Policy Changes Monitor

<#
.TITLE
    Policy Changes Monitor

.SYNOPSIS
    Monitor and report on recent changes to Policies in Microsoft Intune.

.DESCRIPTION
    This script connects to Microsoft Graph and retrieves recent changes to Policies
    configured in Intune. It checks audit logs for policy modifications, creations, deletions, and
    assignments within a specified time period. The script generates detailed reports in CSV format,
    highlighting policy changes with details about who made the changes, when they occurred, and
    what was modified. This helps administrators track configuration drift and maintain governance
    over device configuration policies.

.TAGS
    Monitoring

.MINROLE
    Intune Administrator

.PERMISSIONS
    DeviceManagementApps.Read.All,DeviceManagementConfiguration.Read.All

.AUTHOR
    Ugur Koc

.VERSION
    1.0

.CHANGELOG
    1.0 - Initial release

.LASTUPDATE
    2025-05-29

.EXAMPLE
    .\check-policy-changes.ps1
    Generates a report of policy changes from the last 30 days

.EXAMPLE
    .\check-policy-changes.ps1 -DaysBack 30 -OutputPath "C:\Reports"
    Generates a report of policy changes from the last 30 days and saves to specified directory

.EXAMPLE
    .\check-policy-changes.ps1 -OnlyShowChanges -SendEmailAlert -AlertEmailAddress "admin@contoso.com"
    Shows only modified policies and sends email alerts for changes

.NOTES
    - Requires Microsoft.Graph.Authentication module: Install-Module Microsoft.Graph.Authentication
    - Requires appropriate permissions in Azure AD
    - Policies use modern configuration templates
    - Policies require beta Graph endpoint access
    - Audit data is available for up to 30 days by default
    - Critical for maintaining configuration governance and compliance
    - Monitor for unauthorized changes to security policies
#>

[CmdletBinding()]
param(
    [Parameter(Mandatory = $false, HelpMessage = "Number of days to look back for changes")]
    [ValidateRange(1, 90)]
    [int]$DaysBack = 30,
    
    [Parameter(Mandatory = $false, HelpMessage = "Directory path to save reports")]
    [ValidateNotNullOrEmpty()]
    [string]$OutputPath = ".",
    
    [Parameter(Mandatory = $false, HelpMessage = "Only show policies with changes")]
    [switch]$OnlyShowChanges,
    
    [Parameter(Mandatory = $false, HelpMessage = "Send email alert for policy changes")]
    [switch]$SendEmailAlert,
    
    [Parameter(Mandatory = $false, HelpMessage = "Email address to send alerts to")]
    [string]$AlertEmailAddress = "",
    
    [Parameter(Mandatory = $false, HelpMessage = "Include detailed change information")]
    [switch]$IncludeDetails,
    
    [Parameter(Mandatory = $false, HelpMessage = "Force module installation without prompting")]
    [switch]$ForceModuleInstall
)

# ============================================================================
# ENVIRONMENT DETECTION AND SETUP
# ============================================================================

function Initialize-RequiredModule {
    <#
    .SYNOPSIS
    Ensures required modules are available and loaded
    #>
    param(
        [string[]]$ModuleNames,
        [bool]$IsAutomationEnvironment,
        [bool]$ForceInstall = $false
    )
    
    foreach ($ModuleName in $ModuleNames) {
        Write-Verbose "Checking module: $ModuleName"
        
        # Check if module is available
        $module = Get-Module -ListAvailable -Name $ModuleName | Select-Object -First 1
        
        if (-not $module) {
            if ($IsAutomationEnvironment) {
                $errorMessage = @"
Module '$ModuleName' is not available in this Azure Automation Account.

