Directory Services 7.4.3

Sample password policies

Lock accounts after repeated bind failures

To help you prevent brute-force attacks, where an attacker tries many passwords in the hope of eventually guessing correctly, DS password policies support configurable account lockout. This feature is an important part of a secure password policy.

When you configure account lockout as part of password policy, DS servers lock an account after the specified number of consecutive authentication failures. Account lockout is not transactional across all replicas in a deployment. Global account lockout occurs as soon as the authentication failure times have been replicated.

The following commands demonstrate a subentry password policy that locks accounts for five minutes after three consecutive bind failures. With this policy, the directory server records failure times, and slowly discards them. As a result, a brute-force attack is hopefully too slow to be effective, but no administrative action is needed when a user temporarily forgets or mistypes their password.

Once an account is locked, binds continue to fail for the lockout period, even if the credentials are correct. An account administrator can use the manage-account command to view the account status, and to change it if necessary:

Show example commands 
# Set the password policy:
$ ldapmodify \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=admin \
 --bindPassword password << EOF
dn: cn=Lock After Repeated Bind Failures,dc=example,dc=com
objectClass: top
objectClass: subentry
objectClass: ds-pwp-password-policy
cn: Lock After Repeated Bind Failures
ds-pwp-password-attribute: userPassword
ds-pwp-default-password-storage-scheme: PBKDF2-HMAC-SHA256
ds-pwp-lockout-duration: 5 m
ds-pwp-lockout-failure-count: 3
ds-pwp-lockout-failure-expiration-interval: 2 m
subtreeSpecification: { base "ou=people", specificationFilter "(objectClass=posixAccount)" }
EOF

# Attempt to bind three times using the wrong password:
$ ldapsearch \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDn uid=bjensen,ou=people,dc=example,dc=com \
 --bindPassword wrongPassword \
 --baseDn dc=example,dc=com \
 "(uid=bjensen)"

The LDAP bind request failed: 49 (Invalid Credentials)

$ ldapsearch \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDn uid=bjensen,ou=people,dc=example,dc=com \
 --bindPassword wrongPassword \
 --baseDn dc=example,dc=com \
 "(uid=bjensen)"

The LDAP bind request failed: 49 (Invalid Credentials)

$ ldapsearch \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDn uid=bjensen,ou=people,dc=example,dc=com \
 --bindPassword wrongPassword \
 --baseDn dc=example,dc=com \
 "(uid=bjensen)"

The LDAP bind request failed: 49 (Invalid Credentials)

# Observe the results:
$ manage-account \
 get-all \
 --hostname localhost \
 --port 4444 \
 --bindDN uid=admin \
 --bindPassword password \
 --targetDN uid=bjensen,ou=people,dc=example,dc=com \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin

Password Policy DN:  cn=Lock After Repeated Bind Failures,dc=example,dc=com
Seconds Until Authentication Failure Unlock:  <seconds>

Enforce regular password changes

The following commands configure a subentry password policy that sets age limits on passwords, requiring that users change their passwords at least every 13 weeks, but not more often than every 4 weeks. The policy also sets the number of passwords to keep in the password history of the entry, preventing users from reusing the same password on consecutive changes:

$ ldapmodify \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=admin \
 --bindPassword password << EOF
dn: cn=Enforce Regular Password Changes,dc=example,dc=com
objectClass: top
objectClass: subentry
objectClass: ds-pwp-password-policy
cn: Enforce Regular Password Changes
ds-pwp-password-attribute: userPassword
ds-pwp-default-password-storage-scheme: PBKDF2-HMAC-SHA256
ds-pwp-max-password-age: 13 w
ds-pwp-min-password-age: 4 w
ds-pwp-password-history-count: 7
subtreeSpecification: { base "ou=people" }
EOF

When modifying a password, DS checks the new password against each hashed password value in the entry.

If the password policy specifies a computationally intensive password storage scheme, such as Argon2, Bcrypt, PKCS5S2, or a PBKDF2-based scheme, enabling password history multiplies the cost of changing the password.

DS must calculate the computationally intensive hash from the new password separately for each comparison with a hashed password in the password history. As a result, if it takes 100 ms to calculate the hash for a new password, and the applicable password policy has a password history count of 7, the calculations to modify the password can take up to 700 ms.

