JHacker Watch Standard Edition for Jooma! 3
For personal, one-man business and non-profit websites only. Limited support.
Current version 2.3.0. Compatible with PHP 5.3.10+ and PHP 7, PHP 8.
Updates through the Joomla! Update System.
Purchase includes one (1) year free updates.
Optional Remote Monitoring service (1 week trial for only € 1.25).

Also available as a Business Edition with executive configuration options, see documentation.

A plug-in that continuously monitors your Joomla! install and analyses whether critical user account details have been changed or directories and files have either been modified, added or are not part of a standard Joomla! install. It therefore provides an additional line of defense against website hacking attempts. The plug-in slows down repeated back-end log-in attempts to make brute force attacks frustratingly ineffective.

The plug-in does NOT prevent hacking attempts and cannot guarantee that your website will never be hacked, but it counteracts certain unusual activities and - most importantly - notifies the site administrator(s) of these activities, thus making sure that hack attempts will not go unnoticed and providing more specific information for the website administrator(s) to remediate these.

Install or upgrade via Joomla! backend.

Configuration overview: see here.

Requirements: Joomla! 3.x

Basic install, upgrade and setup instructions are in the documentation that comes with the download package.

Backend language: English.

License: For personal, one-man business and non-profit use only. License terms are here.
Support: Limited support. Support terms are here. You may find the answer to your question on our forum.

Discount and refund policy: see here.

You may want to try the freeware edition first. The freeware edition does not expire, but has limited options and is meant for evaluation only.