IMPORTANT: No additional bug fixes or documentation updates will be released for this version. For the latest information, see the current release documentation.

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Microsoft 365 Exchange Transport Rule Creation

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Microsoft 365 Exchange Transport Rule Creation

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Identifies a transport rule creation in Microsoft 365. Exchange Online mail transport rules should be set to not forward email to domains outside of your organization as a best practice. An adversary may create transport rules to exfiltrate data.

Rule type: query

Rule indices:

filebeat-*
logs-o365*

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: now-30m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

Elastic
Cloud
Microsoft 365
Continuous Monitoring
SecOps
Configuration Audit

Version: 5

Rule authors:

Elastic

Rule license: Elastic License v2

Investigation guide

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## Config

The Office 365 Logs Fleet integration, Filebeat module, or similarly structured data is required to be compatible with this rule.

Rule query

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

Framework: MITRE ATT&CK^TM

Tactic:
- Name: Exfiltration
- ID: TA0010
- Reference URL: https://attack.mitre.org/tactics/TA0010/
Technique:
- Name: Transfer Data to Cloud Account
- ID: T1537
- Reference URL: https://attack.mitre.org/techniques/T1537/

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