Imagine that you are in the following situation:
- You have forgotten your password,
- Following a wrong manipulation you can not access to your personal space anymore,
- You found a computer without supervision.
With a bootable USB key on Ubuntu, you can change the password of the target computer and recover its file system.
First, plug your USB drive into the target computer, choose your key as the boot device for the target computer to boot to the Ubuntu system on your USB drive. On a DELL computer, press
F12 to access this selection. This information is visible on the welcome screen of the manufacturer of your computer.
Start by choosing the following option:
Then select the
You access a device as a
If you need to access the internet, select the network entry before. To verify that you have access to the web you can ping 18.104.22.168 on the Google DNS server, then make nslookup 22.214.171.124 to check that the DNS resolution works. If that does not work, add this line nameserver 126.96.36.199 to the file /etc/resolv.conf (this will be deleted when you restart the computer) and restart your service network-manager with service network-manager restart.
For the moment the file system is only in
read only, type the following command to mount the file system in
read / write at the root of your key:
mount -o remount, rw /
Now you can copy the file system to an external hard drive, and then you can choose the new user password by typing:
If you do not know the users on this machine, you can do ls /home. Certainly a user of this machine corresponds to a directory name in /home/, or even view the file /etc/passwd, or else you can create a user as you are root.
Type in the new password and confirm.
You can shut down the computer.
shutdown -h now
You can now turn on the computer normally and log in with the chosen user and password.
Beware the morality of this article is that a person physically accessing your computer does not need login /password to access your computer. If you want to protect yourself from this attack, you must encrypt your hard drive.
Well done !