Attempts to Brute Force a Microsoft 365 User Accountedit

Identifies attempts to brute force a Microsoft 365 user account. An adversary may attempt a brute force attack to obtain unauthorized access to user accounts.

Rule type: threshold

Rule indices:

  • filebeat-*
  • logs-o365*

Severity: high

Risk score: 73

Runs every: 5 minutes

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

Maximum alerts per execution: 100

Tags:

  • Elastic
  • Cloud
  • Microsoft 365
  • Continuous Monitoring
  • SecOps
  • Identity and Access

Version: 1

Added (Elastic Stack release): 7.11.0

Rule authors: Elastic

Rule license: Elastic License

Potential false positivesedit

Automated processes that attempt to authenticate using expired credentials and unbounded retries may lead to false positives.

Investigation guideedit

The Microsoft 365 Fleet integration or Filebeat module must be enabled to use this rule.

Rule queryedit

event.dataset:o365.audit and event.provider:AzureActiveDirectory and
event.category:authentication and event.action:UserLoginFailed and
event.outcome:failure

Threat mappingedit

Framework: MITRE ATT&CKTM