Cfxtrjtrk

I recently used @Harsh 's mkusb instructions to successfully create an Ubuntu 18.04 live USB with persistence greater than 4 GB. The default user is Ubuntu and the default password is , that is to say blank (just hit enter).

Can I run the sudo passwd Ubuntu command and add an actual password to this live USB system? I want a password required on boot and on the lock screen as well. I don't know what issues this would present, if any. I do understand somebody could still mount my live USB system on another Linux machine, and have access to my files. My password requirement is a very low level of defense, that I'm comfortable with, and want.

Alternatively, could I simply delete the Ubuntu user, and add myself jason as the only user, create a password for jason, and be done with it?

Persistent live Ubuntu

• 
  

  I tested, and yes, you can remove the original ubuntu user after creating a custom user ID with a good password and admin (sudo) permissions.

  
  
  

  sudo add-apt-repository universe
  
  sudo apt update
  
  sudo apt install gnome-system-tools
  
  

  
  
  

  and you get a convenient tool to create a custom user,

  
  
  

  users-admin
  
  

  
  
  

  Remember the admin (sudo) permissions!

  
  

• 
  

  It is a good idea to set the permissions of your subdirectories (in your home directory) to only allow your own user to see them. And set the permissions for the files in a corresponding way.

  
  
  

  cd
  
  find * -type d -exec chmod 700 {} ;
  
  find * -type f -exec chmod 600 {} ;
  
  

  
  
  

  Using * instead of . excludes the hidden directories and files from these actions.

  
  

Test:

Logging in live-only, 'Try Ubuntu', does not give direct access to files saved in Documents. but the default ubuntu live has sudo permissions, and can access these files that way.

ubuntu@ubuntu:/media/ubuntu/casper-rw/upper/home/tester$ ls -l

total 44

drwx------ 2 1000 1000 4096 Jan 24 20:28 Desktop

drwx------ 2 1000 1000 4096 Jan 24 20:58 Documents

drwx------ 2 1000 1000 4096 Jan 24 20:28 Downloads

drwx------ 2 1000 1000 4096 Jan 24 20:28 Music

drwx------ 2 1000 1000 4096 Jan 24 20:28 Pictures

drwx------ 2 1000 1000 4096 Jan 24 20:28 Public

drwx------ 2 1000 1000 4096 Jan 24 20:28 Templates

drwx------ 2 1000 1000 4096 Jan 24 20:28 Videos

-rw------- 1 1000 1000 8980 Jan 24 20:27 examples.desktop

ubuntu@ubuntu:/media/ubuntu/casper-rw/upper/home/tester$ ls -l Documents/

ls: cannot open directory 'Documents/': Permission denied

ubuntu@ubuntu:/media/ubuntu/casper-rw/upper/home/tester$ sudo ls -l Documents/

total 8

-rw-r--r-- 1 1000 1000 7 Jan 24 20:54 hej

-rw-r--r-- 1 1000 1000 6 Jan 24 20:58 hi

ubuntu@ubuntu:/media/ubuntu/casper-rw/upper/home/tester$ cat Documents/hi

cat: Documents/hi: Permission denied

ubuntu@ubuntu:/media/ubuntu/casper-rw/upper/home/tester$ sudo cat Documents/hi

hello

ubuntu@ubuntu:/media/ubuntu/casper-rw/upper/home/tester$ 

Installed Ubuntu in a USB pendrive

• 
  

  If you want security it is much better to create an installed system in your USB pendrive, installed like into an internal drive (but into a pendrive). See the instructions at the following link:

  
  
  

  How do I install Ubuntu to a USB key? (without using Startup Disk Creator).

  
  



• If you wish, you can encrypt it (LVM with LUKS encryption). In that case, do it at the partitioning window during the installation.