UltraVnc and UAC

[Step]

Hello,

Yes, another question related to UAC.

I've tested several cases but it seems there is only one solution to be able to interact with elevated windows when UAC is enabled : Winvnc as a service

Am i right ?

[Rudi De Vos]

yes

But,

You can also start winvnc with "runas admin" in application mode.
This allow to interact with UAC windows, but i'm not sure if you can press the UAC accept button.

[Step]

I tried to launch winvnc as admin (i read this here previously) but if I can see the UAC windows, I can't click.

Is this the normal behaviour ?

[Rudi De Vos]

*You A) a system windows that is protected bu UAC
*the popup B) that ask permission

B) Always require a service, the popup window is started on a secure desktop ( like the winlogon) and an application doesn't have permission
to interact with a secure desktop, this priviledge is for services

If winvnc is started with "runas admin" you should be able to interact with A) , this only works if someone already openend the window for you
as you can't see and click UAC accept button.

[Step]

Ok, now I understand the difference between the protected window (A) and the UAC popup (B). I didn't understand that there are 3 modes.

In summary when is UAC is enabled :
- With winvnc in user mode (Application mode), we can use the distant computer with only user rights. We can't see nor interact with program which need admin rights.
- With winvnc in admin mode (Application mode), we can use the distant computer, see the UAC popup, (B) but need a real user in front of it to click. They we can interact with the elevated window (installer, system settings...)
- With winvnc as a service (Service mode), we have the full control of the computer (we can click yes/no on the UAC popup)