Appdome Detect Unknown Sources is a mobile app security plugin that monitors app installation paths and OS settings to identify when Android apps are installed from unauthorized sources outside of Google Play or trusted marketplaces. The plugin detects when the "allow app installs from unknown sources" setting is enabled on Android devices, helping prevent malware distribution through third-party app stores, sideloaded APKs, or direct downloads. The solution operates without requiring SDK integration or code changes. It supports multiple Android app frameworks including Java, JavaScript, C++, C#, Kotlin, Flutter, React Native, Unity, Xamarin, and Cordova. The plugin can be configured to either enforce protection automatically or pass threat intelligence to the app's business logic through Appdome's Threat-Events framework. Developers can customize user notifications when unknown sources are detected, including localized messages and unique threat codes generated by AI for each security event. The plugin integrates into CI/CD pipelines through Appdome's API and supports both APK and AAB Android formats. The detection capability aligns with compliance requirements including PCI DSS, PSD2, and GDPR by ensuring app integrity and blocking unverified installations that could lead to device compromise, unauthorized modifications, or fraud.