How does UAC in Windows 8 work?

Question

Is UAC in Windows 8 any different than in Windows 7, I've heard about access tokens and different application privileges, can you shed more light on that?

Answer 1

As part of UAC, Windows 8 by default detects application installations and prompts users for elevation to continue the installation. Installation packages for UAC-compliant applications is application manifest that contain run-level designations to help track required privileges. Application manifests define the application's privileges as one of the following:

RunAsInvoker

Run the application with the same privileges as the user. Any user can run the application. For a standard user or a user who is a member of the Administrators group, the application runs with a standard access token. The application runs with higher privileges only if the parent process from which it is started has an administrator access token. For example, if you open an elevated Command Prompt window and then start an application from this window, the application runs with an administrator access token.

RunAsHighest

Run the application with the highest privileges of the user. The application can be run by both administrator users and standard users. The tasks the application can perform depend on the user's privileges. For a standard user, the application runs with a standard access token. For a user who is a member of a group with additional privileges, such as the Backup Operators, Server Operators, or Account Operators group, the application runs with a partial administrator access token that contains only the privileges the user has been granted. For a user who is a member of the Administrator group, the application runs with a full administrator access token.

RunAsAdmin

Run the application with administrator privileges. Only administrators can run the application. For a standard user or a user who is a member of group with additional privileges, the application runs only if the user can be prompted for credentials required to run in elevated mode or if the application is started from an elevated process, such as an elevated Command Prompt window. For a user who is a member of the Administrators group, the application runs with administrator access token.