Due to their widespread use and open architecture, devices running the Android operating system are a popular target of malware, which is often installed by users themselves. On Android, it is relatively easy to install apps not only from Google's Play Store, but also from alternative sources or via direct download. In addition to the app stores monitored by Google, device manufacturers, and other providers, apps are also offered for installation from more dubious sources. Since it is not mandatory to install apps from the official Google Play Store on Android, an attacker could, for example, infect a popular app with malware and then make it available for download.