Incident Response & Digital Forensics

Disk Forensics & Imaging

  • May 9, 2025
  • 0

Sherlocked Security – Disk Forensics & Imaging

Uncover the Evidence on the Storage Media – A Deep Dive into Hard Drive and Storage Device Analysis for Cybersecurity Investigations

1. Statement of Work (SOW)

Service Name: Disk Forensics & Imaging
Client Type: Enterprises, SaaS Providers, FinTech, Government Agencies, Incident Response Teams
Service Model: On-Demand Engagement & Retainer Support
Compliance Alignment: NIST 800-53, ISO/IEC 27001, PCI-DSS, SOC 2, GDPR, HIPAA

Disk Forensics & Imaging Covers:

  • Data Recovery (Deleted Files, Partitions)
  • Malware Artifacts on Storage Media
  • File System Analysis (NTFS, FAT, EXT, APFS)
  • File Carving and Extraction
  • Volume Shadow Copy and Backup Analysis
  • Disk Imaging & Preservation (Bit-by-bit Copies)
  • Investigating Rootkits, Ransomware, and Other Malicious Activity

2. Our Approach

[Preparation] → [Disk Imaging] → [File System Analysis] → [Data Carving] → [Malware & Artifact Detection] → [Incident Documentation] → [Forensic Reporting] → [Remediation Guidance]

3. Methodology

  • Pre-Incident Setup: Setup forensic tools and environment for capturing and analyzing disk images.
  • Disk Imaging: Securely capture a bit-for-bit image of suspect storage devices to preserve data integrity.
  • File System Analysis: Analyze the file system to recover deleted files, check metadata, and examine directory structures for evidence of tampering.
  • Data Carving: Use advanced carving techniques to recover deleted files that may have been overwritten or partially corrupted.
  • Malware Detection: Scan the disk image for malware artifacts, rootkits, and ransomware remnants.
  • Root Cause Analysis: Identify the attack vector by analyzing disk artifacts, logs, and file system anomalies.
  • Incident Documentation: Build a timeline of events based on file system metadata, timestamps, and recovered data.
  • Forensic Reporting: Generate a report with evidence, IOCs, and recommendations for incident response.
  • Remediation Guidance: Advise on prevention strategies based on the attack findings, including file system hardening and malware mitigation.

4. Deliverables to the Client

  1. Disk Image: A bit-for-bit copy of the suspect storage device (external hard drives, SSDs, cloud storage, etc.) securely preserved.
  2. Forensic Disk Analysis Report: A detailed report documenting the analysis, including recovered files, timestamps, and findings.
  3. Indicators of Compromise (IOCs): Extracted hashes, IP addresses, file paths, and other relevant IOCs.
  4. Malware Artifacts: Identification and documentation of malware found on the disk, including rootkits and ransomware.
  5. Recovered Files & Data: Extracted files and data recovered from deleted or corrupted sectors.
  6. Timeline of Events: A reconstructed timeline of activities based on file metadata and recovered evidence.
  7. Recommendations for Remediation: Suggestions for blocking similar attacks in the future, such as strengthening access controls and improving file integrity monitoring.

5. What We Need from You (Client Requirements)

  • Suspected System Storage Devices: Hard drives, SSDs, USBs, or any storage device from which data needs to be extracted.
  • Access to Internal IT/Security Teams: For coordination during the collection of evidence and to ensure data preservation.
  • Initial Incident Information: Information regarding the suspected incident, including potential attack vectors or indicators of compromise.
  • Secure Environment: Ensure that the forensic workstation or environment used for disk analysis is isolated and protected to avoid contamination.
  • Chain of Custody Documentation: Proper tracking of the storage devices and the imaging process.

6. Tools & Technology Stack

  • Disk Imaging Tools:
    • FTK Imager
    • dd (Linux tool for creating bit-for-bit images)
    • X1 Social Discovery (for cloud and social media analysis)
    • Guymager (for Linux-based forensic imaging)
  • File System Analysis:
    • Autopsy (digital forensics platform)
    • EnCase (disk and file system analysis tool)
    • The Sleuth Kit (TSK)
    • X-Ways Forensics (file system analysis)
  • Data Carving & Recovery:
    • PhotoRec
    • Scalpel (file carving tool)
    • R-Studio (data recovery)
  • Malware Detection:
    • VirusTotal (for file hash checks)
    • YARA (for signature-based malware detection)
    • Volatility (for memory forensics, if applicable)
    • Custom Malware Analysis Tools (based on requirements)

