Microsoft 365 - Potential Ransomware Activity — Sigma Rule

Rule metadata and linked tags

Author: austinsonger. Source status: test; severity: medium. Source dates: 2021-08-19 / 2022-10-09.

{
  "service": "threat_management",
  "product": "m365"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 0f49f02a6b499404bd26542317b846b55cd6372d0d0283bdb49f64069034cc0b

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Microsoft 365 - Potential Ransomware Activity
id: bd132164-884a-48f1-aa2d-c6d646b04c69
status: test
description: Detects when a Microsoft Cloud App Security reported when a user uploads files to the cloud that might be infected with ransomware.
references:
    - https://learn.microsoft.com/en-us/defender-cloud-apps/anomaly-detection-policy
    - https://learn.microsoft.com/en-us/defender-cloud-apps/policy-template-reference
author: austinsonger
date: 2021-08-19
modified: 2022-10-09
tags:
    - attack.impact
    - attack.t1486
logsource:
    service: threat_management
    product: m365
detection:
    selection:
        eventSource: SecurityComplianceCenter
        eventName: 'Potential ransomware activity'
        status: success
    condition: selection
falsepositives:
    - Unknown
level: medium

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://learn.microsoft.com/en-us/defender-cloud-apps/anomaly-detection-policy
• https://learn.microsoft.com/en-us/defender-cloud-apps/policy-template-reference