I just came across the same issue. Here's my solution since mod_auth_pam is dead and no one has addressed the original question,
"authenticate via local system accounts...in a specified group"
I'm using Ubuntu 18.04, so flavor the package installation to your own system. For this example, I'm hosting a directory /var/www/data and only want users in the data group to have access. I'm assuming you have an Apache installation running and the data group already created.
As mentioned before, you'll need to grab pwauth and the authnz software. Additionally, you will need mod-authz-unixgroup for group authentication. You can install them using,
apt install libapache2-mod-authz-unixgroup libapache2-mod-authnz-external pwauth
Next, change the permissions of pwauth (this was fixed on 2020-06-02, but I'll leave this here for older releases) by using,
chmod u+s /usr/sbin/pwauth
Then, write up your apache2 VirtualHost configuration. Here's a very simple example,
<VirtualHost *:80> # Host Info ServerName cool.things ServerAdmin [email protected] DocumentRoot /var/www # Where the logs go ErrorLog ${APACHE_LOG_DIR}/error.log CustomLog ${APACHE_LOG_DIR}/access.log combined # Setup external authentication <IfModule mod_authnz_external.c> AddExternalAuth pwauth /usr/sbin/pwauth SetExternalAuthMethod pwauth pipe </IfModule> # Load an _h5ai index <Directory "/var/www/data"> Options Indexes FollowSymLinks MultiViews DirectoryIndex index.html index.php /data/_h5ai/public/index.php # Setup Basic Authentication AuthType Basic AuthName "data group members only" AuthBasicProvider external AuthExternal pwauth # Only allow members of the "data" group Require unix-group data </Directory> </VirtualHost>
Finally, you'll need to reload, restart, and check the status of Apache for errors.
service apache2 reload service apache2 restart service apache2 status