Understanding the adversary and stopping them in their tracks
How do you “carve a file”?
File carving in cybersecurity is a technique used to recover and extract files or data from a storage medium, such as a hard drive, solid-state drive, or memory card when the file system or metadata is damaged, corrupted, or unavailable. This process is often employed in digital forensics and incident response to retrieve valuable information from compromised or damaged devices.
How does file carving work?
Here’s how file carving works:
- Header and Footer Signatures: File carving tools look for specific header and footer signatures or markers that indicate the beginning and end of a file. These signatures are unique to certain file types (e.g., PDF, JPEG, DOCX), allowing the tool to identify the boundaries of files even when file system structures are missing or damaged.
- Data Fragmentation: When files are deleted or storage media is damaged, file fragments may be scattered throughout the storage medium. File carving tools are designed to identify and piece together these fragments to reconstruct complete files.
- File Reconstruction: Once the header and footer of a file are identified, the carving tool attempts to extract and reconstruct the file by combining the data fragments found between these markers. This process may involve reordering and reassembling the fragments.
- File Validation: After reconstruction, file carving tools may perform validation checks to ensure the integrity and correctness of the recovered file. Validation checks can include checking for the appropriate file size, verifying file checksums, and examining the internal file structure.
When can cybersecurity professionals use file carving?
File carving is a valuable technique for various cybersecurity and forensic scenarios, including:
- Data Recovery: It can be used to recover data from damaged or formatted storage media.
- Digital Forensics: Investigators use file carving to extract evidence from compromised systems when file system metadata has been intentionally or unintentionally tampered with.
- Incident Response: In cybersecurity incidents, file carving can help recover malicious files or artifacts left by attackers, aiding in the investigation and attribution process.
- File System Analysis: It can be used to analyze file systems to identify hidden or deleted files that may contain critical information.
It’s important to note that while file carving is a powerful technique, it may not always produce perfect results. The extracted files may be incomplete or corrupted, and their original file names and directory structures may not be recoverable. Nevertheless, it remains a crucial tool in the toolkit of cybersecurity professionals and digital forensic experts for data recovery and analysis in challenging situations.
Want to try out file carving?
Why not take a pick from this list of tools that you can use?
- Scalpel (Linux/macOS)
- PhotoRec (Linux/macOS/Windows)
- Foremost (Linux/macOS)
- R-Studio (Linux/macOS/Windows)
- EnCase Forensics (Windows)