Spike in Failed Logon Eventsedit

A machine learning job found an unusually large spike in authentication failure events. This can be due to password spraying, user enumeration or brute force activity and may be a precursor to account takeover or credentialed access.

Rule type: machine_learning

Machine learning job: auth_high_count_logon_fails

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



  • Elastic
  • Authentication
  • Threat Detection
  • ML
  • Credential Access

Version: 3 (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

A misconfigured service account can trigger this alert. A password change on an account used by an email client can trigger this alert. Security test cycles that include brute force or password spraying activities may trigger this alert. ==== Threat mapping


Rule version historyedit

Version 3 (8.4.0 release)
  • Formatting only
Version 2 (7.15.0 release)
  • Formatting only