Anti-forensic resilient memory acquisition

Memory analysis has gained popularity in recent years proving to be an effective technique for uncovering malware in compromised computer systems. The process of memory acquisition presents unique evidentiary challenges since many acquisition techniques require code to be run on a potential compromised system, presenting an avenue for anti-forensic subversion. In this paper, we examine a number of simple anti-forensic techniques and test a representative sample of current commercial and free memory acquisition tools. We find that current tools are not resilient to very simple anti-forensic measures. We present a novel memory acquisition technique, based on direct page table manipulation and PCI hardware introspection, without relying on operating system facilities - making it more difficult to subvert. We then evaluate this technique's further vulnerability to subversion by considering more advanced anti-forensic attacks.     

Dynamic recreation of kernel data structures for live forensics

The role of live forensics in digital forensic investigations has become vital due to the importance of volatile data such as encryption keys, network activity, currently running processes, in memory only malware, and other key pieces of data that are lost when a device is powered down. While the technology to perform the first steps of a live investigation, physical memory collection and preservation, is available, the tools for completing the remaining steps remain incomplete. First-generation memory analyzers performed simple string and regular expression operations on the memory dump to locate data such as passwords, credit card numbers, fragments of chat conversations, and social security numbers. A more in-depth analysis can reveal information such as running processes, networking information, open file data, loaded kernel modules, and other critical information that can be used to gain insight into activity occurring on the machine when a memory acquisition occurred. To be useful, tools for performing this in-depth analysis must support a wide range of operating system versions with minimum configuration. Current live forensics tools are generally limited to a single kernel version, a very restricted set of closely related versions, or require substantial manual intervention.This paper describes techniques developed to allow automatic adaptation of memory analysis tools to a wide range of kernel versions. Dynamic reconstruction of kernel data structures is obtained by analyzing the memory dump for the instructions that reference needed kernel structure members. The ability to dynamically recreate C structures used within the kernel allows for a large amount of information to be obtained and processed. Currently, this capability is used within a tool called RAMPARSER that is able to simulate commands such as ps and netstat as if an investigator were sitting at the machine at the time of the memory acquisition. Other applications of the developed capabilities include kernel-level malware detection, recovery of processes memory and file mappings, and other areas of forensics interest.     

An evaluation platform for forensic memory acquisition software

Memory forensics has gradually moved into the focus of researchers and practitioners alike in recent years. With an increasing effort to extract valuable information from a snapshot of a computer's RAM, the necessity to properly assess the respective solutions rises as well. In this paper, we present an evaluation platform for forensic memory acquisition software. The platform is capable of measuring distinct factors that determine the quality of a generated memory image, specifically its correctness, atomicity, and integrity. Tests are performed for three popular open source applications, win32dd, WinPMEM, and mdd, as well as for different memory sizes.     

Graph clustering and anomaly detection of access control log for forensic purposes

Attacks on operating system access control have become a significant and increasingly common problem. This type of security threat is recorded in a forensic artifact such as an authentication log. Forensic investigators will generally examine the log to analyze such incidents. An anomaly is highly correlated to an attacker's attempts to compromise the system. In this paper, we propose a novel method to automatically detect an anomaly in the access control log of an operating system. The logs will be first preprocessed and then clustered using an improved MajorClust algorithm to get a better cluster. This technique provides parameter-free clustering so that it automatically can produce an analysis report for the forensic investigators. The clustering results will be checked for anomalies based on a score that considers some factors such as the total members in a cluster, the frequency of the events in the log file, and the inter-arrival time of a specific activity. We also provide a graph-based visualization of logs to assist the investigators with easy analysis. Experimental results compiled on an open dataset of a Linux authentication log show that the proposed method achieved the accuracy of 83.14% in the authentication log dataset.     

