Microsoft Exchange Server
TMA-EXCHANGE-1.4
Ensure 'Blank sender field' is configured
MediumLevel 1Automatedexchange
Description
When the Sender Filter Agent takes on messages from blocked senders or domains, the Action parameter is what is used when deciding what to do with these messages. Prints compliant when sender filter Action is Reject and BlankSenderBlockingEnabled is True. Run on each Edge Transport server. Run from an Exchange Management Shell or after `Add-PSSnapin Microsoft.Exchange.Management.PowerShell.SnapIn`; the audit loads the snap-in itself when Get-ExchangeServer is missing and fails if it cannot.
How it is checked
Audit method: Shell command
shell
$ErrorActionPreference = 'Stop'; if (-not (Get-Command Get-ExchangeServer -ErrorAction SilentlyContinue)) { Add-PSSnapin Microsoft.Exchange.Management.PowerShell.SnapIn -ErrorAction Stop }; if (-not (Get-Command Get-ExchangeServer -ErrorAction SilentlyContinue)) { throw 'Exchange Management Shell cmdlets are not available' }; $c = Get-SenderFilterConfig -ErrorAction Stop; if ("$($c.Action)" -eq 'Reject' -and $c.BlankSenderBlockingEnabled -eq $true) { 'compliant' } else { 'noncompliant' }- Expected output
compliant
How it is fixed
Fix method: Guidance or infrastructure patch
Set-SenderFilterConfig -Action Reject -BlankSenderBlockingEnabled $true
Properties
- Operating systems
- Any
- Tags
- exchangeantispam
- Reference
- CIS Microsoft Exchange Server 2019 Benchmark v1.0.1 - 1.4 Ensure 'Blank sender field' is configured
Check this host
Run this on a machine you are allowed to audit. The scan is read-only.
shell
tmaegis scan --target exchange