SameSiteattribuutit

SameSite is a cookie attribute that developers can use to indicate whether cookies should be sent with cross-site requests. Its primary purpose is to mitigate the risk of cross-site request forgery (CSRF) attacks. The attribute can take three possible values: Strict, Lax, or None.

Strict is the most restrictive setting. When a cookie is set with Strict, it will only be sent in requests that originate from the exact same site as the cookie. This means the cookie will not be sent even if the user navigates to the site from another site (e.g., by clicking a link).

Lax is the default behavior in many modern browsers. With Lax, cookies are sent with cross-site requests that are initiated by top-level navigation (e.g., clicking a link to another site) or by same-site requests. However, they are not sent with cross-site requests initiated by methods like POST, AJAX, or iframes. This provides a balance between security and usability.

None is the least restrictive setting. When a cookie is set with None, it will be sent with all requests, both same-site and cross-site. However, to use None, the cookie must also have the Secure attribute, meaning it will only be sent over HTTPS connections. This is often used for scenarios where cross-site cookie access is intentionally required, such as for third-party authentication or embedded content.

The introduction of SameSite attributes has significantly improved web security by reducing the attack surface for CSRF vulnerabilities. Browsers have progressively implemented these attributes, making them a crucial aspect of modern web development practices.