Analyzing Windows Shellbag Artifacts

Overview

Shellbags are Windows registry artifacts that track how users interact with folders through Windows Explorer, storing view settings such as icon size, window position, sort order, and view mode. From a forensic perspective, Shellbags provide definitive evidence of folder access -- even folders that no longer exist on the system. When a user browses to a folder via Windows Explorer, the Open/Save dialog, or the Control Panel, a Shellbag entry is created or updated in the user's registry hive. These entries persist after folder deletion, drive disconnection, and even across user profile resets, making them invaluable for proving that a user navigated to specific directories on local drives, USB devices, network shares, or zip archives.

When to Use

When investigating security incidents that require analyzing windows shellbag artifacts
When building detection rules or threat hunting queries for this domain
When SOC analysts need structured procedures for this analysis type
When validating security monitoring coverage for related attack techniques

Prerequisites

Familiarity with digital forensics concepts and tools
Access to a test or lab environment for safe execution
Python 3.8+ with required dependencies installed
Appropriate authorization for any testing activities

Registry Locations

Windows 7/8/10/11

Hive	Key Path	Stores
NTUSER.DAT	Software\Microsoft\Windows\Shell\BagMRU	Folder hierarchy tree
NTUSER.DAT	Software\Microsoft\Windows\Shell\Bags	View settings per folder
UsrClass.dat	Local Settings\Software\Microsoft\Windows\Shell\BagMRU	Desktop/Explorer shell
UsrClass.dat	Local Settings\Software\Microsoft\Windows\Shell\Bags	Additional view settings

BagMRU Structure

The BagMRU key contains a hierarchical tree of numbered subkeys representing the directory structure. Each subkey value contains a Shell Item (SHITEMID) binary blob encoding the folder identity:

Root (BagMRU): Desktop namespace root
BagMRU\0: Typically "My Computer"
BagMRU\0\0: First drive (e.g., C:)
BagMRU\0\0\0: First subfolder on C:

Each Shell Item contains:

Item type (folder, drive, network, zip, control panel)
Short name (8.3 format)
Long name (Unicode)
Creation/modification timestamps
MFT entry/sequence for NTFS folders

Analysis with EZ Tools

SBECmd (Command Line)

powershell

# Parse shellbags from a directory of registry hives
SBECmd.exe -d "C:\Evidence\Registry" --csv C:\Output --csvf shellbags.csv

# Parse from a live system (requires admin)
SBECmd.exe --live --csv C:\Output --csvf live_shellbags.csv

# Key output columns:
# AbsolutePath - Full reconstructed path
# CreatedOn - When the folder was first browsed
# ModifiedOn - When view settings were last changed
# AccessedOn - Last access timestamp
# ShellType - Type of shell item (Directory, Drive, Network, etc.)
# Value - Raw shell item data

ShellBags Explorer (GUI)

powershell

# Launch GUI tool for interactive analysis
ShellBagsExplorer.exe

# Load registry hives: File > Load Hive
# Navigate the tree structure to see folder hierarchy
# Right-click entries for detailed shell item properties

Forensic Investigation Scenarios

Proving USB Device Browsing

text

Shellbag Path: My Computer\E:\Confidential\Project_Files
ShellType: Directory (on removable volume)
CreatedOn: 2025-03-15 09:30:00 UTC

This proves the user navigated to E:\Confidential\Project_Files
via Windows Explorer, even if the USB drive is no longer connected.
The volume letter E: and directory timestamps can be correlated
with USBSTOR and MountPoints2 registry entries.

Detecting Network Share Access

text

Shellbag Path: \\FileServer01\Finance\Q4_Reports
ShellType: Network Location
AccessedOn: 2025-02-20 14:15:00 UTC

This proves the user browsed to a network share, even if
the share has been decommissioned or access revoked.

Identifying Deleted Folder Knowledge

text

Shellbag Path: C:\Users\suspect\Documents\Exfiltration_Staging
ShellType: Directory
CreatedOn: 2025-01-10 08:00:00 UTC

Even though C:\Users\suspect\Documents\Exfiltration_Staging
no longer exists, the Shellbag entry proves the user
created and navigated to this folder.

