How To Stop An Ethical Hacker Breaking Into Your WordPress Site

Posted on 08. Apr, 2010 by Alex Denning in Security

In this month’s .net magazine (known as Practical Web Design in the US) there was an interesting article where an ethical hacker showed how he would break into your site — and what you can do to stop him. In this post we’ll look past “X Plugins To Save Your Blog” and see what effective steps you can take to stop a real life hacker.

Hiding WordPress

One of the first things our “ethical hacker” did was to find out what software the site was running on. That means in order to stop him you’ll have to hide any indication that you’re using WordPress. Which is slightly harder than it appears at first.

If I look at a site to me it’s pretty obvious if it’s running WordPress. Let’s take a look at DesignInformer’s head tag:

We’ll come to wp-content in a sec, but first to RSS feeds. I don’t know how other CMSes do feeds, but to me when I see /feed/ and /comments/feed/ immediately I think WordPress. You can get around this by using something like Feedburner for your RSS feeds.

If you’re using plugins which are leaving their mark, quite literally, then the best thing to do is to manually edit the plugin to get rid of the comment. All you need to do is click ‘Plugins’, ‘Editor’, select the offending plugin and then search for the comment. Delete it and save. It’s gone! It will get overwritten if you update though, so just make sure you repeat the process with each upgrade.

Remove ‘Stuff’ WordPress Spits Out Into wp_head

As Jeff explains, WordPres spits out a load of quite useless stuff into wp_head, all of which you can easily remove with this code in your functions.php:

// remove junk from head
remove_action('wp_head', 'rsd_link');
remove_action('wp_head', 'wp_generator');
remove_action('wp_head', 'feed_links', 2);
remove_action('wp_head', 'index_rel_link');
remove_action('wp_head', 'wlwmanifest_link');
remove_action('wp_head', 'feed_links_extra', 3);
remove_action('wp_head', 'start_post_rel_link', 10, 0);
remove_action('wp_head', 'parent_post_rel_link', 10, 0);
remove_action('wp_head', 'adjacent_posts_rel_link', 10, 0);

With all that removed, there’s no immediate indication you’re running WordPress.

Hiding wp-content

This one’s a bit more difficult, but it’s still doable, as the codex explains:

Set WP_CONTENT_DIR to the full local path of this directory (no trailing slash), e.g.

define( 'WP_CONTENT_DIR', $_SERVER['DOCUMENT_ROOT'] . '/blog/wp-content' );

Set WP_CONTENT_URL to the full URI of this directory (no trailing slash), e.g.

define( 'WP_CONTENT_URL', 'http://example/blog/wp-content');

Hiding wp-admin

Even if you’ve moved everything from the head, going to /wp-admin/ will tell me immediately whether you’re running WordPress or not. It’s actually surprisingly easy to move the entire wp-admin folder, Michi explains – you just need some .htaccess code to redirect the whole lot to another folder. You could be sneaky and redirect it to /administrator to fool any hacker

Powered by…

Pretty obvious,  but worth a mention – don’t forget to remove ‘Powered by WordPress’ from your theme!

Stopping the hacker gaining access

In the article the hacker just goes through the different software used on the site, listing out of date software with vulnerabilities. That means it’s imperative to keep your site updated. That doesn’t necessarily mean the latest version though. Sites like Mashable stay a version number behind at the latest stable version in order to protect themselves from new vulnerabilities - quite a clever way of staying secure.

The article specifically mentions blocking access to the backend by IP is a good idea — the following code will do the trick:

order deny,allow
allow from a.b.c.d # This is your static IP
deny from all

Rounding up

And that’s it. Hopefully this post has been helpful to you and shown you how a real world hacker would hack your very real world site – yours. Don’t be too scared; be prepared instead!

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