Complete Digital Forensics Investigation Cheat Sheet

Introduction

Digital forensics is the scientific process of identifying, preserving, analyzing, and presenting digital evidence in a manner that is legally admissible in court. This field is critical for cybercrime investigations, incident response, litigation support, and corporate security breaches. Digital forensics professionals must maintain chain of custody, use validated tools, and follow established methodologies to ensure evidence integrity and legal admissibility.

Core Concepts & Principles

Fundamental Principles

• Preservation: Maintain original evidence integrity without alteration
• Identification: Locate and document all potential digital evidence
• Collection: Acquire evidence using forensically sound methods
• Analysis: Examine evidence to extract relevant information
• Documentation: Record all procedures, findings, and chain of custody
• Presentation: Communicate findings clearly to technical and non-technical audiences

Legal Framework

• Chain of Custody: Documented trail of evidence handling from collection to court
• Best Evidence Rule: Original evidence preferred over copies when possible
• Daubert Standard: Scientific reliability and relevance requirements for expert testimony
• Fourth Amendment: Search and seizure protections in criminal investigations
• GDPR/Privacy Laws: Data protection regulations affecting international investigations

Types of Digital Evidence

• Volatile Data: RAM, network connections, running processes (lost when power off)
• Non-Volatile Data: Hard drives, SSDs, USB devices, mobile devices
• Network Evidence: Logs, packet captures, firewall records
• Cloud Evidence: SaaS data, virtual machines, distributed storage
• Mobile Evidence: Smartphones, tablets, IoT devices

Step-by-Step Digital Forensics Process

Phase 1: Preparation & Planning

1. Obtain Legal Authorization – Search warrants, court orders, or written consent
2. Assess the Scene – Identify potential evidence sources and risks
3. Prepare Equipment – Forensic workstation, write blockers, imaging tools
4. Document Initial State – Photographs, diagrams, system configurations
5. Establish Communication Plan – Coordinate with legal team and stakeholders

Phase 2: Identification & Collection

1. Volatile Data Collection – Memory dumps, network connections, running processes
2. Live System Analysis – If shutdown risks data loss or system damage
3. Physical Evidence Seizure – Computers, storage devices, mobile phones
4. Power Down Procedures – Safe shutdown to preserve evidence
5. Evidence Packaging – Anti-static bags, tamper-evident seals, documentation

Phase 3: Preservation & Imaging

1. Write Blocking – Prevent accidental modification of original evidence
2. Bit-for-Bit Imaging – Create exact copies using validated tools
3. Hash Verification – MD5/SHA-256 checksums to verify image integrity
4. Multiple Copies – Working copy, master copy, backup copy
5. Storage Security – Encrypted storage, access controls, environmental protection

Phase 4: Analysis & Examination

1. Timeline Analysis – Reconstruct sequence of events using timestamps
2. File Recovery – Deleted file carving, unallocated space analysis
3. Keyword Searching – Targeted searches for relevant terms and phrases
4. Metadata Examination – File properties, EXIF data, system logs
5. Communication Analysis – Email, chat logs, social media activity
6. Malware Analysis – Identify malicious software and attack vectors

Phase 5: Reporting & Presentation

1. Technical Analysis Report – Detailed findings for forensic team
2. Executive Summary – High-level findings for management/legal team
3. Expert Testimony Preparation – Court presentation materials
4. Evidence Documentation – Complete chain of custody records
5. Case Archive – Secure long-term storage of evidence and reports

Key Tools & Technologies by Category

Forensic Imaging Tools

Analysis Platforms

Specialized Tools

• Mobile Forensics: Cellebrite UFED, Oxygen Detective, XRY Mobile
• Memory Analysis: Volatility, Rekall, WinDbg
• Network Forensics: NetworkMiner, Xplico, Security Onion
• Cloud Forensics: MSAB XRY Cloud, Magnet AXIOM Cloud
• Mac Forensics: BlackLight, OSXCollector, mac_apt

Free/Open Source Tools

• The Sleuth Kit (TSK): File system analysis
• Autopsy: Graphical interface for TSK
• SANS SIFT Workstation: Complete Linux forensics distribution
• Volatility: Memory forensics framework
• Wireshark: Network protocol analyzer
• Hashcat: Password recovery tool

Digital Evidence Types & Locations

Windows Systems

Linux/Unix Systems

Mobile Devices

File System Analysis Guide

File System Types

Timeline Analysis Artifacts

System Level:

• File system timestamps (Created, Modified, Accessed, Changed)
• Registry key timestamps
• Event log entries
• Prefetch file creation times

Application Level:

• Browser history timestamps
• Email sent/received times
• Document modification times
• Chat message timestamps

Network Level:

