Wednesday, December 14, 2016
December 14, 2016
Analysis vs. Translation
Very often, examiners get called upon to do what may be referred to as "push-button forensics". Meaning that we acquire data, plug it into a tool, and wait for the processing and output from that tool to tell us what we have that may be relevant to the case. Unfortunately, this isn't forensics at all, it's allowing software to do a job for us. Perhaps that's why some prefer forensic tools such as X-Ways Forensics, because while tools like X-Ways make the examiner's job easier, the data is not necessarily served up on a "silver platter" and the examiner still has to know how the tool works and how & where to find the relevant data. This is analysis and investigation, not simple data extraction & reporting. But there are nuances to this practice that go even beyond the analysis for the final product to be useful and understandable.
In digital forensics, analysis levels are important to know and distinguish. Very often, the quick acquisition of evidence and triage of data can lead to a break in a case of a missing juvenile or help stem further data loss to mitigate a breach. Triaging evidence can also help identify which pieces are more likely relevant and help examiners spend less time weeding through data that is simply not important. However, triage is a very low-level type of analysis. It's so low-level that triage of digital evidence is being taught to non-examiners just to help streamline the overall examination process. Triage evidence should be used for investigative leads only as very often the finer points about where the data is stored, how it got there, who put it there and other key factors are not part of a triage of evidence.
When we dive deeper into the analysis of the evidence, we start to get into the nuts and bolts of forensics. Important factors can include the type of file system, the users on the system, the time offset on the system, files and metadata. This is the area where some push-button tools operate, because they do dive deeper than triage or preview levels, but it's also a danger zone for many would-be examiners. Push-button tools are great for pointing you in the right direction, but sometimes lack with the detail that is often necessary in forensics. And as any experienced examiner will tell you, the devil is in the details.
Deeper levels of examination, analysis and investigation require intense, skill and above all, experience. No course of study can prepare an examiner for trying to prove or disprove the really hard cases. For example, will a push-button tool really help you prove a child exploitation case without any images being present on the system? Probably not. Even if it did present some valuable evidence, you'd have to dive deeper and search for fragments, history and other evidence that may be "hidden" or very difficult to locate. Most push-button tools won't dive deeper into slack space or volume shadow copies. They're designed to streamline the digital evidence process to decrease backlogs and get cases out the door faster. This is a dangerous trap in forensics and one examiners must constantly work to avoid.
So once we've done our in-depth analysis and completed the digital forensic portion of the investigation, then what do we do? This is where the intangible asset of translation becomes the point where the proverbial rubber meets the road. Without it, the evidence is almost useless.
The Value of Translation
A wise man once said, "You can make a cop a geek, but you can't make a geek a cop!" So what's a "geek" and what's a "cop" and why is it only a one-way street? In this discussion, the term "geek" is used to describe a person who is good with computers, good with technology, enjoys gadgets and all of the new innovations on the market today and even goes so far as to learn more about them, study them, hone their knowledge of them. These are skills that are necessary for a good digital forensic examiner. One can be taught about file systems, operating systems, metadata, slack & unallocated space, but without the ability to articulate what those things are and why their important (i.e., relevant) in your investigation, those skills are only utilitarian.
In this discussion, a "cop" is someone who has an inquisitive nature. A truth-seeker. A trained hunter of facts. Someone who has honed the ability to weed out what may be irrelevant and concentrate on what facts or evidence help prove or disprove the matter at hand which is being investigated. Most importantly, they've honed the ability to explain and articulate that evidence for stake-holders in the case, being other investigators, attorneys, judges and juries (i.e., laypeople). It is this intangible asset which turns the analysis into something meaningful. Because all of the technical skills in the world don't matter if you cannot articulate what you did, why you did it, what you found, where and how it got there. Even the ability to explain what you may not have found is an asset to a trained examiner. Sometimes the absence of evidence can be evidence in itself.
So when it's said that you "...can't make a geek a cop", what it means is that many "geeks" don't have this intangible ability in large part. Think back to the last time you asked a really technical person a question. You probably received a very technical answer, which is not something that lay people understand very often. The ability to whittle down the minutiae into specific, articulable and understandable talking points is something many people in general don't possess, let alone highly technical people.
Wrapping it up
Analysis is but one important component of digital forensics. The translation of that analysis into specific articulated facts is quite another. It's hard for technical schools to teach students two basic, yet very important skills: critical thinking and effective communication. So just because someone has a degree/certification in digital forensics or law or medicine doesn't always mean they can effectively translate (i.e., communicate) what they know, suspect or conclude based upon the evidence at hand. This ability comes from one primary source: experience.
Patrick J. Siewert
Professional Digital Forensic Consulting, LLC
Virginia DCJS #11-14869
Based in Richmond, Virginia
We Find the Truth for a Living!
Computer Forensics -- Mobile Forensics -- Specialized Investigation
About the Author:
Patrick Siewert is the Principal Consultant of Pro Digital Forensic Consulting, based in Richmond, Virginia. In 15 years of law enforcement, he investigated hundreds of high-tech crimes, incorporating digital forensics into the investigations, and was responsible for investigating some of the highest jury and plea bargain child exploitation investigations in Virginia court history. Patrick is a graduate of SCERS, BCERT, the Reid School of Interview & Interrogation and multiple online investigation schools (among others). He continues to hone his digital forensic expertise in the private sector while growing his consulting & investigation business marketed toward litigators, professional investigators and corporations, while keeping in touch with the public safety community as a Law Enforcement Instructor.