Exchange filtered messages must be archived.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-259611	SRG-APP-000261	EX19-ED-000125	SV-259611r961161_rule	2024-12-06	2

Description
By performing filtering at the perimeter, up to 90 percent of spam, malware, and other undesirable messages are eliminated from the message stream rather than admitting them into the mail server environment. This significantly reduces the attack vector for inbound email-borne spam and malware. As messages are filtered, it is prudent to temporarily host them in an archive for evaluation by administrators or users. The archive can be used to recover messages that might have been inappropriately filtered, preventing data loss, and to provide a base of analysis that can provide future filter refinements.

Description

By performing filtering at the perimeter, up to 90 percent of spam, malware, and other undesirable messages are eliminated from the message stream rather than admitting them into the mail server environment. This significantly reduces the attack vector for inbound email-borne spam and malware. As messages are filtered, it is prudent to temporarily host them in an archive for evaluation by administrators or users. The archive can be used to recover messages that might have been inappropriately filtered, preventing data loss, and to provide a base of analysis that can provide future filter refinements.

ℹ️ Check
Note: If third-party anti-spam product is being used, the anti-spam product must be configured to meet the requirement. Open the Exchange Management Shell and enter the following command: Get-ContentFilterConfig \| Select-Object -Property Name, quarantineMailbox If no SMTP address is assigned to "quarantineMailbox", this is a finding.

✔️ Fix
Open the Exchange Management Shell and enter the following command: Set-ContentFilterConfig -quarantineMailbox <'quarantineMailbox SmtpAddress'> Note: The <quarantineMailbox SmtpAddress> value must be in quotes.