Site isolation for every site must be enabled.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-235760	EDGE-00-000047	SV-235760r626523_rule		Medium

Description
The "SitePerProcess" policy can be used to prevent users from opting out of the default behavior of isolating all sites. The "IsolateOrigins" policy can be used to isolate additional, finer-grained origins. Enabling this policy prevents users from opting out of the default behavior where each site runs in its own process. If this policy is not disabled or configured, a user can opt out of site isolation (e.g., by using "Disable site isolation" entry in edge://flags.) Disabling the policy or not configuring the policy does not turn off Site Isolation.

Description

The "SitePerProcess" policy can be used to prevent users from opting out of the default behavior of isolating all sites. The "IsolateOrigins" policy can be used to isolate additional, finer-grained origins. Enabling this policy prevents users from opting out of the default behavior where each site runs in its own process. If this policy is not disabled or configured, a user can opt out of site isolation (e.g., by using "Disable site isolation" entry in edge://flags.) Disabling the policy or not configuring the policy does not turn off Site Isolation.

STIG	Date
Microsoft Edge Security Technical Implementation Guide	2021-06-23

Details

Check Text ( C-38979r626476_chk )
The policy value for "Computer Configuration/Administrative Templates/Microsoft Edge/Enable site isolation for every site" must be set to "enabled". Use the Windows Registry Editor to navigate to the following key: HKLM\SOFTWARE\Policies\Microsoft\Edge If the value for "SitePerProcess" is not set to "REG_DWORD = 1", this is a finding.

Fix Text (F-38942r626477_fix)
Set the policy value for "Computer Configuration/Administrative Templates/Microsoft Edge/Enable site isolation for every site" to "enabled".