Joomla is a CMS (Content Management System) that is widely used. In addition to its ease of use, as well as support for plugin and theme that can be found on the internet. However, that does not mean it does not necessarily make the ease of Joomla secure and convenient to use. Themes and plugins which are found on the internet, created by many and varied levels of knowledge, giving rise to the name of security bugs due to the gap of the script  themes / plugins that are used. Usually the hackers exploit this vulnerability to change your Joomla admin password, and can freely edit the content of your website based on Joomla.If it’s like this, then the only way to take back your Joomla admin access is to change it via cPanel. Here are the steps:

• Log into your cpanel account, usually accessible via https://yourdomain.com:2082 (make sure you added your domain in the place of yourdomain.com)
• Go to the menu phpMyAdmin .
• Look on the left, click on the name of your joomla database (usually containing the words Joom),
• Still on the left menu, scroll down until you find the table called “jos_user”.
• Click edit on the table jos_user.
• There are 4 fields, the name (Administrator), username (admin), e-mail (e-mail address that can be accessed, for facility use joomla forgot password) and password (in particular joomla md5 format) . If not appropriate, then change those fields, specifically for the password field, you first need to set function be MD5, and fill the column with the new password that you want (eg password). Then look down, and click Go,
• At this point, your Joomla admin password has been successfully changed. Please try again access via address yourdomain.com/administrator. Do not forget to check plugins / theme you are likely affected by hackers, and re-upload your joomla to ensure the data on your website clean of malware.