Preserving the Data
To ensure the original hard drive is never modified, forensic examiners create a perfect, bit-by-bit copy, or forensic image, of the disk.
Write Blockers
Before imaging, a hardware or software write blocker is used to ensure the forensic workstation cannot accidentally write data back to the original evidence drive, preserving its integrity.
Imaging Tools
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dd(Disk Dump): A powerful, native Linux command used to create raw forensic images. bashExample to copy disk /dev/sda to image.dd
dd if=/dev/sda of=/mnt/evidence/image.dd bs=4M status=progress
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FTK Imager (Forensic Toolkit Imager): A popular free tool on Windows that creates forensic images in common formats (like E01) and automatically calculates cryptographic hashes during the acquisition process.