NAME¶

dacs_passwd - manage private DACS passwords

SYNOPSIS¶

dacs_passwd [dacsoptions[1]]

DESCRIPTION¶

This program is part of the DACS suite.

The dacs_passwd web service is used to manage usernames and passwords recognized by local_passwd_authenticate[2], a DACS authentication module. This utility serves a similar purpose for local_passwd_authenticate that Apache's htpasswd(1)[3] command does for its mod_authn_file[4] and mod_authn_dbm[5] modules. These accounts and passwords are used only by local_passwd_authenticate and are completely separate from any other accounts and passwords.

Note

Much of the functionality of this program is also available as a DACS utility, dacspasswd(1)[6], which operates on the same password files. Because dacs_admin(8)[7] provides the same functionality and more, dacs_passwd may be removed in a future release.

Security

This web service enforces several requirements over and above those specified by its access control rule. The USERNAME argument must be syntactically valid and lowercase. The user must already be authenticated. To change his password, a (non-admin) user must enter his current password.

The default DACS ACL restricts use of this web service to a DACS administrator and to users who are setting the password for their own DACS account at the receiving jurisdiction. Administrators should ensure that the ACL for dacs_passwd is correct for their environment.

OPTIONS¶

Web Service Arguments¶

In addition to the standard CGI arguments[8], dacs_passwd understands the following CGI arguments:

OPERATION

The following operations are supported:

•ADD

Like SET but add or replace an entry for USERNAME.

•DELETE

Delete the account for USERNAME.

•DISABLE

Disable the account for USERNAME.

•ENABLE

Enable the account for USERNAME.

•LIST

List USERNAME, if it exists, otherwise all usernames. A disabled account is indicated by a '*' (which is not a valid character in a username).

•SET

Sets or resets a DACS password for USERNAME to NEW_PASSWORD. The CONFIRM_NEW_PASSWORD argument must also be given and be identical to NEW_PASSWORD. Unless the operation is performed by a DACS administrator (i.e., an ADMIN_IDENTITY[9]) or disabled by the PASSWORD_OPS_NEED_PASSWORD[10] directive, the current password for USERNAME must be given as PASSWORD.

Security
For users other than a DACS administrator, a password must meet certain requirements on its length and the character set from which it is comprised. Note that these requirements are only significant at the time a password is set or changed; existing passwords are unaffected by changes to the configuration directives. Please refer to the PASSWORD_CONSTRAINTS[11] directive.

Users should be made aware of security issues related to passwords, including better techniques for selecting passwords and keeping them private.

How to choose better passwords
Most users can benefit from adopting a method for password selection similar to the one described in this proposal[12]. It suggests that users construct site-specific passwords from three separate components:

1.PIN-1, a short, random string that is common to all of the user's passwords, kept secret, and unlikely to be in any dictionary;

2.SITE, a string that is derived from a site's name (or domain name) using some simple and easy-to-remember procedure (e.g., using an obvious abbreviation or prefix, or the first four letters or consonents, perhaps mixing upper and lower case); and

3.PIN-2, a short, site-specific random string that is different for each of the user's passwords, and not likely to be in any dictionary.

PIN-1 is memorized by the user. The other two components may be written down but must be kept in a relatively secure location (such as in the user's wallet or in a locked desk drawer).

The user forms passwords by combining these three components in any order that is easy to remember, like:

SITE PIN-2 PIN-1

Following that ordering, for the site www.example.net, a user might select the password "exampleRB8s#i8", where "example" (component 2, SITE) is derived from the site's domain name, "RB8s" is a random string used with this password only (component 3, PIN-2), and "#i8" is the user's secret PIN (component 1, PIN-1). Because it is probably difficult to remember, the user might create a note with "www.example.net RB8s" written on it but not PIN-1.

For httpd.apache.org, the same user might select the password "httpd33ABB#i8".

For the site dacs.dss.ca, the user might select the password "dacsceIM#i8".

Note that because the characters comprising PIN-1 must be acceptable in all sites' passwords, and some sites accept a rather limited character set for their passwords, it may be necessary to restrict PIN-1 to the alphanumeric alphabet. The other two components can be chosen from whatever password characters are permitted by the particular site. As some sites unfortunately allow only relatively short passwords, it is preferable to shorten SITE rather than either of the other two components.

Provided the basic rules are followed, a user can strengthen the method by making minor changes. As a simple example, one or more separating characters, also from a restricted character set, might be added before and after the middle component:

SITE Z PIN-2 Z PIN-1

In this example, a 'Z' is used as a separating character.

Since most people are not very good at it, the random strings should be chosen using a good-quality random generator, such as the random()[13] function:

% dacsexpr -e "random(string, 4, 'a-zA-Z0-9,./;@#')"
"y2FJ"

Or, on FreeBSD or macOS:

% jot -r -c 20 33 126 | rs -g 0 4
ib2Y
25$z
vI9Z
^KpZ
51b7

In addition to being difficult to guess because of their random components and reasonably large character set, these passwords are different for each site; should one password be compromised, the others are not immediately available to an attacker. Similarly, the written strings cannot be immediately exploited if they are stolen or copied. The strength of the method can be increased by making either or both PIN components longer, chosen from a larger space of characters, or by inserting one or more characters between components. Software is available to help evaluate password strength (e.g., How Big is Your Haystack?[14]), but avoid giving out the actual password you intend to use.

ACCOUNT

Either PASSWD (the default) or SIMPLE, case insensitively, to select between the item types passwds and simple, respectively. The requested item type must be configured (see dacs.conf(5)[15]).

USERNAME

The DACS username of interest.

FORMAT

By default, output is emitted in HTML. Several varieties of XML output can be selected, however, using the FORMAT argument (please refer to dacs(1)[16] and dacs_passwd.dtd[17]).