Track last login time

The following command configures a subentry password policy that keeps track of the last successful login:

  1. Create the password policy to write the timestamp to the attribute on successful login:

    $ dsconfig \
 create-password-policy \
 --hostname localhost \
 --port 4444 \
 --bindDN uid=admin \
 --bindPassword password \
 --policy-name "Track Last Login Time" \
 --type password-policy \
 --set default-password-storage-scheme:PBKDF2-HMAC-SHA256 \
 --set password-attribute:userPassword \
 --set last-login-time-attribute:ds-last-login-time \
 --set last-login-time-format:"yyyyMMddHH'Z'" \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --no-prompt

The last-login-time-format setting must:

  • Use GeneralizedTime syntax.

  • Be a valid format string for the java.text.SimpleDateFormat class.

With the setting shown in the example, last-login-time-format:"yyyyMMddHH’Z'", DS records last login time to the nearest hour. For each bind where the timestamp changes, DS updates the timestamp on the entry. So this recommended setting avoids updating entries often for users who bind repeatedly over a short period. If the deployment requires a fine-grained last login timestamp, use a format that includes minutes or seconds. For example, to get last login times that are accurate to the second, use last-login-time-format:"yyyyMMddHHmmss’Z'".

For examples using last login time in LDAP searches, refer to Active accounts.

Deprecate a password storage scheme

The following commands configure a subentry password policy for deprecating a password storage scheme. This policy uses elements from Enforce regular password changes. The DS server applies the new password storage scheme to re-encode passwords:

  • When they change.

  • When the user successfully binds with the correct password, and the password is currently hashed with a deprecated scheme.

$ dsconfig \
 set-password-storage-scheme-prop \
 --hostname localhost \
 --port 4444 \
 --bindDN uid=admin \
 --bindPassword password \
 --scheme-name "Salted SHA-512" \
 --set enabled:true \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --no-prompt

$ ldapmodify \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=admin \
 --bindPassword password << EOF
dn: cn=Deprecate a Password Storage Scheme,dc=example,dc=com
objectClass: top
objectClass: subentry
objectClass: ds-pwp-password-policy
cn: Deprecate a Password Storage Scheme
ds-pwp-password-attribute: userPassword
ds-pwp-default-password-storage-scheme: PBKDF2-HMAC-SHA256
ds-pwp-deprecated-password-storage-scheme: Salted SHA-512
ds-pwp-max-password-age: 13 w
ds-pwp-min-password-age: 4 w
ds-pwp-password-history-count: 7
subtreeSpecification: { base "ou=people" }
EOF

Lock idle accounts

The following commands configure a subentry password policy that locks accounts idle for more than 13 weeks. This policy extends the example from Track last login time. The DS server must track last successful login time to calculate how long the account has been idle:

$ ldapmodify \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=admin \
 --bindPassword password << EOF
dn: cn=Lock Idle Accounts,dc=example,dc=com
objectClass: top
objectClass: subentry
objectClass: ds-pwp-password-policy
cn: Lock Idle Accounts
ds-pwp-password-attribute: userPassword
ds-pwp-default-password-storage-scheme: PBKDF2-HMAC-SHA256
ds-pwp-idle-lockout-interval: 13 w
ds-pwp-last-login-time-attribute: ds-last-login-time
ds-pwp-last-login-time-format: yyyyMMddHH'Z'
subtreeSpecification: { base "ou=people" }
EOF

Allow log in to change an expired password

The following commands configure a subentry password policy that lets users log in twice with an expired password to set a new password:

$ ldapmodify \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=admin \
 --bindPassword password << EOF
dn: cn=Allow Grace Login,dc=example,dc=com
objectClass: top
objectClass: subentry
objectClass: ds-pwp-password-policy
cn: Allow Grace Login
ds-pwp-password-attribute: userPassword
ds-pwp-default-password-storage-scheme: PBKDF2-HMAC-SHA256
ds-pwp-grace-login-count: 2
subtreeSpecification: { base "ou=people" }
EOF

Require password change on add or reset

The following commands configure a subentry password policy that requires new users to change their password after logging in for the first time. This policy also requires users to change their password after it is reset:

$ ldapmodify \
 --hostname localhost \
 --port 1636 \
 --useSsl \
 --usePkcs12TrustStore /path/to/opendj/config/keystore \
 --trustStorePassword:file /path/to/opendj/config/keystore.pin \
 --bindDN uid=admin \
 --bindPassword password << EOF
dn: cn=Require Password Change on Add or Reset,dc=example,dc=com
objectClass: top
objectClass: subentry
objectClass: ds-pwp-password-policy
cn: Require Password Change on Add or Reset
ds-pwp-password-attribute: userPassword
ds-pwp-default-password-storage-scheme: PBKDF2-HMAC-SHA256
ds-pwp-force-change-on-add: true
ds-pwp-force-change-on-reset: true
subtreeSpecification: { base "ou=people" }
EOF