Forensic Methods and Tools for Web Environments

abstract: The Web is one of the most exciting and dynamic areas of development in today’s technology. However, with such activity, innovation, and ubiquity have come a set of new challenges for digital forensic examiners, making their jobs even more difficult. For examiners to become as effective with evidence from the Web as they currently are with more traditional evidence, they need (1) methods that guide them to know how to approach this new type of evidence and (2) tools that accommodate web environments’ unique characteristics. In this dissertation, I present my research to alleviate the difficulties forensic examiners currently face with respect to evidence originating from web environments. First, I introduce a framework for web environment forensics, which elaborates on and addresses the key challenges examiners face and outlines a method for how to approach web-based evidence. Next, I describe my work to identify extensions installed on encrypted web thin clients using only a sound understanding of these systems’ inner workings and the metadata of the encrypted files. Finally, I discuss my approach to reconstructing the timeline of events on encrypted web thin clients by using service provider APIs as a proxy for directly analyzing the device. In each of these research areas, I also introduce structured formats that I customized to accommodate the unique features of the evidence sources while also facilitating tool interoperability and information sharing.Dissertation/ThesisDoctoral Dissertation Computer Science 201

A Digital Forensics Case Study of the DJI Mini 3 Pro and DJI RC

The consumer drone market is rapidly expanding with new drone models featuring unique variations of hardware and software. The rapid development of drone technology and variability in drone systems can make it difficult for digital forensic investigators and tools to keep pace and effectively extract and analyse digital evidence from drones. Furthermore, the growing popularity of drones and their increased use in illegal and harmful activities, such as smuggling, espionage, and even terrorism, has led to an increase in the number of drone forensic cases for authorities to manage. To assist forensic investigators, a static digital forensic case study was conducted on two drone devices recently released by Da-Jiang Innovations (DJI): the Mini 3 Pro drone, and its remote controller, the DJI RC. The study discovered the presence of several digital artefacts on both devices, including recorded media, flight logs, and other information that could help investigators trace the drone's usage and identify its operator. Additionally, this paper explored several methods for extracting and visualising the drone's flight history, and highlights some of the potential methods used to limit, obscure, or remove key types of digital evidence.Comment: 20 Pages, 23 figure

Mobile Forensics – The File Format Handbook

This open access book summarizes knowledge about several file systems and file formats commonly used in mobile devices. In addition to the fundamental description of the formats, there are hints about the forensic value of possible artefacts, along with an outline of tools that can decode the relevant data. The book is organized into two distinct parts: Part I describes several different file systems that are commonly used in mobile devices. · APFS is the file system that is used in all modern Apple devices including iPhones, iPads, and even Apple Computers, like the MacBook series. · Ext4 is very common in Android devices and is the successor of the Ext2 and Ext3 file systems that were commonly used on Linux-based computers. · The Flash-Friendly File System (F2FS) is a Linux system designed explicitly for NAND Flash memory, common in removable storage devices and mobile devices, which Samsung Electronics developed in 2012. · The QNX6 file system is present in Smartphones delivered by Blackberry (e.g. devices that are using Blackberry 10) and modern vehicle infotainment systems that use QNX as their operating system. Part II describes five different file formats that are commonly used on mobile devices. · SQLite is nearly omnipresent in mobile devices with an overwhelming majority of all mobile applications storing their data in such databases. · The second leading file format in the mobile world are Property Lists, which are predominantly found on Apple devices. · Java Serialization is a popular technique for storing object states in the Java programming language. Mobile application (app) developers very often resort to this technique to make their application state persistent. · The Realm database format has emerged over recent years as a possible successor to the now ageing SQLite format and has begun to appear as part of some modern applications on mobile devices. · Protocol Buffers provide a format for taking compiled data and serializing it by turning it into bytes represented in decimal values, which is a technique commonly used in mobile devices. The aim of this book is to act as a knowledge base and reference guide for digital forensic practitioners who need knowledge about a specific file system or file format. It is also hoped to provide useful insight and knowledge for students or other aspiring professionals who want to work within the field of digital forensics. The book is written with the assumption that the reader will have some existing knowledge and understanding about computers, mobile devices, file systems and file formats

