Web Proxy Authentication

Last year, I wrote about how the new Microsoft Edge’s adoption of the Chromium stack changed proxy determination away from the Windows Service (WinHTTP Proxy Service) to similar but not identical code in Chromium. This change mostly goes unnoticed, but it can have performance and functionality implications. In today’s post, I want to explore anotherContinue reading “Web Proxy Authentication”

window.close() Restrictions

Sometimes, Web Developers are surprised to find that the window.close() API doesn’t always close the browser window. When looking at the Developer Tools console, they’ll see a message like: Scripts may close only the windows that were opened by them. Why Do Browsers Limit close()? Before we dive into what factors govern what happens whenContinue reading “window.close() Restrictions”

Sandboxing vs. Elevated Browsing (As Administrator)

The Web Browser is the most security-critical application on most users’ systems– it accepts untrusted input from servers anywhere in the world, parses that input using dozens to hundreds of parsers, and renders the result locally as fast as it can. For performance reasons, almost all code in almost all browsers is written in memory-unsafeContinue reading “Sandboxing vs. Elevated Browsing (As Administrator)”

Simply Making Simple Fixes Simple for Chromium

Google recently introduced a cool web-based editing tool for Chromium source code, a very stripped down version of the Willy Wonka tooling Googlers get to use for non-Chromium projects. I’ve used this tool to submit two trivial change lists (CLs, aka PRs) to Chromium, but I was curious about whether this new feature would workContinue reading “Simply Making Simple Fixes Simple for Chromium”

Client Certificates and Logout

Back in May, 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” of a site that uses thatContinue 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”

Images Keeping You Awake?

A Microsoft Edge user recently complained that her screensaver was no longer activating after the expected delay, and she thought that this might be related to her browser. It was, in a way. To troubleshoot issues where your PC’s screensaver and power-saving options aren’t working correctly, you can use the Power Config command line tool.Continue reading “Images Keeping You Awake?”

Debugging Browsers – Tools and Techniques

Last update: Sept 30, 2020 Earlier this year, I shared a post on how you can become an expert on web browsers from the comfort of your desk… or anywhere else you have an internet connection. In that post, I mostly covered how to search through the source, review issue reports, and find design documentation.Continue reading “Debugging Browsers – Tools and Techniques”

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”