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Analyze-TeamsExternalChats.PS1
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Analyze-TeamsExternalChats.PS1
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# Analyze-TeamsExternalChats.PS1
# Analyze User chats to find chats with people outside the tenant
# Because the chat API uses delegated access in interactive mode, this code can only process
# chats for other users when run as an app or in an Azure Automation runbook
# V1.0 1 Nov 2023
# https://github.com/12Knocksinna/Office365itpros/blob/master/Analyze-TeamsExternalChats.PS1
# Permissions used:
# CrossTenantInformation.ReadBasic.All: Read tenant id and return tenant name
# User.Read.All: Read user information
# Chat.Read.All: Read user chats
# Directory.Read.All: Read tenant information from directory
# Mail.Send: Send email with results
Function Add-MessageRecipients {
# Function to build an addressee list to send email
[cmdletbinding()]
Param(
[array]$ListOfAddresses )
ForEach ($SMTPAddress in $ListOfAddresses) {
@{
emailAddress = @{address = $SMTPAddress}
}
}
}
# Start of processing
# Define the home tenant where the job will run
$HomeTenantId = 'a662313f-14fc-43a2-9a7a-d2e27f4f3478'
$CSVFile = "c:\temp\TeamsExternalAccessScan.csv"
# Define the settings used for certificate-based authentication for the registered app you want to use
# Thumbprint for the X.509 certificate uploaded to the registered app
$CertificateThumbPrint = "F79286DB88C21491110109A0222348FACF694CBD"
# Application (client) identifier for the registered app. Get this value from the app properties
$AppId = "8f005189-8c58-4fb5-a226-8851e13490cb"
# Connect to the Graph and Teams endpoints using certificate-based authentication
# Certificate-based authentication depends on the tenant id, app id, and certificate thumbprint. All must be
# defined and accurate as otherwise authentication will fail
Write-Host "Connecting to the Graph SDK endpoint..."
Connect-MgGraph -NoWelcome -ClientId $AppId -CertificateThumbprint $CertificateThumbPrint -TenantId $HomeTenantId
Write-Host "Now connecting to the Microsoft Teams endpoint..."
$Status = Connect-MicrosoftTeams -TenantId $HomeTenantId -ApplicationId $AppId -Certificate $CertificateThumbPrint
If (!($Status.Account -ne $AppId)) {
Write-Host "Whoops... can't connect!"; break
} Else {
Write-Host "All connected. Now setting things up..."
}
# Fetch organization information
$HomeTenant = Get-MgOrganization
# Find domains in the tenant so that we can discard chats with local people
[array]$Domains = Get-MgDomain | Select-Object -ExpandProperty Id
# Create hash table to store information about external tenants
$ExternalTenants = @{}
# Find user accounts to check
[array]$Users = Get-MgUser -Filter "assignedLicenses/`$count ne 0 and userType eq 'Member'" `
-ConsistencyLevel eventual -CountVariable Records -All | Sort-Object displayName
Write-Output ("Found {0} user accounts to process..." -f $users.Count)
$ChatReport = [System.Collections.Generic.List[Object]]::new()
ForEach ($User in $Users) {
Write-Output ("Looking for chats for user {0}..." -f $User.DisplayName)
# Find the OneOnOne chats for this user
[array]$Chats = Get-MgBetaUserChat -Userid $User.Id -All -Filter "ChatType eq 'oneOnOne'"
If ($Chats) {
Write-Output ("Found {0} one-on-one chats for {1}" -f $Chats.count, $User.DisplayName)
ForEach ($Chat in $Chats) {
# Find participants
Try {
[array]$Participants = Get-MgChatMember -ChatId $Chat.Id
# Remove the user we're processing
[array]$OtherParticipant = $Participants | `
Where-Object {$_.additionalProperties.email -ne $User.userPrincipalName}
} Catch {
Write-Output ("Can't fetch participant information for chat {0}" -f $Chat.Id)
}
If ($OtherParticipant.displayName) {
$TenantName = $Null
# See if we can get a domain name for the other participant
Try {
$EmailDomain = $OtherParticipant.additionalProperties.email.split('@')[1]
} Catch {
$EmailDomain = $Null
}
# Only process a chat if the other participant comes from a domain outside the home tenant
If ($EmailDomain -notin $Domains) {
# Check if the owning domain for the chat is the home or the external tenant
$ExternalTenantId = $OtherParticipant.additionalProperties.tenantId.ToString()
If ($ExternalTenantId -ne $HomeTenantId) {
Try {
$TenantName = $ExternalTenants[$ExternalTenantId] }
Catch {
Write-Output ("Resolving tenant id {0}" -f $ExternalTenantId)
}
$ChatCount = "N/A"
If (!($TenantName)) {
