PSAzureFunctions.psm1

Function Connect-GraphAPI {
    <#
    .SYNOPSIS
    Connect to Azure Graph API
     
    .DESCRIPTION
    Connect to Azure Graph API with either a Secret value from your Azure Application
    OR
    Connect with a uploaded certificate, you need to install the certificate in your LocalMachine\My store for this to work.
    When connected you recieve a header variable $azureGraphAuthenticationHeader that you can use with your own Invoke-RestMethod commands if needed.
    All the Modules within this Module already uses this value so you never need to add it anywhere if you are not doing your own things.
     
    .PARAMETER AzureTenantID
    Your Azure Tenant ID
     
    .PARAMETER ApplicationID
    The Azure Application ID for your Application.
     
    .PARAMETER APISecret
    If CertThumbprint is not used then this should be supplied - the Secret value created from your Azure Application
     
    .PARAMETER CertThumbprint
    Your Certificate Thumbprint that is installed in your 'LocalMachine\My' store and Uploaded to the Azure Application
     
    .PARAMETER LogToFile
    This parameter is connected to the Module PSLoggingFunctions mot information can be found on the GitHub.
    https://github.com/rakelord/PSLoggingFunctions
     
    .EXAMPLE
    Connect-GraphAPI -AzureTenantID "1533bb8f-4d6a-54b3-a5d3-48463a22ca25" -ApplicationID "2cf231fa-236d-4ew1-ja72-a14a45web451" -APISecret "ZTasdergearbgaerbnreanrae=" -LogToFile $True
    Connect-GraphAPI -AzureTenantID "1533bb8f-4d6a-54b3-a5d3-48463a22ca25" -ApplicationID "2cf231fa-236d-4ew1-ja72-a14a45web451" -CertThumbprint "40F51F9DCA3245FSDG7654GTSDSGDF1D78031C9" -LogToFile $False
     
    #>

    param(
        [parameter(mandatory)]
        $AzureTenantID,
        [parameter(mandatory)]
        $ApplicationID,
        $APISecret,
        $CertThumbprint,
        [parameter(mandatory)]
        [ValidateSet("True","False")]
        $LogToFile
    )
    $Body = @{
        Grant_Type    = "client_credentials"
        Scope         = "https://graph.microsoft.com/.default"
        client_Id     = "$ApplicationID"
        Client_Secret = "$APISecret"
    }

    $OAUTH2Url = "https://login.microsoftonline.com/$AzureTenantID/oauth2/v2.0/token"

    $Cert = Get-X509Certificate -thumbPrint $CertThumbprint -storeName "My"

    Write-Log -Message "Connecting to Azure Graph API" -Active $LogToFile
    
    if ($Cert){ # Certificate
        $binaryCertificateFingerprint = Convert-HexStringToByteArray($Cert.Thumbprint)
        $base64EncodedFingerprint = [System.Convert]::ToBase64String($binaryCertificateFingerprint)

        $JWT_Header = @{
            alg = "RS256"
            x5t = $base64EncodedFingerprint
            typ = "JWT"
        } | ConvertTo-Json

        $now = (Get-Date).ToUniversalTime()
        $createDate = (New-TimeSpan -Start 1970-01-01 -End ($now).DateTime).TotalSeconds
        $expiryDate = (New-TimeSpan -Start 1970-01-01 -End ($now).AddMinutes(60).DateTime).TotalSeconds
        $JWT_Payload = @{
            iss = $ApplicationID
            sub = $ApplicationID
            aud = $OAUTH2Url
            iat = $createDate
            nbf = $createDate
            exp = $expiryDate
            jti = (New-Guid).Guid
        } | ConvertTo-Json

        $JWT_Token = New-Jwt -Cert $Cert -PayloadJson $JWT_Payload -Header $JWT_Header

        $Form = @{
            grant_type              = "client_credentials"
            client_assertion_type   = "urn:ietf:params:oauth:client-assertion-type:jwt-bearer"
            client_id               = $ApplicationID
            scope                   = "https://graph.microsoft.com/.default"
            client_assertion        = $JWT_Token
        }

        $Headers = @{
            "Content-Type" = "application/x-www-form-urlencoded;charset=UTF-8"
        }
        
