Causal Inconsistencies are Normal in Windows Memory Dumps (too)

Abstract

Main memory contains valuable information for criminal investigations, e.g., process information or keys for disk encryption. Taking snapshots of memory is therefore common practice during a digital forensic examination. Inconsistencies in such memory dumps can, however, hamper their analysis. In this paper, we perform a systematic assessment of causal inconsistencies in memory dumps taken on a Windows 10 machine using the kernel-level acquisition tool WinPmem. We use two approaches to measure the quantity of inconsistencies in Windows 10: (1) causal inconsistencies within self-injected memory data structures using a known methodology transferred from the Linux operating system, and (2) inconsistencies in the memory management data structures of the Windows kernel using a novel measurement technique based on properties of the virtual address descriptor (VAD) tree. Our evaluation is based on a dataset of more than 180 memory dumps. As a central result, both types of inconsistency measurement reveal that a high number of inconsistencies is the norm rather than the exception. We also correlate workload and execution time of the memory acquisition tool to the number of inconsistencies in the respective memory snapshot. By controlling these factors it is possible to (somewhat) control the level of inconsistencies in Windows memory dumps.