Published: 16 February 2024
Contributors: Annie Badman, Amber Forrest
Digital forensics is the process of collecting and analyzing digital evidence in a way that maintains its integrity and admissibility in court.
Digital forensics is a field of forensic science. It is used to investigate cybercrimes but can also help with criminal and civil investigations. For instance, cybersecurity teams may use digital forensics to identify the cybercriminals behind a malware attack, while law enforcement agencies may use it to analyze data from the devices of a murder suspect.
Digital forensics has broad applications because it treats digital evidence like any other form of evidence. Just as officials use specific processes to gather physical evidence from a crime scene, digital forensics investigators follow a strict forensics process (also known as a chain of custody) when handling digital evidence to avoid tampering.
Digital forensics and computer forensics are often referred to interchangeably. However, digital forensics technically involves gathering evidence from any digital device, whereas computer forensics involves gathering evidence specifically from computing devices, such as computers, tablets, mobile phones and devices with a CPU.
Digital forensics and incident response (DFIR) is an emerging cybersecurity discipline that integrates computer forensics and incident response activities to accelerate the remediation of cyber threats while ensuring that any related digital evidence is not compromised.
Digital forensics, or digital forensic science, first surfaced in the early 1980s with the rise of personal computers and gained prominence in the 1990s.
However, it wasn’t until the early 21st century that countries like the United States formalized their digital forensics policies. The shift toward standardization resulted from the rise of computer crimes in the 2000s and the nationwide decentralization of law enforcement agencies.
With more crimes involving digital devices—and more individuals involved in prosecuting those crimes—officials needed procedures to ensure criminal investigations dealt with digital evidence in a way that was admissible in a court of law.
Today, digital forensics is only becoming more relevant. To understand why, consider the overwhelming amount of digital data available on practically everyone and everything.
As society continues to rely more on computer systems and cloud computing technologies, individuals continue to conduct more of their lives online across an ever-increasing number of devices, including mobile phones, tablets, IoT devices, connected devices, and more.
The result is more data—from more sources in more formats than ever before—that investigators can use as digital evidence to analyze and understand a growing range of criminal activity, including cyberattacks, data breaches, and criminal and civil investigations.
Additionally, like all evidence, physical or digital, investigators and law enforcement agencies must collect, handle, analyze and store it correctly. Otherwise, data may be lost, tampered with or rendered inadmissible in court.
Forensics experts are responsible for performing digital forensics investigations, and as demand for the field grows, so do the job opportunities. The Bureau of Labor Statistics estimates computer forensics job openings will increase 31 percent through 2029 (link resides outside ibm.com).
The National Institute of Standards and Technology (NIST) (link resides outside ibm.com) outlines four steps in the digital forensic analysis process.
Those steps include:
Identify the digital devices or storage media containing data, metadata or other digital information relevant to the digital forensics investigation.
For criminal cases, law enforcement agencies will seize the evidence from a potential crime scene to ensure a strict chain of custody.
To preserve evidence integrity, forensics teams make a forensic duplicate of the data using a hard drive duplicator or forensic imaging tool.
After the duplication process, they secure the original data and conduct the rest of the investigation on the copies to avoid tampering.
Investigators comb through data and metadata for signs of cybercriminal activity.
Forensic examiners can recover digital data from various sources, including web browser histories, chat logs, remote storage devices, deleted space, accessible disk spaces, operating system caches and virtually any other part of a computerized system.
Forensic analysts use different methodologies and digital forensic tools to extract data and insights from digital evidence.
For instance, to uncover "hidden" data or metadata, they might use specialized forensic techniques, like live analysis, which evaluates still-running systems for volatile data, or reverse steganography, which exposes data hidden using steganography (a method for concealing sensitive information within ordinary-looking messages).
Investigators may also reference proprietary and open-source tools to link findings to specific threat actors.
Once the investigation is over, forensic experts create a formal report that outlines their analysis, including what happened and who may be responsible.
Reports vary by case. For cyber crimes, they might have recommendations for fixing vulnerabilities to prevent future cyberattacks. Reports are also frequently used to present digital evidence in a court of law and shared with law enforcement agencies, insurers, regulators and other authorities.
When digital forensics emerged in the early 1980s, there were few formal digital forensics tools. Most forensics teams relied on live analysis, a notoriously tricky practice that posed a significant risk of tampering.
By the late 1990s, the increased demand for digital evidence prompted the development of more sophisticated tools like EnCase and FTK, which allowed forensic analysts to examine copies of digital media without resorting to live forensics.
Today, forensic experts employ a wide range of digital forensics tools. These tools can be hardware or software-based and analyze data sources without tampering with the data. Common examples include file analysis tools, which extract and analyze individual files, and registry tools, which gather information from Windows-based computing systems that catalog user activity in registries.
Certain providers also offer dedicated open-source tools for specific forensic purposes—with commercial platforms, like Encase and CAINE, offering comprehensive functions and reporting capabilities. CAINE, specifically, boasts an entire Linux distribution tailored to the needs of forensic teams.
Digital forensics contains discrete branches based on the different sources of forensic data.
Some of the most popular branches of digital forensics include:
- Computer forensics (or cyber forensics): Combining computer science and legal forensics to gather digital evidence from computing devices.
- Mobile device forensics: Investigating and evaluating digital evidence on smartphones, tablets, and other mobile devices.
- Database forensics: Examining and analyzing databases and their related metadata to uncover evidence of cybercrimes or data breaches.
- Network forensics: Monitoring and analyzing data found in computer network traffic, including web browsing and communications between devices.
- File system forensics: Examining data found in files and folders stored on endpoint devices like desktops, laptops, mobile phones, and servers.
- Memory forensics: Analyzing digital data found in a device's random access memory (RAM).
When computer forensics and incident response—the detection and mitigation of cyberattacks in progress—are conducted independently, they can interfere with each other and negatively impact an organization.
Incident response teams can alter or destroy digital evidence while removing a threat from the network. Forensic investigators can delay threat resolution while they hunt down and capture evidence.
Digital forensics and incident response, or DFIR, combines computer forensics and incident response into an integrated workflow that can help information security teams stop cyber threats faster while also preserving digital evidence that might be lost in the urgency of threat mitigation.
2 major benefits of DFIR include:
- Forensic data collection happening alongside threat mitigation: Incident responders use computer forensic techniques to collect and preserve data while they’re containing and eradicating the threat, ensuring the proper chain of custody is followed and that valuable evidence isn’t altered or destroyed.
- Post-incident review including examination of digital evidence: In addition to preserving evidence for legal action, DFIR teams use it to reconstruct cybersecurity incidents from start to finish to learn what happened, how it happened, the extent of the damage and how similar attacks can be avoided.
DFIR can lead to faster threat mitigation, more robust threat recovery, and improved evidence for investigating criminal cases, cybercrimes, insurance claims and other security incidents.
DFIR combines two cybersecurity fields to streamline threat response while preserving evidence against cybercriminals.
Computer forensics involves gathering digital evidence from computing devices to ensure its admissibility in court.