Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Date of Graduation

Fall 2012

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Department of Computer Science

Abstract

Modern day digital forensics investigations rely on timelines as a principal method for normalizing and chronologically categorizing artifacts recovered from computer systems. Timelines provide investigators with a chronological representation of digital evidence so they can depict altered and unaltered digital forensics data in-context to drive conclusions about system events and/or user activities. While investigators rely on many system artifacts such as file system time/date stamps, operating system artifacts, program artifacts, logs, and/or registry artifacts as input for deriving chronological representations, using only the available or most recent version of the artifacts may provide a limited picture of historical changes on a system. For instance, if previous versions of artifacts and/or previous artifact metadata changes are overwritten and/or are not retained on a system, analysis of current versions of artifacts and artifact metadata, such as time/date stamps and operating system/program/registry artifacts, may provide only a limited picture of activities for the system. Recently, the Microsoft Windows Operating System implemented a backup mechanism that is capable of retaining multiple versions of data storage units for a system, effectively providing a highly-detailed record of system changes. This backup mechanism, the Windows Volume Shadow Copy Service (VSS), exists as a service of modern Microsoft Windows Operating Systems and allows data backups to be performed while applications on a system continue to write to the system's live volume(s). This allows a running system to preserve the system's state to backup media at any given point while the system continues to change in real-time. After multiple VSS backups are recorded, digital investigators now have the ability to incorporate multiple versions of a system's artifacts into a chronological representation, which provides a more comprehensive picture of the system's historical changes. In order to effectively incorporate VSS backup, or Volume Shadow Copy (VSC), data into a chronological representation, the data must be accessed and extracted in a consistent, repeatable, and, if possible, automated manner. Previous efforts have produced a variety of manual and semi-automated methods for accessing and extracting VSC data in a repeatable manner. These methods are time consuming and often require significant storage resources if dealing with multiple VSCs. The product of this research effort is the advancement of the methodology to automate accessing and extracting directory-tree and file attribute metadata from multiple VSCs of the Windows 7 Operating System. The approach extracts metadata from multiple VSCs and combines it as one conglomerate data set. By capturing the historical changes recorded within VSC metadata, this approach enhances timeline generation. Additionally, it supports other projects which could use the metadata to visualize change-over-time by depicting how the individual metadata and the conglomerate data set changed (or remained unchanged) throughout an arbitrary snapshot of time.

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