Understanding SmartScreen and Network Protection

The vast majority of cyberthreats arrive via one of two related sources: That means that by combining network-level sensors and throttles with threat intelligence (about attacker sites), security software can block a huge percentage of threats. Protection Implementation On Windows systems, that source of network threat information is commonly called SmartScreen, and support for queryingContinue reading “Understanding SmartScreen and Network Protection”

Security Software – An Overview

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 take over your computer) to designingContinue reading “Security Software – An Overview”

Best Practices for SmartScreen AppRep

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, a call to SmartScreen’s web-based reputation service is made, and four possible outcomes can occur: As a software developer, it’s natural thatContinue reading “Best Practices for SmartScreen AppRep”

Defensive Technology: Controlled Folder Access

Most client software’s threat models (e.g. Edge, Chrome) explicitly exclude threats where the local computer was compromised by malware. That’s because, without a trusted computing base, it’s basically impossible to be secure against attackers. This concept was immortalized decades ago in the Ten Immutable Laws of Security: In the intervening years, new technologies (like SecureContinue reading “Defensive Technology: Controlled Folder Access”

Defensive Technology: Antimalware Scan Interface (AMSI)

Endpoint security software faces a tough challenge — it needs to be able to rapidly distinguish between desired and unwanted behavior with few false positives and false negatives, and attackers work hard to obfuscate (or cloak) their malicious code to prevent detection by security scanners. To maximize protection, security software wants visibility into attack chainsContinue reading “Defensive Technology: Antimalware Scan Interface (AMSI)”