As we have installed Joomla 3 using one of the Siteground installation wizards an additional security plugin, developed by Siteground, has been installed. With this plugin your Joomla web site is automatically protected against some of the more popular hacking attempts. The plugin itself has several options and you can see those if you go to Extensions and Plugin Manager. If you search for the plugin you will see Security -jHackGuard you can see all the different options that are enabled by default. As we've said many times "If you don't know what something is just leave it at the default settings"