A survey of main memory acquisition and analysis techniques for the windows operating system

Traditional, persistent data-oriented approaches in computer forensics face some limitations regarding a number of technological developments, e.g., rapidly increasing storage capabilities of hard drives, memory-resident malicious software applications, or the growing use of encryption routines, that make an in-time investigation more and more difficult. In order to cope with these issues, security professionals have started to examine alternative data sources and emphasize the value of volatile system information in RAM more recently. In this paper, we give an overview of the prevailing techniques and methods to collect and analyze a computer's memory. We describe the characteristics, benefits, and drawbacks of the individual solutions and outline opportunities for future research in this evolving field of IT security.     

A RAM triage methodology for Hadoop HDFS forensics

This paper discusses the challenges of performing a forensic investigation against a multi-node Hadoop cluster and proposes a methodology for examiners to use in such situations. The procedure's aim of minimising disruption to the data centre during the acquisition process is achieved through the use of RAM forensics. This affords initial cluster reconnaissance which in turn facilitates targeted data acquisition on the identified DataNodes. To evaluate the methodology's feasibility, a small Hadoop Distributed File System (HDFS) was configured and forensic artefacts simulated upon it by deleting data originally stored in the cluster. RAM acquisition and analysis was then performed on the NameNode in order to test the validity of the suggested methodology. The results are cautiously positive in establishing that RAM analysis of the NameNode can be used to pinpoint the data blocks affected by the attack, allowing a targeted approach to the acquisition of data from the DataNodes, provided that the physical locations can be determined. A full forensic analysis of the DataNodes was beyond the scope of this project.     

Forensic investigation of cross platform massively multiplayer online games: Minecraft as a case study

Minecraft, a Massively Multiplayer Online Game (MMOG), has reportedly millions of players from different age groups worldwide. With Minecraft being so popular, particularly with younger audiences, it is no surprise that the interactive nature of Minecraft has facilitated the commission of criminal activities such as denial of service attacks against gamers, cyberbullying, swatting, sexual communication, and online child grooming. In this research, there is a simulated scenario of a typical Minecraft setting, using a Linux Ubuntu 16.04.3 machine (acting as the MMOG server) and Windows client devices running Minecraft. Server and client devices are then examined to reveal the type and extent of evidential artefacts that can be extracted.     

A case study on anonymised sharing platforms and digital traces left by their usage

Non-local forms of file storage and transfer provide investigatory concerns. Whilst mainstream cloud providers offer a well-established challenge to those involved in criminal enquiries, there are also a host of services offering non-account based ‘anonymous’ online temporary file storage and transfer. From the context of a digital forensic investigation, the practitioner examining a suspect device must detect when such services have been utilised by a user, as offending files may not be resident on local storage media. In addition, identifying the use of a service may also expose networks of illegal file distribution, supporting wider investigations into criminal activity. This work examines 16 anonymous file transfer services and identifies and interprets the digital traces left behind on a device following their use to support law enforcement investigations.     

Modelling and refinement of forensic data acquisition specifications

This paper defines a model of a special type of digital forensics tools, known as data acquisition tools, using the formal refinement language Event-B. The complexity and criticality of many types of computer and Cyber crime nowadays combined with improper or incorrect use of digital forensic tools calls for more robust and reliable specifications of the functionality of digital forensics applications. As a minimum, the evidence produced by such tools must meet the minimum admissibility standards the legal system requires, in general implying that it must be generated from reliable and robust tools. Despite the fact that some research and effort has been spent on the validation of digital forensics tools by means of testing, the verification of such tools and the formal specification of their expected behaviour remains largely under-researched. The goal of this work is to provide a formal specification against which implementations of data acquisition procedures can be analysed.     

A comparison of forensic evidence recovery techniques for a windows mobile smart phone

Acquisition, decoding and presentation of information from mobile devices is complex and challenging. Device memory is usually integrated into the device, making isolation prior to recovery difficult. In addition, manufacturers have adopted a variety of file systems and formats complicating decoding and presentation.A variety of tools and methods have been developed (both commercially and in the open source community) to assist mobile forensics investigators. However, it is unclear to what extent these tools can present a complete view of the information held on a mobile device, or the extent the results produced by different tools are consistent.This paper investigates what information held on a Windows Mobile smart phone can be recovered using several different approaches to acquisition and decoding. The paper demonstrates that no one technique recovers all information of potential forensic interest from a Windows Mobile device; and that in some cases the information recovered is conflicting.     

