Azure Alert Suppression Rule Created or Modified

Identifies the creation of suppression rules in Azure. Suppression rules are a mechanism used to suppress alerts previously identified as false positives or too noisy to be in production. This mechanism can be abused or mistakenly configured, resulting in defense evasions and loss of security visibility.

Rule type: query

Rule indices:

filebeat-*
logs-azure*

Severity: low

Risk score: 21

Runs every: 5m

Searches indices from: now-25m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

Elastic
Cloud
Azure
Continuous Monitoring
SecOps
Configuration Audit

Version: 5

Rule authors:

Austin Songer

Rule license: Elastic License v2

Investigation guide

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## Setup

The Azure Fleet integration, Filebeat module, or similarly structured data is required to be compatible with this rule.

Rule query

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event.dataset:azure.activitylogs and azure.activitylogs.operation_name:"MICROSOFT.SECURITY/ALERTSSUPPRESSIONRULES/WRITE" and
event.outcome: "success"

Framework: MITRE ATT&CK^TM

Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
Technique:
- Name: Impair Defenses
- ID: T1562
- Reference URL: https://attack.mitre.org/techniques/T1562/

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