What is computer forensics?

Forensics, or digital forensics, refers to the set of digital analysis and investigation methods aimed at identifying, understanding, and documenting a security incident.
Its goal is to recover, preserve, and interpret the digital evidence left on information systems following a security breach, data theft, or intrusion.

This discipline combines technical expertise, methodological rigor, and legal validity.
Today, it is an essential pillar of cybersecurity, as it not only helps us understand how an attack occurred but also enables us to strengthen security to prevent it from happening again.

The Objectives of Forensic Investigation

The primary purpose of a forensic analysis is to:

• Identify the cause and method of the intrusion (phishing, vulnerability exploitation, compromised account, etc.)

• Assess the extent of the damage (leaked data, affected servers, attacker persistence)

• Collect and preserve digital evidence for internal, legal, or insurance purposes

• Reconstruct the timeline of events to understand how the attack unfolded

• Propose corrective and preventive measures to strengthen the system's resilience

A well-executed forensic investigation turns an incident into an opportunity for learning and continuous improvement of the security posture.

Key Steps in a Forensic Analysis

A digital investigation follows a rigorous and documented process, ensuring the reliability and value of the results.
The main steps are:

1. Preservation of evidence: Isolation of affected systems to prevent any data corruption.

2. Evidence collection: extraction of logs, system files, disks, RAM, and digital artifacts.

3. Technical Analysis: An in-depth examination of digital traces to identify attack techniques, the tools used, and the access points established.

4. Correlation and Timeline: Reconstructing the Attack Scenario and Identifying the Point of Entry.

5. Investigation Report: Summary of Technical Findings and Recommendations for Remediation.

This methodology is based on recognized standards (ISO/IEC 27037, NIST SP 800-86, and recommendations from ANSSI and CERT-FR).

Forensic Tools and Techniques

Forensic experts use a wide range of specialized tools and methods, including:

• Analysis of Disks and File Systems (Extraction, Signatures, Access Timeline)

• Memory (RAM) scan to detect traces of active processes or malware

• Review of system, server, and network logs

• Reconstruction of Sessions and User Activities

• Decryption and Recovery of Deleted Data

• Malware Analysis and Reverse Engineering

The Importance of Forensics in Incident Response

When an attack occurs, every minute counts.
Forensics enables incident response teams (CSIRTs) to quickly understand the nature of the incident, limit its spread, and identify any traces left behind by the attacker.

As part of continuous monitoring through the ITrust SOC, the forensic capabilities enable:

• respond effectively to a confirmed incident,

• document the detected indicators of compromise (IoC),

• and contribute to threat intelligence databases.

As a result, forensics is becoming both a strategic decision-making tool and a driver of cyber resilience.

The Legal and Strategic Value of Forensics

Beyond the technical aspect, digital forensics has a legal dimension:
the evidence collected can be used in the context of a complaint, an internal investigation, or a compliance audit.
It must therefore be preserved in accordance with strict protocols to ensure its integrity and admissibility in court.

But forensics isn't just reactive—it's also strategic.
Post-incident analyses help enhance security intelligence, adjust defense policies, and strengthen detection mechanisms.