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”
Category Archives: security
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”
Mark-of-the-Web: Real-World Protection
Two years ago, I wrote up some best practices for developers who want to take a file’s security origin into account when deciding how to handle it. That post was an update of a post I’d written six years prior explaining how internet clients (e.g. browsers) mark a file to indicate that it originated fromContinue reading “Mark-of-the-Web: Real-World Protection”
Security Software – An Overview
Last Update: 15 September 2026 I’ve spent nearly my entire professional career in software security: designing software to prevent abuse by bad actors. I’ve been battling the bad guys for over two decades now, from hunting security bugs in Microsoft Office (I once won an Xbox for finding a vulnerability that allowed malicious clipart takeContinue reading “Security Software – An Overview”
Best Practices for SmartScreen AppRep
Last Updated: September 24, 2026 Last year, I wrote about how Windows integrates SmartScreen Application Reputation to help ensure users have a secure and smooth experience when running downloaded software. tl;dr: When a user runs a downloaded program, Windows/Edge call SmartScreen web-based reputation service. There are four possible outcomes: As a software developer, it’s naturalContinue reading “Best Practices for SmartScreen AppRep”