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« Persistence via Folder Action Script Potential Password Spraying of Microsoft 365 User Accounts »
Elastic Docs ›Elastic Security Solution [8.16] ›Downloadable rule update v0.13.2

Attempts to Brute Force a Microsoft 365 User Account

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Attempts to Brute Force a Microsoft 365 User Account

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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: 5m

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

Maximum alerts per execution: 100

References:

Tags:

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

Version: 5

Rule authors:

  • Elastic
  • Willem D’Haese
  • Austin Songer

Rule license: Elastic License v2

Investigation guide

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## Config

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

Rule query

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event.dataset:o365.audit and event.provider:(AzureActiveDirectory or Exchange) and
  event.category:authentication and event.action:(UserLoginFailed or PasswordLogonInitialAuthUsingPassword) and
  not o365.audit.LogonError:(UserAccountNotFound or EntitlementGrantsNotFound or UserStrongAuthEnrollmentRequired or
                             UserStrongAuthClientAuthNRequired or InvalidReplyTo) and event.outcome:failure

Framework: MITRE ATT&CKTM

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