A cron job is a scheduled task on Unix-like systems, usually managed by the cron daemon. It runs a command or script at a fixed time or interval, such as every minute, every hour, or on a specific day. Administrators use cron for backups, log rotation, updates, and other automation that should happen without manual intervention.
In cyber security, cron jobs matter because they execute with the permissions of the account that created them, and often with elevated privileges. If an attacker can create, modify, or trigger a cron entry, they may turn a web-level flaw into server-side code execution or persistence. Defenders should audit cron directories and scheduled entries, restrict who can edit them, and monitor for unexpected jobs, unusual scripts, or changes made through control panels and automation features.