Debian - Reset Any User Password

Procedure:

1. Connect file system to another Debian machine

2. Mount file system and verify:

1. lsblk (find sdx1 device)
2. sudo mkdir /mnt/microsd
3. sudo mount /dev/sdx1 /mnt/microsd
4. ls /mnt/microsd

3. Open shadow file in nano

1. sudo nano /mnt/microsd/etc/shadow

4. The file is /etc/shadow, there will be lines like:

user:asdfasdfasdf$$$$asdfasdfasdfsadfasdf::17178:0:98899:7:::

5. You must remove the fist field between : and :

user:THIS_IS_WHAT_WAS_REMOVED:17178:0:98899:7:::

6. Unmount the file system from the rescue machine.

1. umount /mnt/microsd

7. Reconnect to target OS via serial.

8. Boot and login with root.

9. Change password with passwd.

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