• Connection establishment times
• DNS query timestamps
• Firewall log entries
• Intrusion detection alerts

Common Challenges & Solutions

Technical Challenges

Challenge: Encrypted storage devices Solution: Live imaging if possible, password recovery tools, legal compulsion for passwords

Challenge: Anti-forensics techniques Solution: Multiple analysis methods, specialized tools, timeline correlation

Challenge: Large data volumes Solution: Targeted analysis, keyword filtering, automated processing tools

Challenge: Cloud evidence collection Solution: Legal process for service providers, API access, user consent

Challenge: Mobile device security Solution: Specialized extraction tools, exploit-based methods, SIM card analysis

Legal/Procedural Challenges

Challenge: Chain of custody documentation Solution: Detailed logs, photographs, witness signatures, tamper-evident packaging

Challenge: Cross-border investigations Solution: Mutual legal assistance treaties, international cooperation protocols

Challenge: Privacy law compliance Solution: Legal review, data minimization, jurisdictional analysis

Challenge: Expert testimony preparation Solution: Detailed documentation, peer review, continuing education

Best Practices & Pro Tips

Evidence Collection Best Practices

• Document everything – Photographs, diagrams, environmental conditions
• Use write blockers for all storage device connections
• Create multiple images – Working copy, master copy, court copy
• Verify image integrity using cryptographic hashes
• Maintain detailed chain of custody records
• Consider live imaging for encrypted or critical systems

Analysis Optimization

• Start with timeline analysis to understand sequence of events
• Use keyword lists developed from case facts and intelligence
• Correlate multiple evidence sources for comprehensive picture
• Focus on user activity – what did they do, when, and how
• Document negative results – what you didn’t find is also important
• Validate findings with multiple tools when possible

Professional Development Tips

• Stay current with technology trends and new tools
• Maintain certifications (EnCE, GCFA, CCE, etc.)
• Practice on test images and participate in forensic challenges
• Build standard operating procedures for common tasks
• Network with peers through professional organizations
• Document lessons learned from each case

Court Preparation Strategies

• Know your tools – capabilities, limitations, error rates
• Prepare visual aids – screenshots, timelines, diagrams
• Anticipate challenges to methodology and findings
• Use plain language to explain technical concepts
• Bring backup documentation for all claims and opinions

Quick Reference Commands

Linux/Unix Command Line

# Create forensic image
dd if=/dev/sda of=evidence.img bs=512 conv=noerror,sync

# Generate hash
md5sum evidence.img > evidence.md5
sha256sum evidence.img > evidence.sha256

# Mount read-only
mount -o ro,loop evidence.img /mnt/evidence

# File recovery
foremost -i evidence.img -o recovered/

# Memory analysis
volatility -f memory.dump --profile=Win7SP1x64 pslist

Windows PowerShell

# Get system information
Get-ComputerInfo | Out-File system_info.txt

# Export event logs
Get-WinEvent -LogName System | Export-Csv system_events.csv

# File hash calculation
Get-FileHash -Path evidence.img -Algorithm SHA256

# Network connections
Get-NetTCPConnection | Export-Csv connections.csv

Professional Certifications & Training

Industry Certifications

Training Resources

• SANS Institute: Comprehensive forensics training courses
• Guidance Software: EnCase certification programs
• AccessData: FTK and forensics training
• Cellebrite: Mobile forensics certification
• Local Universities: Graduate programs in digital forensics

Professional Organizations

• International Association of Computer Investigative Specialists (IACIS)
• High Technology Crime Investigation Association (HTCIA)
• Digital Forensics Research Workshop (DFRWS)
• Association of Digital Forensics, Security and Law (ADFSL)

Resources for Further Learning

Technical Resources

• NIST Computer Forensics Tool Testing: Tool validation and testing
• Digital Forensics Research Workshop: Academic research and methodologies
• SANS Reading Room: White papers and case studies
• Forensics Wiki: Community-maintained technical documentation

Legal Resources

• Digital Evidence and Electronic Signature Law Review: Legal precedents
• Electronic Crime Scene Investigation Guide: DOJ best practices
• Search and Seizure Manual: Legal procedures for digital evidence

Practical Learning

• Digital Corpora: Practice evidence images and scenarios
• Forensic Challenges: Monthly challenges from various organizations
• Capture The Flag (CTF): Digital forensics competitions
• Incident Response Exercises: Hands-on scenario training

Industry Publications

• Digital Investigation Journal: Peer-reviewed research
• Forensic Focus: Industry news and technical articles
• SANS Digital Forensics Blog: Current techniques and tools
• Volatility Labs Blog: Memory forensics research

Last Updated: May 2025 | This cheatsheet reflects current digital forensics practices and emerging technologies in cybersecurity investigations.