Microsoft 365 Exchange Malware Filter Policy Deletionedit

Identifies when a malware filter policy has been deleted in Microsoft 365. A malware filter policy is used to alert administrators that an internal user sent a message that contained malware. This may indicate an account or machine compromise that would need to be investigated. Deletion of a malware filter policy may be done to evade detection.

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



  • Elastic
  • Cloud
  • Microsoft 365
  • Continuous Monitoring
  • SecOps
  • Configuration Audit

Version: 5

Rule authors:

  • Elastic

Rule license: Elastic License v2

Investigation guideedit

## Config

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

Rule queryedit

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