'
     SYNTAX '1.3.6.1.4.1.1466.115.121.1.15'
   )
   ( 2.16.840.1.113730.3.1.101
     NAME 'passwordInHistory'
     DESC 'the number of passwords the directory server	stores in history'
     EQUALITY 'caseIgnoreMatch'
     SYNTAX '1.3.6.1.4.1.1466.115.121.1.15'
   )
   ( 2.16.840.1.113730.3.1.102
     NAME 'passwordChange'
     DESC 'a flag which	indicates whether users	can change their passwords'
     EQUALITY 'caseIgnoreMatch'
     SYNTAX '1.3.6.1.4.1.1466.115.121.1.15'
   )
   ( 2.16.840.1.113730.3.1.103
     NAME 'passwordCheckSyntax'
     DESC 'a flag which	indicates whether the password syntax will be checked
	   before the password is saved'
     EQUALITY 'caseIgnoreMatch'
     SYNTAX '1.3.6.1.4.1.1466.115.121.1.15'
   )
   ( 2.16.840.1.113730.3.1.104
     NAME 'passwordWarning'
     DESC 'the number of seconds before	a user's password is due to expire that
	   the user will be sent a warning message'
     EQUALITY 'caseIgnoreMatch'
     SYNTAX '1.3.6.1.4.1.1466.115.121.1.15'
   )
   ( 2.16.840.1.113730.3.1.105
     NAME 'passwordLockout'



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     DESC 'a flag which	indicates whether users	will be	locked out of the
	   directory after a given number of consecutive failed	bind attempts'
     EQUALITY 'caseIgnoreMatch'
     SYNTAX '1.3.6.1.4.1.1466.115.121.1.15'
   )
   ( 2.16.840.1.113730.3.1.106
     NAME 'passwordMaxFailure'
     DESC 'the number of consecutive failed bind attempts after	which a	user
	   will	be locked out of the directory'
     EQUALITY 'caseIgnoreMatch'
     SYNTAX '1.3.6.1.4.1.1466.115.121.1.15'
   )
   ( 2.16.840.1.113730.3.1.108
     NAME 'passwordUnlock'
     DESC 'a flag which	indicates whether a user will be locked	out of the
	   directory for a given number	of seconds or until the	administrator
	   resets the password after an	account	lockout'
     EQUALITY 'caseIgnoreMatch'
     SYNTAX '1.3.6.1.4.1.1466.115.121.1.15'
   )
   ( 2.16.840.1.113730.3.1.109
     NAME 'passwordLockoutDuration'
     DESC 'the number of seconds that users will be locked out of the directory
	   after an account lockout
     EQUALITY 'caseIgnoreMatch'
     SYNTAX '1.3.6.1.4.1.1466.115.121.1.15'
   )
   ( 2.16.840.1.113730.3.1.220
     NAME 'passwordMustChange'
     DESC 'a flag which	indicates whether users	must change their passwords when
	   they	first bind to the directory server'
     EQUALITY 'caseIgnoreMatch'
     SYNTAX '1.3.6.1.4.1.1466.115.121.1.15'
   )
   ( 2.16.840.1.113730.3.1.221
     NAME 'passwordStorageScheme'
     DESC 'the type of hash algorithm used to store directory server passwords'
     EQUALITY 'caseIgnoreMatch'
     SYNTAX '1.3.6.1.4.1.1466.115.121.1.15'
   )
   The description of password storage scheme can be found in [RFC-2307].
   ( 2.16.840.1.113730.3.1.222
     NAME 'passwordMinAge'
     DESC 'the number of seconds that must elapse before a user	can change their
	   password again'
     EQUALITY 'caseIgnoreMatch'
     SYNTAX '1.3.6.1.4.1.1466.115.121.1.15'
   )



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   ( 2.16.840.1.113730.3.1.223
     NAME 'passwordResetFailureCount'
     DESC 'the number of seconds after which the password failure counter will
	   be reset'
     EQUALITY 'caseIgnoreMatch'
     SYNTAX '1.3.6.1.4.1.1466.115.121.1.15'
   )

