Users must not be allowed to ignore Windows Defender SmartScreen filter warnings for unverified files in Microsoft Edge.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-220841	WN10-CC-000235	SV-220841r569187_rule		Medium

Description
The Windows Defender SmartScreen filter in Microsoft Edge provides warning messages and blocks potentially malicious websites and file downloads. If users are allowed to ignore warnings from the Windows Defender SmartScreen filter they could still download potentially malicious files.

STIG	Date
Windows 10 Security Technical Implementation Guide	2021-08-18

Details

Check Text ( C-22556r555008_chk )
This is applicable to unclassified systems, for other systems this is NA. Windows 10 LTSC\B versions do not include Microsoft Edge, this is NA for those systems. If the following registry value does not exist or is not configured as specified, this is a finding. Registry Hive: HKEY_LOCAL_MACHINE Registry Path: \SOFTWARE\Policies\Microsoft\MicrosoftEdge\PhishingFilter\ Value Name: PreventOverrideAppRepUnknown Type: REG_DWORD Value: 0x00000001 (1)

Check Text ( C-22556r555008_chk )

This is applicable to unclassified systems, for other systems this is NA.

Windows 10 LTSC\B versions do not include Microsoft Edge, this is NA for those systems.

If the following registry value does not exist or is not configured as specified, this is a finding.

Registry Hive: HKEY_LOCAL_MACHINE
Registry Path: \SOFTWARE\Policies\Microsoft\MicrosoftEdge\PhishingFilter\

Value Name: PreventOverrideAppRepUnknown

Type: REG_DWORD
Value: 0x00000001 (1)

Fix Text (F-22545r555009_fix)
Configure the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> Microsoft Edge >> "Prevent bypassing Windows Defender SmartScreen prompts for files" to "Enabled". Windows 10 includes duplicate policies for this setting. It can also be configured under Computer Configuration >> Administrative Templates >> Windows Components >> Windows Defender SmartScreen >> Microsoft Edge.

Fix Text (F-22545r555009_fix)

Configure the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> Microsoft Edge >> "Prevent bypassing Windows Defender SmartScreen prompts for files" to "Enabled".

Windows 10 includes duplicate policies for this setting. It can also be configured under Computer Configuration >> Administrative Templates >> Windows Components >> Windows Defender SmartScreen >> Microsoft Edge.