[ Thanks to firstbase for this link.
]
“For those of you lucky enough to use either Slack or have a
non-PAM-poisoned distro… I have some suggestions for your ‘su’
configuration.“Most people don’t appear to know/remember that ‘su’ has a
configuration file. This configuration file is ‘/etc/suauth’. The
/etc/suauth file can be extremely useful in setting up additional
security for ‘su’…”