<#
.TITLE
    Get Defender Status Report

.SYNOPSIS
    Reports Microsoft Defender health across all Windows devices: protection state, signature age, and devices needing attention.

.DESCRIPTION
    This script reads the tenant-wide device protection overview and the per-device
    Windows protection state to report Microsoft Defender health: real-time
    protection, tamper protection, malware protection, signature currency, overdue
    scans, pending reboots, and devices whose state is not clean. Use it to find the
    machines where Defender is silently off or outdated before they become incident
    tickets.

.TAGS
    Security,Monitoring

.MINROLE
    Intune Administrator

.PERMISSIONS
    DeviceManagementManagedDevices.Read.All

.AUTHOR
    Ugur Koc

.VERSION
    1.2

.CHANGELOG
    1.2 - Added Azure Automation contract validation, portal-safe boolean parameters, beta Graph endpoints, and terminating paging errors
    1.1 - Azure Automation now records script progress, outcomes, and summaries in job history
    1.0 - Initial release

.LASTUPDATE
    2026-07-30

.EXAMPLE
    .\get-defender-status-report.ps1
    Reports Defender health for all Windows devices

.EXAMPLE
    .\get-defender-status-report.ps1 -OnlyIssues "true"
    Lists only devices with at least one Defender health issue

.EXAMPLE
    .\get-defender-status-report.ps1 -ExportToCsv "true"
    Exports the full per-device Defender state to a timestamped CSV

.NOTES
    - Requires Microsoft.Graph.Authentication module
    - Protection state is fetched per device (one request each); large tenants take a few minutes
    - Devices that never reported protection state are listed separately
    - Uses beta Graph endpoints because windowsProtectionState is exposed there
    - Local interactive sign-in uses the MgGraphCommunity module to avoid the Graph SDK's mandatory WAM broker on Windows
#>

[CmdletBinding()]
param(
    [Parameter(Mandatory = $false, HelpMessage = "Show only devices with Defender issues")]
    [ValidateSet("true", "false", "1", "0", '$true', '$false')]
    [string]$OnlyIssues,

    [Parameter(Mandatory = $false, HelpMessage = "Export results to CSV")]
    [ValidateSet("true", "false", "1", "0", '$true', '$false')]
    [string]$ExportToCsv,

    [Parameter(Mandatory = $false, HelpMessage = "Output path for exports")]
    [string]$OutputPath = ".",

    [Parameter(Mandatory = $false, HelpMessage = "Force module installation without prompting")]
    [ValidateSet("true", "false", "1", "0", '$true', '$false')]
    [string]$ForceModuleInstall
)

# Normalize the local module-install override for Azure Automation parameter binding.
$forceModuleInstallRaw = [string]$ForceModuleInstall
Remove-Variable -Name ForceModuleInstall
if ([string]::IsNullOrWhiteSpace($forceModuleInstallRaw)) {
    $ForceModuleInstall = $false
}
elseif ($forceModuleInstallRaw.Trim().ToLowerInvariant() -in @("true", "1", '$true')) {
    $ForceModuleInstall = $true
}
elseif ($forceModuleInstallRaw.Trim().ToLowerInvariant() -in @("false", "0", '$false')) {
    $ForceModuleInstall = $false
}
else {
    throw "Parameter 'ForceModuleInstall' accepts only true, false, 1, 0, $true, or $false."
}

# Azure Automation supplies portal parameter values as strings. Normalize the
# public boolean parameters once so local and runbook execution use real booleans.
foreach ($runbookBooleanParameter in @('OnlyIssues', 'ExportToCsv')) {
    $runbookBooleanRaw = [string](Get-Variable -Name $runbookBooleanParameter -ValueOnly)
    Remove-Variable -Name $runbookBooleanParameter

    if ([string]::IsNullOrWhiteSpace($runbookBooleanRaw)) {
        Set-Variable -Name $runbookBooleanParameter -Value $false
        continue
    }

    switch ($runbookBooleanRaw.Trim().ToLowerInvariant()) {
        { $_ -in @("true", "1", '$true') } {
            Set-Variable -Name $runbookBooleanParameter -Value $true
        }
        { $_ -in @("false", "0", '$false') } {
            Set-Variable -Name $runbookBooleanParameter -Value $false
        }
        default {
            throw "Parameter '$runbookBooleanParameter' accepts only true, false, 1, 0, $true, or $false."
        }
    }
}

