LangurTrace: Forensic analysis of local LLM applications

A wide variety of applications have been developed to simplify the use of Large Language Models (LLMs), raising the importance of systematically analyzing their forensic artifacts. This study proposes a structured framework for LLM application environments, categorizing applications into backend runtime, client interface, and integrated platform components. Through experimental analysis of representative applications, we identify and classify artifacts such as chat records, uploaded fils, generated files, and model setup histories. These artifacts provide valuable insight into user behavior and intent. For instance, LLM-generated files can serve as direct evidence in criminal investigations, particularly in cases involving the creation or distribution of illicit media, such as CSAM. The structured environment model further enables investigators to anticipate artifacts even in applications not directly analyzed. This study lays a foundational methodology for LLM application forensics, offering practical guidance for forensic investigations. To support practical adoption and reproducibility, we also release LangurTrace , an open-source tool that automates the collection and analysis of these artifacts.