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Asked: 2018-12-11 08:56:55 +0800 CST

Ctrl + Alt + Del prior to Windows 10 logon no longer needed?

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I was running Windows 7 at work; power up the desktop pc and always had to hit Ctrl + Alt + Del before entering your username and password.

I am now running Windows 10 at work, Windows 10 Enterprise if I look on my PC. I no longer have to hit Ctrl + Alt + Del before logging in, and I am pretty sure it is not just me.

Is the existing link with rationale explained no longer relevant with Windows 10? What changed?

Is this no longer relevant? : How does CTRL-ALT-DEL to log in make Windows more secure?

Update:

From Interactive logon: Do not require CTRL+ALT+DEL:

Not having to press CTRL+ALT+DEL leaves users susceptible to attacks that attempt to intercept the users' passwords. Requiring CTRL+ALT+DEL before users log on ensures that users are communicating by means of a trusted path when entering their passwords... A malicious user might install malware that looks like the standard logon dialog box for the Windows operating system, and capture a user's password. The attacker can then log on to the compromised account with whatever level of user rights that user has.

I am having trouble understanding this rationale for Ctrl + Alt + Del I mean if a malicious user installs malware that looks like the standard logon screen shouldn't I first be worried about that having happened where malware got installed? Can someone at least provide examples of those attacks user's are left susceptible to?

For so long we've all be marching to the tune of must do Ctrl + Alt + Del prior to logon, and ironically it is worded "Interactive logon: Do not require CTRL+ALT+DEL = Disabled".

Recently NIST revised their password recommendations, I believe it's publication 800-63B. As such, you can read numerous articles and opinions on the subject. My favorite is Stack Overflow cofounder Jeff Atwood's rage: password rules are b.s.. I don't need to go much further than that title to summarize that topic, basically admission that some password rules were security theater. So now I am sort of questioning the credibility of Ctrl + Alt + Del, because (1) it seems it was suddenly dropped in Windows 10, and (2) to me the [official] wording from Microsoft is quite vague.

If you use any computer you are susceptible to attacks in a variety of ways, so I am looking for technical specifics that I can wrap my head around regarding Ctrl + Alt + Del providing value prior to logon.

windows

2 Answers

  1. Aaron Margosis who writes for the Microsoft Security Guidance blog on TechNet addressed this specifically a couple of times regarding the change to "Not Configured" for Secure Attention Sequence aka Ctrl Alt Del. It basically boils down to the fact that users can't tell if they're at the secure desktop, it's easier to steal the same user credentials inside the desktop, and it's hard to implement on keyboard-less devices.

    Changes from the Windows 8.1 baseline to the Windows 10 (TH1/1507) baseline (20151118)
Aaron Margosis November 18, 2015

Enforcement of Ctrl+Alt+Del at logon to protect credentials from theft.

    "This is not particularly strong protection. First, it depends on a user that’s looking at a spoofed logon screen remembering that he or she hadn’t pressed Ctrl+Alt+Del before typing a password. Second, so many apps prompt the user for the same credentials on the user’s desktop that the credentials can easily be stolen there. Third, if the adversary has gained administrative control of the computer, the “secure desktop” is no longer a protected space. Finally, with devices offering more keyboard-free logon experiences such as facial recognition, Ctrl+Alt+Del becomes an annoying interference."

    from "Security baseline for Windows 10 – DRAFT" by Aaron Margosis, October 8, 2015

    "[Aaron Margosis] Great question. One is the increase in systems where a Secure Attention Sequence (SAS) isn't feasible. Second is that the SAS has probably been a very low-value protection, overall. See the discussion about a setting where we made it possible to go overboard on the SAS and how that didn't really work out well:"

    from Unintended Consequences of Security Lockdowns

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  2. It's still in force, but Microsoft did that to make the device more accessible to people with disability.

    You can easily enforce back the default ctrl-alt-del key combo.

    Microsoft developed this feature to make it easier for users with certain types of physical impairments to log on to device running the Windows operating system; however, not having to press the CTRL+ALT+DELETE key combination leaves users susceptible to attacks that attempt to intercept their passwords. Requiring CTRL+ALT+DELETE before users log on ensures that users are communicating by means of a trusted path when entering their passwords.

    GPO : Disable CTRL+ALT+DEL requirement for logon at

    Computer Configuration\Windows Settings\Security Settings\Local Policies\Security Options

    Reference there

    ps; If the windows 10 is under a workgroup, you can change that setting in the control panel in the advanced tab of the user management applet.

    Edit 1 - As your question evolved

    In Windows OS, WinLogon register the crtl-alt-delete sequence, and allow no one else to listen to that. It's called a Secure Attention Key.

    A malware would need to modify or hijack the winlogon process to achieve the goal to capture that sequence.

    The sequence is considered secure and the process do launch the login prompt.

    Per the official documentation;

    When Winlogon initializes, it registers the CTRL+ALT+DEL secure attention sequence (SAS) with the system, and then creates three desktops within the WinSta0 window station.

    Registering CTRL+ALT+DEL makes this initialization the first process, thus ensuring that no other application has hooked that key sequence.

    WinSta0 is the name of the window station object that represents the physical screen, keyboard and mouse. Winlogon creates the following desktops in the WinSta0 object.

    You could also see that answer there for the same reason told; https://security.stackexchange.com/questions/34972/whats-the-rationale-behind-ctrl-alt-del-for-login

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