SV-235760r960963: Site isolation for every site must be enabled. | Microsoft Edge STIG SCAP Benchmark

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Assessment Title

Rule Text

Site isolation for every site must be enabled.

Description

Discussion Text

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.

How this relates to the STIG checklist: STIG vs SCAP benchmark.

IA Controls

NIST SP 800-53

Not mappedCCI-000381

References

DPMS Target Microsoft Edge DISA DPMS Target Microsoft Edge 5280

Checks

DISA STIG (Manual Reference)

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.

SCC Automation Reference

The reconstructed evaluation script behind this rule's OVAL check(s) — every module a compound check combines, with this rule's own concrete values and DISA's SCC tool's real per-module mechanism curated from static teardown of SCC releases.

# Windows PowerShell
# Reconstructed from oval:mil.disa.stig.edge:def:135
# Site isolation for every site must be enabled.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# Check that the setting 'Enable site isolation for every site' is enabled.
# registry_object (registry_test)
function test_1 {
  return (((@{String='reg_sz';ExpandString='reg_expand_sz';Binary='reg_binary';DWord='reg_dword';MultiString='reg_multi_sz';QWord='reg_qword';None='reg_none'}[(Get-Item -Path 'Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Edge').GetValueKind('SitePerProcess').ToString()]) -eq 'reg_dword') -and (((Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Edge' -Name 'SitePerProcess' -ErrorAction SilentlyContinue) | Select-Object -ExpandProperty 'SitePerProcess') -eq 1))
}

if (test_1) {
  Write-Output "PASS"
} else {
  Write-Output "FAIL"
}

Assessment Script Powered by AISyntax-verified

A standalone PowerShell script to assess this control automatically. Review before running it in your environment.

Syntax-checked as valid PowerShell. Not executed here — running it for real needs the actual ms_edge target this check assesses.

# OVAL Definition: oval:mil.disa.stig.edge:def:135
$registryPath = "HKLM:\SOFTWARE\Policies\Microsoft\Edge"
$registryName = "SitePerProcess"
$registryValue = 1

if (Test-Path $registryPath -and (Get-ItemProperty -Path $registryPath -ErrorAction SilentlyContinue).SitePerProcess -eq $registryValue) {
    Write-Output "PASS"
    exit 0
} else {
    Write-Output "FAIL"
    exit 1
}

Remediation

Set the policy value for "Computer Configuration/Administrative Templates/Microsoft Edge/Enable site isolation for every site" to "enabled".