administrative templatesUser ConfigurationNot configured

Configure security zones for trusted sites

Adds sites to trusted security zone with relaxed restrictions. Essential for MSP support of internal LOB applications requiring specific security context.

10 May 20264 min —

Policy path: User Configuration > Policies > Administrative Templates > Windows Components > Internet Explorer > Internet Control Panel > Security Page
Supported on: Windows 10, Windows 11, Windows Server 2016 and later

Adds sites to trusted security zone with relaxed restrictions. Essential for MSP support of internal LOB applications requiring specific security context. Security baselines recommend setting it to Custom.

Description

Configure security zones for trusted sites is a Windows Group Policy setting located under User Configuration > Policies > Administrative Templates > Windows Components > Internet Explorer > Internet Control Panel > Security Page. It applies to the User Configuration branch and is classified as a Warning-level policy in the Internet Explorer / Edge Legacy category.

Adds sites to trusted security zone with relaxed restrictions. Essential for MSP support of internal LOB applications requiring specific security context.

Microsoft sets the default value to Not configured while industry security baselines (CIS, NIST, DISA STIG) recommend Custom.

Under the hood, this policy is enforced through the Windows registry at HKCU\Software\Policies\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap using the value name Domains. Modifying the value directly through regedit.exe or PowerShell produces the same effect as configuring the GPO, but going through Group Policy is preferred so that the setting is centrally managed and survives reboots, image rebuilds, and policy refresh cycles.

In-depth explanation

This setting has a meaningful impact on the security posture or operational stability of the system. Leaving it at the Microsoft default is acceptable for standalone or low-risk environments, but most security baselines (CIS, NIST, DISA STIG) explicitly call for hardening it before the device is exposed to untrusted users or networks.

The policy is grouped under Internet Explorer / Edge Legacy, which means it is typically applied through a domain-wide GPO linked at the OU level. In a multi-tenant MSP context, scope it through WMI filters or security group filtering rather than linking at the domain root, so that you can roll out progressively (pilot OU → wider rings → all production).

The setting takes effect after the next Group Policy refresh (gpupdate /force for immediate testing, or by default within ~90 minutes for workstations and ~5 minutes on domain controllers). For computer-side policies a reboot may be required; for user-side policies, a sign-off/sign-on cycle is enough.

Use cases

Apply organization-wide hardening of internet explorer / edge legacy on all domain-joined Windows endpoints.
Roll out a CIS Benchmark-aligned baseline targeting 'Configure security zones for trusted sites' via a dedicated GPO.
Reduce attack surface for accounts that handle privileged credentials or sensitive data.
Standardize the configuration across multiple customer tenants for an MSP-managed fleet.

Security implications

Leaving this policy at default does not directly grant an attacker access, but it widens the blast radius once initial access is obtained – passwords are easier to guess, lockout doesn't fire, audit trails are incomplete, or lateral movement is quieter. Most regulators and cyber-insurance underwriters now expect this control to be in place at least at the recommended level.

How to configure

Open Group Policy Management Console (gpmc.msc) on a domain controller or a workstation with RSAT installed.
Create or edit a GPO linked to the OU containing the target user configurations. We recommend a dedicated baseline GPO (e.g. SEC – Internet Explorer / Edge Legacy) instead of editing Default Domain Policy.
Navigate to User Configuration > Policies > Administrative Templates > Windows Components > Internet Explorer > Internet Control Panel > Security Page.
Open Configure security zones for trusted sites and set it to Custom.
Click OK and close the editor.
On the target endpoint, run gpupdate /force (or wait for the next refresh cycle), then verify with rsop.msc or gpresult /h report.html.

Direct registry path: HKCU\Software\Policies\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap\Domains. You can apply the same change with PowerShell:

New-Item -Path 'HKCU\Software\Policies\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap' -Force | Out-Null
Set-ItemProperty -Path 'HKCU\Software\Policies\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap' -Name 'Domains' -Value <value> -Type DWord

Registry mapping

Registry pathHKCU\Software\Policies\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap

Value nameDomains

Value typeREG_DWORD

Enabled valueCustom

Disabled valueNot configured

Frequently asked questions

What does the Configure security zones for trusted sites Group Policy do?

Adds sites to trusted security zone with relaxed restrictions. Essential for MSP support of internal LOB applications requiring specific security context.

Where do I find this setting in the GPO editor?

Open <code>gpmc.msc</code>, then navigate to <code>User Configuration > Policies > Administrative Templates > Windows Components > Internet Explorer > Internet Control Panel > Security Page</code> and look for <strong>Configure security zones for trusted sites</strong>.

What is the Microsoft default value?

<code>Not configured</code> on a fresh Windows install. Domain-joined machines may inherit a different value if a baseline GPO is already in place.

What value do security baselines recommend?

<code>Custom</code> – aligned with CIS, NIST, and DISA STIG guidance for current Windows versions.

Can I configure this without a GPO?

Yes, by writing to <code>HKCU\Software\Policies\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap\Domains</code> directly via <code>regedit</code>, PowerShell, or Intune. A GPO is preferred for centrally managed environments because it survives reimaging and is easier to audit.