Limitations

Shellbags only record folder-level interactions, not individual file access
Only created through Windows Explorer shell and Open/Save dialogs
Command-line access (cmd, PowerShell) does not generate Shellbag entries
Programmatic file access via APIs does not generate Shellbag entries
Timestamps may reflect view setting changes, not necessarily folder access
Windows may batch-update Shellbag entries during Explorer shutdown

References

Shellbags Forensic Analysis 2025: https://www.cybertriage.com/blog/shellbags-forensic-analysis-2025/
SANS Shellbag Forensics: https://www.sans.org/blog/computer-forensic-artifacts-windows-7-shellbags
Magnet Forensics Shellbag Analysis: https://www.magnetforensics.com/blog/forensic-analysis-of-windows-shellbags/
ShellBags Explorer: https://ericzimmerman.github.io/

Example Output

text

$ SBECmd.exe -d "C:\Evidence\Users\jsmith" --csv /analysis/shellbag_output

SBECmd v2.1.0 - ShellBags Explorer (Command Line)
====================================================
Processing hives for user: jsmith
  NTUSER.DAT:  C:\Evidence\Users\jsmith\NTUSER.DAT
  UsrClass.dat: C:\Evidence\Users\jsmith\AppData\Local\Microsoft\Windows\UsrClass.dat

[+] NTUSER.DAT shellbag entries:   456
[+] UsrClass.dat shellbag entries: 1,234
[+] Total shellbag entries:        1,690

--- Folder Access Timeline (Incident Window) ---
Last Accessed (UTC)     | Folder Path                                             | Type        | Access Count
------------------------|---------------------------------------------------------|-------------|-------------
2024-01-15 14:34:05     | C:\Users\jsmith\Downloads                               | File System | 45
2024-01-15 14:36:25     | C:\ProgramData\Updates                                  | File System | 3
2024-01-15 15:05:00     | \\FILESERV01\Finance                                    | Network     | 2
2024-01-15 15:12:30     | \\FILESERV01\Finance\Q4_Reports                          | Network     | 1
2024-01-15 15:30:00     | E:\                                                     | Removable   | 4
2024-01-15 15:30:45     | E:\Backup                                               | Removable   | 3
2024-01-15 15:31:20     | E:\Backup\Corporate_Data                                | Removable   | 2
2024-01-15 16:12:45     | \\FILESERV01\HR\Employees                                | Network     | 1
2024-01-15 16:15:00     | \\FILESERV01\HR\Employees\Records_2024                   | Network     | 1
2024-01-16 02:35:00     | C:\Windows\Temp                                         | File System | 5
2024-01-17 02:44:00     | C:\ProgramData\svc                                     | File System | 2
2024-01-18 01:10:00     | C:\Users\jsmith\AppData\Local\Temp                      | File System | 8

--- Network Share Access ---
  \\FILESERV01\Finance             First: 2023-09-10  Last: 2024-01-15
  \\FILESERV01\Finance\Q4_Reports  First: 2024-01-15  Last: 2024-01-15  (NEW)
  \\FILESERV01\HR\Employees        First: 2024-01-15  Last: 2024-01-15  (NEW)
  \\DC01\SYSVOL                    First: 2023-03-15  Last: 2024-01-16  (anomalous access time)

--- Removable Device Access ---
  E:\ (USB Drive)
    Volume Name:    BACKUP_DRIVE
    First Accessed: 2024-01-15 15:30:00 UTC
    Last Accessed:  2024-01-15 15:45:22 UTC
    Folders Browsed: 3 (E:\, E:\Backup, E:\Backup\Corporate_Data)

--- Deleted/No Longer Existing Paths ---
  C:\ProgramData\Updates\                (folder deleted, shellbag persists)
  C:\ProgramData\svc\                    (folder deleted, shellbag persists)
  C:\Windows\Temp\tools\                 (folder deleted, shellbag persists)

Summary:
  Total unique folders accessed:  1,690
  Network shares accessed:        4 (2 newly accessed during incident)
  Removable media:                1 USB device (data staging suspected)
  Deleted folder evidence:        3 paths (anti-forensics indicator)
  CSV exported to:                /analysis/shellbag_output/

analyzing-windows-shellbag-artifacts

NPX Install

Tags

SKILL.md Content

Analyzing Windows Shellbag Artifacts

Overview

When to Use

Prerequisites

Registry Locations

Windows 7/8/10/11

BagMRU Structure

Analysis with EZ Tools

SBECmd (Command Line)

ShellBags Explorer (GUI)

Forensic Investigation Scenarios

Proving USB Device Browsing

Detecting Network Share Access

Identifying Deleted Folder Knowledge

Limitations

References

Example Output