Exchange must have accepted domains configured.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-80489	EX16-ED-000030	SV-95199r1_rule		Medium

Description
Exchange may be configured to accept email for multiple domain names. This setting identifies the domains for which the server will accept mail. This check verifies the email server is not accepting email for unauthorized domains.

STIG	Date
Microsoft Exchange 2016 Edge Transport Server Security Technical Implementation Guide	2018-08-28

Details

Check Text ( C-80221r1_chk )
Review the Email Domain Security Plan (EDSP). Determine the Accepted Domain values. Open the Exchange Management Shell and enter the following command: Get-AcceptedDomain \| Select Name, DomainName, Identity, Default If the value of "Default" is not set to "True", this is a finding. or If the "Default" value for "AcceptedDomains" is set to another value other than "True" and has signoff and risk acceptance in the EDSP, this is not a finding.

Check Text ( C-80221r1_chk )

Review the Email Domain Security Plan (EDSP).

Determine the Accepted Domain values.

Open the Exchange Management Shell and enter the following command:

Get-AcceptedDomain | Select Name, DomainName, Identity, Default

If the value of "Default" is not set to "True", this is a finding.

or

If the "Default" value for "AcceptedDomains" is set to another value other than "True" and has signoff and risk acceptance in the EDSP, this is not a finding.

Fix Text (F-87341r1_fix)
Update the EDSP. Open the Exchange Management Shell and enter the following command: Set-AcceptedDomain -Identity <'IdentityName'> -MakeDefault $true Note: The value must be in single quotes.