To resolve this issue:
1. Go to Azure Portal
2. Navigate to your Automation Account
3. Go to 'Modules' > 'Browse Gallery'
4. Search for '$ModuleName'
5. Click 'Import' and wait for installation to complete

Alternative: Use PowerShell to import the module:
Import-Module Az.Automation
Import-AzAutomationModule -AutomationAccountName "YourAccount" -ResourceGroupName "YourRG" -Name "$ModuleName"
"@
                throw $errorMessage
            }
            else {
                # Local environment - attempt to install
                Write-Information "Module '$ModuleName' not found. Attempting to install..." -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 {
                    # Check if running as administrator for AllUsers scope
                    $isAdmin = ([Security.Principal.WindowsPrincipal] [Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([Security.Principal.WindowsBuiltInRole] "Administrator")
                    $scope = if ($isAdmin) { "AllUsers" } else { "CurrentUser" }
                    
                    Write-Information "Installing '$ModuleName' in scope '$scope'..." -InformationAction Continue
                    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 the module
        try {
            Write-Verbose "Importing module: $ModuleName"
            Import-Module -Name $ModuleName -Force -ErrorAction Stop
            Write-Verbose "✓ Successfully imported '$ModuleName'"
        }
        catch {
            throw "Failed to import module '$ModuleName': $($_.Exception.Message)"
        }
    }
}

# Detect execution environment
if ($PSPrivateMetadata.JobId.Guid) {
    Write-Output "Running inside Azure Automation Runbook"
    $IsAzureAutomation = $true
}
else {
    Write-Information "Running locally in IDE or terminal" -InformationAction Continue
    $IsAzureAutomation = $false
}

# Initialize required modules
$RequiredModules = @(
    "Microsoft.Graph.Authentication"
)

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) {
        # Azure Automation - Use Managed Identity
        Write-Output "Connecting to Microsoft Graph using Managed Identity..."
        Connect-MgGraph -Identity -NoWelcome -ErrorAction Stop
        Write-Output "✓ Successfully connected to Microsoft Graph using Managed Identity"
    }
    else {
        # Local execution - Use interactive authentication
        Write-Information "Connecting to Microsoft Graph with interactive authentication..." -InformationAction Continue
        $Scopes = @(
            "DeviceManagementApps.Read.All",
            "DeviceManagementConfiguration.Read.All"
        )
        Connect-MgGraph -Scopes $Scopes -NoWelcome -ErrorAction Stop
        Write-Information "✓ Successfully connected to Microsoft Graph" -InformationAction Continue
    }
}
catch {
    Write-Error "Failed to connect to Microsoft Graph: $($_.Exception.Message)"
    exit 1
}

# ============================================================================
# HELPER FUNCTIONS
# ============================================================================

# Function to get all pages of results from Graph API
function Get-MgGraphAllPage {
    param(
        [Parameter(Mandatory = $true)]
        [string]$Uri,
        [int]$DelayMs = 100
    )
    
    $AllResults = @()
    $NextLink = $Uri
    $RequestCount = 0
    
    do {
        try {
            # Add delay to respect rate limits
            if ($RequestCount -gt 0) {
                Start-Sleep -Milliseconds $DelayMs
            }
            
            $Response = Invoke-MgGraphRequest -Uri $NextLink -Method GET
            $RequestCount++
            
            if ($Response.value) {
                $AllResults += $Response.value
            }
            else {
                $AllResults += $Response
            }
            
            $NextLink = $Response.'@odata.nextLink'
        }
        catch {
            if ($_.Exception.Message -like "*429*" -or $_.Exception.Message -like "*throttled*") {
                Write-Information "`nRate limit hit, waiting 60 seconds..." -InformationAction Continue
                Start-Sleep -Seconds 60
                continue
            }
            Write-Warning "Error fetching data from $NextLink : $($_.Exception.Message)"
            break
        }
    } while ($NextLink)
    
    return $AllResults
}

# Function to format change details
function Format-ChangeDetail {
    param(
        [object]$AuditLog
    )
    
    $ChangeDetails = @()
    
    if ($AuditLog.resources) {
        foreach ($Resource in $AuditLog.resources) {
            if ($Resource.modifiedProperties) {
                foreach ($Property in $Resource.modifiedProperties) {
                    $ChangeDetail = [PSCustomObject]@{
                        PropertyName = $Property.displayName
                        OldValue     = if ($Property.oldValue) { $Property.oldValue -replace "`n", " " } else { "N/A" }
                        NewValue     = if ($Property.newValue) { $Property.newValue -replace "`n", " " } else { "N/A" }
                    }
                    $ChangeDetails += $ChangeDetail
                }
            }
        }
    }
    
    return $ChangeDetails
}

# Function to determine change severity
function Get-ChangeSeverity {
    param(
        [string]$Activity,
        [string]$Result
    )
    
    if ($Result -eq "failure") {
        return "High"
    }
    
    switch -Wildcard ($Activity) {
        "*Delete*" { return "High" }
        "*Create*" { return "Medium" }
        "*Update*" { return "Medium" }
        "*Assign*" { return "Low" }
        default { return "Low" }
    }
}

