[REQ-END-078] Disable OneDrive File Sync

Target Scope

Applicable Systems: Tier 2 client workstations and member servers.
Operating Systems: Windows 10 (and above) Enterprise/Professional, Windows Server 2016 (and above).

Implementation Details

Priority: Medium
GPO Path / Registry Location:
- GPO Path: Computer Configuration\Administrative Templates\Windows Components\OneDrive
- Registry Location:
  - HKLM\SOFTWARE\Policies\Microsoft\Windows\OneDrive
    - DisableFileSyncNGSC = 1 (REG_DWORD)

Rationale

Preventing OneDrive files from syncing automatically protects endpoints against automated synchronization of encrypted files during a ransomware event, and prevents unauthorized data exfiltration.

Legacy Impact & Compatibility

OneDrive file synchronization will be completely disabled. Alternate storage paths must be used.

Implementation Steps

Option A: Group Policy Object (GPO) Configuration (Preferred)

Navigate to: Computer Configuration\Administrative Templates\Windows Components\OneDrive
Set 'Prevent the usage of OneDrive for file storage' to 'Enabled'

Option B: PowerShell & Registry Configuration (Remediation / Non-GPO)

Download Script: Configure-DisableOneDriveSync.ps1

# Configure-DisableOneDriveSync.ps1
$Path = "HKLM:\SOFTWARE\Policies\Microsoft\Windows\OneDrive"
if (-not (Test-Path $Path)) { New-Item -Path $Path -Force | Out-Null }
Set-ItemProperty -Path $Path -Name "DisableFileSyncNGSC" -Value 1 -Type DWord -Force

To audit the hardening status: Download Script: Get-DisableOneDriveSyncStatus.ps1

# Get-DisableOneDriveSyncStatus.ps1
$Path = "HKLM:\SOFTWARE\Policies\Microsoft\Windows\OneDrive"
$Reg = Get-ItemProperty -Path $Path -Name "DisableFileSyncNGSC" -ErrorAction SilentlyContinue
if ($Reg -and $Reg.DisableFileSyncNGSC -eq 1) {
    Write-Output "Compliant"
    exit 0
} else {
    Write-Output "Non-Compliant"
    exit 1
}

Sources & Compliance References

CIS Microsoft Windows 10 Benchmark: Section 18.9 (Windows Defender Antivirus configuration parameters)
ANSSI Active Directory Hardening Guide: Protective controls baselines on client workstations

REQ-END-078 - Disable OneDrive File Sync