        $GraphAPIToken = Invoke-RestMethod -Method POST -Uri $OAUTH2Url -Body $Form -Headers $Headers
        $azureGraphAuthenticationHeader = @{ Authorization = "$($GraphAPIToken.token_type) $($GraphAPIToken.access_token)" }
    }
    else { # Secret
        $GraphAPIToken = Invoke-RestMethod -Uri "$OAUTH2Url" -Method POST -Body $Body
        $azureGraphAuthenticationHeader = @{ Authorization = "$($GraphAPIToken.token_type) $($GraphAPIToken.access_token)" }
    }

    # Verify connection
    $global:AzureGraphAPIAuthenticated = $false
    if ($GraphAPIToken.access_token){
        $global:AzureGraphAPIAuthenticated = $true
        Write-Log -Message "Azure Graph API Authenticated: $AzureGraphAPIAuthenticated" -Active $LogToFile
        Write-Host "Azure Graph API Authenticated: $AzureGraphAPIAuthenticated"
        Write-Host "Use Header Connection Variable ="'$azureGraphAuthenticationHeader'
        $global:azureGraphAuthenticationHeader = $azureGraphAuthenticationHeader
        return ""
    }
    Write-Log -Message "Azure Graph API Authenticated: $AzureGraphAPIAuthenticated" -Active $LogToFile
    Write-Host "Azure Graph API Authenticated: $AzureGraphAPIAuthenticated"
    return $false
}

function Find-AzureGraphAPIConnection {
    if (!$AzureGraphAPIAuthenticated){
        Write-Warning "Azure Graph API is not authenticated, you need to run Connect-GraphAPI and make sure you put in the correct credentials!"
        return $false
    }
    return $true
}

function Convert-HexStringToByteArray {
    param (
        [string]$hex
    )

    $byteArray = [byte[]]::new($hex.length / 2)
    for ($i = 0; $i -lt $hex.length; $i += 2) {
        $byteArray[$i / 2] = [byte]::Parse($hex.Substring($i, 2), [System.Globalization.NumberStyles]::HexNumber)
    }

    return $byteArray
}

Function Get-EndpointManagerDevices {
    <#
    .SYNOPSIS
    Retrieve all Endpoint Manager Devices from Azure
     
    .DESCRIPTION
    Retrieve all Endpoint Manager Devices from Azure and the ability to get the data as a HashTable or a normal Powershell object.
    Also gives all objects a separation if they are mobile phones or computers.
     
    .PARAMETER LogToFile
    This parameter is connected to the Module PSLoggingFunctions mot information can be found on the GitHub.
    https://github.com/rakelord/PSLoggingFunctions
 
    .PARAMETER AsHashTable
    Great a HashTable with the serialNumber property as the Key value $Object[$serialNumber]
     
    .EXAMPLE
    Get-EndpointManagerDevices -AsHashTable -LogToFile $True
    Get-EndpointManagerDevices -LogToFile $False
 
    .NOTES
    You need these Azure Application permissions for this to work.
    Application - DeviceManagementManagedDevices.Read.All
 
    #>

    param(
        [parameter(mandatory)]
        [ValidateSet("True","False")]
        $LogToFile,
        [switch]
        $AsHashTable
    )

    if (Find-AzureGraphAPIConnection){
        $Uri = "https://graph.microsoft.com/beta/deviceManagement/managedDevices"
        $EndpointDevices = @()
        do {
            $Results = Invoke-TryCatchLog -InfoLog "Retrieving 1000 Endpoint devices" -LogToFile $LogToFile -ScriptBlock {
                Invoke-RestMethod -Headers $azureGraphAuthenticationHeader -Uri $Uri -UseBasicParsing -Method "GET" -ContentType "application/json"
            }
            if ($Results.value) {
                $EndpointDevices += $Results.value
            }
            else {
                $EndpointDevices += $Results
            }
            $uri = $Results.'@odata.nextlink'
        } until (!($uri))

