Auth.log cron spam

From Flo's Knowledge in a Nutshell

Spam messages in Auth.log

pam_unix(cron:session): session opened for user root by (uid=0)
...

Solution

just add the following line before the pam_unix.so call in /etc/pam.d/common-session-noninteractive:

session [success=1 default=ignore] pam_succeed_if.so service in cron quiet use_uid