MUI Cache

The MUI Cache, a component of the Windows operating system, plays a crucial role in the localization and quick access of program names. It's a repository that holds details about the applications executed on the system, specifically the names of these applications, to support the display of these names in the user's preferred language. This artifact is particularly valuable in digital forensics and incident response (DFIR) for understanding program execution history on a Windows machine.

Key Insights

• Location in the Registry:

  • Windows XP/2003: HKCU\Software\Microsoft\Windows\ShellNoRoam\MUICache

  • Windows Vista and above: HKCU\Software\Classes\Local Settings\Software\Microsoft\Windows\Shell\MuiCache

• Windows 7 and above specific locations:

  • HKCU\Software\Microsoft\Windows\Shell\MuiCache

  • HKCU\Software\Classes\Local Settings\Software\Microsoft\Windows\Shell\MuiCache

Entries within the MUI Cache include the full path to the executable and the application's name as it should appear in the UI. This information can assist in identifying which applications were executed and are therefore of interest in an investigation.

Overview

The MUI (Multilingual User Interface) Cache is stored within the Windows Registry, which contains entries for each executable (EXE) file that has been run on the system. These entries help Windows quickly display the correct name of an application in the user interface, catering to the system's set language preferences. For forensic analysts, the MUI Cache is a goldmine of information because it provides evidence of program execution, even if the actual executables are no longer present on the system.

The MUI Cache does not only store information about system applications but also about third-party software executed by the user. This makes it a valuable artifact for forensic analysts to determine the scope of software use on a suspect's computer. However, it's important to note that the MUI Cache gets updated frequently, and entries can be overwritten. Thus, its contents provide a snapshot of application usage rather than a comprehensive history.

Analyzing The MUI Cache

To analyze the MUI Cache from the command line, one can use Windows Registry command-line tools or third-party forensic tools that can export and analyze registry data. The command-line tool reg query can be used to access registry keys and their values directly from the command prompt.

Example Command to Access MUI Cache on Windows 10:

reg query HKCU\Software\Classes\Local Settings\Software\Microsoft\Windows\Shell\MuiCache

The output of this command will list the registry entries under the MUI Cache, showing the paths to executables and the associated application names.

• Understanding the Outputs:

  • Executable Path: Indicates the location of the application executed. This can help identify unknown or suspicious programs.

  • Application Name: Provides the name of the application as displayed to the user, aiding in understanding the application's purpose or function.