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Remote Assistance and UAC prompts

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Recently, I received some e-mail sent to one of our internal DLs describing an issue a customer is facing when using Remote Assistance:

My customers engineer requests to connect to a user’s machine via remote assistance.

The user accepts and the engineer requests to take control.

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The user ticks the box to allow the engineer to respond to UAC prompts – then selects Yes.

However – this change requires admin rights and the user is prompted for admin credentials (which they obviously don’t have)

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Is there a way to work around this?

Why, yes! Enter UIAccess.

The way Remote Assistance “remote control” feature works is through an OS feature called UIAccess, which allows the app the ability to control the desktop programmatically. By combining this with RDP/TS, Remote Assistance is able to provide the “remote control” feature.

However, in order for this to work properly in scenarios that prompt for elevation (i.e. UAC prompt), you have to enable a certain group policy:

User Account Control: Allow UIAccess applications to prompt for elevation without using the secure desktop

What this will do is it will enable Remote Assistance to show the UAC prompt on the user’s desktop, as opposed to the secure desktop. If you don’t enable this, the user being helped (call him novice) will get the prompt on his local machine – so the expert cannot interact with it since RA will only remote out the user’s desktop. At that point, the novice may not know what to do with it, and/or he may not have the administrator password. So it is important that you enable this group policy in order to have the UAC prompt show up in the user’s desktop and have RA remote out this dialog to the expert’s machine.

However, there was a bug with RA and how it determined where to show the UAC prompt. However I’m happy to say that my team fixed this bug recently, and you can now download a hotfix that should fix this issue.

You can download this hotfix here: https://support.microsoft.com/kb/2614066 (“Black screen during a Remote Assistance session in Windows Vista, in Windows Server 2008, in Windows 7, or in Windows Server 2008 R2”)

Comments

  • Anonymous
    May 08, 2012
    The comment has been removed
  • Anonymous
    May 10, 2012
    Hi SKahn, thanks for reading and posting!If you're seeing a black screen in the RA session regardless of UAC prompt interactions, it sounds like the issue you're facing is different, as the scenario described in this post is black screens resulting from the UAC prompt showing up on the secure desktop instead of showing up in the remoted desktop [when the appropriate group policies are applied].
  • Anonymous
    February 07, 2013
    The comment has been removed
  • Anonymous
    October 03, 2014
    This needs to be added to the Microsoft Update Catalog for ease of deployment.