What is Digital Forensics?

Digital forensics, a branch of forensic science, deals with the acquisition and analysis of digital evidence. This evidence is crucial in investigating cybersecurity incidents or other criminal activities, contributing to legal procedures and incident response efforts. 

Digital evidence can generally be classified into two main types: 

• Volatile data: Temporary data that is lost once the system is powered off. This data provides real-time information about the system and is usually collected first during digital forensics. Examples include Random Access Memory (RAM) contents, Central Processing Unit (CPU) cache data, and running processes. 
• Non-volatile data: Data stored in permanent mediums such as Hard Disk Drives (HDDs), Solid-State Drives (SSDs), and Non-Volatile Memory (NVM).  

Why is Digital Forensics Important? 

As our world becomes increasingly digital, attackers relentlessly exploit vulnerabilities in systems, making online criminal activity a pervasive threat. With criminal evidence increasingly residing on electronic devices, digital forensics has become a critical tool in combating cyber threats and cybercrime. These digital crimes encompass cybersecurity incidents and cyberattacks involving data breaches, unauthorised access, or disruptions to business operations. In the context of cybersecurity, digital forensics serves several purposes: 

Cyber Incident Investigation: Digital forensics plays a vital role in cybercrime investigations. Using specialised tools and techniques, investigators can identify attack sources, reconstruct incidents, and track down cybercriminals. 

Legal Purposes: During cybersecurity incidents, digital forensics ensures that digital evidence is preserved and intact. This is essential to prevent any loss or modification of evidence, which could compromise its admissibility in court. Evidence is necessary for auditors or legal authorities to: 

• Apprehend cybercriminals with documented evidence as justification. 
• Prove the organisation’s adherence to legal requirements and regulations, thereby avoiding or minimising penalties. 

Assist Incident Response Teams: Digital forensics works in synergy with incident response teams to enhance organisational defence strategies. Forensic analysis not only supports the remediation efforts of incident response teams but also provides insights used to refine the organisation’s incident response strategy. As cybersecurity incidents become increasingly advanced and challenging, organisations have formed Digital Forensics and Incident Response (DFIR) teams, consisting of specialists trained in both forensic investigation and incident response. This combined approach streamlines the process of incident response and forensics, giving DFIR teams a more comprehensive view of cybersecurity incidents. It helps eliminate inefficiencies that arise from communication between separate units and avoid situations where incident response teams delete or modify crucial evidence needed for digital forensics. 

Types of Digital Forensics 

There are various types of digital forensics, each focusing on different types of digital data for investigations. Some common types include: 

• Computer Forensics: Involves the recovery and analysis of data stored on computers, laptops, servers, and other storage media. 
• Network Forensics: Monitors and analyses network events or traffic to identify the source of cybersecurity incidents. 
• Mobile Device Forensics: Analyses electronic evidence extracted from mobile devices such as phones, digital cameras, tablets, or smartwatches. 
• Cloud Forensics: Involves recovery and investigation of data from cloud storage platforms and services. 
• Memory Forensics: Studies the volatile data found in devices’ RAM. 
• Database Forensics: Examines databases and their metadata to identify fraudulent transactions or the validity of transactions through timestamps. 
• Forensic Data Analysis: Involves analysing structured and unstructured data, often used for financial crime investigations. 

Stages of Digital Forensics 

Various frameworks outline the digital forensics process, each differing in how they break down the process into steps and terms. While methodologies differ, the fundamental stages remain consistent. Some digital forensics frameworks include the National Institute of Standards and Technology Special Publication 800-86 (NIST SP 800-86), Digital Forensic Research Workshop (DFRWS) Investigative Model, Abstract Digital Forensics Model (ADFM), and others. Organisations and investigators often refer to a model that suits their specific needs and adapt it as needed during investigations. According to the NIST digital forensics model, there are four main phases: 

Phase 1: Collection

Investigators identify and collect data from all possible sources relevant to the investigation. Proper handling of data is essential to ensure that the materials or information are not tampered with and are preserved well for legal and subsequent digital forensics purposes. The chain of custody documentation should be maintained to ensure data integrity. Digital forensics investigators may collaborate with incident response teams to align their containment efforts during cybersecurity incidents. 

Phase 2: Examination

The collected data is examined to retrieve needed information. Forensic tools and techniques are utilised in this stage to help investigators filter through large amounts of data and select those specific to the scope of the investigation. 

Phase 3: Analysis

In this stage, digital forensics investigators derive insights from the findings by correlating evidence and contextual details related to the cybersecurity incident. This process enables them to draw conclusions about critical aspects such as the extent of impact, timeline of events, involved stakeholders, and other pertinent information. 

Phase 4: Reporting

The final phase involves documenting and presenting the information for stakeholders who require the forensic report, such as legal authorities or internal management. The findings and conclusions are crucial for guiding the organisation in addressing identified weaknesses, refining incident response strategies, and enhancing overall cybersecurity defences against future incidents. 

Digital Forensics Techniques 

Investigators use various techniques during the digital forensics process to achieve different objectives and optimise their workflows. Some commonly used methods include: 

• Reverse Steganography: Extracts hidden data within digital files using tools like Steghide and Binwalk. These data could be messages embedded in picture files or data concealed within text documents. 
• Cross-Drive Analysis: Correlates data across multiple storage devices or hard drives to make sense of the evidence and discover insights. Tools such as EnCase and Forensic Toolkit (FTK) are often used in cross-drive analysis for their capabilities in disk imaging and analysis. 
• Live Analysis: Often used in memory forensics, it analyses a running system’s volatile data stored in RAM. Tools like Volatility can support this. 
• Stochastic Forensics: Focuses on statistical patterns to identify any signs of attack or threat that would otherwise not be detected, as these activities do not produce digital artefacts. 
• Network Traffic Analysis: Used in network forensics, it monitors and studies network traffic for any unusual activities or potential security threats. Tools like Wireshark are commonly used for this purpose. 
• Keyword Searching: In digital forensics, this involves using tools like Autopsy to search for specific keywords or phrases, which is particularly useful in extracting evidence from large datasets. 
• File System Analysis: Examines data within file systems, commonly using disk and data capturing tools like The Sleuth Kit (TSK). File system analysis is frequently used in data carving and deleted file recovery. 

Comprehensive Forensics and Investigation with Ensign 

Digital forensics involves many technical and procedural challenges. Investigators must possess the necessary expertise to effectively utilise tools for extracting and preserving relevant evidence. Time constraints add to the complexity, and even minor errors can have serious repercussions. 

Ensign’s Digital Forensic and Incident Response (DFIR) service ensures meticulous evidence preservation, providing trustworthy advisory services and reporting for authorities. We are here to support your organisation through emergencies with structure and assurance.