What is the essential tool to prevent alteration of evidence when imaging a drive?

• A. Use a write-blocker
• B. Run Windows in Safe Mode
• C. Install antivirus
• D. Use a network sniffer

Answer: (A)

Preventing alteration of evidence during imaging hinges on blocking all writes to the source drive. A write-blocker sits between the drive and the forensic workstation and provides read-only access, so imaging software can read every sector without making any changes to the original drive. This guarantees the evidence remains intact, allowing the produced image to be a faithful copy. With a write-blocker, you can compute and compare hashes on the image and the source to verify that no modifications occurred, including changes to metadata, slack space, or hidden data that could be triggered by normal OS activity.

Other approaches like Safe Mode, antivirus, or a network sniffer don’t offer the same guaranteed protection against writes to the disk during imaging, so they don’t ensure the same level of evidentiary integrity.