Multiple vulnerabilities fixed in Security and Malware Scan by CleanTalk plugin.

The Security & Malware Scan by CleanTalk plugin for WordPress (5,000+ active installations) fixed a vulnerability affecting version 2.50 and below that could allow any authenticated user to interact with all its AJAX actions.

Security Nonce Leak

The plugin registers 40+ AJAX actions in the “security-malware-firewall/inc/spbc-admin.php” script. Most of them do not check the user capability but rely only on a security nonce populated in the spbc_enqueue_scripts function:

292   function spbc_enqueue_scripts($hook) {
294      global $spbc;
296      // For ALL admin pages
297      wp_enqueue_style ('spbc_admin_css', SPBC_PATH . '/css/spbc-admin.min.css', array(), SPBC_VERSION, 'all');
299      wp_enqueue_script('spbc-common-js', SPBC_PATH . '/js/spbc-common.min.js', array('jquery'), SPBC_VERSION, false);
300      wp_enqueue_script('spbc-admin-js',  SPBC_PATH . '/js/spbc-admin.min.js',  array('jquery'), SPBC_VERSION, false);
302      wp_localize_script('jquery', 'spbcSettings', array(
303         'wpms'         => (int)is_multisite(),
304         'is_main_site' => (int)is_main_site(),
305         'tc_enabled'   => $spbc->tc_enabled ? 1 : 0,
306         'img_path'     => SPBC_PATH . '/images',
307         'key_is_ok'    => $spbc->key_is_ok,
308         'ajax_nonce'   => wp_create_nonce("spbc_secret_nonce"),
309         'ajaxurl'      => admin_url('admin-ajax.php'),
310         'debug'        => !empty($debug) ? 1 : 0,
311      ));

The function is loaded by the admin_enqueue_scripts hook, i.e., each time someone accesses the backend, in the “security-malware-firewall/security-malware-firewall.php” script:

292   add_action('admin_enqueue_scripts', 'spbc_enqueue_scripts');

The nonce is therefore accessible to any logged-in user, including a subscriber, in the source of the HTML page:

An attacker could use it to interact with all AJAX actions, which could lead to multiple vulnerabilities from arbitrary file deletion and download to PHP function injection among other issues:


The vulnerability was reported to the authors on June 04th, 2020 and a new version 2.51 was released on June 30, 2020.


Upgrade immediately if you have version 2.50 or below. If you are using our web application firewall for WordPress, NinjaFirewall WP Edition (free) and NinjaFirewall WP+ Edition (premium), you are protected against this vulnerability.

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