BodySnatcher: Towards reliable volatile memory acquisition by software

Recently there has been a surge in interest in memory forensics: the acquisition and analysis of the contents of physical memory obtained from live hosts. The emergence of kernel level rootkits, anti-forensics, and the threat of subversion that they pose threatens to undermine the reliability of such memory images and digital evidence in general. In this paper we propose a method of acquiring the contents of volatile memory from arbitrary operating systems in a manner that provides point in time atomic snapshots of the host OS volatile memory. Additionally the method is more resistant to subversion due to its reduced attack surface. Our method is to inject an independent, acquisition specific OS into the potentially subverted host OS kernel, snatching full control of the host's hardware. We describe an implementation of this proposal, which we call BodySnatcher, which has demonstrated proof of concept by acquiring memory from Windows 2000 operating systems.     

USB Storage Device Forensics for Windows 10

Significantly increased use of USB devices due to their user‐friendliness and large storage capacities poses various threats for many users/companies in terms of data theft that becomes easier due to their efficient mobility. Investigations for such data theft activities would require gathering critical digital information capable of recovering digital forensics artifacts like date, time, and device information. This research gathers three sets of registry and logs data: first, before insertion; second, during insertion; and the third, after removal of a USB device. These sets are analyzed to gather evidentiary information from Registry and Windows Event log that helps in tracking a USB device. This research furthers the prior research on earlier versions of Microsoft Windows and compares it with latest Windows 10 system. Comparison of Windows 8 and Windows 10 does not show much difference except for new subkey under USB Key in registry. However, comparison of Windows 7 with latest version indicates significant variances.     

Reliability and validity of the original and revised legal attitudes questionnaire

The Legal Attitudes Questionnaire (LAQ) predicts juror bias, but there is little evidence concerning its reliability and construct validity. Two studies provide such evidence for two versions of the LAQ. In Study 1 a questionnaire containing both versions of the LAQ, measures of related and unrelated constructs, and demographic questions was completed by 294 undergraduates. In Study 2 a shortened questionnaire was completed by 102 jury-eligible adults. In both studies, the revised version of the LAQ was superior to the original LAQ in terms of missing data, internal reliability, and construct validity. A refined version of the revised scale is presented, evaluated, and recommended for future use.This article is an expanded version of a poster presented at the meeting of the American Psychology and Law Society in March, 1992. We are grateful to Barbara Martin and Ray Wolfe for their comments on a previous version of this article. We would like to thank Sean Henriques, Tracy Chavez, Jennifer Devenport, Alex Milov, and Cathy Mucha for their assistance in data acquisition, entry, and verification. Finally, we thank the Miami Beach Kiwanis for participating in this study.     

Integrity verification of user space code

We present a novel approach for the construction and application of cryptographic hashes to user space memory for the purposes of verifying the provenance of code in memory images. Several key aspects of Windows behaviour which influence this process are examined in-depth. Our approach is implemented and evaluated on a selection of malware samples with user space components as well as a collection of common Windows applications. The results demonstrate that our approach is highly effective at reducing the amount of memory requiring manual analysis, highlighting the presence of malicious code in all the malware sampled.     

A study of user data integrity during acquisition of Android devices

At the time of this writing, Android devices are widely used, and many studies considering methods of forensic acquisition of data from Android devices have been conducted. Similarly, a diverse collection of smartphone forensic tools has also been introduced. However, studies conducted thus far do not normally guarantee data integrity required for digital forensic investigations. Therefore, this work uses a previously proposed method of Android device acquisition utilizing ‘Recovery Mode’. This work evaluates Android Recovery Mode variables that potentially compromise data integrity at the time of data acquisition. Based on the conducted analysis, an Android data acquisition tool that ensures the integrity of acquired data is developed, which is demonstrated in a case study to test tool's ability to preserve data integrity.     