Mobile Forensics – The File Format Handbook

This open access book summarizes knowledge about several file systems and file formats commonly used in mobile devices. In addition to the fundamental description of the formats, there are hints about the forensic value of possible artefacts, along with an outline of tools that can decode the relevant data. The book is organized into two distinct parts: Part I describes several different file systems that are commonly used in mobile devices. · APFS is the file system that is used in all modern Apple devices including iPhones, iPads, and even Apple Computers, like the MacBook series. · Ext4 is very common in Android devices and is the successor of the Ext2 and Ext3 file systems that were commonly used on Linux-based computers. · The Flash-Friendly File System (F2FS) is a Linux system designed explicitly for NAND Flash memory, common in removable storage devices and mobile devices, which Samsung Electronics developed in 2012. · The QNX6 file system is present in Smartphones delivered by Blackberry (e.g. devices that are using Blackberry 10) and modern vehicle infotainment systems that use QNX as their operating system. Part II describes five different file formats that are commonly used on mobile devices. · SQLite is nearly omnipresent in mobile devices with an overwhelming majority of all mobile applications storing their data in such databases. · The second leading file format in the mobile world are Property Lists, which are predominantly found on Apple devices. · Java Serialization is a popular technique for storing object states in the Java programming language. Mobile application (app) developers very often resort to this technique to make their application state persistent. · The Realm database format has emerged over recent years as a possible successor to the now ageing SQLite format and has begun to appear as part of some modern applications on mobile devices. · Protocol Buffers provide a format for taking compiled data and serializing it by turning it into bytes represented in decimal values, which is a technique commonly used in mobile devices. The aim of this book is to act as a knowledge base and reference guide for digital forensic practitioners who need knowledge about a specific file system or file format. It is also hoped to provide useful insight and knowledge for students or other aspiring professionals who want to work within the field of digital forensics. The book is written with the assumption that the reader will have some existing knowledge and understanding about computers, mobile devices, file systems and file formats

Advanced Techniques for Improving the Efficacy of Digital Forensics Investigations

Digital forensics is the science concerned with discovering, preserving, and analyzing evidence on digital devices. The intent is to be able to determine what events have taken place, when they occurred, who performed them, and how they were performed. In order for an investigation to be effective, it must exhibit several characteristics. The results produced must be reliable, or else the theory of events based on the results will be flawed. The investigation must be comprehensive, meaning that it must analyze all targets which may contain evidence of forensic interest. Since any investigation must be performed within the constraints of available time, storage, manpower, and computation, investigative techniques must be efficient. Finally, an investigation must provide a coherent view of the events under question using the evidence gathered. Unfortunately the set of currently available tools and techniques used in digital forensic investigations does a poor job of supporting these characteristics. Many tools used contain bugs which generate inaccurate results; there are many types of devices and data for which no analysis techniques exist; most existing tools are woefully inefficient, failing to take advantage of modern hardware; and the task of aggregating data into a coherent picture of events is largely left to the investigator to perform manually. To remedy this situation, we developed a set of techniques to facilitate more effective investigations. To improve reliability, we developed the Forensic Discovery Auditing Module, a mechanism for auditing and enforcing controls on accesses to evidence. To improve comprehensiveness, we developed ramparser, a tool for deep parsing of Linux RAM images, which provides previously inaccessible data on the live state of a machine. To improve efficiency, we developed a set of performance optimizations, and applied them to the Scalpel file carver, creating order of magnitude improvements to processing speed and storage requirements. Last, to facilitate more coherent investigations, we developed the Forensic Automated Coherence Engine, which generates a high-level view of a system from the data generated by low-level forensics tools. Together, these techniques significantly improve the effectiveness of digital forensic investigations conducted using them

Introductory Computer Forensics

INTERPOL (International Police) built cybercrime programs to keep up with emerging cyber threats, and aims to coordinate and assist international operations for ?ghting crimes involving computers. Although signi?cant international efforts are being made in dealing with cybercrime and cyber-terrorism, ?nding effective, cooperative, and collaborative ways to deal with complicated cases that span multiple jurisdictions has proven dif?cult in practic

Facilitating forensic examinations of multi-user computer environments through session-to-session analysis of internet history

