Digital forensics leverages specialized techniques and tools to investigate various forms of computer-related crimes. Digital crimes may include network intrusion, illicit use, and many different forms of computer intrusions. On the other hand, the real aim of digital forensics is to present evidence exactly as it is on the system, in a way that can be replicated by following the exact same steps the forensic investigator took. Meanwhile, Forensic detectives have proficient techniques and tools that assist them with re-forming what occurred with a system. On account of these techniques, analysts can find how an attacker employed the system to perpetrate a crime. Given that, today we will talk about current tools and techniques in digital forensics heavily used during investigation of cybercrime. So, let’s get the ball rolling.
Tools in Digital Forensics
Let’s go through a few popular and most used digital forensics tools.
The Sleuth Kit
Essentially, the Sleuth Kit concentrates on the hard drive. Anyhow, it is not the only place where artifacts and forensic data can get stored on a machine. Critical forensic information is stored in RAM. For this reason, analysts must first collect artifacts from this volatile memory. It is the case since it must be forensically useful and valid.
TSK is a kit of command lines for system investigation, which explores through the records from the suspicious system without modifying anything on it. Also, this tool can show a point-by-point rundown of deleted and hidden files. It also bolsters different kinds of partitions, for example, Sun, Mac, BSD, DOS, etc. The only little drawback of this tool is that you need to remember all the commands.
An open-source digital forensic software called Autopsy is put to use heavily for carrying out hard drive investigations. Corporate investigators and government agencies use it to conduct digital investigations. Moreover, the military and law enforcement agencies leverage the tool as well. While it is available for both Linux and Windows, it comes pre-installed in Kali Linux.
It is a tool with a graphical UI and a browser. It’s not a standalone tool, it rather complements the command line digital investigation analysis tools in The Sleuth Kit. Together, they can analyze Windows and UNIX disks and file systems to investigate the evidence. Autopsy can examine various sorts of data configurations, for example, FAT, Ext2/Ext3, NTFS, and so forth. One of its strengths lies in the option to browse through all the image formats present on the system, as well as an option to keep your findings and IOCs in your central repository, so that you can leverage them in your other investigations. Additionally, it depends on HTML, which permits the connection with Autopsy’s server using an internet browser. Moreover, Autopsy’s interface named “File Manager” displays information on deleted data.
Like Autopsy, ProDiscover Basic has a GUI (graphical user interface) as well. Also, it is a free digital forensic tool. Without modifying any data, the tool intends to make replicas of the hard disk. It also allows to preview and search suspect files, reading the entire drive byte-by-byte and without altering any data or metadata. Besides, it allows for creating USB flash memory images, BIOS images, RAM images, and hard drive images. A user can analyze the evidence in detail as soon as the image is ready.
The SANS SIFT (Investigative Forensic Toolkit) is an Ubuntu-based live CD. It covers all the tools required to carry out an in-depth incident response investigation or forensic. It supports analysis of Advanced Forensic Format (AFF), RAW (dd) evidence formats, and Expert Witness Format (E01). SIFT incorporates tools such as log2timeline as well. It helps generate a timeline from system logs, Rifiuti for examining the recycle bin, Scalpel for data file carving, etc.
For the analysis of volatile memory, Volatility is the most well-known tool. Identical to the Sleuth Kit, Volatility is also open-source, free, and supports third-party plugins. The Volatility Foundation conducts a yearly contest to develop the most innovative and useful extension to users’ framework.
Techniques in Digital Forensics
Now, let’s go through some different digital forensic investigation techniques.
Preserving the Evidence
Forensic analysts can employe a tool called write blocker to make an exact copy of the original data. In essence, a write blocker prevents any device or program from making changes to original data. Hardware write blockers are used to create bit by bit copy of the disc. Also, forensic software write blockers can be used for the same purpose if hardware write blocker is not available, or as an extension. The commonly employed software tools include Encase, Forensic Toolkit (FTK), SIFT, etc.
Web Activity Reconstruction
It is a technique to get back browsing history, temporary internet files, and accepted cookies. It is helpful to use when a user removes them in order to plead plausible deniability.
File Signature Verification
It is a way to compare the header and footer information of suspicious files with already known files. Subsequently, files with matching signatures are most probably safe.
Network Device Investigation
An investigation is conducted involving all the logs kept by the network. Meanwhile, the probe includes routers, switches, and firewalls to investigate suspicious DNS requests, connections to unknown IPs or unexpected spikes in network activity. By the way, this kind of digital forensic investigation technique is intricate. It usually gets employed when logs of servers are unavailable for some reason.
Recovering Hidden Files
Forensic analysts use different methods of decryption, cryptanalysis and drive or image analysis to actively look for hidden data and files. The ultimate aim is to gain access to them.
Today we discussed some of the popular digital forensic tools and techniques. Nevertheless, companies are developing more advanced tools periodically as cybercriminals are turning advanced with their tactics. To get help along the same lines, take advantage of cybersecurity Forensics Services.