Let Apps Access Contacts
Controls whether apps can access the contacts list.
- Policy path
- Computer Configuration > Administrative Templates > Windows Components > App Privacy
- Supported on
- Windows 10, Windows 11, Windows Server 2016 and later
Controls whether apps can access the contacts list. Security baselines recommend setting it to 2 (Force Deny).
Description
Let Apps Access Contacts is a Windows Group Policy setting located under Computer Configuration > Administrative Templates > Windows Components > App Privacy. It applies to the Computer Configuration branch and is classified as a Informational-level policy in the App Privacy category.
Controls whether apps can access the contacts list.
Microsoft sets the default value to Not configured while industry security baselines (CIS, NIST, DISA STIG) recommend 2 (Force Deny).
Under the hood, this policy is enforced through the Windows registry at HKLM\Software\Policies\Microsoft\Windows\AppPrivacy using the value name LetAppsAccessContacts. 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 is primarily an operational or user-experience setting. It does not directly raise or lower the security posture, but it standardizes behavior across the fleet, which is important for predictable support, training, and troubleshooting in an MSP-managed environment.
The policy is grouped under App Privacy, 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 app privacy on all domain-joined Windows endpoints.
- Roll out a CIS Benchmark-aligned baseline targeting 'Let Apps Access Contacts' 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
This control is primarily about consistency and supportability rather than security. The main risk of leaving it unconfigured is divergence between machines, which makes troubleshooting and standardized imaging harder, especially across multiple customer tenants in an MSP context.
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 computer configurations. We recommend a dedicated baseline GPO (e.g. SEC – App Privacy) instead of editing Default Domain Policy.
- Navigate to
Computer Configuration > Administrative Templates > Windows Components > App Privacy. - Open Let Apps Access Contacts and set it to
2 (Force Deny). - Click OK and close the editor.
- On the target endpoint, run
gpupdate /force(or wait for the next refresh cycle), then verify withrsop.mscorgpresult /h report.html.
Direct registry path: HKLM\Software\Policies\Microsoft\Windows\AppPrivacy\LetAppsAccessContacts. You can apply the same change with PowerShell:
New-Item -Path 'HKLM\Software\Policies\Microsoft\Windows\AppPrivacy' -Force | Out-Null
Set-ItemProperty -Path 'HKLM\Software\Policies\Microsoft\Windows\AppPrivacy' -Name 'LetAppsAccessContacts' -Value <value> -Type DWordRegistry mapping
HKLM\Software\Policies\Microsoft\Windows\AppPrivacyLetAppsAccessContactsREG_DWORD2 (Force Deny)Not configured