detection.wiki

Detection rules › Sigma

Anomalous User Activity

Status
test
Severity
high
Log source
product azure, service riskdetection
Author
Mark Morowczynski '@markmorow', Gloria Lee, '@gleeiamglo'
Source
github.com/SigmaHQ/sigma

Indicates that there are anomalous patterns of behavior like suspicious changes to the directory.

MITRE ATT&CK coverage

TacticTechniques
PersistenceT1098 Account Manipulation
Privilege EscalationT1098 Account Manipulation

Rule body yaml

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

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    riskEventType: 'anomalousUserActivity'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
riskEventTypeeq
  • anomalousUserActivity