Authentication Directives and Password Considerations - From Apache: The Definitive Guide

AuthUserFile

AuthUserFile filename

AuthUserFile is a file of usernames and their encrypted passwords. There is quite a lot to this; see the section Passwords Under Unix, Passwords Under Win32, and Passwords over the Web later in this chapter.

AuthAuthoritative

AuthAuthoritative on|off
Default: AuthAuthoritative on
directory, .htaccess

Setting the AuthAuthoritative directive explicitly to off allows for both authentication and authorization to be passed on to lower-level modules (as defined in the Config and modules.c files) if there is no user ID or rule matching the supplied user ID. If there is a user ID and/or rule specified, the usual password and access checks will be applied, and a failure will give an Authorization Required reply.

So if a user ID appears in the database of more than one module or if a valid Require directive applies to more than one module, then the first module will verify the credentials, and no access is passed on — regardless of the AuthAuthoritative setting.

A common use for this is in conjunction with one of the database modules, such as mod_auth_db.c, mod_auth_dbm.c, mod_auth_msql.c, and mod_auth_anon.c. These modules supply the bulk of the user-credential checking, but a few (administrator) related accesses fall through to a lower level with a well-protected AuthUserFile.

Default

By default, control is not passed on, and an unknown user ID or rule will result in an Authorization Required reply. Not setting it thus keeps the system secure.

Security

Do consider the implications of allowing a user to allow fall-through in her .htaccess file, and verify that this is really what you want. Generally, it is easier just to secure a single .htpasswd file than it is to secure a database such as mSQL. Make sure that the AuthUserFile is stored outside the document tree of the web server; do not put it in the directory that it protects. Otherwise, clients will be able to download the AuthUserFile.

Apache: The Definitive Guide, Chapter 5: Authentication

Default

Security