# ============================================================================
# MAIN SCRIPT LOGIC
# ============================================================================

try {
    Write-Information "Starting Policies changes analysis..." -InformationAction Continue
    
    # Calculate start date
    $StartDate = (Get-Date).AddDays(-$DaysBack)
    $StartDateFormatted = $StartDate.ToString("yyyy-MM-ddTHH:mm:ssZ")
    
    Write-Information "Analyzing changes from: $($StartDate.ToString('yyyy-MM-dd HH:mm:ss'))" -InformationAction Continue
    
    # ========================================================================
    # GET AUDIT LOGS FOR SETTINGS CATALOG CHANGES
    # ========================================================================
    
    Write-Information "Retrieving audit logs for Policies changes..." -InformationAction Continue
    
    try {
        # Query for Policies changes (DeviceConfiguration category)
        $AuditLogsUri = "https://graph.microsoft.com/beta/deviceManagement/auditEvents?`$filter=activityDateTime ge $StartDateFormatted and category eq 'DeviceConfiguration'&`$orderby=activityDateTime desc&`$top=50"
        $AuditLogs = Get-MgGraphAllPage -Uri $AuditLogsUri
        
        Write-Information "Retrieved $($AuditLogs.Count) DeviceConfiguration audit events" -InformationAction Continue
        
        # Filter for Policies (DeviceManagementConfigurationPolicy) activities
        $PoliciesActivities = $AuditLogs | Where-Object { 
            $_.activityType -like "*DeviceManagementConfigurationPolicy*"
        }
        
        Write-Information "✓ Found $($PoliciesActivities.Count) policy changes" -InformationAction Continue
    }
    catch {
        Write-Warning "Failed to retrieve audit logs: $($_.Exception.Message)"
        $PoliciesActivities = @()
    }
    
    # ========================================================================
    # FILTER AND PROCESS CHANGES
    # ========================================================================
    
    Write-Information "Processing Policies policy changes..." -InformationAction Continue
    
    # Filter changes if OnlyShowChanges is specified
    if ($OnlyShowChanges) {
        $PoliciesActivities = $PoliciesActivities | Where-Object {
            $_.activityType -like "*Update*" -or $_.activityType -like "*Modify*"
        }
        Write-Information "Filtered to show only policy modifications: $($PoliciesActivities.Count) changes" -InformationAction Continue
    }
    
    # Get the last 5 changes
    $Last5Changes = $PoliciesActivities | Select-Object -First 5
    
    if ($Last5Changes.Count -eq 0) {
        Write-Information "No Policies policy changes found in the specified time period." -InformationAction Continue
        return
    }
    
    Write-Information "`n========================================" -InformationAction Continue
    Write-Information "LAST 5 POLICIES POLICY CHANGES" -InformationAction Continue
    Write-Information "========================================" -InformationAction Continue
    
    # Prepare CSV data for export
    $CsvData = @()
    
    $ChangeNumber = 1
    foreach ($Change in $Last5Changes) {
        try {
            # Get policy name and user info
            $PolicyName = "Unknown Policy"
            $UserName = "System"
            
            if ($Change.resources -and $Change.resources.Count -gt 0) {
                $PolicyName = $Change.resources[0].displayName
            }
            
            if ($Change.actor -and $Change.actor.userPrincipalName) {
                $UserName = $Change.actor.userPrincipalName
            }
            
            Write-Information "`n[$ChangeNumber] $($Change.activityDateTime)" -InformationAction Continue
            Write-Information "Policy: $PolicyName" -InformationAction Continue
            Write-Information "Action: $($Change.activityType)" -InformationAction Continue
            Write-Information "User: $UserName" -InformationAction Continue
            Write-Information "Result: $($Change.activityResult)" -InformationAction Continue
            
