how to use it to secure your website and cookies?

how to use it to secure your website and cookies? – Minecraft Online Free

Cookies are ubiquitous on the Web and allow publishers to store a certain amount of information directly on the Internet user’s browser.

In particular used to identify the user’s session and allow the server to recognize it throughout its navigation, cookies often contain personal and/or sensitive information. They should therefore be protected accordingly.

Attention : the use of cookies to identify a user is legally framed by the prior collection of consent to the processing that you will do later. If one of the solutions you use needs to work without this consent, do not hesitate to contact the publisher to request it. For example, and even if the CS Digital tag is specially designed to provide your visitors with all the guarantees in terms of privacy and security, it requires prior consent. A configuration guide is however available with the CNILallowing use without consent.

The HTTP Set-Cookie header

As a reminder, a cookie is generally created on the browser at the request of the server to store a state, which will then be retransmitted on the next requests. The web server uses the Set-Cookie header in an HTTP response for this.

Here is the syntax of this header:

Set-Cookie: =[; <Max-Age>=<age>] [; expires=<date>][; domain=<domain_name>] [; path=<some_path>][; secure][; HttpOnly]

The cookie is identified by a name to which a value is associated. It may have a period of validity and/or an expiry date. It should be noted that if the 2 instructions are present, it is the duration of validity (max-age) which will take over. Finally, it is possible for the server to define a path and a domain for which the cookie should be used. By default, a cookie is only sent to the domain responsible for placing it. The domain and path instructions allow you to possibly restrict its scope, or conversely to extend it, for example by authorizing its use on all subdomains.

A first good practice for securing your cookies consists precisely in mastering their respective scopes.

The last two instructions secure et HttpOnly, relate specifically to safety. It should be noted that they do not accept values, it is their presence or not that characterizes the behavior of the browser vis-à-vis the cookie.

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Forbid the use of the client-side cookie with the HttpOnly statement

A cookie can be positioned and used by a server, but also directly on the browser in JavaScript.

In the case of an XSS flaw, an attacker could manage to inject JavaScript, and therefore potentially access cookies which, it should be remembered, often contain sensitive information. Obviously, it’s best to avoid XSS vulnerabilities first. Then, their exploitation can be prevented by defining a Content Security Policy.

The use of the “HttpOnly” instruction prevents access to cookies in JavaScript: if, despite the aforementioned protections, an attacker were to inject JavaScript, the cookies will not be accessible, which will limit the scope of the attack.

Prohibit the use of cookies without HTTPs with the Secure flag

We repeat it regularly on this blog, HTTPs is necessary for your website. If you have adopted this secure protocol, and you have followed the previous advice, you may be thinking that the cookie transits over a secure communication, that it is not accessible in JavaScript and therefore not vulnerable to an XSS attack .

Unfortunately, there remains one notable problem.

And if your user accesses your site in HTTP, simply by entering the address directly without specifying https://? This can also be the case if your page contains mixed content.

Admittedly, setting up an HSTS (HTTP Strict Transport Security) header, which makes it possible to force the use of HTTPS for any subsequent visit, can greatly limit the first case. But this is not supported by all browsers, and it always remains the case of the first visit. The Content Security Policy can mitigate the second case, avoiding any risk of mixed content for browsers that support it.

Only the secure attribute will allow you to prevent a Cookie from ever being communicated in simple HTTP.

The interest of this instruction is also clearly mentioned in the RFC HTTP State Management Mechanism.

Of course, keep in mind that a cookie using the Secure statement will not be sent on the plain HTTP version of your site at all. Be careful, for example, if your site still coexists spaces in HTTPs and others in simple HTTP (in which case, we invite you to migrate these pages to a secure version which will bring a better UX to your users and will be better perceived by search engines).

In conclusion, don’t forget that our web page analysis tool will allow you in a few moments to ensure that your cookies are secure, by checking the correct use of HttpOnly and Secure!

Httply Best Practices

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