[REQ-PAW-111] Configure User Rights: Restore files and directories for PAWs

Target Scope

  • Applicable Systems: Privileged Access Workstations (PAWs) dedicated to Tier 0 and critical administrative functions. (For Tier 2 Client Workstations and Member Servers, refer to standard baseline REQ-END-121). (For Domain Controllers, refer to REQ-DC-132).
  • Operating Systems: Windows 10 Enterprise (1809 and above) and Windows 11 Enterprise.

Implementation Details

  • Priority: Medium
  • GPO Path / Registry Location:
    • Policy Display Name: Restore files and directories
    • Privilege Constant: SeRestorePrivilege
    • GPO Path: Computer Configuration\Policies\Windows Settings\Security Settings\Local Policies\User Rights Assignment\Restore files and directories
    • Registry Location: Stored inside local security database under privilege SeRestorePrivilege set to *S-1-5-32-544 (Administrators).

Rationale

The SeRestorePrivilege grants the caller the capability to bypass all write-access security controls (DACLs) across the entire NTFS filesystem and Windows Registry. When a process opens a file or registry key handle specifying FILE_FLAG_BACKUP_SEMANTICS in Win32 APIs, the kernel explicitly bypasses standard security descriptor DACL checks, allowing the process to write to, overwrite, or delete any file or key on the system. In addition, this privilege grants the ability to set any valid user or group SID as the owner of an object.

1. Technical Threat Vector & Abuse Mechanics

An adversary who obtains SeRestorePrivilege has immediate, trivial local privilege escalation to NT AUTHORITY\SYSTEM: (1) System File Replacement: The attacker can overwrite core operating system binaries or DLLs (e.g., C:\Windows\System32\utilman.exe, osk.exe, or service DLLs) with malicious payloads, which execute automatically as SYSTEM upon reboot or logon; (2) Registry Service Hijacking: The attacker can overwrite protected registry keys under HKLM\SYSTEM\CurrentControlSet\Services to change service binary paths (ImagePath) to point to malicious executables; (3) SAM/SECURITY Hive Overwriting: The attacker can overwrite local account password hashes or security settings directly.

2. Architectural Defense & Least Privilege Enforcement

Privileged Access Workstations (PAWs) serve as the clean-source platform for managing Tier 0 Active Directory and cloud infrastructure. Because administrative credentials exist in memory on these devices, strict isolation must be maintained at the operating system level. Restricting this user right strictly prevents lower-tier sessions, third-party software, or interactive users from interfering with administrative operations, upholding the Clean Source Principle and preventing token kidnapping or session hijacking.

This privilege must be restricted strictly to Administrators (S-1-5-32-544). Broad groups such as Backup Operators should be stripped of this privilege on Tier 0 systems (Domain Controllers and PAWs). Automated enterprise restore agents should operate under tightly controlled, dedicated service identities.

3. MITRE ATT&CK Mapping

  • T1068 - Exploitation for Privilege Escalation
  • T1574 - Hijack Execution Flow
  • T1543.003 - Create or Modify System Process: Windows Service
  • T1222.001 - File and Directory Permissions Modification: Windows DACL

Legacy Impact & Compatibility

  • Operational Impact: Restricting SeRestorePrivilege prevents write-bypass exploitation while preserving standard file access controls. Enterprise disaster recovery tools running under non-administrative accounts will require explicit delegation or membership in a dedicated restore management role. Monitor Security Event ID 4672 and Event ID 4673 for invocations of SeRestorePrivilege.

Implementation Steps

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

  1. Open the Group Policy Management Console (gpmc.msc).
  2. Navigate to the targeted GPO linked to Tier 0 PAW systems (e.g., GPO_Hardening_PAW).
  3. In the console tree, browse to: Computer Configuration\Policies\Windows Settings\Security Settings\Local Policies\User Rights Assignment
  4. Open the policy Restore files and directories.
  5. Select the Define these policy settings check box.
  6. Configure the security principal allocation to: *S-1-5-32-544 (Administrators).
  7. Click Apply and OK.
  8. Apply and verify policy enforcement across target hosts using gpupdate /force and inspect with secedit /export /cfg C:\Windows\Temp\sec_audit.cfg.