   Currently  in  Netscape  Directory  password	 policy	 implementation,
   passwordMaxAge,  passwordMinLength,	passwordInHistory, passwordWarn-
   ing,	passwordMaxFailure, passwordLockoutDuration, passwordMinAge, and
   passwordResetFailureCount	  attributes	  are	  defined     as
   1.3.6.1.4.1.1466.115.121.1.15 ('Directory  String').	  It  is  recom-
   mented to change them to 1.3.6.1.4.1.1466.115.121.1.27 ('Integer') in
   the future implementation.

   The	attributes  which  are	used  as  a   flag   have   the	  syntax
   '1.3.6.1.4.1.1466.115.121.1.15' ('Directory String').  A value of '1'
   represents 'true', while '0'	represents 'false'.  It	 is  recommented
   to  change  them  to	 1.3.6.1.4.1.1466.115.121.1.7 ('Boolean') in the
   future implementation.

4.3.  The passwordObject Object	Class

The passwordObject object class	holds the password policy state	informa-
tion  for  each	 user.	For  example,  how many	consecutive bad	password
attempts an user made.	The information	is located in each user	entries.
The description	of passwordObject object class:

   ( 2.16.840.1.113730.3.2.12
     NAME 'passwordObject'
     AUXILIARY
     SUP top
     DESC 'Password object class to hold password policy information for each
	   entry'
     MAY (
	   passwordExpirationTime $ passwordExpWarned $	passwordRetryCount $
	   retryCountResetTime $ accountUnlockTime $ passwordHistory $
	   passwordAllowChangeTime
	 )
   )

4.4.  The new attribute	types used in the passwordObject Object	Class:
   ( 2.16.840.1.113730.3.1.91
     NAME 'passwordExpirationTime'
     DESC 'the time the	entry's	password expires'
     SYNTAX 1.3.6.1.4.1.1466.115.121.1.24
     EQUALITY generalizedTimeMatch



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     ORDERING generalizedTimeOrderingMatch
     SINGLE-VALUE
     USAGE directoryOperation
   )
   ( 2.16.840.1.113730.3.1.92
     NAME 'passwordExpWarned'
     DESC 'a flag which	indicates whether a password expiration	warning	is sent
	   to the client'
     EQUALITY 'caseIgnoreMatch'
     SYNTAX '1.3.6.1.4.1.1466.115.121.1.15'
     SINGLE-VALUE
     USAGE directoryOperation
   )
   ( 2.16.840.1.113730.3.1.93
     NAME 'passwordRetryCount'
     DESC 'the count of	consecutive failed password attempts'
     EQUALITY 'caseIgnoreMatch'
     SYNTAX '1.3.6.1.4.1.1466.115.121.1.15'
     SINGLE-VALUE
     USAGE directoryOperation
   )
   ( 2.16.840.1.113730.3.1.94
     NAME 'retryCountResetTime'
     DESC 'the time to reset the passwordRetryCount'
     SYNTAX 1.3.6.1.4.1.1466.115.121.1.24
     EQUALITY generalizedTimeMatch
     ORDERING generalizedTimeOrderingMatch
     SINGLE-VALUE
     USAGE directoryOperation
   )
   ( 2.16.840.1.113730.3.1.95
     NAME 'accountUnlockTime'
     DESC 'the time that the user can bind again after an account lockout'
     SYNTAX 1.3.6.1.4.1.1466.115.121.1.24
     EQUALITY generalizedTimeMatch
     ORDERING generalizedTimeOrderingMatch
     SINGLE-VALUE
     USAGE directoryOperation
   )
   ( 2.16.840.1.113730.3.1.96
     NAME 'passwordHistory'
     DESC 'the history of user's passwords'
     SYNTAX 1.3.6.1.4.1.1466.115.121.1.5
     EQUALITY bitStringMatch
     USAGE directoryOperation
   )
   ( 2.16.840.1.113730.3.1.214
     NAME 'passwordAllowChangeTime'



