Digital forensics is the process of collecting, storing, and quantifying digital evidence to be used as the result of some action that takes place.
Most forensics are going to take place from one of two reasons.
For in-house incident, which means somebody has broken an important policy and we need to be able to document that they've done this and have to go through a process of forensics.
For outside world incident, which is mostly from a legal hold.
Legal holds are documents that are sent to an organization from another organization. Lets assume organization A and organization B. The intent is to let the other organization B know that the organization A is going to do some exploratory information and that another organization B has to provide that information for them in such a way that they, organization A, can do legal discovery they need to do to.
First concept to be understood from digital forensics is the chain of custody.
The whole idea behind chain of custody is the fact that you or someone underneath your purview is going to be gather evidence against somebody or something. This someone has been looked at as a suspect. And that somebody or something has a chance of losing their job or losing money or losing freedom or even losing honor.
The presenting evidence of the data that has been collected should be of high integrity, means that there should be no claim from the suspect that the name has been changed, the time of the incident gathered has been manipulated, the data collected has been tempered. or the data was gathered days later.
So the whole idea of chain of custody is to show good integrity of the evidence itself.
So the best way to do this is through the chain of custody process.
The cornerstone of chain of custody is a chain of custody form.
Custody forms contain very specific types of information, such as,
1. Defining the evidence, like what are we actually collecting here,
and what does it look like, how does it form? That could be an image of a hard drive. It could be an image from a thumb drive. It could be a video. Whatever it might be, but we define it.
2. Documenting the collection method, one of the big things that we have to worry about is that people will challenge us that we may have changed data.
So there's a number of collection methods that allow us to grab data from mass storage without affecting it.
3. Date and time collected, It can be very important that we determine exactly when this particular evidence was collected.
4. The people handling the evidence, we need to know the names that includes contact information email that type of information.
Exactly telling who's handled the evidence and we're not just talking about the people who collected it, and anybody down the chain as well.
5. The function of the person handling the evidence, that actually means, is this person an in-house I.T. person etc.
In particular we do this to show that these people are qualified to do whatever part of the chain of custody they're involved in.
6. Locations of the evidence, evidence will move over time from the initial collection to being stored in a storage room to potentially be moved to law enforcement. We need to be able to document all of those steps.
When you approach a computer to begin gathering data, one big concern is the order of volatility. We will cover the volatility and other concepts in the subsequent blogs.