23 Nov
2011
23 Nov
'11
11:09 a.m.
On Tuesday 22 November 2011 10:47:12 pm Timothy
Pearson wrote:
Never heard of it, nor have I ever seen CTRL+ALT+Del in Linux
The problem boils down to the fact that I can make a perfect copy of the
login (or lock) screen, leave it running as a non-priviledged user (e.g.
on a public computer), and grab your password. There is no way for you to
know the real login screen from a good fake. The SAK allows the operating
system to reserve a secure keypress (in this case Ctrl+Alt+Del) that no
userspace application will ever be able to see, therefore preventing
emulation of the logon sequence before any passwords are typed.
Whenever
my screen locks (e.g. from my screen saver or from manually
locking) and I go to unlock, I'm told to press CTRL+ALT+Del, and it
says
it's displaying that so the login screen
doesn't get spoofed.
When logging out, I get a window saying it's saving my settings.
Both of these remind me of WinXP. The CTRL+ALT+Del thing is of WinNT
(XP
is based on NT).
Is there a way to turn this off?
Also, if the CTRL+ALT+Del thing is used for unlocking, why not too for
logging in?
It is normally used for both unlock and login. It is a generic
implementation of a Secure Attention Key (SAK), without which Linux is
actually less secure than Windows. The SAK support can be turned off in the KDM
control center module.
I don't see it anywhere under Login Manager or KDM Theme Manager. These
are the only two modules that show up when I type kdm into the search box
for kcontrol.