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     DESC 'the time that the user is allowed change the	password'
     SYNTAX 1.3.6.1.4.1.1466.115.121.1.24
     EQUALITY generalizedTimeMatch
     ORDERING generalizedTimeOrderingMatch
     SINGLE-VALUE
     USAGE directoryOperation
   )

5.  Password Expiration	and Expiration Warning

New attributes,	passwordExp,  passwordMaxAge,  and  passwordWarning  are
defined	 to  specify whether the password will expire, when the	password
expires	and when a warning message will	be sent	to  the	 client	 respec-
tively.	 The  actual  expiration time for a password will be stored in a
new attribute, passwordExpirationTime attribute	in the user entry.

After bind operation succeed  with  authentication,  the  server  should
check  for password expiration.	 If the	password expiration policy is on
and the	account's password is  expired,	 the  server  should  send  bin-
dResponse  with	 the  resultCode: LDAP_INVALID_CREDENTIALS along with an
error message to inform	the client that	the password  has  expired.   If
the  password  is going	to expire sooner than the password warning dura-
tion,  the  server  should  send  bindResponse	with   the   resultCode:
LDAP_SUCCESS,  and  should  include the	password expiring control in the
controls field of the bindResponse message:

    controlType:  2.16.840.1.113730.3.4.5,

    controlValue: an octet string to indicate the time in seconds until
		  the password expires.

    criticality:  false


The server should send at least	one warning message to the client before
expiring the client's password.

6.  Password Minimum Age

This policy defines the	number of seconds that must pass before	 a  user
can  change  the password again.  This policy can be used in conjunction
with the password history policy to prevent users from	quickly	 cycling
through	passwords in history so	that they can reuse the	old password.  A
value of zero indicates	that the user can change  the  password	 immedi-
ately.

During the modify password operation, the server  should  check	 if  the
user  is  allowed  to  change password at this time.  If not, the server



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should send the	LDAP_CONSTRAINT_VIOLATION result code back to the client
and  an	 error	message	 to indicate that the password cannot be changed
within password	minimum	age.

7.  Password History

passwordHistory	and passwordInHistory  attributes  control  whether  the
user  can  reuse  passwords  and how many passwords the	directory server
stores in history.

During the modify password operation, the server should	check for  pass-
word  history.	 If  password history is on and	the new	password matches
one  of	 the  old  passwords  in  history,  the	  server   should   send
modifyResponse	   back	    to	   the	   client    with    resultCode:
LDAP_CONSTRAINT_VIOLATION, and an error	 message  to  indicate	the  new
password is in history,	choose another password.

8.  Password Syntax and	Minimum	length

The passwordCheckSyntax	attribute indicates whether the	password  syntax
will  be  checked before a new password	is saved.  If this policy is on,
the directory server should check that the new password	meets the  pass-
word minimum length requirement	and that the string does not contain any
trivial	words such as the user's name, user id and so on.

The passwordMinLength attribute	defines	the minimum number of characters
that must be used in a password.

During the modify or add password operation, the server	should check for
password  syntax.   If	password check syntax is on and	the new	password
fail the syntax	checking,  the	server	should	send  modifyResponse  or
addResponse	 back	  to	 the	 client	    with     resultCode:
LDAP_CONSTRAINT_VIOLATION, and an error	 message  to  indicate	the  new
password  failed  the  syntax  checking,  the user should choose another
password.

9.  User Defined Passwords

This policy defines whether the	users can change  their	 own  passwords.
During	the  modify  password  operation, the server should check if the
user is	allowed	to change password. If not, the	server	should	send  to
the  client  the LDAP_UNWILLING_TO_PERFORM result code and an error mes-
sage to	indicate that the user is not allowed to change	password.

