Vulnerability Discussion

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.

Check

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

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.