libapache2-mod-authn-sasl - 1.2-2+b2 main

This module provides the mod_auth_basic authentication front-end
a way to authenticate users by checking credentials via the Cyrus SASL library.
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Username and password are checked against the SASL password checking backends,
kerberos5, pam, rimap, shadow and ldap are some of the supported mechanisms.
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One of the interesting parts of using a SASL backend is that you do not need
to elevate Apache HTTPD's access rights to superuser privileges, even when
validating through shadow database.