# ============================================================================
# ENVIRONMENT DETECTION AND SETUP
# ============================================================================

function Initialize-RequiredModule {
    param(
        [string[]]$ModuleNames,
        [bool]$IsAutomationEnvironment,
        [bool]$ForceInstall = $false
    )

    foreach ($ModuleName in $ModuleNames) {
        Write-Verbose "Checking module: $ModuleName"

        $module = Get-Module -ListAvailable -Name $ModuleName | Select-Object -First 1

        if (-not $module) {
            if ($IsAutomationEnvironment) {
                throw "Module '$ModuleName' is not available in Azure Automation"
            }
            else {
                Write-Information "Module '$ModuleName' not found. Installing..." -InformationAction Continue

                if (-not $ForceInstall) {
                    $response = Read-Host "Install module '$ModuleName'? (Y/N)"
                    if ($response -notmatch '^[Yy]') {
                        throw "Module '$ModuleName' is required but installation was declined."
                    }
                }

                try {
                    $isAdmin = ([Security.Principal.WindowsPrincipal] [Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([Security.Principal.WindowsBuiltInRole] "Administrator")
                    $scope = if ($isAdmin) { "AllUsers" } else { "CurrentUser" }

                    Install-Module -Name $ModuleName -Scope $scope -Force -AllowClobber -Repository PSGallery
                    Write-Information "✓ Successfully installed '$ModuleName'" -InformationAction Continue
                }
                catch {
                    throw "Failed to install module '$ModuleName': $($_.Exception.Message)"
                }
            }
        }

        Import-Module -Name $ModuleName -Force -ErrorAction Stop
    }
}

# Detect execution environment
$IsAzureAutomation = $null -ne $PSPrivateMetadata.JobId.Guid

# Initialize required modules
$RequiredModules = @("Microsoft.Graph.Authentication")

# MgGraphCommunity gives WAM-free interactive sign-in for local runs
if (-not $IsAzureAutomation) {
    $RequiredModules += "MgGraphCommunity"
}

try {
    Initialize-RequiredModule -ModuleNames $RequiredModules -IsAutomationEnvironment $IsAzureAutomation -ForceInstall $ForceModuleInstall
    Write-Verbose "✓ All required modules are available"
}
catch {
    Write-Error "Module initialization failed: $_"
    exit 1
}

# ============================================================================
# AUTHENTICATION
# ============================================================================

try {
    if ($IsAzureAutomation) {
        Write-Output "Connecting to Microsoft Graph using Managed Identity..."
        Connect-MgGraph -Identity -NoWelcome -ErrorAction Stop
    }
    else {
        Write-Output "Connecting to Microsoft Graph..."
        $Scopes = @(
            "DeviceManagementManagedDevices.Read.All"
        )
        Connect-MgGraphCommunity -Scopes $Scopes -NoWelcome -ErrorAction Stop
    }
    Write-Output "✓ Successfully connected to Microsoft Graph"
}
catch {
    Write-Error "Failed to connect to Microsoft Graph: $($_.Exception.Message)"
    exit 1
}

# ============================================================================
# HELPER FUNCTIONS
# ============================================================================

function Get-MgGraphAllPage {
    param(
        [string]$Uri,
        [int]$DelayMs = 100
    )

    $allResults = @()
    $nextLink = $Uri

    do {
        try {
            if ($allResults.Count -gt 0) {
                Start-Sleep -Milliseconds $DelayMs
            }

            $response = Invoke-MgGraphRequest -Uri $nextLink -Method GET

            if ($null -ne $response.value) {
                $allResults += $response.value
            }
            else {
                $allResults += $response
            }

