Ensure Firewall is active
IPtables is an application that allows a system administrator to configure the IPv4 tables, chains and rules provided by the Linux kernel firewall. ufw was developed to ease IPtables firewall configuration.
Restrict at/cron to Authorized Users
Configure /etc/cron.allow and /etc/at.allow to allow specific users to use these services. If /etc/cron.allow or /etc/at.allow do not exist, then /etc/at.deny and /etc/cron.deny are checked. Any user not specifically defined in those files is allowed to use at and cron. By removing the files, only users in /etc/cron.allow and /etc/at.allow are allowed to use a ...