*** This bug is a security vulnerability ***

You have been subscribed to a public security bug by Seth Arnold (seth-arnold):

Basically I installed ubuntu 18.04.1 LTS on an old machine (on a blank
SSD), and when I just when had finished the configuration installing
just a few apps, I thought I had seen the admin's user password during
Power Off (in the boot text screen that blinks) - as it's an old
computer I could see this text blinking.

I didn't even use this machine.

After some tests, I found out that after performing these steps:
 - turning the machine on, logging into admin user
 - logging off the admin user
 - logging in a non admin user
 - logging off the non admin user
 - logging in back to the admin user

By running `sudo cat /dev/tty1` I could see everything which was typed
in the login screen. And that is the content that appears during the
power off text screen.

For more info, please see https://askubuntu.com/questions/1114802

The steps I can remember while setting up this machine were:
 - changing region to Portuguese (brazil) and configuring keyboard
 - installing Gweled, Pitivi, VLC, Spotify and SuperTuxKart through 'Ubuntu 
Software'
 - installing Google Chrome and Skype by downloading their deb packages from 
the official websites
 - uninstalled Thunderbird
 - updated everything

As you can see in the AskUbuntu question, I tried to simulate this by
repeating these steps in a virtual machine, but was not able to
reproduce it. One difference is that this is a HP Pavilion old laptop
with all sorts of things on it, so many drivers may be needed which will
not be present in the VM. I booted with 4.15.0-29-generic and it behaved
the same. However, during the session booting with the 4.15.0.29
recovery mode, I could not detect that sympton!

I'll keep this machine for a few days, but then I'll reinstall
everything, if it persists, I'll update here.

```
uname -a
Linux spider 4.15.0-45-generic #48-Ubuntu SMP Tue Jan 29 16:28:13 UTC 2019 
x86_64 x86_64 x86_64 GNU/Linux
```

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: gnome-screensaver (not installed)
ProcVersionSignature: Ubuntu 4.15.0-45.48-generic 4.15.18
Uname: Linux 4.15.0-45-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.5
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Sat Feb  2 13:38:45 2019
InstallationDate: Installed on 2019-01-30 (2 days ago)
InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
SourcePackage: gnome-screensaver
Symptom: security
Title: Screen locking issue
UpgradeStatus: No upgrade log present (probably fresh install)

** Affects: gnome-screensaver (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug bionic
-- 
After switching users, I can see the passwords in /dev/tty1
https://bugs.launchpad.net/bugs/1814388
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which is subscribed to the bug report.

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