Here are 10 of the best free tools that will help you conduct a digital forensic investigation. Whether it’s for an internal human resources case, an investigation into unauthorized access to a server, or if you just want to learn a new skill, these suites and utilities will help you conduct memory forensic analysis, hard drive forensic analysis, forensic image exploration, forensic imaging and mobile forensics. As such, they all provide the ability to bring back in-depth information about what’s “under the hood” of a system.
The SANS Investigative Forensic Toolkit (SIFT) is an Ubuntu based Live CD which includes all the tools you need to conduct an in-depth forensic or incident response investigation. It supports analysis of Expert Witness Format (E01), Advanced Forensic Format (AFF), and RAW (dd) evidence formats. SIFT includes tools such as log2timeline for generating a timeline from system logs, Scalpel for data file carving, Rifiuti for examining the recycle bin, and lots more.
When you first boot into the SIFT environment, I suggest you explore the documentation on the desktop to help you become accustomed to what tools are available and how to use them. There is also a good explanation of where to find evidence on a system. Use the top menu bar to open a tool, or launch it manually from a terminal window.
ProDiscover Basic is a simple digital forensic investigation tool that allows you to image, analyse and report on evidence found on a drive. Once you add a forensic image you can view the data by content or by looking at the clusters that hold the data. You can also search for data using the Search node based on the criteria you specify.
When you launch ProDiscover Basic you first need to create or load a project and add evidence from the ‘Add’ node. You can then use the ‘Content View’ or ‘Cluster View’ nodes to analyse the data and the Tools menu to perform actions against the data. Click the ‘Report’ node to view important information about the project.
Volatility is a memory forensics framework for incident response and malware analysis that allows you to extract digital artefacts from volatile memory (RAM) dumps. Using Volatility you can extract information about running processes, open network sockets and network connections, DLLs loaded for each process, cached registry hives, process IDs, and more.
If you are using the standalone Windows executable version of Volatility, simply place volatility-2.1.standalone.exe into a folder and open a command prompt window. From the command prompt, navigate to the location of the executable file and type “volatility-2.1.standalone.exe –f <FILENAME> –profile=<PROFILENAME> <PLUGINNAME>” without quotes – FILENAME would be the name of the memory dump file you wish to analyse, PROFILENAME would be the machine the memory dump was taken on and PLUGINNAME would be the name of the plugin you wish to use to extract information.
Note: In the example above I am using the ‘connscan’ plugin to search the physical memory dump for TCP connection information.
The Sleuth Kit is an open source digital forensics toolkit that can be used to perform in-depth analysis of various file systems. Autopsy is essentially a GUI that sits on top of The Sleuth Kit. It comes with features like Timeline Analysis, Hash Filtering, File System Analysis and Keyword Searching out of the box, with the ability to add other modules for extended functionality.
Note: You can use The Sleuth Kit if you are running a Linux box and Autopsy if you are running a Windows box.
When you launch Autopsy, you can choose to create a new case or load an existing one. If you choose to create a new case you will need to load a forensic image or a local disk to start your analysis. Once the analysis process is complete, use the nodes on the left hand pane to choose which results to view.
FTK Imager is a data preview and imaging tool that allows you to examine files and folders on local hard drives, network drives, CDs/DVDs, and review the content of forensic images or memory dumps. Using FTK Imager you can also create SHA1 or MD5 hashes of files, export files and folders from forensic images to disk, review and recover files that were deleted from the Recycle Bin (providing that their data blocks haven’t been overwritten), and mount a forensic image to view its contents in Windows Explorer.
Note: There is a portable version of FTK Imager that will allow you to run it from a USB disk.
When you launch FTK Imager, go to ‘File > Add Evidence Item…’ to load a piece of evidence for review. To create a forensic image, go to ‘File > Create Disk Image…’ and choose which source you wish to forensically image.
06 Linux ‘dd’
dd comes by default on the majority of Linux distributions available today (e.g. Ubuntu, Fedora). This tool can be used for various digital forensic tasks such as forensically wiping a drive (zero-ing out a drive) and creating a raw image of a drive.
Note: dd is a very powerful tool that can have devastating effects if not used with care. It is recommended that you experiment in a safe environment before using this tool in the real world.
Tip: A modified version of dd is available from
http://sourceforge.net/projects/dc3dd/ – dc3dd includes additional features that were added specifically for digital forensic acquisition tasks.
To use dd, simply open a terminal window and type dd followed by a set of command parameters (which command parameters will obviously depend on what you want to do). The basic dd syntax for forensically wiping a drive is:
dd if=/dev/zero of=/dev/sdb1 bs=1024
where if = input file, of = output file, bs = byte size
Note: Replace /dev/sdb1 with the drive name of the drive you want to forensically wipe and 1024 with the size of the byte blocks you want to write out.
The basic dd syntax for creating a forensic image of a drive is:
dd if=/dev/sdb1 of=/home/andrew/newimage.dd bs=512 conv=noerror,sync
where if = input file (or in this case drive), of = output file, bs = byte size, conv = conversion options
Tip: For additional usage info, from a terminal window, type “man dd” without quotes to bring up the help manual for the dd command.
CAINE (Computer Aided INvestigative Environment) is Linux Live CD that contains a wealth of digital forensic tools. Features include a user-friendly GUI, semi-automated report creation and tools for Mobile Forensics, Network Forensics, Data Recovery and more.
When you boot into the CAINE Linux environment, you can launch the digital forensic tools from the CAINE interface (shortcut on the desktop) or from each tool’s shortcut in the ‘Forensic Tools’ folder on the applications menu bar.
If you are investigating a case that requires you to gather evidence from a mobile phone to support your case, Oxygen Forensics Suite (Standard Edition) is a tool that will help you achieve this. Features include the ability to gather Device Information (Manufacturer, OS Platform, IMEI, Serial Number, etc.), Contacts, Messages (Emails, SMS, MMS, etc.) and recovery of deleted messages, Call Logs, and Calendar and Task information. It also comes with a file browser which allows you to access and analyse user photos, videos, documents and device databases.
When you launch Oxygen Forensic Suite, hit the ‘Connect new device’ button on the top menu bar to launch the Oxygen Forensic Extractor wizard that guides you through selecting the device and type of information you wish to extract.
Free Hex Editor Neo is a basic hex editor that was designed to handle very large files. While a lot of the additional features are found in the commercial versions of Hex Editor Neo, I find this tool useful for loading large files (e.g. database files or forensic images) and performing actions such as manual data carving, low-level file editing, information gathering, or searching for hidden data.
Use ‘File > Open’ to load a file into Hex Editor Neo. The data will appear in the middle window where you can begin to navigate through the hex manually or press CTRL + F to run a search.
bulk_extractor is a computer forensics tool that scans a disk image, file, or directory of files and extracts information such as credit card numbers, domains, e-mail addresses, URLs, and ZIP files. The extracted information is output to a series of text files (which can be reviewed manually or analysed using other forensics tools or scripts).
Tip: Within the output text files you will find entries for data that resemble a credit card number, e-mail address, domain name, etc. You will also see a decimal value in the first column of the text file that, when converted to hex, can be used as the pointer on disk where the entry was found (i.e. if you were analysing the disk manually using a hex editor for example, you would jump to this hexadecimal value to view the data).
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