Auth Flows in a Partitioned World

Back in 2019, I explained how browsers’ cookie controls and privacy features present challenges for common longstanding patterns for authentication flows. Such flows often rely upon an Identity Provider (IdP) having access to its own cookies both on top-level pages served by the IdP and when the IdP receives a HTTP request from an XmlHttpRequest/fetchContinue reading “Auth Flows in a Partitioned World”

Q: “Remember this Device, Doesn’t?!?”

Q: Many websites offer a checkbox to “Remember this device” or “Remember me” but it often doesn’t seem to work. For example, this option on AT&T’s website shown when prompting for a 2FA code: …doesn’t seem to work. What’s up with that? A: Unfortunately, there’s no easy answer here. There is no browser standard forContinue reading “Q: “Remember this Device, Doesn’t?!?””

New Recipes for 3rd Party Cookies

Last Updated: 13 April 2023 For privacy reasons, the web platform is moving away from supporting 3rd-party cookies, first with lockdowns, and eventually with removal of support in late 2023 the second half of 2024. Background: What Does “3rd-Party” Mean? A 3rd-party cookie is one that is set or sent from a 3rd-party context onContinue reading “New Recipes for 3rd Party Cookies”

Losing your cookies

“My browser lost its cookies” has long been one of the most longstanding Support complaints in the history of browsers. Unfortunately, the reason that it has been such a longstanding issue is that it’s not the result of a single problem, and if the problem is intermittent (as it often is), troubleshooting the root causeContinue reading “Losing your cookies”

Client Certificates and Logout

Last Updated May 16, 2022 Back in May 2020, I wrote about Client Certificate Authentication, a mechanism that allows websites to strongly validate the identity of their visitors using certificates presented by the visitor’s browser. One significant limitation for client certificate authentication is that there is no standards-based mechanism for a user to “log out”Continue reading “Client Certificates and Logout”

Web “Sessions” in Private Mode

I’ve written about Private Browsing Mode a lot previously, and I’ve written a bit about the behavior of “Session restore” previously, but one topic I haven’t covered is how “Sessions” work while in Private mode. Session Sharing Historically, one of the top-reported Private Mode issues was that users unexpectedly found that opening a new PrivateContinue reading “Web “Sessions” in Private Mode”

Local Data Encryption in Chromium

Back in February, I wrote about browser password managers and mentioned that it’s important to understand the threat model when deciding how to implement features and their security protections. Generally speaking, “keeping secrets from yourself” is a fool’s errand, so it’s a waste of time and effort to encrypt data if you have to storeContinue reading “Local Data Encryption in Chromium”

Seamless Single Sign-On

There are many different authentication primitives built into browsers. The most common include Web Forms authentication, HTTP authentication, client certificate authentication, and the new WebAuthN standard. Numerous different authentication frameworks build atop these, and many enterprise websites support more than one scheme. Each of the underlying authentication primitives has different characteristics: client certificate authentication isContinue reading “Seamless Single Sign-On”

Beating Private Mode Blockers with an Ephemeral Profile

Back in 2018, I explained how some websites use various tricks to detect that visitors are using Private Mode browsers and force such users to log-in. The most common reason that such sites do this is that they’ve implemented a “Your first five articles are free, then you have to pay” model, and cookies orContinue reading “Beating Private Mode Blockers with an Ephemeral Profile”

Same-Site Cookies By Default

The Chrome team is embarking on a clever and bold plan to change the recipe for cookies. It’s one of the most consequential changes to the web platform in almost a decade, but with any luck, users won’t notice anything has changed. But if you’re a web developer, you should start testing your sites andContinue reading “Same-Site Cookies By Default”