dkgcb
dkgcb

Reputation: 103

SameSite attribute in cookies

I have a website a.com that has third party app point to apps.b.com. When I login to a.com, I'm also authenticated to apps.b.com in the background using the same credentials. This is so the users do not have to login to access apps.b.com. I understand that browser sends all the cookies to apps.b.com when making the request to it. This is how it works now. Reading the article https://web.dev/samesite-cookies-explained/ in regards to SameSite attribute, it appears apps.b.com is third party site. Now do I have to configure web server on a.com to set the cookie to SameSite=none;Secure OR do I have to set the SameSite=none;Secure on web server on apps.b.com?

Upvotes: 1

Views: 505

Answers (1)

rowan_m
rowan_m

Reputation: 3050

Any time you are making a cross-site request that needs cookies, then those cookies need to be marked SameSite=None; Secure.

So, for example if the user is on a.com and you have an <iframe> or fetch() to apps.b.com that expects cookies, then the apps.b.com cookies need SameSite=None; Secure.

Vice versa, if the user is on apps.b.com and you are making requests to a.com to check their auth status by relying on the a.com cookies, then those cookies need SameSite=None; Secure.

Essentially the pattern you're looking for is when the site in the browser location bar is different to the site that needs the cookies, then those are the cookies that need marking. So, depending on your set up, it may be one or both.

Upvotes: 1

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