FAILED to open PAM security session (Module is unknown)

Cron Jobs in server were not getting executed automatically

On investigating I could see error like

Jun 16 14:05:01 ok1110 crond[5913]: (root) FAILED to open PAM security session (Module is unknown)
Jun 16 14:05:01 ok1110 crond[5912]: (root) FAILED to open PAM security session (Module is unknown)
Jun 16 14:06:01 ok1110 crond[6021]: (root) FAILED to open PAM security session (Module is unknown)

On deeper investigating I found the issue was in file

 /etc/pam.d/crond

I went ahead and copied file from working server and fixed this issue.

  • PAM configuration is the default:
$ cat /etc/pam.d/crond
#
# The PAM configuration file for the cron daemon
#
#
auth       sufficient pam_env.so
auth       required   pam_rootok.so
auth       include    system-auth
account    required   pam_access.so
account    include    system-auth
session    required   pam_loginuid.so
session    include    system-auth


If this file is modified the crond does not work for any users.