Skip to content
ATO Pathways
Log In
Overview
Search
Catalogs
SCAP
OSCAL
Catalogs
Profiles
Documents
References
Knowledge Base
Platform Documentation
Compliance Dictionary
Platform Changelog
About
Catalogs
XCCDF
Microsoft Exchange 2019 Edge Server Security Technical Implementation Guide
SRG-APP-000261
The Exchange sender filter must block unaccepted domains.
The Exchange sender filter must block unaccepted domains.
An XCCDF Rule
Details
Profiles
Prose
The Exchange sender filter must block unaccepted domains.
Medium Severity
<VulnDiscussion>Spam origination sites and other sources of suspected email-borne malware have the ability to corrupt, compromise, or otherwise limit availability of email servers. Limiting exposure to unfiltered inbound messages can reduce the risk of spam and malware impacts. The Global Deny list blocks messages originating from specific sources. Most block list filtering is done using a commercial block list service, because eliminating threats from known spammers prevents the messages being evaluated inside the enclave where there is more risk they can do harm. Additional sources should also be blocked to supplement the contents of the commercial Block List service. For example, during a zero-day threat action, entries can be added and then removed when the threat is mitigated. An additional best practice is to enter the enterprise's home domains in the block list, because inbound email with a "from" address of the home domain is very likely to be spoofed spam.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>