This paper proposes a new approach to the forensic investigation of Internet history artefacts by aggregating the history from a recovered device into sessions and comparing those sessions to other sessions to determine whether they are one-time events or form a repetitive or habitual pattern. We describe two approaches for performing the session aggregation: fixed-length sessions and variable-length sessions. We also describe an approach for identifying repetitive pattern of life behaviour and show how such patterns can be extracted and represented as binary strings. Using the Jaccard similarity coefficient, a session-to-session comparison can be performed and the sessions can be analysed to determine to what extent a particular session is similar to any other session in the Internet history, and thus is highly likely to correspond to the same user. Experiments have been conducted using two sets of test data, where multiple users have access to the same computer. By identifying patterns of Internet usage that are unique to each user, our approach exhibits a high success rate in attributing particular sessions of the Internet history to the correct user. This can provide considerable help to a forensic investigator trying to establish which user was using the computer when a web-related crime was committed

Forensic imaging and analysis of Apple iOS devices

In this thesis we present our research on digital forensics on the iOS platform, structured along three areas: forensic imaging; forensic analysis; and anti-forensic techniques. In the field of forensic imaging, we demonstrate that the iPad can control external storage devices attached via USB, using Apple's Camera Connection Kit adapters. This results in a 30x speed boost compared to the traditional Wi-Fi transfer. In terms of forensic analysis, we found that printing documents wirelessly via AirPrint leaves a trace in the device that, when recovered, reveals the full contents of the documents that have been printed. Finally, in terms of anti-forensics, we created a proof-of-concept tool that disables a number of system services used by forensic tools to retrieve data. The tool also applies other hardening measures aimed at preventing the abuse of the services that remain activated.Esta tesis presenta nuestra investigación sobre informática forense en la plataforma iOS, estructurada en tres áreas: adquisición forense; análisis forense; y técnicas anti-forenses. En el campo de adquisición forense, demostramos que el iPad puede controlar dispositivos externos de almacenamiento conectados vía USB, usando los adaptadores del Apple Camera Connection Kit. Esto supone una velocidad de transferencia 30 veces superior a la transferencia vía Wi-Fi. En cuanto al análisis forense, observamos que la impresión inalámbrica de documentos vía AirPrint deja un rastro en el dispositivo que, al ser recuperado, revela el contenido completo de los documentos que hayan sido impresos. Por último, en el ámbito de técnicas anti-forenses implementamos una herramienta como prueba de concepto que deshabilita determinados servicios del sistema usados por las herramientas forenses para extraer datos del dispositivo. La herramienta también aplica otras medidas de seguridad para prevenir la explotación de los servicios que continúen activados.Aquesta tesi presenta la nostra investigació sobre informàtica forense a la plataforma iOS, estructurada en tres àrees: adquisició forense; anàlisi forense; i tècniques antiforenses. En el camp d'adquisició forense, demostrem que l'iPad pot controlar dispositius externs d'emmagatzematge connectats via USB, usant els adaptadors de l'Apple Camera Connection Kit. Això suposa una velocitat de transferència 30 vegades superior a la transferència via Wi-Fi. Pel que fa a l'anàlisi forense, observem que la impressió sense fil de documents a partir d'AirPrint deixa un rastre al dispositiu que, en ser recuperat, revela el contingut complet dels documents que hagin estat impresos. Finalment, en l'àmbit de tècniques antiforenses implementem una eina com a prova de concepte que deshabilita determinats serveis del sistema usats per les eines forenses per a extreure dades del dispositiu. L'eina també aplica altres mesures de seguretat per a prevenir l'explotació dels serveis que continuïn activats.Tecnologías de la información y de rede

Improving Memory Forensics Through Emulation and Program Analysis

Memory forensics is an important tool in the hands of investigators. However, determining if a computer is infected with malicious software is time consuming, even for experts. Tasks that require manual reverse engineering of code or data structures create a significant bottleneck in the investigative workflow. Through the application of emulation software and symbolic execution, these strains have been greatly lessened, allowing for faster and more thorough investigation. Furthermore, these efforts have reduced the barrier for forensic investigation, so that reasonable conclusions can be drawn even by non-expert investigators. While previously Volatility had allowed for the detection of malicious hooks and injected code with an insurmountably high false positive rate, the techniques presented in the work have allowed for a much lower false positive rate automatically, and yield more detailed information when manual analysis is required. The second contribution of this work is to improve the reliability of memory forensic tools. As it currently stands, if some component of the operating system or language runtime has been updated, the task of verifying that these changes do not affect the correctness of investigative tools involves a large reverse engineering effort, and significant domain knowledge, on the part of whoever maintains the tool. Through modifications of the techniques used in the hook analysis, this burden can be lessened or eliminated by comparing the last known functionality to the new functionality. This allows the tool to be updated quickly and effectively, so that investigations can proceed without issue