            # Collect change details for CSV export
            $ChangeDetails = ""
            $Severity = Get-ChangeSeverity -Activity $Change.activityType -Result $Change.activityResult
            
            # Show modified properties (before/after values)
            if ($Change.resources -and $Change.resources[0].modifiedProperties) {
                Write-Information "Changes:" -InformationAction Continue
                $ChangeDetailsList = @()
                foreach ($Property in $Change.resources[0].modifiedProperties) {
                    $OldValue = if ($Property.oldValue) { $Property.oldValue } else { "(empty)" }
                    $NewValue = if ($Property.newValue) { $Property.newValue } else { "(empty)" }
                    Write-Information "  - $($Property.displayName): '$OldValue' → '$NewValue'" -InformationAction Continue
                    
                    if ($IncludeDetails) {
                        $ChangeDetailsList += "$($Property.displayName): '$OldValue' → '$NewValue'"
                    }
                }
                $ChangeDetails = $ChangeDetailsList -join "; "
            }
            else {
                Write-Information "  No detailed change information available" -InformationAction Continue
            }
            
            # Add to CSV data
            $CsvRecord = [PSCustomObject]@{
                DateTime   = $Change.activityDateTime
                PolicyName = $PolicyName
                Action     = $Change.activityType
                User       = $UserName
                Result     = $Change.activityResult
                Severity   = $Severity
                Details    = if ($IncludeDetails) { $ChangeDetails } else { "" }
            }
            $CsvData += $CsvRecord
            
            $ChangeNumber++
        }
        catch {
            Write-Warning "Error processing change: $($_.Exception.Message)"
            continue
        }
    }
    
    # ========================================================================
    # EXPORT TO CSV
    # ========================================================================
    
    if ($CsvData.Count -gt 0) {
        $OutputFile = Join-Path -Path $OutputPath -ChildPath "PolicyChanges_$(Get-Date -Format 'yyyyMMdd_HHmmss').csv"
        try {
            $CsvData | Export-Csv -Path $OutputFile -NoTypeInformation -Encoding UTF8
            Write-Information "✓ Report exported to: $OutputFile" -InformationAction Continue
        }
        catch {
            Write-Warning "Failed to export CSV report: $($_.Exception.Message)"
        }
    }
    
    # ========================================================================
    # EMAIL ALERTS
    # ========================================================================
    
    if ($SendEmailAlert -and $AlertEmailAddress -and $CsvData.Count -gt 0) {
        try {
            $Subject = "Policy Changes Alert - $($CsvData.Count) changes detected"
            $Body = @"
Policy Changes Report

Time Period: Last $DaysBack days
Total Changes: $($CsvData.Count)

Recent Changes:
$($CsvData | ForEach-Object { "- $($_.DateTime): $($_.PolicyName) - $($_.Action) by $($_.User)" } | Select-Object -First 10 | Out-String)

For full details, please check the attached CSV report or review the Intune audit logs.
"@
            
            # Note: Email sending would require additional modules like Send-MailMessage or Microsoft Graph
            Write-Information "Email alert prepared for: $AlertEmailAddress" -InformationAction Continue
            Write-Information "Subject: $Subject" -InformationAction Continue
            Write-Warning "Email sending functionality requires additional configuration (SMTP settings or Microsoft Graph permissions)"
        }
        catch {
            Write-Warning "Failed to prepare email alert: $($_.Exception.Message)"
        }
    }
    
    Write-Information "`n✓ Policies changes analysis completed successfully" -InformationAction Continue
}
catch {
    Write-Error "Script failed: $($_.Exception.Message)"
    exit 1
}
finally {
    # Cleanup operations
    try {
        Disconnect-MgGraph -ErrorAction SilentlyContinue | Out-Null
        Write-Information "Disconnected from Microsoft Graph" -InformationAction Continue
    }
    catch {
        Write-Warning "Failed to disconnect from Microsoft Graph: $($_.Exception.Message)"
    }
}

# ============================================================================
# SCRIPT SUMMARY
# ============================================================================

Write-Information "
========================================
Script Execution Summary
========================================
Script: Policies Changes Monitor
Time Period: Last $DaysBack days
Status: Completed
========================================
" -InformationAction Continue