Microsoft 365 Potential ransomware activityedit

Identifies when Microsoft Cloud App Security reported when a user uploads files to the cloud that might be infected with ransomware.

Rule type: query

Rule indices:

  • filebeat-*
  • logs-o365*

Severity: medium

Risk score: 47

Runs every: 5 minutes

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: 1

Added (Elastic Stack release): 7.16.0

Rule authors: Austin Songer

Rule license: Elastic License v2

Potential false positivesedit

If Cloud App Security identifies, for example, a high rate of file uploads or file deletion activities it may represent an adverse encryption process.

Investigation guideedit

## Config

The Microsoft 365 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:SecurityComplianceCenter
and event.category:web and event.action:"Potential ransomware
activity" and event.outcome:success

Threat mappingedit