Rare User Logonedit
A machine learning job found an unusual user name in the authentication logs. An unusual user name is one way of detecting credentialed access by means of a new or dormant user account. An inactive user account (because the user has left the organization) that becomes active may be due to credentialed access using a compromised account password. Threat actors will sometimes also create new users as a means of persisting in a compromised web application.
Rule type: machine_learning
Machine learning job: auth_rare_user
Machine learning anomaly threshold: 75
Severity: low
Risk score: 21
Runs every: 15 minutes
Searches indices from: now-30m (Date Math format, see also Additional look-back time
)
Maximum alerts per execution: 100
References:
Tags:
- Elastic
- Authentication
- Threat Detection
- ML
- Initial Access
Version: 4 (version history)
Added (Elastic Stack release): 7.14.0
Last modified (Elastic Stack release): 8.4.0
Rule authors: Elastic
Rule license: Elastic License v2
Potential false positivesedit
User accounts that are rarely active, such as a site reliability engineer (SRE) or developer logging into a production server for troubleshooting, may trigger this alert. Under some conditions, a newly created user account may briefly trigger this alert while the model is learning. ==== Threat mapping
Framework: MITRE ATT&CKTM
-
Tactic:
- Name: Initial Access
- ID: TA0001
- Reference URL: https://attack.mitre.org/tactics/TA0001/
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Technique:
- Name: Valid Accounts
- ID: T1078
- Reference URL: https://attack.mitre.org/techniques/T1078/
Rule version historyedit
- Version 4 (8.4.0 release)
-
- Formatting only
- Version 3 (7.16.0 release)
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- Formatting only
- Version 2 (7.15.0 release)
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- Formatting only