Part 1

Background

CAINE, which stands for Computer Aided INvestigative Environment, is a Linux environment whose main purpose is to provide specific investigative and reporting tools that would prove useful to a forensic scientists.<ref name = "CAINE">CAINE-Live Website (Last accessed October 19, 2011).</ref> This Linux environment was originally created in Italy and is currently being managed by Mr. Nanni Bassetti (Website in Italian).

Something to consider before diving into what CAINE is used for is to get a quick understanding about the four step process model put in place by the U.S Department of Justice with regards to digital forensics.<ref name = "DigiForen">Digital Forensics - The Enhanced Digital Investigation Process Model (Last accessed October 14th, 2011).</ref>

The four stages of digital forensics:<ref name = "DigiForen"/>

Collection deals with evidence finding, recognition, collection, and some early documentation with details about the evidence.
Examination has the scientist sifting through the already collected evidence with different software. The goal is to find out where the evidence came from and if it is significant. It also may reveal previously unknown information about the piece of evidence with in-depth examination.
Analysis happens after Examination has deemed a piece of evidence significant enough. By piecing together information gained through the Examination stage, the scientist will decide just how relevant the evidence is to the current case.
Reporting, the final stage, is writing a simple report touching on the examination process and giving a detailed look at all the relevant information gathered through Examination and Analysis that will hopefully help the case in some way.

The design goals that CAINE strives to achieve are as follows:<ref name = "CAINE"/>

A diverse environment that gives the flexibility and all the tools necessary to the forensic scientist during all four stages of the digital forensics.

A user-friendly GUI.

A tool which provided a simple, semi-automatic solution for reporting.

Obtaining CAINE is quite simple. The main website hosts the under 700MB .ISO file directly. The direct download link to CAINE can be found here. There is also an 865MB file that is available for netbooks as well. It can be found here.

Finally, CAINE was created with pieces from Ubuntu 10.04 and Remastersys created by Tony Brijeski<ref name = "CAINEFAQ">CAINE FAQs (Last accessed October 17th, 2011)</ref>

Installation/Startup

Initialization

Upon starting up CAINE for the very first time. Something to note is that the installation doesn't actually start upon first boot-up. Since CAINE's .ISO file is a Live CD, it has the full operating system with pre-configured software and settings<ref name = "LiveCD">The Magic of Live CDs (Last accessed October 17th, 2011).</ref>. For the sake of seeing how the installation process works, though, I will go through and ensure that CAINE is actually installed the HDD.

The software that was used to virtualize CAINE was VMWare Workstation, specifically version 7.1.4 build-385536. [Figure 1]

**Figure 1** The initial setup screen for VMWare

The specifications of the virtual machine are as follows:

Typical install (Creates a Workstation 6.5-7.x virtual machine)
Selected the Caine 2.5 .ISO file.
Selected a Linux operating system with type "Other Linux 2.6.x kernel".
Allocated 20GB for the virtual machine and 512MB of RAM.

CAINE booted up with no initial problems with a boot screen full of options. [Figure 2]

The options include:

Booting the Live System (which is chosen if no action is taken in 10 seconds).
Figure 3 CAINE's Live-CD desktop. The time is currently incorrect.
Low-graphics mode for lower-end machines.
Command to start the full-install right away.
Text only mode.
Video diagnostics command.
Debug mode.
Memory diagnostics command.
Boot from the first HDD.

NOTE: At this point, do not attempt to restart the virtual machine. The system will hang and you will have no choice but to force close the virtual machine and re-open.

After either selecting the Live Boot or waiting for 10 seconds, the desktop will be displayed. [Figure 3]

Installation

Note: All choices made in the test install will be written in parantheses.

After clicking on the Install CAINE 2.5 icon, the user is given the option of selecting a language (English). The installation then initializes the clock to some server's clock, and asks for the user to select the time zone by region (Canada) and Time Zone (Canada Toronto). Afterwards, the user is prompted to selected a keyboard, with the suggested option being USA (USA). Next, the user is prompted to specify a partition in which to install Caine 2.5 on (Erase and use the entire disk) [Figure 4]. The user is then prompted to enter their name, username, password, and the name of the computer. Once this is complete, the user is shown a review of all the choices they have made with a final message stating that all these choices will be applied to the disk upon clicking "Install".

