Protect important folders with Controlled folder access

Applies to:

  • Windows 10, version 1709

Audience

  • Enterprise security administrators

Manageability available with

  • Windows Defender Security Center app
  • Group Policy
  • PowerShell
  • Configuration service providers for mobile device management

Controlled folder access helps you protect valuable data from malicious apps and threats, such as ransomware.

It is part of Windows Defender Exploit Guard.

Tip

You can also visit the Windows Defender Testground website at demo.wd.microsoft.com to confirm the feature is working and see how it works.

Controlled folder access works best with Windows Defender Advanced Threat Protection - which gives you detailed reporting into Windows Defender EG events and blocks as part of the usual alert investigation scenarios.

All apps (any executable file, including .exe, .scr, .dll files and others) are assessed by Windows Defender Antivirus, which then determines if the app is malicious or safe. If the app is determined to be malicious or suspicious, then it will not be allowed to make changes to any files in any protected folder.

This is especially useful in helping to protect your documents and information from ransomware that can attempt to encrypt your files and hold them hostage.

A notification will appear on the machine where the app attempted to make changes to a protected folder. You can customize the notification with your company details and contact information. You can also enable the rules individually to customize what techniques the feature monitors.

The protected folders include common system folders, and you can add additional folders. You can also allow or whitelist apps to give them access to the protected folders.

As with other features of Windows Defender Exploit Guard, you can use audit mode to evaluate how Controlled folder access would impact your organization if it were enabled.

Requirements

The following requirements must be met before Controlled folder access will work:

Windows 10 version Windows Defender Antivirus
Insider Preview build 16232 or later (dated July 1, 2017 or later) Windows Defender AV real-time protection must be enabled

Review Controlled folder access events in Windows Event Viewer

You can review the Windows event log to see events that are created when Controlled folder access blocks (or audits) an app:

  1. Download the Exploit Guard Evaluation Package and extract the file cfa-events.xml to an easily accessible location on the machine.

  2. Type Event viewer in the Start menu to open the Windows Event Viewer.

  3. On the left panel, under Actions, click Import custom view...

    Animation showing the import custom view on the Event viewer window

  4. Navigate to where you extracted cfa-events.xml and select it. Alternatively, copy the XML directly.

  5. Click OK.

  6. This will create a custom view that filters to only show the following events related to Controlled folder access:

Event ID Description
5007 Event when settings are changed
1124 Audited Controlled folder access event
1123 Blocked Controlled folder access event

In this section

Topic Description
Evaluate Controlled folder access Use a dedicated demo tool to see how Controlled folder access works, and what events would typically be created.
Enable Controlled folder access Use Group Policy, PowerShell, or MDM CSPs to enable and manage Controlled folder access in your network
Customize Controlled folder access Add additional protected folders, and allow specified apps to access protected folders.