When a user attempts to run a file with elevated privilege, Windows will show a User Account Control elevation prompt that asks whether the user trusts the file to run. For a regular file, the user will see a prompt like this: For a file signed by a certificate in the Untrusted Certificates store, elevationContinue reading “Authenticode and UAC”
Tag Archives: Authenticode
Smart App Control
Users of modern versions of Windows 11 have a powerful security feature for keeping their devices secure, known as Smart App Control. I’ve talked about this feature a few times over the last year, but in April 2026, a powerful improvement landed. Previously, Smart App Control could not be turned back on if you everContinue reading “Smart App Control”
Runtime Signature Checking Threat Model
Telerik developers recently changed Fiddler to validate the signature on extension assemblies before they load. If the assembly is unsigned, the user is presented with the following message: In theory, this seems fine/good– signing files is a good thing! However, it’s important to understand the threat model and tradeoffs here. Validating signatures every time aContinue reading “Runtime Signature Checking Threat Model”
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”
Best Practices for SmartScreen AppRep
Last Updated: September 9, 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”