mirror of
https://git.openldap.org/openldap/openldap.git
synced 2024-12-21 03:10:25 +08:00
1021 lines
31 KiB
Plaintext
1021 lines
31 KiB
Plaintext
|
|
|
|
|
|
|
|
|
|
|
|
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
|
|
|
|
|
|
|
|
Chu [Page 1]
|
|
|
|
|
|
|
|
|
|
|
|
Expires June 1999 INTERNET DRAFT
|
|
|
|
|
|
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.
|
|
|
|
|
|
|
|
|
|
Chu [Page 2]
|
|
|
|
|
|
|
|
|
|
|
|
Expires June 1999 INTERNET DRAFT
|
|
|
|
|
|
- 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'
|
|
|
|
|
|
|
|
Chu [Page 3]
|
|
|
|
|
|
|
|
|
|
|
|
Expires June 1999 INTERNET DRAFT
|
|
|
|
|
|
)
|
|
( 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'
|
|
|
|
|
|
|
|
Chu [Page 4]
|
|
|
|
|
|
|
|
|
|
|
|
Expires June 1999 INTERNET DRAFT
|
|
|
|
|
|
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'
|
|
)
|
|
|
|
|
|
|
|
Chu [Page 5]
|
|
|
|
|
|
|
|
|
|
|
|
Expires June 1999 INTERNET DRAFT
|
|
|
|
|
|
( 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
|
|
|
|
|
|
|
|
Chu [Page 6]
|
|
|
|
|
|
|
|
|
|
|
|
Expires June 1999 INTERNET DRAFT
|
|
|
|
|
|
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'
|
|
|
|
|
|
|
|
Chu [Page 7]
|
|
|
|
|
|
|
|
|
|
|
|
Expires June 1999 INTERNET DRAFT
|
|
|
|
|
|
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
|
|
|
|
|
|
|
|
Chu [Page 8]
|
|
|
|
|
|
|
|
|
|
|
|
Expires June 1999 INTERNET DRAFT
|
|
|
|
|
|
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,
|
|
|
|
|
|
|
|
Chu [Page 9]
|
|
|
|
|
|
|
|
|
|
|
|
Expires June 1999 INTERNET DRAFT
|
|
|
|
|
|
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
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Chu [Page 10]
|
|
|
|
|
|
|
|
|
|
|
|
Expires June 1999 INTERNET DRAFT
|
|
|
|
|
|
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
|
|
|
|
|
|
|
|
|
|
Chu [Page 11]
|
|
|
|
|
|
|
|
|
|
|
|
Expires June 1999 INTERNET DRAFT
|
|
|
|
|
|
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
|
|
|
|
|
|
|
|
Chu [Page 12]
|
|
|
|
|
|
|
|
|
|
|
|
Expires June 1999 INTERNET DRAFT
|
|
|
|
|
|
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
|
|
|
|
|
|
|
|
Chu [Page 13]
|
|
|
|
|
|
|
|
|
|
|
|
Expires June 1999 INTERNET DRAFT
|
|
|
|
|
|
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.
|
|
|
|
|
|
|
|
Chu [Page 14]
|
|
|
|
|
|
|
|
|
|
|
|
Expires June 1999 INTERNET DRAFT
|
|
|
|
|
|
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"
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Chu [Page 15]
|
|
|
|
|
|
|
|
|
|
|
|
Expires June 1999 INTERNET DRAFT
|
|
|
|
|
|
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
|
|
|
|
|
|
|
|
Chu [Page 16]
|
|
|
|
|
|
|
|
|
|
|
|
Expires June 1999 INTERNET DRAFT
|
|
|
|
|
|
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.
|
|
501 E. Middlefield Rd.
|
|
Mountain View, CA 94043
|
|
USA
|
|
+1 650 937-3443
|
|
vchu@netscape.com
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Chu [Page 17]
|
|
|
|
|