Attempts to Brute Force a Microsoft 365 User Account
editAttempts to Brute Force a Microsoft 365 User Account
editIdentifies 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
References:
Tags:
- Elastic
- Cloud
- Microsoft 365
- Continuous Monitoring
- SecOps
- Identity and Access
Version: 5 (version history)
Added (Elastic Stack release): 7.11.0
Last modified (Elastic Stack release): 7.14.0
Rule authors: Elastic, Willem D’Haese, Austin Songer
Rule license: Elastic License v2
Potential false positives
editAutomated processes that attempt to authenticate using expired credentials and unbounded retries may lead to false positives.
Investigation guide
edit## Config The Microsoft 365 Fleet integration, Filebeat module, or similarly structured data is required to be compatible with this rule.
Rule query
editevent.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
Threat mapping
editFramework: MITRE ATT&CKTM
-
Tactic:
- Name: Credential Access
- ID: TA0006
- Reference URL: https://attack.mitre.org/tactics/TA0006/
-
Technique:
- Name: Brute Force
- ID: T1110
- Reference URL: https://attack.mitre.org/techniques/T1110/
Rule version history
edit- Version 5 (7.14.0 release)
-
-
Updated query, changed from:
event.dataset:o365.audit and event.provider:AzureActiveDirectory and event.category:authentication and event.action:UserLoginFailed and event.outcome:failure
-
- Version 3 (7.13.0 release)
-
- Formatting only
- Version 2 (7.12.0 release)
-
- Formatting only