windows-itpro-docs/windows/security/threat-protection/windows-defender-application-control/applocker/dll-rules-in-applocker.md

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DLL rules in AppLocker (Windows 10)	This topic describes the file formats and available default rules for the DLL rule collection.	a083fd08-c07e-4534-b0e7-1e15d932ce8f		dansimp	w10	deploy	library	security	medium	dansimp	dansimp	ITPro	M365-security-compliance	conceptual	09/21/2017

DLL rules in AppLocker

Applies to

• Windows 10
• Windows Server

This topic describes the file formats and available default rules for the DLL rule collection.

AppLocker defines DLL rules to include only the following file formats:

• .dll
• .ocx

The following table lists the default rules that are available for the DLL rule collection.

Purpose	Name	User	Rule condition type
Allows members of the local Administrators group to run all DLLs	(Default Rule) All DLLs
BUILTIN\Administrators	Path: *
Allow all users to run DLLs in the Windows folder	(Default Rule) Microsoft Windows DLLs
Everyone	Path: %windir%*
Allow all users to run DLLs in the Program Files folder	(Default Rule) All DLLs located in the Program Files folder
Everyone	Path: %programfiles%*

Important

If you use DLL rules, a DLL allow rule has to be created for each DLL that is used by all of the allowed apps

Caution

When DLL rules are used, AppLocker must check each DLL that an app loads. Therefore, users may experience a reduction in performance if DLL rules are used.

Related topics

• Understanding AppLocker default rules