Skip to main content

Insecurely generated cookies

Need​

Secure generation and management of cookies

Context​

  • Usage of PHP for server-side scripting and web development
  • Usage of Request for making HTTP requests
  • Usage of Response for handling HTTP responses
  • Usage of cookie for handling HTTP cookies in Node.js

Description​

Non compliant code​

public function setCookie(Request $request) {
    $response = new Response('Hello World');
    $response->withCookie(cookie('name', 'value', 60));
    return $response;
}

The above code is a simple function in a Laravel controller that sets a cookie with the name 'name' and value 'value'. The cookie will expire after 60 minutes.

The vulnerability here is that the cookie is being set without any security attributes. This means that it could be sent over a non-secure connection in plain text, making it vulnerable to interception and misuse. Additionally, the lack of a 'HttpOnly' attribute means that the cookie could be accessed by client-side scripts, potentially leading to cross-site scripting (XSS) attacks if the cookie contains sensitive information.

In the context of Laravel, the withCookie function does not provide any options to set these security attributes. Therefore, this function is not suitable for setting cookies that contain sensitive information.

Steps​

  • Use the secure option when setting the cookie to ensure it is only sent over HTTPS, not HTTP.
  • Set the HttpOnly attribute to prevent access to cookie from client side scripts.
  • Set the SameSite attribute to Strict or Lax to prevent the cookie from being sent in cross-site requests.
  • Encrypt sensitive data stored in cookies.

Compliant code​

public function setCookie(Request $request) {
    $response = new Response('Hello World');
    $response->withCookie(cookie('name', 'value', 60, null, null, true, true, false, 'strict'));
    return $response;
}

The above code fixes the insecure cookie generation vulnerability by setting the secure and HttpOnly attributes when creating the cookie.

  • The secure attribute is set to true to ensure that the cookie is only sent over HTTPS, not HTTP. This prevents the cookie from being sent in plain text, which could be intercepted and read by an attacker.

  • The HttpOnly attribute is set to true to prevent client-side scripts from accessing the cookie. This can help to mitigate cross-site scripting (XSS) attacks, where an attacker might try to access the cookie through JavaScript.

  • The SameSite attribute is set to 'strict' to prevent the cookie from being sent in cross-site requests. This can help to prevent cross-site request forgery (CSRF) attacks, where an attacker might try to trick a user into making a request that includes the cookie.

  • The value of the cookie should be encrypted if it contains sensitive data. Laravel provides an easy way to do this using the encrypt function. However, in this example, the value of the cookie is a simple string, so encryption is not necessary.

Please note that the cookie function parameters might vary based on your Laravel version. Always refer to the official Laravel documentation for the most accurate information.

References​

Last updated on