Thwart Me If You Can: An Empirical Analysis of Android Platform Armoring Against Stalkerware

Stalkerware is a serious threat to individuals' privacy that is receiving increased attention from the security and privacy research communities. Existing works have largely focused on studying leading stalkerware apps, dual-purpose apps, monetization of stalkerware, or the experience of survivors. However, there remains a need to understand potential defenses beyond the detection-and-removal approach, which may not necessarily be effective in the context of stalkerware. In this paper, we perform a systematic analysis of a large corpus of recent Android stalkerware apps. We combine multiple analysis techniques to quantify stalkerware behaviors and capabilities and how these evolved over time. Our primary goal is understanding: how (and whether) recent Android platform changes -- largely designed to improve user privacy -- have thwarted stalkerware functionality; how stalkerware may have adapted as a result; and what we may conclude about potential defenses. Our investigation reveals new insights into tactics used by stalkerware and may inspire alternative defense strategies.