        # sort devices by lastSyncDateTime to fix duplicate issues from Endpoint AND give all devices a device_type with either 'Mobile phone' or 'Computer'
        $EndpointDevices = $EndpointDevices | Sort-Object -Property lastSyncDateTime | Select-Object *,@{
            l='device_type';e={
                if ($_.imei -AND $_.operatingSystem -ne 'Windows'){
                    return "Mobile phone"
                }
                return "Computer"
            }
        }
        
        # Faster filtering if HashTable is used, if you can reference the serialnumber when looking for device in Object list.
        $HashTable = @{}
        foreach ($Device in $EndpointDevices){
            $HashTable[$Device.serialNumber] = $Device
        }
        if ($AsHashTable) { return $HashTable }

        $deviceList = @()
        foreach ($Device in $HashTable.Keys) {
            $deviceList += $HashTable[$Device]
        }
        return $deviceList
    }
}

function Get-X509Certificate {
    Param(
        [parameter(mandatory)]
        $thumbPrint,
        [parameter(mandatory)]
        $storeName
    )
    $store = New-Object System.Security.Cryptography.X509Certificates.X509Store($storeName, "LocalMachine")
    $store.Open([System.Security.Cryptography.X509Certificates.OpenFlags]::ReadOnly)
    $certificates = $store.Certificates.Find([System.Security.Cryptography.X509Certificates.X509FindType]::FindByThumbprint, $thumbPrint, $false)
    $store.Close()

    return $certificates[0]
}
function ConvertTo-Base64UrlString {
    <#
    .SYNOPSIS
    Base64url encoder.
     
    .DESCRIPTION
    Encodes a string or byte array to base64url-encoded string.
     
    .PARAMETER in
    Specifies the input. Must be string, or byte array.
     
    .INPUTS
    You can pipe the string input to ConvertTo-Base64UrlString.
     
    .OUTPUTS
    ConvertTo-Base64UrlString returns the encoded string by default.
     
    .EXAMPLE
     
    PS Variable:> '{"alg":"RS256","typ":"JWT"}' | ConvertTo-Base64UrlString
    eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9
     
    .LINK
    https://github.com/SP3269/posh-jwt
    .LINK
    https://jwt.io/
     
    #>

    [CmdletBinding()]
    param (
        [Parameter(Mandatory=$true,ValueFromPipeline=$true)]$in
    )
    if ($in -is [string]) {
        return [Convert]::ToBase64String([System.Text.Encoding]::UTF8.GetBytes($in)) -replace '\+','-' -replace '/','_' -replace '='
    }
    elseif ($in -is [byte[]]) {
        return [Convert]::ToBase64String($in) -replace '\+','-' -replace '/','_' -replace '='
    }
    else {
        throw "ConvertTo-Base64UrlString requires string or byte array input, received $($in.GetType())"
    }
}

function New-Jwt {
    <#
    .SYNOPSIS
    Creates a JWT (JSON Web Token).
     
    .DESCRIPTION
    Creates signed JWT given a signing certificate and claims in JSON.
     
    .PARAMETER Payload
    Specifies the claim to sign in JSON. Mandatory string.
     
    .PARAMETER Header
    Specifies a JWT header. Optional. Defaults to '{"alg":"RS256","typ":"JWT"}'.
     
    .PARAMETER Cert
    Specifies the signing certificate of type System.Security.Cryptography.X509Certificates.X509Certificate2. Must be specified and contain the private key if the algorithm in the header is RS256.
     
    .PARAMETER Secret
    Specifies the HMAC secret. Can be byte array, or a string, which will be converted to bytes. Must be specified if the algorithm in the header is HS256.
     
    .INPUTS
    You can pipe a string object (the JSON payload) to New-Jwt.
     
    .OUTPUTS
    System.String. New-Jwt returns a string with the signed JWT.
     
