SameSite=strict” value set to reduce CSRF exposure in section A8.
Consider using the “SameSite=strict” flag on all cookies, which is increasingly supported in browsers.
Similar to the way that
Secure attributes have been added, SameSite allows for additional control.
Per the documentation, as of April 2017 the SameSite attribute is implemented in Chrome 51 and Opera 39. Firefox has an open defect, but I would expect it to be added soon to follow Chrome.
Set-Cookie: CookieName=CookieValue; SameSite=Lax;
Set-Cookie: CookieName=CookieValue; SameSite=Strict;
According to the specification you can issue the SameSite flag without a value and Strict will be assumed:
Set-Cookie: CookieName=CookieValue; SameSite
As many programming languages and server runtime environments do not yet support this for session cookies, you can use the Apache Tier1 configuration to append them.
Header edit Set-Cookie ^(JSESSIONID.*)$ $1;SameSite=Strict
Header edit Set-Cookie ^(PHPSESSID.*)$ $1;SameSite=Strict
It looks like PHP.INI might support the following attribute in a future release, but it’s not there yet!