Checkmk Werk 11492: Auth cookies: Specify SameSite attribute to improve cookie security

ID: 11492 Title: Auth cookies: Specify SameSite attribute to improve cookie security Component: Multisite Level: 1 Class: Security fix Version: 1.7.0i1 The authentication cookies of the Checkmk GUI (auth_[site]) previously relied on the browsers default behaviour regarding the same site policy. This resulted in a) an inconsistent cookie handling across the different browsers and b) allow some sort of Cross-site request forgery (CSRF) attacks. With this change we explicitly set the "SameSite=Lax" setting for all authentication cookies created by logins after updating Checkmk. For more information about this HTTP cookie setting have a look at https://web.dev/samesite-cookies-explained/.