windows-itpro-docs/windows/security/threat-protection/microsoft-defender-atp/evaluate-attack-surface-reduction.md

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title	description	keywords	search.product	ms.pagetype	ms.prod	ms.mktglfcycl	ms.sitesec	ms.pagetype	ms.localizationpriority	audience	author	ms.author	ms.date	ms.reviewer	manager
Use a demo to see how ASR rules can help protect your devices	The custom demo tool lets you create sample malware infection scenarios so you can see how ASR would block and prevent attacks	Attack surface reduction, hips, host intrusion prevention system, protection rules, anti-exploit, antiexploit, exploit, infection prevention, evaluate, test, demo	eADQiWindows 10XVcnh	security	w10	manage	library	security	medium	ITPro	levinec	ellevin	04/02/2019		dansimp

Evaluate attack surface reduction rules

Applies to:

• Microsoft Defender Advanced Threat Protection (Microsoft Defender ATP)

Attack surface reduction rules help prevent actions and apps that are typically used by exploit-seeking malware to infect machines. Attack surface reduction rules are supported on Windows Server 2019 as well as Windows 10 clients.

This topic helps you evaluate attack surface reduction rules. It explains how to enable audit mode so you can test the feature directly in your organization.

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.

Use audit mode to measure impact

You can enable attack surface reduction rules in audit mode. This lets you see a record of what apps would have been blocked if you had enabled attack surface reduction rules.

You might want to do this when testing how the feature will work in your organization, to ensure it doesn't affect your line-of-business apps, and to get an idea of how often the rules will fire during normal use.

To enable audit mode, use the following PowerShell cmdlet:

Set-MpPreference -AttackSurfaceReductionRules_Actions AuditMode

This enables all attack surface reduction rules in audit mode.

Tip

If you want to fully audit how attack surface reduction rules will work in your organization, you'll need to use a management tool to deploy this setting to machines in your network(s). You can also use Group Policy, Intune, or MDM CSPs to configure and deploy the setting, as described in the main Attack surface reduction rules topic.

Review attack surface reduction events in Windows Event Viewer

To review apps that would have been blocked, open Event Viewer and filter for Event ID 1121 in the Microsoft-Windows-Windows-Defender/Operational log. The following table lists all network protection events.

Event ID	Description
5007	Event when settings are changed
1121	Event when an attack surface reduction rule fires in block mode
1122	Event when an attack surface reduction rule fires in audit mode

Customize attack surface reduction rules

During your evaluation, you may wish to configure each rule individually or exclude certain files and processes from being evaluated by the feature.

See the Customize attack surface reduction rules topic for information on configuring the feature with management tools, including Group Policy and MDM CSP policies.

Related topics

• Reduce attack surfaces with attack surface reduction rules
• Use audit mode to evaluate Windows Defender