Unable to Access Backend - Masked for frontend

Question

It has been awhile since I went in and updated one of the sites I manage.

The problem:

When I go to the backend of my site (/administrator), it is simply a mask for the front-end.

So when I go to either of the below urls:

http://mysite.com/administrator

http://mysite.com/administrator/index.php

I see the content for

http://mysite.com/

What I tried:

Disabled SEF urls in configuration.php.

Checked the redirects table in the db for weird admin redirects (there are none).

Checked .htaccess file obvious signs of hacking or malicious or really any redirects (there are none and I have just the stock .htaccess).

NOTE: If I disable the .htaccess file (rename via FTP), when I try to go to the admin page, I see a 404 error.

I think it has been hacked or I (or another user) have installed a security plug-in that hides the admin URL. Unfortunately, I cannot remember if I have done the latter. I checked for jsecure, not there. I do have admintools installed and tried disabling it to no avail.

I also tried to update to 3.5.1. I uploaded the update package, still cannot access the backend.

I should note the frontend works fine.

Answer 1

As you mentioned, this is usually the behavior of security extensions like admintools, jSecure to protect the administration area of a Joomla site. If you can't tell if you have any of these, think how difficult is for us to say anything. I would suggest to get a backup of your site and restore it locally, or at another location of your hosting account.

There you can go and review/experiment with everything around your site. Make sure you will also review the extensions table of your database, and see if there are any other 3rd party security extensions.
Generally in the testing site you can disable them one by one and see if and when your admin url access will be restored.

Regarding admintools, normally all you need to do is to go in the plugins directory and rename the admintools plugin folder.

Since you mentioned it, if you believe other users could have installed anything or have implement any such techniques, then it can be a good idea to ask them. After that, I would suggest to discuss between you on how to make your communication better in terms of managing your websites and exchanging critical information.