Solution for ctrl-alt-del on Vista with UAC disabled

[jonclegg]

UltraVNC Users,

I have a fix for sending ctrl-alt-del sequences on Vista with UAC disabled. The trick is use the commercial SasLibEx library. It's quite easy to change the source code to work with that library. I have tested this on Vista and it works exactly as expected.

You can license the SasLibEx library from here:
http://www.remkoweijnen.nl/blog/2009/03 ... ows-vista/

Here is a diff of vnckeymap.cpp to use SasLibEx, this is all you need to change to make it work.

Index: vnckeymap.cpp
===================================================================
@@ -728,10 +731,11 @@
"Vista and runnning as system -> CAD\n");

// Try to run the special Vista cad.exe file...
- HANDLE ThreadHandle2;
- DWORD dwTId;
- ThreadHandle2 = CreateThread(NULL, 0, Cadthread, NULL, 0, &dwTId);
- CloseHandle(ThreadHandle2);
+// HANDLE ThreadHandle2;
+// DWORD dwTId;
+// ThreadHandle2 = CreateThread(NULL, 0, Cadthread, NULL, 0, &dwTId);
+// CloseHandle(ThreadHandle2);
+ DoSAS();
}
else if (vncService::VersionMajor()>=6)
{
@@ -828,3 +832,23 @@
SetShiftState(VK_MENU, FALSE);
}
}
+
+bool DoSAS()
+{
+ //init the library
+ static bool bdoneinit = false;
+ if (!bdoneinit)
+ {
+ if (!SASLibEx_Init()) {
+ return false;
+ }
+ bdoneinit = true;
+ }
+
+ //create CAD request on physical console
+ if (!SASLibEx_SendSAS(SAS_CONSOLE_SESSION)) {
+ return false;
+ }
+ return true;
+}
+

[aponjon]

All of your UAC settings are set to the defaults, so I don't know why that
option in netplwiz would be disabled?

If you have the Business version of Vista, you can simply use the same
option in secpol.msc to make the change.

In secpol.msc, go to Local Poilicies/Security Options and look for the
"Interactive logon: Do not require CTRL+ALT+DEL" policy. This policy is set
to "not defined" by default. If you set this policy to Disabled, this will
then require that CTRL+ALT+DEL to be required at logon.

--

Ronnie Vernon
Microsoft MVP
Windows Shell/User


"Bryan" <Bryan@discussions.microsoft.com> wrote in message
news:BA83F527-25F7-4D32-A07F-F5FAC89B549C@microsoft.com...
>I am running windows Vista Business on a new IBM t60 laptop. I still have
> the same behavior.
> UAC Settings
> UAC Admin approval Mode for Built-in Admin acount: disabled
> UAC Behavior of the elevation prompt for administrators: prompt
> UAC Behavior of elevation prompt for standard users: prompt
> UAC Detect application installation and prompt elevation: enabled
> UAC: Only elevate exe thta are signed: Disabled
> UAC Only elevate UIAcess application that are installed in secure
> location:
> enabled
> UAC: Run all administrators in Admin Approval Mode: enabled
> UAC Switch to secure desktop when prompting for elevation: enabled
> UAC Virtualize file and registry write failures to per user locations:
> enabled
>
>
>
> "Ronnie Vernon MVP" wrote:
>
>> Bryan
>>
>> If that box is not available, do you have User Account Control (UAC)
>> turned
>> off? If so, this could be the problem.
>>
>> Regardless, this will not help with what you want to do. Checking that
>> box
>> will simply display the message "Press CTRL+ALT+DEL to log on" on the
>> Welcome screen when you restart. When you press the keys, it will take
>> you
>> to the standard Welcome screen.
>>
>> --
>>
>> Ronnie Vernon
>> Microsoft MVP
>> Windows Shell/User
>>
>>
>> "Bryan" <Bryan@discussions.microsoft.com> wrote in message
>> news:2284E819-9BDD-4365-92EA-F9A4B0E43972@microsoft.com...
>> >I found this article,
>> > http://www.howtogeek.com/howto/windo...-logon-screen/
>> > which describes Open the Advanced User Accounts panel by typing in
>> > netplwiz
>> > into the start menu search box, and hitting enter. Then click the
>> > Advanced
>> > tab, and you’ll see an option for secured log on. There is a check box
>> > that
>> > says for added security you can require te user to press CTRL+ALT+DEL
>> > before
>> > logging on. I am logged in as an administrator and that option is
>> > greyed
>> > out. Any thoughts.


