Evidence Acquisition Techniques & Tools

Evidence acquisition is crucial in digital forensics, involving the meticulous collection of data from various sources to ensure its authenticity and legal admissibility.

1. Forensic Imaging

Forensic imaging involves creating an exact, bit-by-bit copy of storage media, essential for preserving the original state of data. Tools for forensic imaging include:

• FTK Imager: Allows creation of perfect disk copies, viewing and analyzing data without alteration.

• AFF4 Imager: Open-source tool supporting multiple file systems with compressed imaging capabilities.

• DD and DCFLDD: Unix-based command-line utilities; DCFLDD includes forensic-specific enhancements like hashing.

• Virtualization Tools: Used to acquire images from virtual environments, often through snapshots.

Example: Imaging with FTK Imager

1. Select File > Create Disk Image.

2. Choose the source (Physical/Logical Drive) and specify the destination.

3. Set image type, fragmentation, and compression, then Start.

4. After imaging, FTK Imager verifies and summarizes the results.

Example: Mounting Disk Image with Arsenal Image Mounter

1. Run Arsenal Image Mounter as admin.

2. Mount the image as read-only to maintain integrity.

3. The image appears as a drive, e.g., D:\.

2. Extracting Host-based Evidence & Rapid Triage

Host-based evidence includes artifacts from operating systems like Windows, generated by application execution, file modifications, and user activity. Evidence acquisition is categorized by data volatility:

• Volatile Data: Captured from active memory and includes live memory contents, often containing traces of malware.

  • Memory Acquisition Tools:

    • WinPmem: Open-source memory capture tool for Windows.

    • DumpIt: Simple tool for Windows/Linux memory dumps.

    • MemDump: CLI tool capturing system RAM.

    • Magnet RAM Capture: Free memory capture tool from Magnet Forensics.

• Non-volatile Data: Persists on disk and includes registry entries, Windows Event Logs, and system or application artifacts.

Example: Memory Acquisition with WinPmem

C:\Users\X\Downloads> winpmem_mini_x64_rc2.exe memdump.raw

Rapid Triage with KAPE

KAPE (Kroll Artifact Parser and Extractor) accelerates evidence collection by gathering essential artifacts.

1. Targets: Define the data to collect, stored as .tkape files in the KAPE\Targets directory.

2. Execution:

   • Set source (D:\) and destination paths.

   • Use gkape.exe (GUI) to configure options and start the collection.

3. Results include $MFT and other system directories in the output directory.

Remote Collection with EDR & Velociraptor

• EDR Solutions: Facilitate remote evidence gathering, with capabilities for searching across networks.

• Velociraptor: Uses VQL queries and Hunts to gather artifacts like Windows.KapeFiles.Targets.

3. Extracting Network Evidence

Network evidence analysis is foundational for SOC analysts, involving tools and data sources that capture and interpret network traffic.

• Traffic Capture: Tools like Wireshark and tcpdump capture packets to analyze network communication.

• IDS/IPS Systems: IDS (Intrusion Detection Systems) detect, while IPS (Intrusion Prevention Systems) detect and block suspicious activity.

• Traffic Flow Data: Tools like NetFlow provide high-level traffic behavior insights.

• Firewall Logs: Offer information on attempted exploits and unauthorized access attempts.