VCR: App-Agnostic Recovery of Photographic Evidence from Android Device Memory Images

The ubiquity of modern smartphones means that nearly everyone has easy access to a camera at all times. In the event of a crime, the photographic evidence that these cameras leave in a smartphone's memory becomes vital pieces of digital evidence, and forensic investigators are tasked with recovering and analyzing this evidence. Unfortunately, few existing forensics tools are capable of systematically recovering and inspecting such in-memory photographic evidence produced by smartphone cameras. In this paper, we present VCR, a memory forensics technique which aims to fill this void by enabling the recovery of all photographic evidence produced by an Android device's cameras. By leveraging key aspects of the Android framework, VCR extends existing memory forensics techniques to improve vendor-customized Android memory image analysis. Based on this, VCR targets application-generic artifacts in an input memory image which allow photographic evidence to be collected no matter which application produced it. Further, VCR builds upon the Android framework's existing image decoding logic to both automatically recover and render any located evidence. Our evaluation with commercially available smartphones shows that VCR is highly effective at recovering all forms of photographic evidence produced by a variety of applications across several different Android platforms.