Securing crontab

A /etc/cron.allow file dosn’t exist. Meens that everyone has the right to create a cronjob or can change it? and wen I create the file /etc/cron.allow how is the syntax and must root in there?

Have you checked the crontab manpage? From the man 1p crontab output:


Users shall be permitted to use crontab if their names appear in the file
/usr/lib/cron/cron.allow. If that file does not exist, the file
/usr/lib/cron/cron.deny shall be checked to determine whether the user
shall be denied access to crontab. If neither file exists, only a
process with appropriate privileges shall be allowed to submit a job. If
only cron.deny exists and is empty, global usage shall be permitted. The
cron.allow and cron.deny files shall consist of one user name per line.

Good luck.