10.  Password Change After Reset

This policy forces the user to select a	new password on	 first	bind  or
after  password	reset. After bind operation succeed with authentication,



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the server should check	if the password	change after reset policy is  on
and  this  is  the  first time logon. If so, the server	should send bin-
dResponse with the resultCode:	LDAP_SUCCESS,  and  should  include  the
password  expired control in the controls field	of the bindResponse mes-
sage:

    controlType:  2.16.840.1.113730.3.4.4,

    controlValue: an octet string: "0",

    criticality: false

After that, for	any operation issued by	the user other than modify pass-
word,  bind,  unbind,  abandon,	 or  search,  the server should	send the
response message with  the  resultCode:	 LDAP_UNWILLING_TO_PERFORM,  and
should include the password expired control in the controls field of the
response message:

    controlType:  2.16.840.1.113730.3.4.4,

    controlValue: an octet string: "0",

    criticality: false

11.  Password Guessing limit

This policy enforces the limit of number of tries the client has to  get
the  password right.  The user will be locked out of the directory after
a given	number of consecutive failed attempts to bind to the  directory.
This policy protects the directory from	automated guessing attacks.

The server should keep	a  failure  counter  in	 the  passwordRetryCount
attribute  for	each  entry.   The  server  should increment the failure
counter	when a bind operation fails  with  the	LDAP_INVALID_CREDENTIALS
error  code.   The  server  should clear the failure counter when a bind
operation succeeds with	authentication,	the account password is	reset by
administrator, or when the failure counter reset time is reached.

During the bind	operation, the server should check for password	guessing
limit.	 If password guessing limit policy is on and the password guess-
ing limit is reached, the server should	send bindResponse  back	 to  the
client	with resultCode: LDAP_CONSTRAINT_VIOLATION, and	an error message
to indicate the	password failure limit is reached.

12.  Server Implementation






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12.1.  Password	policy initialization

The passwordPolicy object class	holds the password policy settings for a
set  of	user accounts.	During the server initial startup, password pol-
icy should be assigned a set of	initial	values.	 The settings should  be
modified  only by the directory	administrators and should be readable by
anyone.	 The server should preserve the	settings  over	server	restart.
Currently  in the Netscape Directory implementation, the password policy
settings are stored in "cn=config" entry and an	identical copy	is  kept
in a configuration file	which is used as bootstrap.  The Netscape Direc-
tory password default settings are listed below	as an example.

  -    User may	change password

  -    Do not need to change password first time logon

  -    Use SHA as the password hash algorithm

  -    No password syntax check

  -    Password	minimum	length:	6

  -    No password expiration

  -    Expires in 100 days

  -    No password minimum age

  -    Send warning one	day before password expires

  -    Do not keep password history

  -    Six passwords in	history

  -    No account lockout

  -    Lockout after 3 bind failures

  -    Do not lockout forever

  -    Lock account for	60 minutes

  -    Reset retry count after 10 minutes

  In ldif format:

  passwordchange: on




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  passwordmustchange: off

  passwordstoragescheme: SHA

  passwordchecksyntax: off

  passwordminlength: 6

  passwordexp: off

  passwordmaxage: 8640000

  passwordminage: 0

  passwordwarning: 86400

  passwordkeephistory: off

  passwordinhistory: 6

  passwordlockout: off

  passwordmaxfailure: 3

  passwordunlock: on

  passwordlockoutduration: 3600

  passwordresetfailurecount: 600

12.2.  Bind Operations

12.2.1.	 During	bind operations, the server should  check  for	password
guessing  limit.   If password guessing	limit policy is	on and the pass-
word guessing limit is reached,	the server should send bindResponse back
to  the	 client	with resultCode: LDAP_CONSTRAINT_VIOLATION, and	an error
message	to indicate the	password failure limit	is  reached.   Otherwise
the server should continue the bind operation.