7. Engagement Lifecycle

  1. Client Onboarding & Initial Briefing
  2. Disk Imaging & Evidence Preservation
  3. File System & Malware Analysis
  4. Data Recovery & Carving
  5. Root Cause Identification
  6. Incident Reporting & Event Timeline Construction
  7. IOC Documentation & Malware Artifacts
  8. Remediation Advice & Actionable Recommendations
  9. Post-Incident Playbook Updates

8. Why Sherlocked Security?

Feature Sherlocked Advantage
Forensic-Grade Disk Imaging Bit-for-bit imaging to preserve evidence without tampering.
Advanced Data Carving Techniques Recover deleted, corrupted, or hidden files with precision.
Malware Detection Expertise In-depth expertise in finding and analyzing malware artifacts on storage media.
File System Integrity Checks Assess file system structures for signs of tampering, unauthorized access, and data manipulation.
Holistic Forensic Analysis Cross-discipline approach combining disk forensics, memory analysis, and malware detection.
Tailored Remediation Advice Provide specific steps to prevent future attacks and harden disk-based storage systems.

9. Real-World Case Studies

Ransomware Attack on Financial Institution

Issue: Financial systems were compromised, and files were encrypted.
Findings: Disk analysis revealed a ransomware strain that left behind encrypted files and traces of the malware executable.
Outcome: The infected machine’s disk image was preserved, and ransomware remnants were analyzed. The root cause was identified as a phishing email that allowed initial access. Recommendations were provided to improve email security and backup strategies.

Insider Threat in Healthcare Organization

Client: Healthcare provider with sensitive patient data.
Findings: An internal employee was suspected of accessing confidential patient records. Disk forensics revealed unauthorized file transfers and timestamps that aligned with the employee’s actions.
Outcome: A full investigation was conducted, and the exfiltrated data was recovered from the disk. Access logs were used to track the timeline of events, and the individual’s access was revoked.

10. SOP – Standard Operating Procedure

  1. Disk Imaging: Acquire a bit-for-bit copy of the suspect storage device to preserve evidence.
  2. Evidence Preservation: Ensure proper chain of custody documentation is followed, and storage media is safely handled.
  3. File System Integrity Check: Examine the file system for signs of tampering, unauthorized access, or malware.
  4. Data Carving: Recover deleted or corrupted files using carving tools to identify evidence of attack or data exfiltration.
  5. Malware Artifact Analysis: Analyze any suspicious files or malware artifacts found on the disk.
  6. Root Cause Analysis: Reconstruct the attack timeline using file system metadata, timestamps, and logs.
  7. Incident Report: Create a detailed report outlining the findings, timeline, IOCs, and recommended mitigation actions.
  8. Remediation Guidance: Advise on measures to strengthen disk security and prevent future incidents.

11. Disk Forensics & Imaging – Readiness Checklist

1. Pre-Incident Setup

  • [ ] Forensic Imaging Tools Ready: Ensure imaging tools (FTK Imager, dd, etc.) are configured and operational.
  • [ ] Secure Environment Setup: Set up isolated systems for handling and analyzing disk images.
  • [ ] Chain of Custody Procedure: Define processes for ensuring proper evidence handling and documentation.
  • [ ] Incident Response Plan: Ensure disk forensics is included in your IR plan and team is trained on the procedure.

2. During Disk Forensics

  • [ ] Disk Image Acquired: Perform a bit-for-bit image of the storage device using trusted tools.
  • [ ] File System Analysis: Check the integrity of the file system for signs of manipulation or unauthorized access.
  • [ ] Data Recovery & Carving: Attempt to recover deleted or partially overwritten files.
  • [ ] Malware Analysis: Identify and analyze any suspicious files or malware artifacts present on the disk.
  • [ ] Timeline Construction: Build an attack timeline using recovered files, metadata, and logs.

3. Post-Analysis Response

  • [ ] IOC Documentation: Share relevant IOCs discovered during the analysis with threat intelligence platforms and detection systems.
  • [ ] Malware Remediation: Provide advice on blocking detected malware and improving system defenses.
  • [ ] File System Hardening: Recommend steps to improve file system security and integrity.
  • [ ] Report Generation: Create a comprehensive forensic report with findings, recommendations, and remediation steps.

4. Continuous Improvement

  • [ ] Incident Review: Perform a post-incident review to integrate lessons learned into the response playbook.
  • [ ] System Monitoring: Implement better monitoring tools for disk activity and file system integrity.
  • [ ] Training & Awareness: Conduct regular training on disk forensics and data recovery techniques.
eDiscovery Support
Artifact Hunting & IOC Extraction