How To: Use Vista's UAC Feature To Avoid Always Requiring Admin Rights (Channel 9)

Windows Vista's UAC feature is designed to minimize security risks by running most applications under a standard user token, lessening the risk that an attacker could gain admin rights to the machine. This is a great step forward for users, but it may leave developers wondering what to do when their apps do really need admin rights to complete a task.

Ian Griffiths to the rescue, with another screencast showing how to structure an app to enable certain admin tasks to run in an elevated context.

Be sure to also check out the UAC team's blog.

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jmazner

Jun 29, 2006 at 1:52 PM

Details on CoCreateInstanceAsAdmin and how to use the elevate moniker are here. It boils down to this:

Elevation:Administrator!new:{guid}
jmazner

Jun 29, 2006 at 1:56 PM

Here's the snippet from the RGS files to register the COM component correctly for elevation:

HKCR
{
  NoRemove CLSID
{
  ForceRemove {8E29BED3-2E02-49DC-A9B7-3A5984BCD95F} = s 'CanElevateWork Class'
  {
   ProgID = s 'CanElevate.CanElevateWork.1'
   VersionIndependentProgID = s 'CanElevate.CanElevateWork'
   ForceRemove 'Programmable'
   InprocServer32 = s '%MODULE%'
   {
    val ThreadingModel = s 'Apartment'
   }
   val AppID = s '%APPID%'
   'TypeLib' = s '{25CA48AF-1D18-4A9F-9749-7354C41CDCEC}'
   Elevation
   {
       val Enabled = d 1
   }
   val LocalizedString = s '@%MODULE%,-101'
  }
}
}

HKCR
{
NoRemove AppID
{
  '%APPID%' = s 'CanElevate'
  {
      val DllSurrogate = s ''
  }
  'CanElevate.DLL'
  {
   val AppID = s '%APPID%'
  }
}
}
larry_lai

Jul 31, 2006 at 2:28 AM

Hi jmazner,

Can we have your sample codes for reference?

Thanks,
Larry
djmitchella

Jul 31, 2006 at 4:22 PM

Not directly related to the content, but I'm wondering how you made that recording? The video has footage of the UAC desktop -- isn't that meant to be secure and inaccessible to normal applications like screen grabbers -- did you point a camera at your monitor, or is there some other way for apps to "see" that they're at the UAC desktop?

I know you can try things like OpenInputDesktop(0,FALSE,0) and watch for failure to know if the secure desktop is up, but that's the opposite, that's _failing_ to get the desktop, not capturing images of it..
sintaxasn

Oct 03, 2006 at 4:45 AM

Hi Guys,
I'm having a really tough time trying to implement the elevated COM method under VB.NET. I'm not an API guru, but need to be able to migrate some of my VB.NET utils for my company to use UAC.

I've managed to create my own custom control which implements the Shield icon via a SendMessage API call, but the actual UAC part, I'm really stuck on.

I've segmented out my Admin functions into COM classes, but am having a lot of difficulty figuring out how to use CoCreateAdminAsInstance through VB.NET.

There doesn't seem to be any sample code available for VB.NET so any help in explaining this to me, or assisting in any way would be greatly appreciated!

Thanks in advance, Dan.
eak

Nov 23, 2006 at 7:21 AM

The computer may restart when you add a manifest that has the Windows Vista extension to an .exe file or to a .dll file in Windows XP Service Pack 2 (SP2)

http://support.microsoft.com/Default.aspx?kbid=921337

Resolution
http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=463884&SiteID=1
robgarrett

Feb 20, 2007 at 7:25 AM

Check out this managed wrapper -:

http://robgarrett.com/cs/blogs/software/archive/2007/02/12/net-wrapper-for-com-elevation.aspx

Encapsulates all the hard stuff for non-C++ and non-COM developers.
VincentKao

Apr 11, 2007 at 1:18 AM

Hi jmazner,

Could I have your sample codes for reference?

Thank you,

Vincent Kao
SugarDaddy

May 16, 2007 at 12:36 PM

Hello,

That is an excellent video. Your help is very much appreciated. I noticed you have a video showing how to include the manifest with managed applications...

When I launch a "requireAdministrator" .NET app, it gives the ugly "Allow/Cancel" prompt instead of the nice "Continue/Cancel" prompt -- the consent prompt. But when I sign the file with an authenticode signature, it uses the consent prompt. However, I don't know how to specify the application name like you do in this COM elevation demo. Basically what I'm asking is how do you set the application / assembly name in a Managed app. I've tried the <assemblyIdentity> element in the uac.manifest, but it seems to have no effect. Any help? Thanks.
Jesp

Aug 30, 2007 at 1:16 AM

Hi jamazner,

Can I have your sample code for reference ?

Jesper Lin
IanG IanG

May 15, 2008 at 9:33 AM

"I'm wondering how you made that recording? The video has footage of the UAC desktop -- isn't that meant to be secure and inaccessible to normal applications like screen grabbers -- did you point a camera at your monitor,"

A bit late to be replying, but better late than never I suppose...

The video capture was done by a 2nd PC with a video capture card whose input was wired into the VGA output of my laptop.

So it was slightly higher tech than pointing a camera at the laptop, but it sort of has the same effect: it lets you grab exactly what's on screen, without falling foul of internal security barriers in the machine.

Ian Griffiths