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”

HTTPS Goofs: Forgetting the Bare Domain

As I mentioned, the top failure of HTTPS is failing to use it, and that’s particularly common in in-bound links sent via email, in newsletters, and the like. Unfortunately, there’s another common case, whereby the user simply types your bare domain name (example.com) in the browser’s address bar without specifying https:// first. For decades, manyContinue reading “HTTPS Goofs: Forgetting the Bare Domain”

Certificate Revocation in Microsoft Edge

When you visit a HTTPS site, the server must present a certificate, signed by a trusted third-party (a Certificate Authority, aka CA), vouching for the identity of the bearer. The certificate contains an expiration date, and is considered valid until that date arrives. But what if the CA later realizes that it issued the certificateContinue reading “Certificate Revocation in Microsoft Edge”

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”

Offline NetLog Viewing

A while back, I explained how you can use Telerik Fiddler or the Catapult NetLog Viewer to analyze a network log captured from Microsoft Edge, Google Chrome, or another Chromium or Electron-based application. While Fiddler is a native app that runs locally, the Catapult NetLog Viewer is a JavaScript application that runs in your browser.Continue reading “Offline NetLog Viewing”

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”

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”

Web Proxy Auto Discovery (WPAD)

Back in the mid-aughts, Adam G., a colleague on the IE team, used the email signature “IE Networking Team – Without us, you’d be browsing your hard drive.” And while I’m sure it was meant to be a bit tongue-in-cheek, it’s really true– without a working network stack, web browsers aren’t nearly as useful. BackgroundContinue reading “Web Proxy Auto Discovery (WPAD)”

Client Certificate Authentication

While most HTTPS sites only authenticate the server (using a certificate sent by the website), HTTPS also supports a mutual authentication mode, whereby the client supplies a certificate that authenticates the visiting user’s identity. Such a certificate might be stored on a SmartCard, or used as a part of an OS identity feature like WindowsContinue reading “Client Certificate Authentication”

Enigma Conference 2020 – Browser Privacy Panel

Brave, Mozilla Firefox, Google Chrome and Microsoft Edge presented on our current privacy work at the Enigma 2020 conference in late January. The talks were mostly high-level, but there were a few feature-level slides for each browser. My ~10 minute presentation on Microsoft Edge was first, followed by Firefox, Chrome, and Brave. At 40 minutesContinue reading “Enigma Conference 2020 – Browser Privacy Panel”