API-based evidence acquisition in the cloud - a survey

Abstract

Cloud services and cloud storage solutions are special challenges in digital forensic investigations. Cloud services allow their users, with relatively little technical knowledge, store, manage and share content with others. At the same time investigators are faced with a wide range of technical, legal and organizational issues. Unfortunately, evidence acquisition for such services still follows the traditional way of collecting artefacts on a client device. In this article, first, an overview of the state of research is given. Next, technical and legal challenges related to the forensically sound acquisition of cloud data are presented. Since accessing these data is highly challenging, basic techniques for acquiring data from the cloud are discussed and compared, using the example of 30 cloud storage services. We introduce the concept of an API-based evidence acquisition for cloud services that utilize the officially supported API of the service. We show how well this approach applies to most current cloud drive services in the survey context. We present the first glance of a proof-of-concept acquisition framework called CLOUDxTRACT, which can acquire evidence from selected cloud service providers.