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”

Windows: Choose Where To Get Apps

Modern versions of Windows offer a setting named “Choose where to get apps” which can reduce attack surface by limiting the locations from which applications can be installed. Internally, we’ve called this feature “Smart Install”. By default, this option is set to “Anywhere“, which means that Windows will allow an executable downloaded from the InternetContinue reading “Windows: Choose Where To Get Apps”

Security Software False Positives

Software developers and end-users are often interested in understanding how to resolve incorrect detections from their antivirus/security software, including Microsoft Defender. Such False Positives (FPs) can disrupt your use of your device by incorrectly blocking innocuous files or processes. However, you should take extreme care before concluding that a given detection is a false positiveContinue reading “Security Software False Positives”

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 2024

My 2021-2024 Authenticode certificate expired yesterday, so I began the process of getting a replacement last week. As in past years, I again selected a 3 year OV certificate from DigiCert. Validation was straightforward. After placing my order, I got a request for high-resolution photos of me holding my ID (I sent my passport andContinue reading “Authenticode in 2024”