The Exchange Spam Evaluation filter must be enabled.

From MS Exchange 2013 Edge Transport Server Security Technical Implementation Guide

Associated with: CCI-001308

SV-84499r1_rule The Exchange Spam Evaluation filter must be enabled.

Vulnerability discussion

By performing filtering at the perimeter, up to 90 percent of spam, malware, and other undesirable messages may be eliminated from the transport message stream, preventing their entry into the Exchange environment. This significantly reduces the attack vector for inbound email-borne spam and malware.Spam Evaluation filters scan inbound email messages for evidence of spam and other attacks that primarily use "social engineering" techniques. Upon evaluation completion, a rating is assigned to each message estimating the likelihood of its being spam. Upon arrival at the destination mailbox, the junk mail filter threshold (also configurable) determines whether the message will be withheld from delivery, delivered to the junk mail folder, or delivered to the user’s inbox.

Check content

Open the Exchange Management Shell and enter the following command: Get-ContentFilterConfig | Select Name, Identity, Enabled If the value of Enabled is not set to True, this is a finding.

Fix text

Open the Exchange Management Shell and enter the following command: Set-ContentFilterConfig -Enabled $true

Pro Tips

Lavender hyperlinks in small type off to the right (of CSS class id, if you view the page source) point to globally unique URIs for each document and item. Copy the link location and paste anywhere you need to talk unambiguously about these things.

You can obtain data about documents and items in other formats. Simply provide an HTTP header Accept: text/turtle or Accept: application/rdf+xml.