ORCA.118.1 - Domains are not being allow listed in an unsafe manner in Anti-Spam Policies.

Contributed by Thomas SchmidtAll contributors →

Overview

Emails coming from allow listed domains bypass several layers of protection within Exchange Online Protection. If domains are allow listed, they are open to being spoofed from malicious actors.

Remediation action

Remove allow listing on domains.

Related Links

• Microsoft 365 Defender Portal - Anti-spam settings
• Use Anti-Spam Policy Sender/Domain Allow lists

Test Metadata

Field	Value
Test ID	ORCA.118.1
Severity	High
Suite	ORCA
Product	Defender
Related products	Exchange Online
Feature	Anti-spam
Area	Email and collaboration protection
Resource type	Policy
User impact	Low
Implementation cost	Low
MITRE ATT&CK	T1566 Phishing, T1684.002 Email Spoofing
Supports controls	nist-800-53-r5:SI-8
PowerShell test	Test-ORCA118_1
Services	ExchangeOnline

Source

• Test: tests/orca/Test.ORCA.118.1.ps1
• Documentation: tests/orca/Test.ORCA.118.1.md