Magic-jack

[vexation]

Sooo.... what's the likelihood of this finding it's way to UltraVNC at some point? I'm guessing not likely due to it being a commercial library?

It's killing me not being able to easily access some Vista machines remotely.. the whole CAD not working with UAC enabled/disabled is an added complication considering I've (sometimes) no idea what other people have done to the computer.

Sure, there's always a way around it but I'm trying to make my own life a little easier.

[lwinstead]

What ways around it? It's been driving me nuts since Vista came out, and it seems every day I try to figure out another way to make it work, but I got NOTHING. Do you know something I don't? *frustrated*

[lwinstead]

Jeez, nevermind. Heh. I don't understand why I only figure these things out AFTER I post a question about them on the web. ...
Here's my "workaround":
1. Enable UAC
2. Don't touch the local security policy about requiring CTRL+ALT+DEL
3. Modify local security policy to NOT prompt for elevation for administrators (due to a couple custom applications, we require all users to be local admins... I know, not good)

The affect is that I can use CAD.exe to remotely control the Vista logon, and UAC is basically OFF for any admin account using that computer. Not perfect, and absolutely not the recommended way to do it, but it works for me. Thanks for listening!

[vexation]

What ways around it? It's been driving me nuts since Vista came out, and it seems every day I try to figure out another way to make it work, but I got NOTHING. Do you know something I don't? *frustrated*

Ah, I just wrote some scripts that.
1. Check that the RemoteRegistry service is running on the remote computer, if not, starts it.
2. Query HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Polices\System\EnableLUA to check the status of UAC on the remote machine, then gives you a choice to disable or enable UAC and then reboot the remote machine.
3. Can push UltraVNC+CAD.exe if necessary.

After which (assuming UAC is enabled) you should be able to CAD the Vista machine. Make whatever changes you need and then (if necessary) change UAC again and reboot. I just wish there was a way to enable/disable UAC without forcing a reboot, apparently you can change the key and then end explorer.exe and winlogon.exe but that's a pretty flaky method.

Of course my ultimate wish would now be for a genius UltraVNC developer to write a library similar to SasLibEx (already mentioned in this thread) which can bypass the need for UAC completely but considering this hasn't happened yet, I don't think it particularly likely.

Oh and this is all assuming you're a domain administrator for a network somewhere otherwise it isn't very helpful.

[greenbandit]

I am still unable to log on to my remote Vista based PC because sending CTRL+ALT+DEL does nothing.
UAC is on but I am not allowed to play around with its settings. While installing V1.0.8.2, it did ask if cad.exe was to be installed, but I cannot see it listed in Task Manager. Is this the reason why I still cannot logon using WinVNC?
The only work around I have is to use LogMeIn to send the CTRL+ALT+DEL (at least they managed to get it working) then fall back to (the much superior) UltraVNC to login and control the PC.
Its not that UltraVNC won't work once I'm logged in, it is just the CTRL+ALT+DEL aspect that stops me from being able to login.
Surely (says he being an unknowing non-programmer ) there must be a simple solution here.

[stage]

do you also have an anwser for a windows 7 user that wants this?

[SamuelVi]

do you also have an anwser for a windows 7 user that wants this?

http://softltd.com/simulate-ctrl-alt-de ... rver-2008/

Samuel

[B]

Oh I didn't realize this was a sticky thread.

I should add that ColtB45 contributed a completely <b>free and open source</b> solution to this issue a while back at [topic=17476][/topic]

(It still relies on cad.exe, which is not open sourced.)

[aircard]

do you also have an anwser for a windows 7 user that wants this?

http://softltd.com/simulate-ctrl-alt-de ... rver-2008/

Samuel

Didn't work for me,I'm windows 7 ultimate x64

[redge]

what the version of ultravnc do you use ?

Didn't work for me,I'm windows 7 ultimate x64

old ultravnc until 1.0.9.5 use cad.exe and require validation from external site verisign for check validity of certificate authenticity.
new ultravnc after 1.0.9.6 use native existing sas.dll on win7/2008r2 or downloaded for vista/2008r1

[SamuelVi]

do you also have an anwser for a windows 7 user that wants this?

http://softltd.com/simulate-ctrl-alt-de ... rver-2008/

Samuel

Didn't work for me,I'm windows 7 ultimate x64

Url was wrong, correct is
http://www.ospv.com/simulate-ctrl-alt-d ... rver-2008/

[kahoko]

For Windows 7 i just use the on screen keyboard. There is a little icon in the bottom left corner of the logon screen. Just click on that and enable the on-screen keyboard. Then you can do a ctrl-alt-del.

Kahoko