Demystifying Removed Apps in iOS App Store

With the popularity of mobile devices, mobile applications have become an essential part of people's lives. To provide secure mobile application download channels for users, various modern app markets are maintained by different companies. For example, Google maintains Google Play for Android users, while Apple maintains App Store for iOS, iPadOS, and MacOS users. Though app markets have come up with strict policies which impose restrictions on developers to avoid the potential harmful applications, we still have quite limited knowledge on the process of app vetting and the status of potential harmful apps. To fill this gap, this paper takes the initiative to conduct a large-scale and longitudinal study of removed apps in the iOS app store. Our analysis reveals that although most of the removed apps are low-quality apps, a number of them are quite popular. Furthermore, the mis-behaviors of these apps are reflected on app metadata, which makes it possible to distinguish potential harmful apps.