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SMTP automated banner response must be set.


Overview

Finding ID Version Rule ID IA Controls Severity
Exch-ED-200 Exch-ED-200 Exch-ED-200_rule Medium
Description
Automated connection responses occur as a result of FTP or Telnet connections, when connecting to those services. They report a successful connection by greeting the connecting client, stating the name, release level, and (often) additional information regarding the responding product. While useful to the connecting client, connection responses can also be used by a third party to determine operating system (OS) or product release levels on the target server. The result can include disclosure of configuration information to third parties, paving the way for possible future attacks. For example, when querying the SMTP service on port 25, the default response looks similar to this one: 220 exchange.mydomain.org Microsoft ESMTP MAIL Service, Version: 6.0.3790.211 ready at Wed, 2 Feb 2005 23:40:00 -0500 Changing the response to hide local configuration details reduces the attack profile of the target.
STIG Date
Microsoft Exchange 2010 Edge Transport Server Role 2012-05-31

Details

Check Text ( C-_chk )
Open the Exchange Management Shell and enter the following command.

Get-ReceiveConnector | Select Name, Identity, Banner

If the value of "Banner" is not set to <'DomainName'> "SMTP Server Ready", this is a finding.
Fix Text (F-_fix)
Open the Exchange Management Shell and enter the following command.

Set-ReceiveConnector -Identity <'ReceiveConnector'> -Banner "DomainName SMTP Server Ready"