dd

Complete wiping of a USB drive

• Suppose we have a Kali live instance (with persistence) on our USB drive that we wish to completely wipe

# view the block devices
$ lsblk
...
sda           8:0    1  57.3G  0 disk 
├─sda1        8:1    1   4.3G  0 part /media/user/Kali Live
├─sda2        8:2    1     1M  0 part /media/user/xxxx-xxxx
└─sda3        8:3    1    53G  0 part /media/user/persistence
...

# unmount the partitions
$ sudo umount /dev/sda1 /dev/sda2 /dev/sda3

# erase filesystem signatures: prevents any form of data corruptions, and other related issues
$ sudo wipefs -a /dev/sda

# wipe the data in the device
$ sudo dd if=/dev/zero of=/dev/sda bs=4M status=progress

a. wipefs

• -a, -all: erase all available signatures

b. dd

• if=FILE: read from FILE instead of stdin

  • if=/dev/zero simply reads from /dev/zero (produces as many null characters (0x00) as needed)

• of: write to FILE instead of stdout

  • of=/dev/sda simply writes to the specified /dev/sda block device

• bs=BYTES: read and write up to BYTES at a time