Je suis aller faire une petit tour avec cette commande (/var/log/auth.log) et voici ce que je peux y trouver :
Jan 9 23:31:50 Debian-82-jessie-64-minimal groupadd[19329]: group added to /etc/group: name=munin, GID=116
Jan 9 23:31:50 Debian-82-jessie-64-minimal groupadd[19329]: group added to /etc/gshadow: name=munin
Jan 9 23:31:50 Debian-82-jessie-64-minimal groupadd[19329]: new group: name=munin, GID=116
Jan 9 23:31:50 Debian-82-jessie-64-minimal useradd[19333]: new user: name=munin, UID=111, GID=116, home=/var/lib/munin, shell=/bin/false
Jan 9 23:31:51 Debian-82-jessie-64-minimal usermod[19338]: change user 'munin' password
Jan 9 23:31:51 Debian-82-jessie-64-minimal chage[19343]: changed password expiry for munin
Jan 9 23:31:51 Debian-82-jessie-64-minimal chfn[19346]: changed user 'munin' information
Jan 16 15:17:01 Debian-82-jessie-64-minimal CRON[29024]: pam_unix(cron:session): session opened for user root by (uid=0)
Jan 16 15:17:01 Debian-82-jessie-64-minimal CRON[29024]: pam_unix(cron:session): session closed for user root
Jan 16 15:20:01 Debian-82-jessie-64-minimal CRON[29069]: pam_unix(cron:session): session opened for user root by (uid=0)
Jan 16 15:20:01 Debian-82-jessie-64-minimal CRON[29070]: pam_unix(cron:session): session opened for user munin by (uid=0)
Jan 16 15:20:01 Debian-82-jessie-64-minimal CRON[29069]: pam_unix(cron:session): session closed for user root
Jan 16 15:20:09 Debian-82-jessie-64-minimal CRON[29070]: pam_unix(cron:session): session closed for user munin
Jan 16 15:25:01 Debian-82-jessie-64-minimal CRON[29501]: pam_unix(cron:session): session opened for user root by (uid=0)
Jan 16 15:25:01 Debian-82-jessie-64-minimal CRON[29502]: pam_unix(cron:session): session opened for user munin by (uid=0)
Jan 16 15:25:01 Debian-82-jessie-64-minimal CRON[29501]: pam_unix(cron:session): session closed for user root
Jan 16 15:25:08 Debian-82-jessie-64-minimal CRON[29502]: pam_unix(cron:session): session closed for user munin
Jan 16 15:30:01 Debian-82-jessie-64-minimal CRON[29938]: pam_unix(cron:session): session opened for user root by (uid=0)
Jan 16 15:30:01 Debian-82-jessie-64-minimal CRON[29939]: pam_unix(cron:session): session opened for user munin by (uid=0)
Jan 16 15:30:01 Debian-82-jessie-64-minimal CRON[29938]: pam_unix(cron:session): session closed for user root
Jan 16 15:30:10 Debian-82-jessie-64-minimal CRON[29939]: pam_unix(cron:session): session closed for user munin
Jan 16 15:35:01 Debian-82-jessie-64-minimal CRON[30370]: pam_unix(cron:session): session opened for user root by (uid=0)
A quoi celà correspond ?