“Forensics tools” where are your tests?

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“Forensics tools” where are your tests?


In the context of digital forensics and incident response (sometimes referred to as DFIR) I regularly see claims about the latest “forensics tools”, “forensics data formats” or “court approved tools”. These claims are mere speculation (or hallucinations so to speak) when they are not accompanied with reproducible tests.


Digital forensics is the practice to ensure that its findings are reliable enough to influence legal outcomes that affect human liberty and significant financial assets. The transition from "computer equipment" to "forensic evidence" requires a process that is transparent, auditable, and grounded in the scientific method.


Key to a scientific finding is that it can be replicated independently. In the context of digital forensics, this requirement is divided into two distinct but related concepts:

  • Repeatability, which refers to the consistency of results when the same examiner uses the same tool on the same sample at different times.

  • Reproducibility, which is often considered a higher bar for scientific validity, refers to the consistency of results when different examiners analyze the same sample, potentially using different tools or methods.


The absence of documented tests and results renders reproducibility impossible. 


Anyone that relies solely on the output of a tool without documenting the specific parameters, software versions, and verification steps taken, a defense expert or an independent auditor cannot verify the accuracy of the findings. This lack of transparency violates a key principle that scientific laws must be true regardless of who observes them [1].


Modern digital investigations often involve massive datasets, ranging from encrypted mobile devices to vast cloud-based networks. To manage this volume, practitioners rely on advanced automation, with or without artificial intelligence. While these tools are essential for efficiency, their uncritical use introduces a shortcoming of transparency (a "black box") into the forensic process, where the underlying logic is hidden from the examiner and the court.


The danger of over-reliance on tooling is exacerbated by the highly dynamic nature of technology. Operating systems and applications are updated frequently, and a tool that functioned perfectly one week may fail the next if a data structure has changed. Without case-specific verification, such as cross-validating a timestamp across multiple log sources, the examiner remains unaware of potential parsing or representation errors.


Findings must always be user-verifiable; the examiner must retain the final say and be able to connect disparate data points into a coherent, defensible narrative.


Tools are merely the beginning; the true meaning of the forensics lies in an expert's ability to prove that their findings are an accurate and reliable representation of reality.

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