Cron allows you to assign who can execute or not execute any file. The following files can do it:
Cron allow – /etc/cron.allow
Cron deny – /etc/cron.deny
Things to remember:
- Add the name before the file, whether you want to allow or deny this specific name in using cron.
- If you don’t want anyone to use cron, add the line ALL before the cron.deny file.
- If both files do not exist, only the root user can use cron.
- If both cron.allow and cron.deny have the user’s name, then the user still may use cron.
- If cron.deny is present but is empty, all users can use cron.
- If there’s a user in cron.deny, but there’s no cron.allow file, then ALL users can use cron, but not the ones listed in cron.deny.