https://en.wikipedia.org/wiki/Secure_attention_key
And you're right, this needs to be a default part of any login handler. Why don't we use it when logging into a Linux console? The login prompt could easily be spoofed by a user-mode program.
On the VT100 terminals in the computer lab in college (back in the early 90s) someone was doing this. A shell script to harness logins, print it was unsuccessful and log out. .
There was a key at the top of the vt-100 keyboard that would reset it. The "key" part was often pried off (accidental pressing was bad), but you could still press the nub left behind.
Oh, and the VAX-11/780 I had hacked into crashed due to a memory board fault in the minute after I had logged in with my snagged admin password. I spent the remainder of the weekend sweating that I had broken the VAX since I had no idea what had happened. I had just given myself all 32 of the VMS account privileges when it went down.
Wait.... What?
Nice job decoding that.
My guess would be that you did using the microfiche reader at your university or at a library. Before digitization, such devices were fairly common wherever people had a lot of text to archive.
(Aside: https://en.wikipedia.org/wiki/Microform even has a photo of a “DuKane brand microfiche reader with source code printed on the films.”. I couldn’t read enough of the text on the envelope to decide whether that is true from the photograph
30 or so years later I bought a huge stack of DEC microfiche on eBay so I could still do it if I wanted. I don't have equipment to read it though.
Not sure how distributions tend to configure it by default.
sudo dumpkeys | rg --only-matching '=.*' | sort | uniq
If you want to test it then this will set Ctrl-Alt-Esc as your SAK:
echo "control alt keycode 1 = SAK" | loadkeysDepending on configuration, this can be prevented with noexec mount, selinux or SMACK. Grsecurity and RSBAC can prevent unwanted exec.
Systems like apparmor, or grsecurity MAC, TOMOYO or YAMA do not work against executing wrong executables.
IMA (signing and verifying files) can work too.
All bets are off in case there is a local root exploit in kernel or any setuid app.
Keyloggers can still enter the winlogon session and log all keystrokes there, they need to run as a SYSTEM service, but it's very possible to do.
I'm surprised this isn't better documented, but it's pretty much as simple as copying the token from the existing Winlogon process, adjusting the privileges appropriately and calling CreateProcessAsUser() with lpDesktop set to Winsta0\Winlogon.
That makes their threat a moot point...
Any system that relies on humans to do the right thing is doomed to failure. Even something as trivial as hitting three keys each and every time they login; part of the problem with it is that it is so inconsistent (i.e. different Windows machines either do or do not prompt for the key-combination based on their configuration, so users have a mental model of skipping it).
Some of us don't want to use TouchID so, no, it shouldn't.
If yes, this feels utterly nonsensical. They would be able to grab your fingerprint from the sensor anyway, whether you are actively using it or not...
Alternatively you might be spreading some weird conspiracy theory that instead of securely storing a "hash" of the fingerprint on a HSM, current touchid implementations are secretly sharing your fingerprints with Apple.
That's not really any less nonsensical.
Do you just not use the home button?
If your fingerprint gets compromised, you CANT change your finger (erm... probably. I dunno of any easy way in any case)
Biometrics have value for identity verification (username) when used in conjunction with a password
Windows didn’t use this for anything until NT in the early 90s, and it was their choice to do so. Nothing to do with IBM.
When people ask Gates about Ctrl-Alt-Del they’re obviously asking about why it was chosen for a login sequence, but I believe Gates conveniently answers a different question to make it seem like IBM had something to do with that choice.
For example, how do you handle compromise (I suspect fingerprint mills / printers are not ubiquitous just because there is no demand for fake fingerprints; technologically they should be easy to make). Also, do you really want a unique match every time you log in from different devices (e.g., work and home); etc., etc.
Sorry, fingerprint solution may be worse than the disease it is trying to cure.
If you have access to the hardware, that's a whole different attack vector.
I think that even that is catchable (if needed), at least on old Windows XP Embedded, if you used minlogon (which happened very often) you lost ctrl+alt+del access to Task Manager, but there was a third-party service to restore the "hook":
http://www.mp3car.com/forum/mp3car-technical-software/softwa...
Anyway there are other ways, here is one:
http://www.oblita.com/interception.html
about midpage there is a sample to "intercept and block" the sequence.
No idea anyway (since the topic is on iOS) how that OS would behave and what could be the equivalent of a Ctrl+Alt+Del key sequence on a keyboardless device such as a iPhone or iPad.
Unfortunately operating system developers are not considering this attack. But they certainly can defend if they want.