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

Download Script: Configure-PawUraSeRestorePrivilege.ps1

# Configure-PawUraSeRestorePrivilege.ps1
# Configure-PawUraSeRestorePrivilege.ps1
$SecTempDir = Join-Path $env:TEMP "SecurityTemplates"
if (-not (Test-Path $SecTempDir)) { New-Item -Path $SecTempDir -ItemType Directory -Force | Out-Null }
$CfgFile = Join-Path $SecTempDir "ura_serestoreprivilege.cfg"
$DbFile = Join-Path $SecTempDir "secedit_serestoreprivilege.sdb"
$LogFile = Join-Path $SecTempDir "secedit.log"

$Process = Start-Process secedit -ArgumentList "/export /cfg `"$CfgFile`"" -Wait -NoNewWindow -PassThru
if ($Process.ExitCode -ne 0) { Throw "Failed to export security template" }

$ConfigText = Get-Content -Path $CfgFile -Raw
if ($ConfigText -notmatch "\[Privilege Rights\]") {
    $ConfigText += "`r`n[Privilege Rights]`r`n"
}

$Lines = $ConfigText -split "`r?`n"
$NewLines = @()
$InPriv = $false
$KeyAdded = $false

foreach ($Line in $Lines) {
    if ($Line -match "^\[(.*)\]$") {
        if ($Matches[1] -eq "Privilege Rights") {
            $InPriv = $true
        } else {
            $InPriv = $false
        }
    }
    if ($InPriv -and $Line -match "^\s*SeRestorePrivilege\s*=") {
        $NewLines += "SeRestorePrivilege = *S-1-5-32-544"
        $KeyAdded = $true
    } else {
        $NewLines += $Line
    }
}

if (-not $KeyAdded) {
    # Find Privilege Rights section index and insert it right after
    $Idx = $NewLines.IndexOf("[Privilege Rights]")
    if ($Idx -ge 0) {
        $NewLines.Insert($Idx + 1, "SeRestorePrivilege = *S-1-5-32-544")
    } else {
        $NewLines += "SeRestorePrivilege = *S-1-5-32-544"
    }
}

$NewLines | Set-Content -Path $CfgFile -Force
$Proc = Start-Process secedit -ArgumentList "/configure /db `"$DbFile`" /cfg `"$CfgFile`" /areas USER_RIGHTS /log `"$LogFile`"" -Wait -NoNewWindow -PassThru
if ($Proc.ExitCode -ne 0) { Throw "Failed to configure secedit user rights" }
Remove-Item -Path $CfgFile, $DbFile -ErrorAction SilentlyContinue

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

# Get-PawUraSeRestorePrivilegeStatus.ps1
# Get-PawUraSeRestorePrivilegeStatus.ps1
$SecTempDir = Join-Path $env:TEMP "SecurityTemplates"
if (-not (Test-Path $SecTempDir)) { New-Item -Path $SecTempDir -ItemType Directory -Force | Out-Null }
$CfgFile = Join-Path $SecTempDir "ura_audit_serestoreprivilege.cfg"

$Process = Start-Process secedit -ArgumentList "/export /cfg `"$CfgFile`"" -Wait -NoNewWindow -PassThru
if ($Process.ExitCode -ne 0) {
    Write-Output "Non-Compliant"
    exit 1
}

$ConfigText = Get-Content -Path $CfgFile -Raw
Remove-Item -Path $CfgFile -ErrorAction SilentlyContinue

$Match = $ConfigText -match "(?mi)^\s*SeRestorePrivilege\s*=\s*(.*)$"
$CurrentValue = ""
if ($Match) {
    $CurrentValue = $Matches[1].Trim()
}

$Expected = "*S-1-5-32-544"
if ($CurrentValue -eq $Expected) {
    Write-Output "Compliant"
    exit 0
} else {
    Write-Output "Non-Compliant"
    exit 1
}

Sources & Compliance References

  • ANSSI Active Directory Hardening Guide: ANSSI Active Directory Hardening Guide: R28 (User Rights Assignment)
  • CIS Benchmark: 2.2.35 (L1) Ensure 'Restore files and directories' is set to 'Administrators'
  • Microsoft Security Baseline: User Rights Configuration specifications
  • Microsoft Learn: User Rights Assignment Reference

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