Introducing the Microsoft Vista event log file format

Several operating systems provide a central logging service which collects event messages from the kernel and applications, filters them and writes them into log files. Since more than a decade such a system service exists in Microsoft Windows NT. Its file format is well understood and supported by forensic software. Microsoft Vista introduces an event logging service which entirely got newly designed. This confronts forensic examiners and software authors with unfamiliar system behavior and a new, widely undocumented file format.This article describes the history of Windows system loggers, what has been changed over time and for what reason. It compares Vista log files in their native binary form and in a textual form. Based on the results, this paper for the first time publicly describes the key-elements of the new log file format and the proprietary binary encoding of XML. It discusses the problems that may arise during daily work. Finally it proposes a procedure for how to recover information from log fragments. During a criminal investigation this procedure was successfully applied to recover information from a corrupted event log.