Category Archives: tech

Windows Shell Previews – Restricted

Windows users who installed the October 2025 Security Updates may have noticed an unexpected change if they use the Windows Explorer preview pane. When previewing many downloaded files, the preview is now replaced with the following text: While it also occurs when viewing files on remote Internet Zone file shares, the problem doesn’t occur forContinue reading “Windows Shell Previews – Restricted”

AI Injection Attacks

A hot infosec topic these days is “How can we prevent abuse of AI agents?” While AI introduces awesome new capabilities, it also entails an enormous set of risks from the obvious and mundane to the esoteric and elaborate. As a browser security person, I’m most often asked about indirect prompt injection attacks, whereby aContinue reading “AI Injection Attacks”

Family Safety Content Filtering

Microsoft Family Safety is a feature of Windows that allows parents to control their children’s access to apps and content in Windows. The feature is tied to the user accounts of the parent(s) and child(ren). When I visit https://family.microsoft.com and log in with my personal Microsoft Account, I’m presented with the following view: The “Nate”Continue reading “Family Safety Content Filtering”

Web Category Filtering

Since the first days of the web, users and administrators have sought to control the flow of information from the Internet to the local device. There are many different ways to implement internet filters, and numerous goals that organizations may want to achieve: Today’s post explores the last of these: blocking content based on category.Continue reading “Web Category Filtering”

Attack Techniques: Fake Literally Everything! (Escrow Scam)

The team recently got a false-negative report on the SmartScreen phishing filter complaining that we fail to block firstline-trucking.com. I passed it along to our graders but then took a closer look myself. I figured that maybe the legit site was probably at a very similar domain name, e.g. firstlinetrucking.com or something, but no suchContinue reading “Attack Techniques: Fake Literally Everything! (Escrow Scam)”

Defensive Technology: Windows Filtering Platform

Last November, I wrote a post about the basics of security software. In that post, I laid out how security software is composed of sensors and throttles controlled by threat intelligence. In today’s post, we’ll look at the Windows Filtering Platform, a fundamental platform technology introduced in Windows Vista that provides the core sensor andContinue reading “Defensive Technology: Windows Filtering Platform”

Authenticode in 2025 – Azure Trusted Signing

I’ve written about signing your code using Authenticode a lot over the years, from a post in 2015 about my first hardware token to a 2024 post about signing using a Digicert HSM. Recently, Azure opened their Trusted Signing Service preview program up for individual users and I decided to try it out. The documentationContinue reading “Authenticode in 2025 – Azure Trusted Signing”

Guidelines for Secure Filename Display

Many years ago, I wrote the first drafts of Chromium’s Guidelines for Secure URL Display. These guidelines were designed to help feature teams avoid security bugs whereby a user might misinterpret a URL when making a security decision. From a security standpoint, URLs are tricky because they consist of a mix of security-critical information (theContinue reading “Guidelines for Secure Filename Display”

Attack Techniques: “I Already Hacked You” Scams

Scammers often try to convince you that you’ve already been hacked and you must contact them or send them money to prevent something worse from happening. I write about these a bunch: Another common “Bad thing already happened” scam is to send the user an email telling them that their devices were hacked some timeContinue reading “Attack Techniques: “I Already Hacked You” Scams”