Microsoft Disabled App Installer Following Malware Abuse

Microsoft has disabled the App Installer protocol handler in its systems by default following its exploitation by malware groups. Known groups such as Storm-0569 and Storm-1674 had been misusing the feature for stealth installation of malware, with the issue becoming more pervasive since mid-November 2023. To prevent further abuse, Microsoft disabled the protocol in the App Installer build 1.21.3421.0.