Digital evidence analysis is a careful process to uncover information stored on digital devices.
Core Process: Loading and Searching Digital Evidence
The analysis of digital evidence typically begins by creating a forensic image, which is an exact, bit-for-bit copy of the original data source (like a hard drive, USB drive, or mobile phone). This ensures the original evidence remains unaltered.
To analyze this image, the image is typically mounted by or 'loaded into' forensics software, such as FTK Imager from AccessData. Loading the image into specialized software allows forensic analysts to access and examine the data without making changes that could compromise the evidence's integrity.
Once the image is accessible within the software, the analysis usually involves searching various areas on the disk for evidence of malicious activity or presence of malware. This search is comprehensive, examining not just visible files but also hidden areas, deleted data, and system-specific information.
What Analysts Search For
Analysts use sophisticated tools to comb through the loaded digital evidence, looking for specific artifacts or pieces of data relevant to an investigation. The focus is often on reconstructing events and identifying actions performed on the device. This includes searching for:
- Files and Folders: Identifying suspicious documents, programs, or data created, accessed, or modified.
- Internet Activity: Examining web browsing history, search queries, downloaded files, and cached data.
- Communication Records: Analyzing emails, chat logs, and connection information.
- System Artifacts: Investigating logs, Windows Registry keys, event viewer data, and other system-generated information that records user and system actions.
- Hidden and Deleted Data: Recovering files that were intentionally hidden or deleted from the file system.
- Malware Indicators: Searching for known malware signatures, suspicious processes, or unauthorized system changes as mentioned in the reference.
Tools and Techniques
Forensic analysts rely on a suite of specialized software and techniques to perform these searches effectively. These tools can process vast amounts of data and perform tasks that manual examination could not.
Examples of common analysis tasks performed by forensic software include:
| Analysis Task | Description |
|---|---|
| Keyword Searching | Rapidly scanning the entire dataset for specific words or phrases. |
| File Carving | Recovering files based on their headers and footers, regardless of file system entries. |
| Timeline Analysis | Creating a chronological sequence of events based on file timestamps and logs. |
| Registry Analysis | Examining the Windows Registry for evidence of installed software, connected devices, and user activity. |
| Email Analysis | Parsing email files to extract sender, recipient, timestamp, and content information. |
Why Careful Analysis Matters
The integrity of digital evidence is paramount. By working on forensic images loaded into specialized software, analysts ensure that the original evidence is preserved. Every step of the analysis process is carefully documented to maintain a clear chain of custody and ensure the findings are admissible in legal proceedings. The goal is to extract accurate and reliable information that can help answer key questions about digital activities.