12.2.2.	 After Bind Operations succeed with authentication,  the  server
should

  1.   Clear the password failure counter.

  2.   Check if	the password change after reset	policy is on and this is
       the  first  time	 logon.	 If  so,  the server should disallow all
       operations issued by this user except  modify  password,	 bind  ,
       unbind,	abandon, or search.  The server	should send bindResponse



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       with the	resultCode: LDAP_SUCCESS, and should include  the  pass-
       word  expired  control  in the controls field of	the bindResponse
       message.

       controlType:  2.16.840.1.113730.3.4.4,

       controlValue: an	octet string: "0",

       criticality: false

  3.   Check for password expiration.  If the password expiration policy
       is  on  and  the	account's password is expired, the server should
       send bindResponse with the  resultCode:	LDAP_INVALID_CREDENTIALS
       along  with  an error message to	inform the client that the pass-
       word has	expired.

  4.   Check if	the password is	going to expire	sooner than the	password
       warning	duration,  the	server should send bindResponse	with the
       resultCode: LDAP_SUCCESS, and should include the	password  expir-
       ing control in the controls field of the	bindResponse message:

       controlType:  2.16.840.1.113730.3.4.5,

       controlValue: an	octet string to	indicate the time in seconds
		     until the password	expires.

       criticality:  false


12.2.3.	 After Bind Operations fail with  LDAP_INVALID_CREDENTIALS,  the
server should

  1.   Check if	it is time to reset the	password  failure  counter.   If
       so,  set	 the  failure  counter	to  1  and re-calculate	the next
       failure counter reset  time.  Otherwise,	 increment  the	 failure
       counter.

  2.   Check if	failure	counter	exceeds	the allowed maximum  value.   If
       so, the server should lock the user account.

12.3.  Add Password Operations

12.3.1.	 During	the add	password operation, the	server should

  1.   Check for password syntax.  If password check syntax  is	 on  and
       the new password	fail the syntax	checking, the server should send
       addResponse    back    to    the	   client    with    resultCode:
       LDAP_CONSTRAINT_VIOLATION,  and	an error message to indicate the



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       new password failed the syntax checking,	the user  should  choose
       another password.

  2.   Calculate and add passwordexpirationtime	and passwordallowchange-
       time  attributes	 to  the entry if password expiration policy and
       password	minimum	age policy are on respectively.

12.4.  Modify Password Operations

12.4.1.	 During	the modify password operation, the server should

  1.   Check if	the user is allowed to change  password.   If  not,  the
       server  should  send  to	the client the LDAP_UNWILLING_TO_PERFORM
       result code and an error	message	to indicate that the user is not
       allowed to change password.

  2.   Check for password minimum age, password	minimum	length,	password
       history,	 and password syntax.  If the checking fails, the server
       should send modifyResponse back to the  client  with  resultCode:
       LDAP_CONSTRAINT_VIOLATION, and an appropriate error message.

  3.   If it is	the first time logon and the user needs	to change  pass-
       word  the  first	time logon, the	server should check if the user-
       password	attribute is in	this modify request.  If so, the  server
       should  continue	 the  modify  operation.   Otherwise, the server
       should  send  the   response   message	with   the   resultCode:
       LDAP_UNWILLING_TO_PERFORM,   and	  should  include  the	password
       expired control in the controls field of	the response message:

       controlType:  2.16.840.1.113730.3.4.4,

       controlValue: an	octet string: "0",

       criticality: false

12.4.2.	 After modify password operations succeed, the server should

  1.   Update password history in the user's entry, if the password his-
       tory policy is on.

  2.   Update passwordExpirationTime in	the user's entry, if  the  pass-
       word expiration policy is on.

  3.   Update passwordAllowChangeTime in the user's entry, if the  pass-
       word minimum age	policy is on.

  4.   Clear the password failure counter, if the password is reset by a
       directory administrator.



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  5.   Set a flag to indicate the user is the first time logon,	 if  the
       password	 change	 after	reset  policy  is on and the password is
       reset by	a directory administrator.

13.  Client Implementation

13.1.  Bind Response

For every bind response	received, the client needs  to	parse  the  bind
result code, error message, and	controls to determine if any of	the fol-
lowing conditions is true and prompt the user accordingly.

