How to Use a Dictionary File to Increase Password Security

A dictionary file can be used by the Kerberos service to prevent words in the dictionary from being used as passwords when creating new credentials. Preventing the use of dictionary terms as passwords makes it harder for someone else to guess any password. By default the /var/krb5/kadm5.dict file is used, but it is empty.

1. Become superuser on the master KDC.

2. Edit the KDC configuration file (kdc.conf).

   You need add a line to instruct the service to use a dictionary file. In this example, the dictionary that is included with the spell utility is used. See the kdc.conf(4) man page for a full description of the configuration file.

   kdc1 # cat /etc/krb5/kdc.conf [kdcdefaults] kdc_ports = 88,750 [realms] EXAMPLE.COM = { profile = /etc/krb5/krb5.conf database_name = /var/krb5/principal acl_file = /etc/krb5/kadm5.acl kadmind_port = 749 max_life = 8h 0m 0s max_renewable_life = 7d 0h 0m 0s sunw_dbprop_enable = true sunw_dbprop_master_ulogsize = 1000 dict_file = /usr/share/lib/dict/words }

3. Restart the Kerberos daemons.

   kdc1 # svcadm restart -r network/security/krb5kdc kdc1 # svcadm restart -r network/security/kadmin