At WWDC 2025, Apple introduced an interesting new API, NEURLFilter, to respond to a key challenge we’ve talked about previously: the inherent conflict between privacy and security when trying to protect users against web threats. That conflict means that security filtering code usually cannot see a browser’s (app’s) fetched URLs to compare them against availableContinue reading “First Look: Apple’s NEURLFilter API”
Tag Archives: privacy
Content-Blocking in Manifest v3
I’ve written about selectively blocking content in browsers several times over the last two decades. In this post, I don’t aim to convince you that ad-blocking is good or bad, instead focusing on one narrow topic. Circa 2006, I was responsible for changing IE so that you could simply add an advertising site to theContinue reading “Content-Blocking in Manifest v3”
Security Tradeoffs: Privacy
In a recent post, I explored some of the tradeoffs engineers must make when evaluating the security properties of a given design. In this post, we explore an interesting tradeoff between Security and Privacy in the analysis of web traffic. Many different security features and products attempt to protect web browsers from malicious sites byContinue reading “Security Tradeoffs: Privacy”
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?!?””
Smarter Defaults by Paying Attention
As a part of every page load, browsers have to make dozens, hundreds, or even thousands of decisions of varying levels of importance: should a particular API be available? Should a resource load be permitted? Should script be allowed to run? Should video be allowed to start playing automatically? Should cookies or credentials be sentContinue reading “Smarter Defaults by Paying Attention”
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)”
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”
Security Zones in Edge (and Chrome)
Last updated: 25 March 2025 Browsers As Decision Makers As a part of every page load, browsers have to make dozens, hundreds, or even thousands of decisions — should a particular API be available? Should a resource load be permitted? Should script be allowed to run? Should video be allowed to start playing automatically? ShouldContinue reading “Security Zones in Edge (and Chrome)”
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