In‐Depth Analysis of Computer Memory Acquisition Software for Forensic Purposes

The comparison studies on random access memory (RAM) acquisition tools are either limited in metrics or the selected tools were designed to be executed in older operating systems. Therefore, this study evaluates widely used seven shareware or freeware/open source RAM acquisition forensic tools that are compatible to work with the latest 64‐bit Windows operating systems. These tools' user interface capabilities, platform limitations, reporting capabilities, total execution time, shared and proprietary DLLs, modified registry keys, and invoked files during processing were compared. We observed that Windows Memory Reader and Belkasoft's Live Ram Capturer leaves the least fingerprints in memory when loaded. On the other hand, ProDiscover and FTK Imager perform poor in memory usage, processing time, DLL usage, and not‐wanted artifacts introduced to the system. While Belkasoft's Live Ram Capturer is the fastest to obtain an image of the memory, Pro Discover takes the longest time to do the same job.     

Capture – A behavioral analysis tool for applications and documents

In this paper, we present Capture, a tool for behavioral analysis of applications for the Win32 operating system family. Capture is able to monitor the state of a system during the execution of applications and processing of documents, which provides the analyst with insights on how the software operates even if no source code is available. Capture differs from existing behavioral analysis tools in its ability to monitor state changes on a low kernel level and its ability to be easily used across operating systems, various versions and configurations. Capture provides a powerful mechanism to exclude event noise that naturally occurs on an idle system or when using a specific application. This mechanism is fine-grained and allows an analyst to take into account the process that causes the various state changes. As a result, this mechanism even allows Capture to analyze the behavior of documents that execute within the context of an application. We demonstrate Capture's capabilities by analyzing a malicious Microsoft Word document.     

Obtaining forensic value from the cbWndExtra structures as used by Windows Common Controls,specifically for the Editbox control

The Windows Common Controls is a library which facilitates the construction of GUI controls commonly used by Windows applications. Each control is an extension of the basic ‘window’ class. The difference in the extension results in one control over another; for example, an Edit control as opposed to a Button control. The basic window class is documented by Microsoft and the generic information about a Window can be extracted, but this is of very limited use. There is no documentation and very little research into how these extensions are laid out in memory. This paper demonstrates how the extension bytes for the Edit control can be parsed leading to identification of previously unobtainable data which reveal information about the state of the control at runtime. Most notably, the undo buffer, that is, text that was previously present in the control can be recovered – an aspect which traditional disk forensics would simply not provide. The paper explains why previous attempts to achieve similar goals have failed, and how the technique could be applied to any control from the Windows Common Controls library.     

Out of sight,but not out of mind: Traces of nearby devices' wireless transmissions in volatile memory

An IEEE 802.11 wireless device can leave traces of its presence in the volatile memories of nearby wireless devices. While the devices need to be in radio range of each other for this to happen, they do not need to be connected to the same network—or to any network at all. Traces appear in the form of full wire-type frames; a residue of the signals in the ether. We examine types of information that can be extracted from such residual frames and explore the conditions under which traces develop and persist. Their availability is determined by factors in both in the external environment (the types of signals in the ether) and the internal environment (the configuration and particulars of a device's wifi stack). To isolate some of these factors, we have created memory dumps of devices in various environments and configurations. Analysis of the dumps has offered insights into the conditions determining creation and decay of the traces. The results indicate that they will be available in a limited number of real-world scenarios. We conclude with practical advice on triaging and preservation.     

准不动产的物权变动要件——《物权法》第24条及相关条款的解释与完善

通过对《物权法》第24条及相关条款进行文义解释与逻辑解释可知,准不动产物权（抵押权除外）的设立与转让实行“交付生效＋登记对抗”的规范模式。这种模式存在一定的缺陷,而且导致善意取得构成要件的解释结论限制了准不动产善意取得制度的适用范围。将来把《物权法》编入民法典时,应当对第24条、106条进行相应的修改。