    .EXAMPLE
    PS Variable:\> $cert = (Get-ChildItem Cert:\CurrentUser\My)[1]
     
    PS Variable:\> New-Jwt -Cert $cert -PayloadJson '{"token1":"value1","token2":"value2"}'
    eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJ0b2tlbjEiOiJ2YWx1ZTEiLCJ0b2tlbjIiOiJ2YWx1ZTIifQ.Kd12ryF7Uuk9Y1UWsqdSk6cXNoYZBf9GBoqcEz7R5e4ve1Kyo0WmSr-q4XEjabcbaG0hHJyNGhLDMq6BaIm-hu8ehKgDkvLXPCh15j9AzabQB4vuvSXSWV3MQO7v4Ysm7_sGJQjrmpiwRoufFePcurc94anLNk0GNkTWwG59wY4rHaaHnMXx192KnJojwMR8mK-0_Q6TJ3bK8lTrQqqavnCW9vrKoWoXkqZD_4Qhv2T6vZF7sPkUrgsytgY21xABQuyFrrNLOI1g-EdBa7n1vIyeopM4n6_Uk-ttZp-U9wpi1cgg2pRIWYV5ZT0AwZwy0QyPPx8zjh7EVRpgAKXDAg
     
    .EXAMPLE
    $cert = New-Object System.Security.Cryptography.X509Certificates.X509Certificate2("/mnt/c/PS/JWT/jwt.pfx","jwt")
     
    $now = (Get-Date).ToUniversalTime()
    $createDate = [Math]::Floor([decimal](Get-Date($now) -UFormat "%s"))
    $expiryDate = [Math]::Floor([decimal](Get-Date($now.AddHours(1)) -UFormat "%s"))
    $rawclaims = [Ordered]@{
        iss = "examplecom:apikey:uaqCinPt2Enb"
        iat = $createDate
        exp = $expiryDate
    } | ConvertTo-Json
     
    $jwt = New-Jwt -PayloadJson $rawclaims -Cert $cert
     
    $apiendpoint = "https://api.example.com/api/1.0/systems"
     
    $splat = @{
        Method="GET"
        Uri=$apiendpoint
        ContentType="application/json"
        Headers = @{authorization="bearer $jwt"}
    }
     
    Invoke-WebRequest @splat
     
    .LINK
    https://github.com/SP3269/posh-jwt
    .LINK
    https://jwt.io/
     
    #>

    
    [CmdletBinding()]
    param (
        [Parameter(Mandatory=$false)][string]$Header = '{"alg":"RS256","typ":"JWT"}',
        [Parameter(Mandatory=$true, ValueFromPipeline=$true)][string]$PayloadJson,
        [Parameter(Mandatory=$false)][System.Security.Cryptography.X509Certificates.X509Certificate2]$Cert,
        [Parameter(Mandatory=$false)]$Secret # Can be string or byte[] - checks in the code
    )

    Write-Verbose "Payload to sign: $PayloadJson"

    try { $Alg = (ConvertFrom-Json -InputObject $Header -ErrorAction Stop).alg } # Validating that the parameter is actually JSON - if not, generate breaking error
    catch { throw "The supplied JWT header is not JSON: $Header" }
    Write-Verbose "Algorithm: $Alg"

    try { ConvertFrom-Json -InputObject $PayloadJson -ErrorAction Stop | Out-Null } # Validating that the parameter is actually JSON - if not, generate breaking error
    catch { throw "The supplied JWT payload is not JSON: $PayloadJson" }

    $encodedHeader = ConvertTo-Base64UrlString $Header
    $encodedPayload = ConvertTo-Base64UrlString $PayloadJson

    $jwt = $encodedHeader + '.' + $encodedPayload # The first part of the JWT

    $toSign = [System.Text.Encoding]::UTF8.GetBytes($jwt)

    if (-not $PSBoundParameters.ContainsKey("Cert")) {
        throw "RS256 requires -Cert parameter of type System.Security.Cryptography.X509Certificates.X509Certificate2"
    }
    Write-Verbose "Signing certificate: $($Cert.Subject)"
    $rsa = $Cert.PrivateKey
    if ($null -eq $rsa) { # Requiring the private key to be present; else cannot sign!
        throw "There's no private key in the supplied certificate - cannot sign" 
    }
    else {
        # Overloads tested with RSACryptoServiceProvider, RSACng, RSAOpenSsl
        try { $sig = ConvertTo-Base64UrlString $rsa.SignData($toSign,[Security.Cryptography.HashAlgorithmName]::SHA256,[Security.Cryptography.RSASignaturePadding]::Pkcs1) }
        catch { throw New-Object System.Exception -ArgumentList ("Signing with SHA256 and Pkcs1 padding failed using private key $($rsa): $_", $_.Exception) }
    }
    
    $jwt = $jwt + '.' + $sig
    return $jwt
}

function Get-EntraIDUsers {
    <#
    .SYNOPSIS
    Retrieve all users from Azure Entra
     
    .DESCRIPTION
    Retrieve all users from Azure Entra and let the user choose if they want a HashTable object or just normal Powershell Object
    Also the ability to set which property to be the key in the hashtable.
     
