Unable to access the administration (due to hacking)

Your site has been hacked, you have just regained access, but everything is not working properly. Or, more simply, you don’t have access to the administration interface.

Errors can then occur, here is an example:

Fatal error: Uncaught Error: Call to undefined function wp_get_update_data() in ...

It is difficult to determine the source of the problem, as the causes can be many and varied. Missing files, a bad plugin, a failed update, a faulty theme …

The purpose of this post is precisely to help you identify the cause of your problem. It will require some manipulations but the goal is to give you back access to the administration interface.

If your problem occurred after a hacking of your site, do not hesitate to contact an expert to check the situation, especially to verify that there are no more malicious files or accesses to your site.

To better identify the origin of your problem, it will be necessary to carry out two actions and see the results:

To carry out these actions, you must have at least one (S)FTP access to your site. Also, you must be able to access your database.

• Reset your site’s plugins
  • Login to your database
  • If necessary, temporarily, you can deposit a phpmyadmin via (S)FTP on your site. https://www.phpmyadmin.net/downloads/
  • Go to the wp_options table
  • Focus on the option_value field and identify the rows that contain active_plugins
    • Tip: To isolate these lines, you can use this query : SELECT *FROM wp_options WHERE option_name = 'active_plugins';
  • For each plugin, change the value a:1:{} with a:0:{}
    • Connect to your site using (S)FTP
    • Navigate to /wp-content/themes/ and rename the folder that contains your current theme. WordPress will then use the default theme (alternatively, you can download it: https://wordpress.org/themes/twentynineteen/ and upload it to your server in the same place).
• Reset the default theme

Depending on the manipulation you have done, if your site is working again and the administration is accessible, you just have to put back / reactivate your elements (theme, plugins …) 1 by 1. When you encounter the error again, you will then know which one is at fault so that you can make the appropriate corrections.