Fans of classic police investigator shows on television understand the importance of the iconic yellow crime tape. It marks the boundary of a crime scene that restricts access to prevent contamination of the crime scene. Similarly, in the aftermath of a significant ransomware attack or data breach, it’s time for digital and forensic experts to step in and take over. Their role is akin to setting up a virtual crime scene tape and meticulously working to piece together the events that transpired into the crime. With cybersecurity incidents becoming a daily event in today’s digitally transformed world, the role of digital forensics and incident response teams (DFIR) has become highly respected and important, especially as part of a complete MDR solution that demands in-depth investigative capabilities. 

The Mission of a Digital Forensics Expert 

Just as defense in depth in cybersecurity layers multiple safeguards to protect against threats, a digital forensic expert’s investigation process is comparably in-depth and layered. In their quest to unravel the complexities of a cyber incident, these experts systematically sift through various layers of digital evidence that might include surface-level logs, system configuration files and archived data. Each layer peeled back reveals more about the sequence of events, the methods used by attackers, and potentially, their identities.  

Just as in police cases, the depth of the investigation will depend on the extent of the crime and the array of evidence. Digital forensics is not just about understanding the attacker’s methods to apprehend them, but carefully recording how an attack unfolded to bolster security defenses for the future. Much like how an actor portraying a police forensics detective on TV cannot replicate the genuine expertise required for the role, a DFIR team necessitates extensive training and expertise to perform their duties accurately. 

The Handling of Digital Evidence 

Police detectives go to great lengths to protect a crime scene. Evidence is handled wearing latex gloves and stored in isolated containers where they remain protected under lock and key to ensure that the evidence is not corrupted, else the evidence becomes inadmissible in a trial. Similarly, in digital crimes, the integrity of digital evidence is paramount. Forensic experts are required to verify the authenticity of evidence and provide testimony on the methods used for its collection and preservation. This scrupulous process ensures the evidence’s validity and accuracy for legal proceedings. Documenting and time-stamping interactions with the evidence by every individual involved establishes a clear chain of custody, crucial for its admissibility in court. 

What Constitutes Digital Evidence 

If a digital device is involved in an incident, then any piece of data present on an involved device is a potential source of evidence. That includes emails, text messages, photos, graphic images, video and audio files, digital documents, configuration files, databases, internet browsing history, you name it. The sheer amount of data that must be sifted through is one of the biggest challenges these forensic experts are faced with from the beginning. Just knowing where to begin can seem daunting to anyone unfamiliar with the process.  

Data Retrieval Challenges 

Then there is the task of prioritizing the capture of data as not all necessary information resides on hard disks or cloud storage. Much of the essential digital data is volatile and can be lost once a device is turned off. This includes data in CPU cache, RAM, temporary system files, swap files, ARP cache, and dynamic routing tables. Knowing how to prioritize data retrieval efforts and move swiftly is vital to prevent the loss of critical clues. 

Retrieving data from permanent drives also presents its own set of challenges. Investigators need efficient methods to locate specific files within extensive data repositories and archived backups. Many companies are required to encrypt sensitive data to remain compliant and accessing it necessitates specialized decryption tools and techniques. Additionally, the rise of hybrid and remote work complicates the process by necessitating the tracking of mobile devices and pinpointing remote access points. 

Other Challenges Endured by Investigators 

Like any experienced criminal, hackers and other digital threat actors know the importance of lying low and living off the land. While an arrogant criminal may leave a calling card in the movies, in real life, cybercriminals want to move throughout your network as inconspicuous as possible to avoid detection until it is too late. At times, finding the necessary digital evidence can be like finding a needle in a haystack.  

Eliminating digital evidence is significantly easier than concealing a physical crime scene. Common tactics include wiping devices, damaging data systems, or encrypting files to obscure their existence. Attackers may deploy rootkits for deep system access while staying undetected to maintain stealthy control. Polymorphic malware, which alters its code or signature with each infection, evades traditional detection methods. Additionally, attackers might alter or delete logs to remove traces of their actions and entry points or employ ransomware to encrypt evidence of their tracks comprehensively. 

Employing Specialized Tool Sets 

To do the job at hand requires specialized tools to find and extract the information they need to complete their investigations. Such tools include: 

• File recovery tools to recover deleted, corrupted, or inaccessible data. 
• Network analysis applications to capture and analyze network traffic and logs to identify abnormal traffic patterns or malicious activities.  

• Registry analysis tools to examine the Windows registry for information about installed programs, user activities and system settings. 
• Database analyzers to query, extract and analyze information. 
• Email scanners and device scanners 

 
The importance of having the right tools cannot be overstated. Analogous to certain crimes needing resolution before leads grow cold, digital forensic experts adhere to a principle that the initial 72 hours are pivotal. Action must be taken swiftly within this critical period. While acquiring expertise and the necessary tools involves significant investment, it’s justified when considering that cybercrime inflicted a global cost of $8.5 trillion in 2023. In an era marked by an increasing frequency of cyberattacks, access to a skilled team equipped with the appropriate tools is invaluable. 

Conclusion 

It’s a reasonable assumption that your IT estate will continue to grow, as will the threat landscape targeting your business. Given that no cybersecurity tool can halt every attack, the role of DFIR (Digital Forensics and Incident Response) investigators becomes indispensable. These professionals must perpetually familiarize themselves with the latest technological advancements to effectively analyze and record evidence. It is not an easy job, but it is one that they are trained to do exceptionally well.