Elastic Security Detection Rules

Microsoft 365 Exchange Transport Rule Creation

Last updated 7 months ago on 2025-01-15
Created 5 years ago on 2020-11-18

About

Identifies a transport rule creation in Microsoft 365. As a best practice, Exchange Online mail transport rules should not be set to forward email to domains outside of your organization. An adversary may create transport rules to exfiltrate data.
Tags
Domain: CloudData Source: Microsoft 365Use Case: Configuration AuditTactic: ExfiltrationLanguage: kuery
Severity
medium
Risk Score
47
MITRE ATT&CK™

Exfiltration (TA0010)(opens in a new tab or window)

↳ Transfer Data to Cloud Account (T1537)(opens in a new tab or window)

False Positive Examples
A new transport rule may be created by a system or network administrator. Verify that the configuration change was expected. Exceptions can be added to this rule to filter expected behavior.
License
Elastic License v2(opens in a new tab or window)

Definition

Rule Type
Query (Kibana Query Language)
Integration Pack
Prebuilt Security Detection Rules
Index Patterns
filebeat-*logs-o365*
Related Integrations

o365(opens in a new tab or window)

Query
event.dataset:o365.audit and event.provider:Exchange and event.category:web and event.action:"New-TransportRule" and event.outcome:success

Install detection rules in Elastic Security

Detect Microsoft 365 Exchange Transport Rule Creation in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(opens in a new tab or window).