Can't access WordPress Dashboard in an iframe

Question

I have an iframe on http://foo.example.com which targets to http://bar.example.com.

On http://bar.example.com is a WordPress installation. I'm able to view the page and click on all pages and post but when I try to go to the backend I get

Refused to display document because display forbidden by X-Frame-Options.

and the request is aborted.

According to this question I aded this header which gets send successfully:

header('X-Frame-Options: GOFORIT');

What else can limit the access to just the dashboard (and the login screen)?

I have access to both subdomains and can use a htaccess as well

Answer 1

According to this, in WordPress Answers, Receiving “This content cannot be displayed in a frame” error on login page, WordPress sends a special header

X-Frame-Options: SAMEORIGIN

that prevents clickjacking. And hence, embedding the admin as an iframe.

It is possible to eliminate this header removing a couple of actions from wp-includes/default-filters.php, but at your own risk.

Someone might register a domain with a very similar name, embed your login as background iframe and log the login credentials when you try to type them in.

Please, read the full Q&A at WPSE.

Answer 2

Here is a better solution that won't break when you update Wordpress:

remove_action( 'login_init', 'send_frame_options_header' );
remove_action( 'admin_init', 'send_frame_options_header' );

Here's another solution if you're using Apache. Throw this in your .htaccess:

<IfModule mod_headers.c>
    Header unset X-Frame-Options
    Header always unset X-Frame-Options
</IfModule>