Azure Alert Suppression Rule Created or Modified

Elastic Stack Serverless Security

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 (https://www.elastic.co/guide/en/elasticsearch/reference/current/common-options.html#date-math[Date Math format], see also Additional look-back time)

Maximum alerts per execution: 100

References:

• https://docs.microsoft.com/en-us/azure/role-based-access-control/resource-provider-operations
• https://docs.microsoft.com/en-us/rest/api/securitycenter/alerts-suppression-rules/update

Tags:

• Elastic
• Cloud
• Azure
• Continuous Monitoring
• SecOps
• Configuration Audit

Version: 4

Rule authors:

• Austin Songer

Rule license: Elastic License v2

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

Framework: MITRE ATT&CKTM

• 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/