            $nextLink = $response.'@odata.nextLink'
        }
        catch {
            if ($_.Exception.Message -like "*429*") {
                Write-Information "Rate limit hit, waiting 60 seconds..." -InformationAction Continue
                Start-Sleep -Seconds 60
                continue
            }
            throw "Error fetching data: $($_.Exception.Message)"
        }
    } while ($nextLink)

    return $allResults
}

function Get-DefenderIssue {
    param([object]$ProtectionState)

    $issues = [System.Collections.Generic.List[string]]::new()

    if ($ProtectionState.malwareProtectionEnabled -ne $true) { $issues.Add("Malware protection disabled") }
    if ($ProtectionState.realTimeProtectionEnabled -ne $true) { $issues.Add("Real-time protection disabled") }
    if ($ProtectionState.tamperProtectionEnabled -ne $true) { $issues.Add("Tamper protection disabled") }
    if ($ProtectionState.signatureUpdateOverdue -eq $true) { $issues.Add("Signature update overdue") }
    if ($ProtectionState.quickScanOverdue -eq $true) { $issues.Add("Quick scan overdue") }
    if ($ProtectionState.fullScanOverdue -eq $true) { $issues.Add("Full scan overdue") }
    if ($ProtectionState.rebootRequired -eq $true) { $issues.Add("Reboot required") }
    if ($ProtectionState.deviceState -and $ProtectionState.deviceState -ne "clean") { $issues.Add("Device state: $($ProtectionState.deviceState)") }

    return @($issues)
}

# ============================================================================
# MAIN SCRIPT LOGIC
# ============================================================================

try {
    # Tenant-wide overview first - cheap and gives immediate context
    Write-Output "Retrieving tenant protection overview..."
    $overview = $null
    try {
        $overview = Invoke-MgGraphRequest -Uri "https://graph.microsoft.com/beta/deviceManagement/deviceProtectionOverview" -Method GET
    }
    catch {
        Write-Warning "Could not read the device protection overview: $($_.Exception.Message)"
    }

    Write-Output "Retrieving Windows devices..."
    $windowsDevices = Get-MgGraphAllPage -Uri "https://graph.microsoft.com/beta/deviceManagement/managedDevices?`$filter=operatingSystem eq 'Windows'&`$select=id,deviceName,userPrincipalName,lastSyncDateTime"
    Write-Output "✓ Found $(@($windowsDevices).Count) Windows devices - fetching protection state per device..."

    [System.Collections.Generic.List[Object]]$report = @()
    $noStateCount = 0
    $processedCount = 0

    foreach ($device in $windowsDevices) {
        $processedCount++
        if ($processedCount % 50 -eq 0) {
            Write-Output "  Processed $processedCount of $(@($windowsDevices).Count)..."
        }

        $protectionState = $null
        try {
            Start-Sleep -Milliseconds 100
            $protectionState = Invoke-MgGraphRequest -Uri "https://graph.microsoft.com/beta/deviceManagement/managedDevices/$($device.id)/windowsProtectionState" -Method GET
        }
        catch {
            if ($_.Exception.Message -like "*429*") {
                Write-Output "Rate limit hit, waiting 60 seconds..."
                Start-Sleep -Seconds 60
                try {
                    $protectionState = Invoke-MgGraphRequest -Uri "https://graph.microsoft.com/beta/deviceManagement/managedDevices/$($device.id)/windowsProtectionState" -Method GET
                }
                catch {
                    Write-Verbose "No protection state for '$($device.deviceName)': $($_.Exception.Message)"
                }
            }
            else {
                Write-Verbose "No protection state for '$($device.deviceName)': $($_.Exception.Message)"
            }
        }

        if (-not $protectionState -or -not $protectionState.lastReportedDateTime) {
            $noStateCount++
            $report.Add([PSCustomObject]@{
                    DeviceName         = $device.deviceName
                    User               = $device.userPrincipalName
                    DeviceState        = "NotReported"
                    RealTimeProtection = ""
                    TamperProtection   = ""
                    SignatureVersion   = ""
                    SignatureOverdue   = ""
                    LastReported       = ""
                    Issues             = "No Defender state reported"
                    IssueCount         = 1
                })
            continue
        }

