Defensive Techniques: Application Guard

Earlier this year, I mentioned that I load every phishing URL I’m sent to see what it does and whether it tries to use any interesting new techniques. While Edge’s “Enhanced Security Mode” reduces the risks of 0-day attacks against the browser itself, another great defense available for enterprise users is Microsoft Defender Application Guard.Continue reading “Defensive Techniques: Application Guard”

How do Random Credentials Mysteriously Appear?

One commonly-reported issue to browsers’ security teams sounds like: “Some random person’s passwords started appearing in my browser password manager?!? This must be a security bug of some sort!” This issue has been reported dozens of times, and it’s a reflection of a perhaps-surprising behavior of browser login and sync. So, what’s happening? Background EvenContinue reading “How do Random Credentials Mysteriously Appear?”

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”

How Microsoft Edge Updates

By default, Edge will update in the background automatically while you’re not using it. Open Microsoft Edge and you’ll be using the latest version. However, if Edge is already running and an update becomes available, an update notifier icon will show in the Edge toolbar. When you see the update notifier (a green or redContinue reading “How Microsoft Edge Updates”

Improving Native Message Host Reliability on Windows

Last Update: Nov 28, 2023 Update: This change was checked into Chromium 113 before being backed out. The plan is to eventually turn it on-by-default, so extension authors really should read this post and update their extensions if needed. The feature was relanded inside Chrome Canary version 115.0.5789.0. It’s off-by-default, behind a flag on theContinue reading “Improving Native Message Host Reliability on Windows”

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?!?””

Defense Techniques: Reporting Phish

While I have a day job, I’ve been moonlighting as a crimefighting superhero for almost twenty years. No, I’m not a billionaire who dons a rubber bat suit to beat up bad guys– I’m instead flagging phishing websites that try to steal money and personal information from the less tech-savvy among us. I have hadContinue reading “Defense Techniques: Reporting Phish”

Attack Techniques: Phishing via Local Files

One attack technique I’ve seen in use recently involves enticing the victim to enter their password into a locally-downloaded HTML file. The attack begins by the victim receiving an email lure with a HTML file attachment (for me, often with the .shtml file extension): When the user opens the file, a HTML-based credential prompt isContinue reading “Attack Techniques: Phishing via Local Files”

TLS Certificate Verification Changes in Edge

Last Updated August 21 2023: When establishing a secure HTTPS connection with a server, a browser must validate that the certificate sent by the server is valid — that is to say, that: In the past, Chromium running on Windows delegated this validation task to APIs in the operating system, layering a minimal set ofContinue reading “TLS Certificate Verification Changes in Edge”

“Not Secure” Warning for IE Mode

A customer recently wrote to ask whether there was any way to suppress the red “/!\ Not Secure” warning shown in the omnibox when IE Mode loads a HTTPS site containing non-secure images: Notably, this warning isn’t seen when the page is loaded in modern Edge mode or in Chrome, because all non-secure “optionally-blockable” resourceContinue reading ““Not Secure” Warning for IE Mode”