Here are 20 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.
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The most essential tool for sysadmins:
- Automate multiple OS patching
- Scan for vulnerabilities
- Audit hardware and software
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Discover, manage and secure your network
- Monitor & control web activity
- Manage bandwidth & internet usage
- Secure downloads & web browsing
- Control of applications & stronger policy
This is by no means an extensive list and may not cover everything you need for your investigation. You might also need additional utilities such a file viewers, hash generators, and text editors – checkout 101 Free Admin Tools for some of these. My articles on Top 10 Free Troubleshooting Tools for SysAdmins, Top 20 Free Network Monitoring and Analysis Tools for Sys Admins and Top 20 Free File Management Tools for Sys Admins might also come in handy since they contain a bunch of tools that can be used for Digital Forensic Investigations (e.g. BackTrack and the SysInternals Suite or the NirSoft Suite of tools).
Even if you may have heard of some of these tools before, I’m confident that you’ll find a gem or two amongst this list.
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).
Bulk_extractor comes as a command-line tool or a GUI tool. In the example above I set the bulk extractor tool to extract information from a forensics image I took earlier and output the results to a folder called “BE_Output”. The results can then be viewed in the Bulk Extractor Viewer and the output text files mentioned above.
DEFT is another Linux Live CD which bundles some of the most popular free and open source computer forensic tools available. It aims to help with Incident Response, Cyber Intelligence and Computer Forensics scenarios. Amongst others, it contains tools for Mobile Forensics, Network Forensics, Data Recovery, and Hashing.
When you boot using DEFT, you are asked whether you wish to load the live environment or install DEFT to disk. If you load the live environment you can use the shortcuts on the application menu bar to launch the required tools.
Xplico is an open source Network Forensic Analysis Tool (NFAT) that aims to extract applications data from internet traffic (e.g. Xplico can extract an e-mail message from POP, IMAP or SMTP traffic). Features include support for a multitude of protocols (e.g. HTTP, SIP, IMAP, TCP, UDP), TCP reassembly, and the ability to output data to a MySQL or SQLite database, amongst others.
Once you’ve installed Xplico, access the web interface by navigating to http://<IPADDRESS>:9876 and logging in with a normal user account. The first thing you need to do is create a case and add a new session. When you create a new session you can either load a PCAP file (acquired from Wireshark for example) or start a live capture. Once the session has finished decoding, use the navigation menu on the left hand side to view the results.
I briefly touched on LastActivityView when pointing out the NirSoft suite of tools in my Top 10 Free System Troubleshooting Tools for SysAdmins article. LastActivityView allows you to view what actions were taken by a user and what events occurred on the machine. Any activities such as running an executable file, opening a file/folder from Explorer, an application or system crash or a user performing a software installation will be logged. The information can be exported to a CSV / XML / HTML file. This tool is useful when you need to prove that a user (or account) performed an action he or she said they didn’t.
When you launch LastActivityView, it will immediately start displaying a list of actions taken on the machine it is being run on. Sort by action time or use the search button to start investigating what actions were taken on the machine.
The Digital Forensics Framework (DFF) is a digital forensic investigation tool and a development platform that allows you to collect, preserve and reveal digital evidence. Amongst others, DFF’s features include the ability to read RAW, EWF and AFF forensic file formats, access local and remote devices, analyse registry, mailbox and file system data and recover hidden and deleted files.
When you launch DFF, you first need to load an evidence file (i.e. a forensic image you acquired previously) or open a device ready for analysis. You can then process the evidence file or device against one of the in-built modules to begin analysing data.
RedLine offers the ability to perform memory and file analysis of a specific host. It collects information about running processes and drivers from memory, and gathers file system metadata, registry data, event logs, network information, services, tasks, and Internet history to help build an overall threat assessment profile.
When you launch RedLine, you will be given a choice to Collect Data or Analyze Data. Unless you already have a memory dump file available, you’ll need to create a collector to gather data from the machine and let that process run through to completion. Once you have a memory dump file to hand you can begin your analysis.
PlainSight is a Live CD based on Knoppix (a Linux distribution) that allows you to perform digital forensic tasks such as viewing internet histories, data carving, USB device usage information gathering, examining physical memory dumps, extracting password hashes, and more.
When you boot into PlainSight, a window pops up asking you to select whether you want to perform a scan, load a file or run the wizard. Enter a selection to begin the data extraction and analysis process.
HxD is one of my personal favourites. It is a user-friendly hex editor that allows you to perform low-level editing and modifying of a raw disk or main memory (RAM). HxD was designed with easy-of-use and performance in mind and can handle large files without issue. Features include searching and replacing, exporting, checksums/digests, an in-built file shredder, concatenation or splitting of files, generation of statistics and more.
From the HxD interface start your analysis by opening a file from ‘File > Open’, loading a disk from ‘Extras > Open disk…’ or loading a RAM process from ‘Extras > Open RAM…’.
HELIX3 is a Live CD based on Linux that was built to be used in Incident Response, Computer Forensics and E-Discovery scenarios. It is packed with a bunch of open source tools ranging from hex editors to data carving software to password cracking utilities, and more.
Note: The HELIX3 version you need is 2009R1. This version was the last free version available before HELIX was taken over by a commercial vendor. HELIX3 2009R1 is still valid today and makes for a useful addition to your digital forensics toolkit.
When you boot using HELIX3, you are asked whether you want to load the GUI environment or install HELIX3 to disk. If you choose to load the GUI environment directly (recommended), a Linux-based screen will appear giving you the option to run the graphical version of the bundled tools.
NetSleuth is a network forensics analysis tool that identifies devices on your network. It operates in ‘live’ mode (where it will actively capture network packets and interpret device information) or in ‘offline’ mode where it will process a PCAP file that you import.
Note: At the time of writing, NetSleuth is in BETA. It is not recommended that you run this in a production environment. It made this list because it promises to be a handy addition to your forensic toolkit. The author of this tool is currently asking for feedback from the community so now is your chance to contribute!
When you launch NetSleuth, you can either initiate a ‘live’ analysis from the Live Capture tab, or load a PCAP file from the Offline Analysis tab. Once NetSleuth has identified at least one device, you can double click on it to open the Device Information window.
P2 eXplorer is a forensic image mounting tool that allows you to mount a forensic image as a physical disk and view the contents of that image in Windows Explorer or load it into an external forensic analysis tool. P2 eXplorer supports images in RAW, DD, IMG, EX01, SMART and SafeBack format, amongst others.
When you launch P2 eXplorer, choose an available drive letter to mount the image to and click ‘File > Mount Image…’ to choose the image to mount. Once the image has been mounted, double click on the associated drive letter to view the contents of that image in Windows Explorer.
Tip: In Top 20 Free Disk Tools for SysAdmins I mentioned another image mounting tool called OSFMount. OSFMount is very similar to P2 eXplorer but also supports the mounting of VMWare files and the creation of RAM disks. Part of the OSFMount family is a digital forensics suite called OSForensics – the freeware version of this application is available for personal, educational or home use to allow you to experiment and become acquainted with digital forensics concepts.
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