The CAINE operating system will now begin installing to the HDD. Once the installation is complete, the user will be prompted to either restart or continue with manual configurations. Now the virtual machine can be properly restarted without needing to force quit the virtual machine. Upon restarting, the user is asked to choose either the operating system, or the memory diagnostics tool. Something to note is that the operating system that is available isn't called "CAINE", it says "Ubuntu, with Linux 2.6.32-33-generic". This most likely comes from the fact that CAINE was born from Ubuntu and most likely shares a lot of its kernal.

Basic Operation

**Figure 5** Initial screen for CAINE Interface.

(Being a beginner when it comes to all forms of forensics, whether field, digital, or documentation, I will do my best to give an appropriate overview of CAINE.)

Since CAINE was intended specifically for people who work in the digital forensics field, I started looking around the OS for some of the software the developer said could help in all stages of digital forensics. Luckily, right on the desktop was something called "Caine Interface" which seemed to be the hub that linked to all things that have to do with CAINE. [Figure 5]

Upon clicking on it, I was greeted with a slick looking message box that allowed me to create a report. After clicking on it, I was prompted to enter the name of the case and the name of the lead investigator. Afterwards, a handful of tabs popped up with many different programs available. The main types seemed to be disk image file creating and testing to ensure nothing's been corrupted, and different methods of analyzing said image.

One of the programs I tried was AIR, which stands for Automated Image & Recovery. This program is used to create forensic disk images as well as recover them<ref name = "AIR">Automated Image and Restore (Last accessed October 18th, 2011)</ref>. Since CAINE runs on a Live-CD, the ability to create a forensic disk image quickly of a computer that is in the possession of investigators would be quite useful.

**Figure 6** The start of the Autopsy software.

After looking at AIR, I clicked on the tab that led to a lot of different analysis tools. One of the more interesting ones was software called Stegdetect. According to the program itself, its purpose is to search through a folder containing .JPG files to determine if there are any stenographic (secret) content to the image, whether it be a hidden image, data that is secretly attached to the picture, a hidden message (etc).

The main GUI for digital forensics analysis was the Autopsy program. It is useful if the investigators have an image file of an entire disk or partition of a computer that they wish to search through.

The "Autopsy 2.24" icon opened a program that first, launched in a command window which afterwards automatically opened a browser window with the program ready to be used. This software allows for a user to create a new case or open a previously created one. [Figure 6] Upon creating a new case, the software asks for the case name, a short description, and a list of all the investigators that are assigned to this case. Once this has all been filled out, the program then asks for a host to be created. This host is the computer that is currently under investigation. The program then asks for the name of the host computer and a short description. Also, optionally, it asks for a specified timezone, timeskew adjustment (to compensate for how much or little the computer is off from another computer's time), and a hashtable for known good and bad files. Once this is complete, the program asks for an image file, which is interpreted as a filepath. Then it asks if this file path points to a disk or partition, and then finally how to extract the files, either by moving, copying, or simply linking to them.

At this point, I did not have an image file on hand to investigate, so I could not delve further into this program, but from reading through the provided help manual I was able to determine that once an image file has been loaded in, there are some commands that can be used to search for keywords inside the files themselves.

Usage Evaluation

CAINE, I believe, being targeted to people in the digital forensic profession makes a very good case for being a viable solution for digital forensics. An easy install coupled with the option of using the Live-CD desktop gives the user enough options depending on the situation. As I said earlier, the Live-CD would be a great option if they needed to quickly make an image file of a computer that may be partaking in illegal activity.

The choice of having all relevant software in one convenient place was a professional choice. This allows people who may not be too familiar with Linux, or even computers to quickly get access to the software they need to do their job.

From what I have seen of the software provided, CAINE seems to deliver adequately on its promises of providing all tools necessary for all stages in the digital forensics process. Although, because I am not actually a digital forensic scientist, I thoroughly test all the software, it definitely seemed as though everything that a digital forensic scientist would need was available.

In closing, I would recommend CAINE to any forensic scientist who wants a portable, easy-to-use operating system with some great software to help them do their job.

Part II

Software Packaging

As mentioned above, CAINE Linux is designed to meet the needs of digital forensic scientists. This goal is mostly met by the software that is provided with CAINE. As also spoken of beforehand, CAINE comes with a program called "CAINE Interface", which is simple little UI that contains all of the forensic software that is given to the user via this distribution.

References