Per-Site Permissions in Edge

Last year, I wrote about how the new Microsoft Edge browser mostly ignores Security Zones (except in very rare circumstances) to configure security and permissions decisions. Instead, in Chromium per-site permissions are controlled by settings and policies expressed using a simple syntax with limited wildcarding support. Settings Page’s Site Permissions and Group Policy Internet ExplorerContinue reading “Per-Site Permissions in Edge”

Specifying Per-Site Policy with Chromium’s URL Filter Format

Chromium-based browsers like Microsoft Edge make very limited use of Windows Security Zones. Instead, most permissions and features that offer administrators per-site configuration via policy rely on lists of rules in the URL Filter Format. Filters are expressed in a syntax that is similar to other matching rules, but different enough to cause confusion. ForContinue reading “Specifying Per-Site Policy with Chromium’s URL Filter Format”

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”

Revealing Passwords

The Microsoft Edge browser, Edge Legacy, and Internet Explorer all offer a convenient mechanism for users to unmask their typing as they edit a password field: Clicking the little eye icon disables the masking dots so that users can see the characters they’re typing: This feature can be very useful for those of us whoContinue reading “Revealing Passwords”

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)”

Browser Basics: User Gestures

The Web Platform offers a great deal of power, and unfortunately evil websites go to great lengths to abuse it. One of the weakest (but simplest to implement) protections against such abuse is to block actions that were not preceded by a “User Gesture.” Such gestures (sometimes more precisely called User Activations) include a varietyContinue reading “Browser Basics: User Gestures”

Bypassing AppProtocol Prompts

Starting in Microsoft Edge 77 (and Chrome 77), the prompt shown when launching an AppProtocol from the browser was changed to remove the “Always allow” checkbox. That change was made, in large part, because this prompt is the only thing standing between every arbitrary site on the Internet (loaded inside your browser’s sandbox) and aContinue reading “Bypassing AppProtocol Prompts”

Browser Password Managers: Threat Models

All major browsers have a built-in password manager. So we should use them, right? I Do I use my browser’s password manager because it’s convenient: with sync, I get all of my passwords on all of my devices. This convenience means that I can use a different password for every website, improving my security. ThisContinue reading “Browser Password Managers: Threat Models”

Security Zones in Edge

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? Should cookies or credentials be sentContinue reading “Security Zones in Edge”

Retiring Internet Explorer

Prelude In late 2004, I was the Program Manager for Microsoft’s clipart website, delivering a million pieces of clipart to Microsoft Office customers every day. It was great fun. But there was a problem– our “Clip of the Day” feature, meant to spotlight a new and topical piece of clipart every day, wasn’t changing asContinue reading “Retiring Internet Explorer”