Security¶

Handling Blackhole Callbacks¶

SecurityComponent::blackHole(Controller $controller, string $error = '', ?SecurityException $exception = null)¶

If an action is restricted by the Security Component it is ‘black-holed’ as an invalid request which will result in a 400 error by default. You can configure this behavior by setting the blackHoleCallback configuration option to a callback function in the controller.

By configuring a callback method you can customize how the blackhole process works:

public function beforeFilter(EventInterface $event)
{
    parent::beforeFilter($event);

    $this->Security->setConfig('blackHoleCallback', 'blackhole');
}

public function blackhole($type, SecurityException $exception)
{
    if ($exception->getMessage() === 'Request is not SSL and the action is required to be secure') {
        // Reword the exception message with a translatable string.
        $exception->setMessage(__('Please access the requested page through HTTPS'));
    }

    // Re-throw the conditionally reworded exception.
    throw $exception;

    // Alternatively, handle the error. For example, set a flash message &
    // redirect to HTTPS version of the requested page.
}

The $type parameter can have the following values:

• ‘auth’ Indicates a form validation error, or a controller/action mismatch error.

• ‘secure’ Indicates an SSL method restriction failure.

Restrict Actions to SSL¶

This functionality was removed into HTTPS Enforcer Middleware.

Form Tampering Prevention¶

By default the SecurityComponent prevents users from tampering with forms in specific ways. The SecurityComponent will prevent the following things:

• Unknown fields cannot be added to the form.

• Fields cannot be removed from the form.

• Values in hidden inputs cannot be modified.

Preventing these types of tampering is accomplished by working with the FormHelper and tracking which fields are in a form. The values for hidden fields are tracked as well. All of this data is combined and turned into a hash. When a form is submitted, the SecurityComponent will use the POST data to build the same structure and compare the hash.

unlockedFields

Set to a list of form fields to exclude from POST validation. Fields can be unlocked either in the Component, or with FormHelper::unlockField(). Fields that have been unlocked are not required to be part of the POST and hidden unlocked fields do not have their values checked.

validatePost

Set to false to completely skip the validation of POST requests, essentially turning off form validation.

Usage¶

Configuring the security component is generally done in the controller’s initialize or beforeFilter() callbacks:

namespace App\Controller;

use App\Controller\AppController;
use Cake\Event\EventInterface;

class WidgetsController extends AppController
{
    public function initialize(): void
    {
        parent::initialize();
        $this->loadComponent('Security');
    }

    public function beforeFilter(EventInterface $event)
    {
        parent::beforeFilter($event);

        if ($this->request->getParam('prefix') === 'Admin') {
            $this->Security->setConfig('validatePost', false);
        }
    }
}

The above example would disable form tampering prevention for admin prefixed routes.

CSRF Protection¶

CSRF or Cross Site Request Forgery is a common vulnerability in web applications. It allows an attacker to capture and replay a previous request, and sometimes submit data requests using image tags or resources on other domains. To enable CSRF protection features use the Cross Site Request Forgery (CSRF) Middleware.

Disabling Form Tampering for Specific Actions¶

There may be cases where you want to disable form tampering prevention for an action (ex. AJAX requests). You may “unlock” these actions by listing them in $this->Security->unlockedActions in your beforeFilter():

namespace App\Controller;

use App\Controller\AppController;
use Cake\Event\EventInterface;

class WidgetController extends AppController
{
    public function initialize(): void
    {
        parent::initialize();
        $this->loadComponent('Security');
    }

    public function beforeFilter(EventInterface $event)
    {
        parent::beforeFilter($event);

        $this->Security->setConfig('unlockedActions', ['edit']);
    }
}

This example would disable all security checks for the edit action.