Cosimo, please tell us about your work as an Associate Professor at the Università del Piemonte Orientale. What does a typical day look like for you?
The University of Piemonte Orientale is a mid-sized University located in Piemonte, in the North-West of Italy. I work in the Computer Science Institute, which is located in Alessandria, one of the three campuses of the university.
As a Professor, my duties are research and teaching. My current research fields are digital forensics and distributed systems. My typical day consists in doing research in the lab (both directly and by coordinating my collaborators), mentoring students, and teaching. At the moment I teach classes in Digital Forensics, in Operating Systems, and in Distributed Systems, both at the undergraduate and at the graduate level.
I am also the Director of the CyberCrime Research Center of my University, that I contributed to founding several years ago.How did you first become interested in digital forensics as a field?
My interest in digital forensics arose about 10 years ago, when I was visiting some U.S. universities, and I saw various books focusing on computer forensics in the bookstore located in the campus of one of them. I started browsing some of these books, and shortly after (or, at least, after an amount of time that seemed short to me, although I spent three hours reading these books), I purchased a bunch of them and had them shipped to Italy.
After reading these books, I started experimenting in my lab at the university with the techniques described there, and I really enjoyed it, and shortly after I started looking at interesting problems in digital forensics that were still in search of solutions.
At the same time, I started collaborating with some police forces in Italy working on high tech crimes, and I had the chance of using computer forensics techniques in the field. This experience gave me a more thorough understanding of the issues that have to be dealt with, and where current techniques fall short, when one deals with real digital forensics cases.
For a researcher, this is vital information, as it gives a clear view on what are the current challenges that deserve attention, so in my research I strive to keep the interaction with law enforcement as active as I can.
You have recently released a paper on the forensic analysis of WhatsApp Messenger on Android smartphones. Could you give us a brief overview of the aims of the research, and how you went about conducting the study?
The paper was published in the September 2014 issue of the Digital Investigation journal, and discusses the forensic analysis of the artifacts left on Android devices by WhatsApp Messenger.
My interest in WhatsApp forensics was sparked from the observation that, although the databases where it stores information had been already identified, and the information stored there had been already decoded, work linking user actions to digital artifacts was still lacking.
Therefore, I decided to fill that gap by studying what data are generated by the various actions that a user can carry out with WhatsApp, how these data are encoded and where they are stored, and how subsets of these artifacts can be correlated among them to infer user actions.
In particular, the paper provides a complete description of all the artifacts generated by WhatsApp on Android devices, discusses the decoding and the interpretation of each one of them, and shows how they can be correlated together to infer various types of information that cannot be obtained by considering each one of them in isolation.
By using the results discussed in paper, an analyst will be able to reconstruct the list of contacts and the chronology and content of the messages that have been exchanged by users and, thanks to the correlation of multiple artifacts, to infer information like when a specific contact has been added and to recover deleted contacts and their time of deletion, as well as to determine which messages have been deleted, when these messages have been exchanged, and the users that exchanged them.
What were the main challenges you encountered when you started the analysis? How did you overcome them?
The main challenge I found was how to access the restricted memory area of the mobile devices used in the experiments, as the data generated by WhatsApp are stored there. At the time of the research, indeed, I did not have access to any mobile forensics platform providing acquisition capabilities, and did not want to root the devices used for the experiments in order to avoid possible alterations of the data stored there.
Therefore, I came up with the solution of using a virtualization platform (YouWave), that is able to emulate Android smartphones that behave like real smartphones, and provides easy access to their restricted memory (which is implemented as a file that can be easily parsed by current forensics tools).
This provided me with the additional benefit of having total control of the experiments, something which is usually hard to obtain with a real device that interacts with the network. For instance, there was no need to physically shield the device (as it was not really connected to the radio network), or to figure out if any one of the running applications could interfere with the experiments (as it was easy to inspect the status of the device and to identify and terminate those applications). Another benefit was that the collection of the experimental results was quick, as it amounted to reading the content of a file, compared to the time required by memory extraction on a real smartphone.
Amid increasing concerns over user privacy and security, a growing number of apps are automatically encrypting data. What challenges does this present for investigators, and what can be done to address these?
Of course, strong encryption is a big problem for the forensic analyst. However, not all the applications that claim they use encryption when transmitting data actually encrypt data on local, persistent storage.
For those applications that actually encrypt data also locally, recent works on extracting encoding keys from main memory have demonstrated that, at least in some cases, encrypted data can be decrypted by using the encryption keys stored in the volatile memory of the device. At the moment, these techniques are still in their early stage, and are mostly applied in an ad-hoc manner, but their potential is clear. I believe that further work should be devoted to make them as general, and as forensically sound, as possible.
In your opinion, what is the "next big thing" in mobile forensics?
In my opinion, there are two phenomena that are gaining momentum in the mobile world. One is wearable devices, like smartwatches, smartglasses, and other “smart” wearable items that will be certainly developed in the near future. The other one is the Internet of Things, where a very large number of small devices, able to interconnect among themselves, will exchange data.
The convergence of these two worlds will result in new ways of using, misusing, and abusing mobile devices, that in turn will require the development of novel forensic analysis methodologies.
Do you have any advice for students who are looking for their first digital forensics role after graduating?
I actually have two pieces of advice for them.
The first one is to look for internships, possibly with law enforcement in countries where this is possible, where they have the chance of practising in the wild the techniques studied at the university.
There is a big difference in using these techniques in a university lab, where nothing really bad can actually happen (the worst thing that can occur is to fail the exam), and in the field, where the weight of the responsibilities puts on a lot of pressure, thus raising the chance of errors.
Experience is what you learn when things go wrong, so the transition from student to professional requires that the person is exposed to situations when things can go bad, under the supervision of an expert that can provide guidance on how to handle those situations.
My second advice is to continue studying, in order to keep the pace of the technological changes in the mobile forensics field.
Finally, what do you do in your spare time?
I spend most of my spare time with my family. In the remaining part, I play tennis and read books.