SameSiteevästeille

SameSiteevästeille, or SameSite cookies in English, are a security feature introduced to mitigate cross-site request forgery (CSRF) attacks. This mechanism controls when cookies are sent with cross-site requests. The SameSite attribute can be set to one of three values: Strict, Lax, or None.

Strict is the most restrictive setting. When a cookie is set to Strict, it will only be sent when the request originates from the exact same site as the cookie. This means it won't be sent even if the user clicks a link from another site to your site.

Lax is the default value in modern browsers. With Lax, cookies are sent with cross-site requests that are initiated by top-level navigation, such as clicking a link, or in secure contexts like a GET request. However, they are not sent with cross-site POST requests or requests initiated by scripts.

None requires explicit opt-in and must be accompanied by the Secure attribute, meaning the cookie will only be sent over HTTPS. Cookies set to None will be sent with all cross-site requests, regardless of how they are initiated. This setting is crucial for third-party contexts, such as embedded content or cross-site login flows, but it also increases the risk of CSRF attacks if not handled carefully.

The implementation of SameSite cookies aims to enhance user privacy and security by preventing websites from tracking users across different sites without their explicit consent and by defending against malicious actions where a user's browser is tricked into performing an unwanted action on another site where they are authenticated. Developers need to configure this attribute appropriately for their cookies to ensure correct functionality and security.