    .PARAMETER HashTableKey
    The $variable[keyvalue] - The key value that will be the filter
     
    .PARAMETER AsHashTable
    If the function should return a HashTable otherwise it will be normal powershell object.
     
    .PARAMETER LogToFile
    This parameter is connected to the Module PSLoggingFunctions mot information can be found on the GitHub.
    https://github.com/rakelord/PSLoggingFunctions
     
    .EXAMPLE
    Return a HashTable with the userprincipalName as Hash Key and create a log
    Get-EntraUsers -AsHashTable -HashTableKey "userprincipalName" -LogToFile $True
     
    Return a Normal Powershell object and do not Log
    Get-EntraUsers -LogToFile $False
     
    .NOTES
    You need these Azure Application permissions for this to work.
    Application - User.Read.All
 
    #>

    Param(
        [switch]
        $AsHashTable,
        $HashTableKey,
        [parameter(mandatory)]
        [ValidateSet("True","False")]
        $LogToFile
    )
    if (Find-AzureGraphAPIConnection){
        $Uri = "https://graph.microsoft.com/beta/users?" + '$top=999'
        $UserObjects = @()
        do {
            $Results = Invoke-TryCatchLog -InfoLog "Retrieving 1000 Entra User objects" -LogToFile $LogToFile -ScriptBlock {
                Invoke-RestMethod -Headers $azureGraphAuthenticationHeader -Uri $Uri -UseBasicParsing -Method "GET" -ContentType "application/json"
            }
            if ($Results.value) {
                $UserObjects += $Results.value
            }
            else {
                $UserObjects += $Results
            }
            $uri = $Results.'@odata.nextlink'
        } until (!($uri))

        if ($AsHashTable){
            $HashTable = @{}
            foreach ($user in $UserObjects) {
                $HashTable[$user."$HashTableKey"] = $user
            }
            return $HashTable
        }

        return $UserObjects
    }
}

Function Get-AzureTenantSecurityScore {
    <#
    .SYNOPSIS
    Retrieve the Azure Tenants Security Score
     
    .DESCRIPTION
    Retrieve the Azure Tenants Security Score, only get the latest score instead of a long list.
    And only retrieve the Secore + Comparable Tenants Score
     
    .PARAMETER LogToFile
    This parameter is for logging, check GitHub for PSLoggingFunctions if you want to learn more, just set $True if you want logging or $False if you don't want any logging.
     
    .EXAMPLE
    Get-AzureTenantSecurityScore -LogToFile $False
     
    *OUTPUT*
    ComparableTenantsSecurityScore TenantSecurityScore
    ------------------------------ -------------------
                             40,43 60,64
 
    .NOTES
    You need these Azure Application permissions for this to work.
    Application - SecurityEvents.Read.All
 
    #>

    Param(
        [parameter(mandatory)]
        [ValidateSet("True","False")]
        $LogToFile
    )

    if (Find-AzureGraphAPIConnection){
        $securityScore = Invoke-TryCatchLog -InfoLog "Retrieving Security Score for Tenant" -LogToFile $LogToFile -ScriptBlock {
            Invoke-RestMethod -Method GET -Uri 'https://graph.microsoft.com/beta/security/secureScores?$top=1' -Headers $azureGraphAuthenticationHeader
        }
        return @{
            TenantSecurityScore = [math]::Round(($securityScore.value.currentScore / $securityScore.value.maxScore) * 100,2)
            ComparableTenantsSecurityScore = ($securityScore.value.averageComparativeScores | Where-Object {$_.basis -eq 'TotalSeats'}).averageScore
        }
    }
}

Export-ModuleMember -Function * -Alias *