Anomalous User Activity — Sigma Rule

Rule metadata and linked tags

Author: Mark Morowczynski '@markmorow', Gloria Lee, '@gleeiamglo'. Source status: test; severity: high. Source dates: 2023-09-03 / not supplied.

{
  "product": "azure",
  "service": "riskdetection"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: ca0da9f5af62455644a571c520ae3958628ad9cc72e75dd62f84ccb6ab72ffe8

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Anomalous User Activity
id: 258b6593-215d-4a26-a141-c8e31c1299a6
status: test
description: Indicates that there are anomalous patterns of behavior like suspicious changes to the directory.
references:
    - https://learn.microsoft.com/en-us/entra/id-protection/concept-identity-protection-risks#anomalous-user-activity
    - https://learn.microsoft.com/en-us/entra/architecture/security-operations-user-accounts#unusual-sign-ins
author: Mark Morowczynski '@markmorow', Gloria Lee, '@gleeiamglo'
date: 2023-09-03
tags:
    - attack.privilege-escalation
    - attack.t1098
    - attack.persistence
logsource:
    product: azure
    service: riskdetection
detection:
    selection:
        riskEventType: 'anomalousUserActivity'
    condition: selection
falsepositives:
    - We recommend investigating the sessions flagged by this detection in the context of other sign-ins from the user.
level: high

Original YAML and metadata in JSON

False positives

• We recommend investigating the sessions flagged by this detection in the context of other sign-ins from the user.

Source references

• https://learn.microsoft.com/en-us/entra/id-protection/concept-identity-protection-risks#anomalous-user-activity
• https://learn.microsoft.com/en-us/entra/architecture/security-operations-user-accounts#unusual-sign-ins