Forensic analysts and incident response engineers are armed with a slew of open source and commercial forensic toolsets to attempt to understand and analyze break-ins they did not witness. The most critical component of forensic analysis is system log files. In particular, the analyst must be able to understand and recognize footprints that exploits leave on system logfiles. Identifying these signatures, and their impact on the application within the log files, is the key to understanding what took place during a security incident.

This paper will focus on the identification of the footprints that exploits leave on system logfiles and what they mean, as well as the most common traces that some recent exploits leave. It is hoped that this discussion will help to create a set of methodologies for readers to follow when conducting incident response and forensic analysis, thereby introducing readers to the world of forensic analysis using system and application log files as an evidentiary resource in place of intrusion detection systems.

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