Solving LUA Problems with Avecto Privilege Guard

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Configuring applications to run with elevated privileges on-the-fly

Despite all the possible workarounds to launch an application or set of commands with elevated privileges from a standard user account, Windows doesn’t provide any built-in means of allowing system administrators to configure a particular application to launch as the currently logged in standard user, but with an administrative token. Consider a situation where you don’t have time to fix an application that won’t run as a standard user, but don’t want to grant administrative privileges just for the sake of one application. While it may be possible to start the application using a secondary logon, this is impractical in most cases.

Solving LUA problems with Avecto Privilege Guard

Privilege Guard is a third-party solution, from Microsoft Gold Partner Avecto, that allows system administrators to dynamically add or remove privileges by modifying the logged in user’s access token as it’s assigned to new processes. The client-side component, provided as an .exe or .msi file for GPSI deployment, is implemented as a user-mode service and supports Windows XP (or Windows Server 2003) and later. Privilege Guard is licensed on a trust model, so it doesn’t adhere to a strict object count in Active Directory.

Client settings are deployed with User or Computer Group Policy using a flexible architecture that separates policies, applications, messaging and access tokens. Programs can also be grouped together to minimize the number of policies applied.

Defining application groups

For each Application Group, you can define one or more programs using the following categories:

  • Executables
  • Control Panel Applets
  • Management Console snap-ins
  • Windows Installer Packages
  • Windows Scripting Host (WSH), PowerShell scripts and batch files
  • Registry Editor files
  • ActiveX controls (matched by URL or CLSID)

Application Templates can also be used to quickly locate built-in Windows tools such as Performance Monitor or System Restore. In the screenshot that follows, I used an Application Template to locate the Disk Management console (diskmgmt.msc) in Windows 7. The default setting is to match processes by file or folder name, but processes can also be matched by command line switch, file hash, publisher or any combination thereof. Privilege Guard supports matching by publisher certificate when Windows binaries are indirectly signed using Windows Security Catalogs.

Additional options include:

  • The ability to match processes if Privilege Guard detects that an application will trigger UAC.
  • To determine whether child processes spawned by the matched parent process inherit the privileges of the user’s modified access token.
  • To suppress elevated privileges on File Open/Save common dialogs to prevent users from modifying protected files.

Defining access tokens

We can define the rights allotted to access tokens in Privilege Guard based on the privileges assigned to Windows built-in groups. Rights can also be added or removed on an individual basis. The access token below uses the built-in Administrators group as the basis for assigning privileges.

An access token’s integrity level can also be overridden.

Any combination of groups, privileges or integrity levels can be added or removed in an access token.

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