        $issues = Get-DefenderIssue -ProtectionState $protectionState
        $lastReported = if ($protectionState.lastReportedDateTime) { [DateTime]::Parse($protectionState.lastReportedDateTime.ToString()) } else { $null }

        $report.Add([PSCustomObject]@{
                DeviceName         = $device.deviceName
                User               = $device.userPrincipalName
                DeviceState        = $protectionState.deviceState
                RealTimeProtection = $protectionState.realTimeProtectionEnabled
                TamperProtection   = $protectionState.tamperProtectionEnabled
                SignatureVersion   = $protectionState.signatureVersion
                SignatureOverdue   = $protectionState.signatureUpdateOverdue
                LastReported       = if ($lastReported) { $lastReported.ToString("yyyy-MM-dd HH:mm") } else { "" }
                Issues             = ($issues -join "; ")
                IssueCount         = $issues.Count
            })
    }

    # ----- Display results -----
    Write-Output "`nDEFENDER STATUS REPORT"
    Write-Output ("=" * 50)
    Write-Output "Generated: $(Get-Date -Format 'yyyy-MM-dd HH:mm:ss')"
    Write-Output ("=" * 50)

    if ($overview) {
        Write-Output "`nTenant overview:"
        Write-Output "  Reporting devices:        $($overview.totalReportedDeviceCount)"
        Write-Output "  Clean:                    $($overview.cleanDeviceCount)"
        Write-Output "  Critical failures:        $($overview.criticalFailuresDeviceCount)"
        Write-Output "  Pending signature update: $($overview.pendingSignatureUpdateDeviceCount)"
        Write-Output "  Pending restart:          $($overview.pendingRestartDeviceCount)"
        Write-Output "  Inactive agent:           $($overview.inactiveThreatAgentDeviceCount)"
    }

    $devicesWithIssues = @($report | Where-Object { $_.IssueCount -gt 0 })
    $healthyDevices = @($report | Where-Object { $_.IssueCount -eq 0 })

    if ($devicesWithIssues.Count -gt 0) {
        Write-Output "`nDevices with issues ($($devicesWithIssues.Count)):"
        foreach ($row in ($devicesWithIssues | Sort-Object IssueCount -Descending)) {
            Write-Output "  $($row.DeviceName) | $($row.User)"
            Write-Output "    $($row.Issues)"
        }
    }

    if (-not $OnlyIssues -and $healthyDevices.Count -gt 0) {
        Write-Output "`nHealthy devices ($($healthyDevices.Count)):"
        foreach ($row in ($healthyDevices | Sort-Object DeviceName)) {
            Write-Output "  $($row.DeviceName) | signatures $($row.SignatureVersion) | reported $($row.LastReported)"
        }
    }

    # Summary
    Write-Output "`n"
    Write-Output ("=" * 50)
    Write-Output "Summary: $($report.Count) Windows devices | $($healthyDevices.Count) healthy | $($devicesWithIssues.Count) with issues | $noStateCount never reported"
    Write-Output ("=" * 50)

    # Export to CSV if requested
    if ($ExportToCsv) {
        $timestamp = Get-Date -Format "yyyy-MM-dd_HH-mm-ss"
        $csvPath = Join-Path $OutputPath "Defender_Status_$timestamp.csv"
        $report | Export-Csv -Path $csvPath -NoTypeInformation -Encoding UTF8
        Write-Output "✓ CSV report saved: $csvPath"
    }
}
catch {
    Write-Error "Script execution failed: $($_.Exception.Message)"
    exit 1
}
finally {
    try {
        $null = Disconnect-MgGraph
        Write-Output "✓ Disconnected from Microsoft Graph"
    }
    catch {
        Write-Verbose "Graph disconnection completed"
    }
}

# Copia sin cambios de https://github.com/ugurkocde/IntuneAutomation (commit 797bb2e).
# MIT License
#
# Copyright (c) 2025 Ugur Koc | Microsoft MVP
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.