M365 Exchange Inbox Phishing Evasion Rule Created
Identifies when a user creates a new inbox rule in Microsoft 365 that deletes or moves emails containing suspicious keywords. Adversaries who have compromised accounts often create inbox rules to hide alerts,…
Description
Identifies when a user creates a new inbox rule in Microsoft 365 that deletes or moves emails containing suspicious keywords. Adversaries who have compromised accounts often create inbox rules to hide alerts, security notifications, or other sensitive messages by automatically deleting them or moving them to obscure folders. Common destinations include Deleted Items, Junk Email, RSS Feeds, and RSS Subscriptions. This is a New Terms rule that triggers only when the user principal name and associated source IP address have not been observed performing this activity in the past 14 days.
Detection logic
Its licence does not clear it for publishing here
Sunturai publishes a detection's own text where the licence it arrived under has been reviewed and permits it, and Elastic License 2.0 has not. The query as its source wrote it, its canonical form and the hash that pins this revision are in the workspace record.
Detection requirements
- Platform
- ESXiLinuxmacOSOffice SuiteWindows
The rule states no platform. This is derived from the 2 ATT&CK techniques it maps to.
- Log source category
- event_index
MITRE ATT&CK mappings
0 exclusive techniques.This is coverage no other published rule has; it is not this rule's total technique count.
References
| Reference | Cited by |
|---|---|
| blog.barracuda.com/2023/09/20/threat-spotlight-attackers-inbox-rules-evade-detection | Only this detection cites it |
| learn.microsoft.com/en-us/defender-office-365/detect-and-remediate-outlook-rules-forms-attack | Only this detection cites it |
| learn.microsoft.com/en-us/defender-xdr/alert-grading-playbook-inbox-manipulation-rules | Only this detection cites it |
From the source
- At source
- Open at source
- Upstream identifier
- 40fe11c2-376e-11f0-9a82-f661ea17fbcd
- Tagged by the source as
- Data Source: Microsoft 365Data Source: Microsoft 365 Audit LogsDomain: CloudDomain: EmailDomain: SaaSNoise: LowPerformance: NormalPlatform: Microsoft 365Profile: RecommendedResources: Investigation GuideRule Type: New TermsService: Microsoft Exchange OnlineTactic: Defense EvasionThreat: AiTM PhishingUse Case: Threat Detection
Licence
- Published under
- Elastic License 2.0Read the licence
- Attribution
- Required
Authorship
- Written by
- Published
- Sep 20, 2026
- Version
- 3