Introduction to Digital Forensics

Practical Tools, Techniques & Analysis

Section 1 of 12

What is Digital Forensics?

Digital Forensics is the scientific process of collecting, analyzing, and reporting on digital data in a way that is legally admissible in court.

It involves applying scientific methods to identify, preserve, analyze, and present digital evidence from computers, networks, mobile devices, and other digital media.

Used in criminal investigations, corporate incident response, civil litigation, and internal corporate investigations.

The primary goal is to maintain evidence integrity while uncovering the truth about digital incidents.

Types of Digital Forensics

1

Computer Forensics

Analysis of desktop computers, laptops, servers, and storage media. Examines hard drives, SSDs, and file systems to recover deleted files, analyze user activity, and identify malicious software.

2

Mobile Forensics

Examination of smartphones, tablets, GPS devices, and wearables. Extracts call logs, SMS, app data, photos, location history, and deleted content from mobile devices.

3

Network Forensics

Investigation of network traffic and communication patterns. Captures and analyzes packet data to identify intrusions, data exfiltration, and unauthorized access attempts.

4

Memory Forensics

Examination of volatile memory (RAM) for running processes, malware, encryption keys, and passwords. Critical for analyzing live systems and advanced persistent threats (APTs).

5

Cloud Forensics

Analysis of data stored in cloud services (AWS, Azure, Google Cloud, Dropbox, etc.). Deals with unique challenges like multi-tenancy, distributed data, and reliance on cloud provider cooperation.

The Forensic Investigation Process

1

Identification

Recognize and determine what evidence is present. Identify devices, storage media, network logs, and other potential sources of digital evidence at the scene.

2

Preservation

Isolate, secure, and preserve the state of evidence. Use write-blockers, document the scene with photos, and ensure no modifications occur to the original evidence.

3

Collection & Acquisition

Create forensic copies (images) of digital evidence using specialized tools. Record cryptographic hashes to verify data integrity and document the chain of custody.

4

Examination

Process collected data using forensic tools to extract relevant information. Recover deleted files, parse system artifacts, and extract metadata.

5

Analysis

Interpret examined data, create timelines, correlate events, and draw conclusions. Determine what happened, when it happened, who was responsible, and what data was affected.

6

Presentation & Reporting

Summarize findings in a clear, professional report. Present technical findings to non-technical audiences and prepare for potential court testimony.

Chain of Custody

What is it?

A documented chronological record that tracks the seizure, custody, control, transfer, analysis, and disposition of physical and electronic evidence.

Essential for maintaining evidence integrity and ensuring legal admissibility in court proceedings.

⚠️ Critical Rule:

Every single transfer of evidence must be documented with date, time, and the responsible party. A broken chain can make evidence inadmissible!

Key Elements to Document

1

Who Collected It

Name and role of the person who seized the evidence

2

When & Where

Date, time, and location of collection

3

Who Handled It

Everyone who has touched or accessed the evidence

4

Current Custody

Who currently has possession of the evidence

5

Storage Method

How and where the evidence was stored and secured

6

Any Modifications

Document any changes or actions performed on evidence

Legal Framework & Standards

ISO/IEC 27037:2012

International standard providing guidelines for identification, collection, acquisition, and preservation of digital evidence.

  • Covers handling of potential digital evidence
  • Provides best practices for first responders
  • Applicable to all types of digital devices

NIST Guidelines (SP 800-86)

National Institute of Standards and Technology provides comprehensive guides for computer forensics, data collection, and examination.

  • Detailed technical procedures for forensic processes
  • Tool testing and validation methodologies
  • Widely recognized in U.S. federal courts

Daubert Standard

Legal standard for admissibility of expert testimony and scientific evidence in U.S. federal courts.

  • Methods must be scientifically valid and testable
  • Techniques should be peer-reviewed and published
  • Known error rates must be considered
  • General acceptance within relevant community

Other Important Standards

ISO/IEC 27043 - Investigation principles and processes
RFC 3227 - Evidence collection and archiving
ACPO Guidelines - UK digital evidence principles
SWGDE - Scientific Working Group standards