Potential Password Spraying of Microsoft 365 User Accounts

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Potential Password Spraying of Microsoft 365 User Accounts

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Identifies a high number (25) of failed Microsoft 365 user authentication attempts from a single IP address within 30 minutes, which could be indicative of a password spraying attack. An adversary may attempt a password spraying 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: None

Tags:

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

Version: 4

Rule authors:

  • Elastic

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:(Exchange or AzureActiveDirectory) and event.category:authentication and
event.action:("UserLoginFailed" or "PasswordLogonInitialAuthUsingPassword") and event.outcome:failure

Framework: MITRE ATT&CKTM