Characteristics and Detectability of Windows Auto-Start Extensibility Points in Memory Forensics


Computer forensics is performed during a security incident response process on disk devices or on the memory of the compromised system. The latter case, known as memory forensics, consists in dumping the memory to a file and analyzing it with the appropriate tools. Many security incidents are caused by malware that targets and persists as long as possible in a Windows system within an organization. The persistence is achieved using Auto-Start Extensibility Points (ASEPs), the subset of OS and application extensibility points that allow a program to auto-start without any explicit user invocation. In this paper, we propose a taxonomy of the Windows ASEPs, considering the features that are used or abused by malware to achieve persistence. This taxonomy splits into four categories: system persistence mechanisms, program loader abuse, application abuse, and system behavior abuse. We detail the characteristics of each extensibility point (namely, write permissions, execution privileges, detectability in memory forensics, freshness of system requirements, and execution and configuration scopes). Many of these ASEPs rely on the Windows Registry. We also introduce the tool Winesap, a Volatility plugin that analyzes the registry-based Windows ASEPs in a memory dump. Furthermore, we state the order of execution of some of these registry-based extensibility points and evaluate the effectiveness of our tool in memory dumps taken from a Windows OS where extensibility points were used. Winesap was successful in marking all the registry-based Windows ASEPs as suspicious registry keys.

Digital Investigation
Daniel Uroz
Daniel Uroz
PhD Student in Computer Science

My research interests include malware analysis, reverse engineering, network security, and forensics