# Couldn't find the tenant, so resolve its identifier and record its details
$Uri = ("https://graph.microsoft.com/beta/tenantRelationships/findTenantInformationByTenantId(tenantId='{0}')" -f `
$ExternalTenantId)
$ExternalTenantData = Invoke-MgGraphRequest -Uri $Uri -Method Get
$TenantName = $ExternalTenantData.displayName
$ExternalTenants.Add($ExternalTenantId, $TenantName)
}
}
If ($ExternalTenantId -eq $HomeTenantId) {
$TenantName = $HomeTenant.DisplayName
[array]$ChatMessages = Get-MgChatMessage -ChatId $Chat.id -All
$ChatCount = $ChatMessages.Count
}
$Reportline = [PsCustomObject]@{
Chat = $Chat.Id
User = $User.displayName
UPN = $User.userPrincipalName
Participant = $OtherParticipant.displayName
'Participant Email' = $OtherParticipant.additionalProperties.email
Domain = $EmailDomain
'Owning Tenant Name' = $TenantName
Role = $OtherParticipant.Roles
ChatCreated = $Chat.CreatedDateTime
LastUpdated = $Chat.LastUpdatedDateTime
'Chat Messages' = $ChatCount
}
$ChatReport.Add($ReportLine)
# Slight pause before continuing... wouldn't want to be throttled
Start-Sleep -Milliseconds 500
}
}
}
}
}
Write-Output ""
Write-Output ("{0} chats found with external people in the {1} tenant" -f $ChatReport.count, $HomeTenant.displayName)
Write-Output ""
Write-Output "Checking the Teams External Access configuration for the tenant..."
# Find if we need to update the external access configuration
[array]$ExternalDomains = $ChatReport.Domain | Sort-Object -Unique
$DomainConfiguration = Get-CsTenantFederationConfiguration | Select-Object -ExpandProperty AllowedDomains
[array]$ConfiguredDomains = $DomainConfiguration.AllowedDomain.Domain
If (!($ConfiguredDomains)) {
Write-Output ("The {0} tenant doesn't have any configured domains for external access" -f $HomeTenant.displayName)
} Else {
[array]$MissingDomains = $ExternalDomains | Where-Object {$_ -notin $ConfiguredDomains}
If ($MissingDomains) {
$MissingDomainsOutput = $MissingDomains -Join ", "
Write-Output ("The following external domains are not configured for external access: {0}" -f $MissingDomainsOutput)
} Else {
Write-Output ("External Access is configured for all external domains found in the scan")
}
}
# Email the results
$EmailRecipient = "Tony.Redmond@office365itpros.com"
# Send a message from the shared mailbox
$MsgFrom = "Azure.Management.Account@office365itpros.com"
# Add your recipient address here
$ToRecipientList = @( $EmailRecipient )
[array]$MsgToRecipients = Add-MessageRecipients -ListOfAddresses $ToRecipientList
$MsgSubject = "Teams external access review"
$HtmlHead = "<h2>Teams external chat participant report</h2><p>The following chats have been found to involve external participants.</p>"
$HtmlBody = $ChatReport | Select-Object User, UPN, 'Participant Email', Domain, ChatCreated, 'Chat Messages' | `
ConvertTo-Html -Fragment
# Add a line about missing domains if there are any in the external access configuration, else just send the
# data about external chats
If ($MissingDomains) {
$HtmlBody2 = "<h2>The following domains are not in the tenant external access configuration: </h2>" + `
"<p>" + $MissingDomainsOutput + "</p>"
$HtmlMsg = "</body></html><p>" + $HtmlHead + $Htmlbody + "<p>" + $HtmlBody2 + "<p>"
} Else {
$HtmlMsg = "</body></html><p>" + $HtmlHead + $Htmlbody + "<p>"
}
# Construct the message body
$MsgBody = @{
Content = "$($HtmlMsg)"
ContentType = 'html'
}
$Message = @{subject = $MsgSubject}
$Message += @{toRecipients = $MsgToRecipients}
$Message += @{body = $MsgBody}
$Params = @{'message' = $Message}
$Params += @{'saveToSentItems' = $True}
$Params += @{'isDeliveryReceiptRequested' = $True}
# And send the message using the parameters that we've filled in
Send-MgUserMail -UserId $MsgFrom -BodyParameter $Params
Write-Output ("Message containing external chat information sent to {0}!" -f $EmailRecipient)
$ChatReport | Export-Csv -NoTypeInformation $CSVFile
Write-Output ("The complete data file is available in {0}" -f $CSVFile)
# An example script used to illustrate a concept. More information about the topic can be found in the Office 365 for IT Pros eBook https://gum.co/O365IT/
# and/or a relevant article on https://office365itpros.com or https://www.practical365.com. See our post about the Office 365 for IT Pros repository # https://office365itpros.com/office-365-github-repository/ for information about the scripts we write.
# Do not use our scripts in production until you are satisfied that the code meets the need of your organization. Never run any code downloaded from the Internet without
# first validating the code in a non-production environment.