CRON

Jan 1, 0001

Definition

CRON is a time-based job scheduler in Unix-like operating systems that enables users to run scripts or commands at specified times and intervals. It is commonly used for automating system maintenance or administration tasks, such as backups, updates, and monitoring. CRON jobs are defined in a crontab file, which specifies the timing and frequency of execution using a syntax that includes fields for minute, hour, day of the month, month, and day of the week.

Secure Settings Example

# Secure CRON job example
# This job runs a backup script every day at 2 AM with restricted permissions
0 2 * * * /usr/bin/sudo -u backupuser /usr/local/bin/backup.sh > /var/log/backup.log 2>&1
  • The job is executed by a non-privileged user (backupuser) to minimize security risks.
  • Output and errors are logged for auditing and troubleshooting.

Insecure Settings Example

# Insecure CRON job example
# This job runs a script as root without logging
0 2 * * * /usr/local/bin/backup.sh
  • The job runs as the root user, increasing the risk of privilege escalation if the script is compromised.
  • Lack of logging makes it difficult to audit or troubleshoot issues.