1.   The user needs to change  password	 first	time  logon.   The  user
     should be prompted	to change the password immediately.

     resultCode: LDAP_SUCCESS, with the	control
	 controlType: 2.16.840.1.113730.3.4.4,
	 controlValue: "0",
	 criticality: false


2.   This is a warning message that the	server sends to	a user to  indi-
     cate the time in seconds until the	user's password	expires.

     resultCode: LDAP_SUCCESS, with the	control
	 controlType:  2.16.840.1.113730.3.4.5,
	 controlValue: an octet	string to indicate the time in seconds until
		       the password expires.
	 criticality:  false


3.   The password failure limit	is reached.  The  user	needs  to  retry
     later or contact the directory administrator to reset the password.

     resultCode: LDAP_CONSTRAINT_VIOLATION, with an appropriate	error message.
		For example:
		errorMessage: "exceed password retry limit"


4.   The password is expired.  The user	needs to contact  the  directory
     administrator to reset the	password.

     resultCode: LDAP_INVALID_CREDENTIALS, with	an appropriate error message.
		For example:
		errorMessage: "password	expired"






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13.2.  Modify Responses

For the	modify response	received for the change	 password  request,  the
client	needs to check the result code and error message to determine if
it failed the password checking, and either let	the user retry or quit.

1.   The user defined password policy is  disabled.   The  user	 is  not
     allowed to	change password.

     resultCode: LDAP_UNWILLING_TO_PERFORM, with an appropriate	error message.
		For example:
		errorMessage: "user is not allowed to change password"


2.   The new password  failed  the  password  syntax  checking,	 or  the
     current  password	has not	reached	the minimum password age, or the
     new password is in	history.

     resultCode: LDAP_CONSTRAINT_VIOLATION, with an appropriate	error message.
		For example:
		errorMessage: "invalid password	syntax"
		errorMessage: "password	in history"
		errorMessage: "trivial password"
		errorMessage: "within minimum password age"

13.3.  Add Responses

For the	add response received for the  add  entry  request,  the  client
needs  to  check  the  result  code and	error message to determine if it
failed the password checking, and either let the user retry or quit.

1.   The new password failed the password syntax checking.

     resultCode: LDAP_CONSTRAINT_VIOLATION, with an appropriate	error message.
		For example:
		errorMessage: "invalid password	syntax"
		errorMessage: "trivial password"

13.4.  Other Responses

For operations other than bind,	unbind,	abandon, or search,  the  client
needs to check the following result code and control to	determine if the
user needs to change the password immediately.

1.   The user needs to change  password	 first	time  logon.   The  user
     should be prompted	to change the password immediately.

     resultCode: LDAP_UNWILLING_TO_PERFORM, with the control



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	 controlType: 2.16.840.1.113730.3.4.4,
	 controlValue: "0",
	 criticality: false

14.  Security Considerations

The password policy defined in this document is	applied	to the LDAP sim-
ple  authentication  method [RFC-2251] and userPassword	attribute values
only.  The simple authentication method	provides minimal  authentication
facilities,  with  the	contents  of the authentication	field consisting
only of	a cleartext  password.	 Note  that  the  simple  authentication
method	and  password  policy  are designed for	authentication where the
underlying transport service cannot guarantee confidentiality.	 Use  of
simple	authentication	method and password policy may result in disclo-
sure of	the password to	unauthorized parties.  SASL and	 TLS  mechanisms
may be used with LDAP to provide integrity or confidentiality services.


15.  Bibliography


[RFC-2251]Wahl,	M., Howes, T., Kille, S., "Lightweight Directory  Access
	  Protocol (v3)", RFC 2251, August 1997.

[RFC-2307]L. Howard, "An Approach for Using LDAP as a  Network	Informa-
	  tion Service", RFC 2307, March 1998.

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

16.  Author's Addresses

   Valerie Chu
   Netscape Communications Corp.
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