Exchange must not send automated replies to remote domains.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-228396	EX16-MB-000520	SV-228396r879653_rule		Medium

Description
Attackers can use automated messages to determine whether a user account is active, in the office, traveling, and so on. An attacker might use this information to conduct future attacks. Remote users will not receive automated "Out of Office" delivery reports. This setting can be used to determine if all the servers in the organization can send "Out of Office" messages.

STIG	Date
Microsoft Exchange 2016 Mailbox Server Security Technical Implementation Guide	2023-09-13

Details

Check Text ( C-30629r497053_chk )
Note: Automated replies to .MIL or .GOV sites are allowed. Open the Exchange Management Shell and enter the following command: Get-RemoteDomain \| Select Name, Identity, AutoReplyEnabled If the value of “AutoReplyEnabled” is set to “True” and is configured to only Reply to .MIL or .GOV sites, this is not a finding. If the value of "AutoReplyEnabled" is not set to "False", this is a finding.

Check Text ( C-30629r497053_chk )

Note: Automated replies to .MIL or .GOV sites are allowed.

Open the Exchange Management Shell and enter the following command:

Get-RemoteDomain | Select Name, Identity, AutoReplyEnabled
If the value of “AutoReplyEnabled” is set to “True” and is configured to only Reply to .MIL or .GOV sites, this is not a finding.

If the value of "AutoReplyEnabled" is not set to "False", this is a finding.

Fix Text (F-30614r496985_fix)
Open the Exchange Management Shell and enter the following command: Set-RemoteDomain -Identity <'IdentityName'> -AutoReplyEnabled $false Note: The value must be in single quotes.