Here is a little hack to use http auth when credentials or auth is insufficient:

public function executeSecure()
  {
    if (!$this->getUser()->hasAttribute("secure_referer"))
        $this->getUser()->setAttribute("secure_referer", $this->getRequest()->getReferer());
 
    if (!isset($_SERVER['PHP_AUTH_USER']))
    {
      header('WWW-Authenticate: Basic realm="Member Area"');
      header('HTTP/1.0 401 Unauthorized');
 
      return sfView::NONE;
    }
    else
    {   
        if ($this->getUser()->tryLogin($_SERVER['PHP_AUTH_USER'],$_SERVER['PHP_AUTH_PW']))
        {
            return $this->redirect($this->getUser()->getAttribute("secure_referer"));
        }
        else
        {
          header('WWW-Authenticate: Basic realm="Member Area"');
          header('HTTP/1.0 401 Unauthorized');
 
          return sfView::NONE;
        }
    }
  }

No template is needed, as everytime you access it will redirect to the referer. Then change in app/yourapp/config/settings.yml the secure_module and secure_action to match this module.

You will need a myUser::tryLogin function that returns a boolean saying "auth is ok" or "bad auth"

And then you're done :p

[from my Wiki Post ab out that]