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. A user account that is normally inactive, because the user has left the organization, which 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
Version: 1
Added (Elastic Stack release): 7.14.0
Rule authors: Elastic
Rule license: Elastic License v2
Potential false positivesedit
User accounts that are rarely active, such as an SRE or developer logging into a prod 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.