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98-349: MTA: Windows Operating System Fundamentals : Module 2: Understanding Operating System Configuration :

Understanding Types of UAC Prompts and Levels

Microsoft Help:-

UAC elevation prompts The UAC elevation prompts are color-coded to be application-specific, enabling for immediate identification of an application's potential security risk. When an application attempts to run with an administrator's full access token, Windows 7 first analyzes the executable file to determine its publisher. Applications are first separated into three categories based on the executable file's publisher: Windows 7, publisher verified (signed), and publisher not verified (unsigned). The following diagram illustrates how Windows 7 determines which color elevation prompt to present to the user.

The elevation prompt color-coding is as follows:

1.  Red background with a red shield icon: The application is blocked by Group Policy or is from a publisher that is blocked.
2. Blue background with a blue and gold shield icon: The application is a Windows 7 administrative application, such as a Control Panel item.
3. Blue background with a blue shield icon: The application is signed by using Authenticode and is trusted by the local computer.
4. Yellow background with a yellow shield icon: The application is unsigned or signed but is not yet trusted by the local computer.