Log in with FTP and go to the folder of your WordPress website. In the root of your WordPress website there are at least three folders: ‘wp-admin’, ‘wp-content’ and ‘wp-includes’. In the ‘wp-content’ folder all the specific changes to your website are saved, but ‘wp-admin’ and ‘wp-includes’ only contain files from the WordPress core; files that only change when a new version WordPress is released.

To make sure in one go, that there are no files in your WordPress core that have been added or infected you can remove the ‘wp-admin’ en ‘wp-includes’ files and replace them with a clean version by downloading WordPress again.

• Not sure which WordPress version you are running? Check in ‘wp-includes/version.php’ and you will find the version number on line 7.
• Download a zip-file of this version from the WordPress release-archive and unzip it on your computer.
• Remove the ‘wp-admin’ and ‘wp-includes’ using FTP from the root of your WordPress website.
• Upload the ‘wp-admin’ and ‘wp-includes’ from the file you just unzipped.

Along with folders there are also files in the root of your website. Replace these files – except wp-config.php (!) – with the files from the unzipped zip file.

Are there other files and folders in the root of your website? Examine them critically and decide whether or not they are familiar to you; is there any other software running on your site? If not then they may have been placed by the hacker. When in doubt confer with your web host. Sometimes your web host will preinstall a folder like ‘stats’, ‘webstats’, ‘logs’ and ‘cgi-bin’ . Always take a look at these folders and look for files that end in ‘.php’. Because, normally speaking, they shouldn’t be there.

Just like the WordPress core, you can find original clean versions of your plugins in the WordPress plugin repository. It is, however, possible that not all your plugins come from here; you may have purchased premium plugins, for example, elsewhere. Premium plugins cannot always be updated automatically. Either way, to be sure that your plugin folder is clean, you will have to locate all the originals.

• This is a good time to remove inactive plugins and plugins that are used infrequently. Do this first.
• The plugins from the WordPress plugin repository can only be removed via FTP. After removing them download clean versions from the repository and upload them via FTP. A plugin like Wordfence may be able to do this step for you.
• It is also important get clean versions of plugins that do not come from the WordPress repository. Make sure you find these files and repeat the above step for these plugins. Can’t find the original plugin files? Then you will have to remove the entire plugin, because it is very possible that the plugin is (partially) responsible for the hack. More importantly, you will not be able to update the plugin in the future and that could be disastrous to the safety of your website in the future. Often you will be able find an alternative plugin for the functionality you are looking for.

In this step you will update all your plugins to the newest version. That is safe, but may lead to conflicts if your WordPress core or theme, for example, is not compatible with the newest version of the plugin. In that case, replace it with an older version of the plugin or – better yet – update your theme (see the following step) to see if that will resolve the problem.

WordPress themes sometimes contain customization done by you or your website builder. These modifications will be lost if you update the theme, unless the modifications are saved in a separate folder by using a child theme.

Your WordPress website doesn’t use a child theme? Then you have the option to update your theme, as explained in the previous step, but any modification will be lost. Want to keep your modifications? Then you can use this opportunity to first save your modifications in a child theme. The child theme manual by WordPress will explain how (caution: it’s not simple).

Does your WordPress website have a child theme? In that case you can update your WordPress theme as explained in the previous step. Afterwards you will need to make sure that your child theme folder is clean. If you have a local copy of your child theme you can replace it (sometimes an old backup will work just fine, as long as you know that the website wasn’t hacked at the time the backup was made). If you don’t have a copy then you will have to go through the folder containing the child theme by hand. Read the next step for more information.

Finally, do not forget to remove any unused themes; this way you will decrease the chance you’ll run into problems in the future.

You have now cleaned up as much as you can without have to look in detail, but there are always a number of files and folders that you will have to check by hand.

• Look for .php, .asp, .exe, and .sh files in the wp-content/uploads files. These do not belong here and may have been placed by hackers. It takes time, but don’t forget to check all the subfolders. Many FTP programs allow you to search automatically within a folder.
• Some plugins add their own folders to the de wp-contents folder. This is not necessarily bad, but go ahead and go through these folders for above mentioned files.
• Are there php-files that you no longer have the original to, that you will have check by hand? Think about php files in the wp-contents folder (like object-cache.php), your child thema, or wp-config.php in the root. Follow these steps:
  • Open them in text editor and scroll in all directions; sometimes hackers put code in a file ‘out of sight’ by placing it very far to the right or really far down.
  • Keep looking for any worrying code. Look for terms like ‘eval’, ‘exec’, ‘base64’, ‘hash’, ‘decode’ and see if you find any code that doesn’t belong.
  • Not sure about something? Copy a section of the code and look it up in Google. Sometimes you’ll come across all kinds of malware forums and you’ll know that something’s not right.

Up until now you have left the wp-config.php file untouched, but you do have to check it. This file contains all kinds of basic configurations for your WordPress website. Do you have a backup available? Then we advise you use the wp-config.php file from the backup for your website. Edit the list under ‘Authentication Unique Keys and Salts’ by adding a few characters to each line of random code. This way you make sure that any users that are logged in (potentially hackers) will no longer be logged in.

Don’t have a back up? Open your wp-config.php and fill in the values you see in the wp-config.php generator by following all these steps. Chose ‘Auto Generate’ in Authentication Keys & Salts . Click update after the last step and copy and paste the code to your wp-config.php. Then you know for certain that you have generated a clean wp-config.php.

A .htaccess file makes it possible to configure a lot of server settings. If a hacker modifies these kinds of files it can lead to very destructive behavior. There is definitely a .htaccess file in the root of your WordPress website, but in theory there could be one in every folder in your website. Use an FTP program to look for ‘htaccess’ on your website.

The .htaccess file in the root of your website will contain the following lines:

# BEGIN WordPress

RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]

# END WordPress

Is there more code in your .htaccess file? This could have been added by a plugin, but it could be a hack. If in doubt, remove all extra code from your .htaccess file; the plugin may no longer work optimally, but most plugins are able to add the necessary code to the .htaccess file automatically if need be.

Find more .htaccess files?

Go to the place where you found them. Are they in a plugin or theme folder? Then in theory they are safe, since you cleaned up all these folders in the previous steps. However, if you find any in your uploads folder, child theme etc. then it’s a good idea to take a closer look. Sometimes a .htaccess file is placed in wp-content/uploads to prevent visitors from going through your upload folders without permission. In this case you may come across the following line in your .htaccess file:

Options -Indexes

This is not a harmful line, so your can safely leave it as is.