Azure Blob Permissions Modification

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Identifies when the Azure role-based access control (Azure RBAC) permissions are modified for an Azure Blob. An adversary may modify the permissions on a blob to weaken their target’s security controls or an administrator may inadvertently modify the permissions, which could lead to data exposure or loss.

Rule type: query

Rule indices:

  • filebeat-*
  • logs-azure*

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: None (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

  • Domain: Cloud
  • Data Source: Azure
  • Use Case: Identity and Access Audit
  • Tactic: Defense Evasion
  • Data Source: Elastic Defend

Version: 103

Rule authors:

  • Austin Songer

Rule license: Elastic License v2

Investigation guide

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Rule query

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event.dataset:azure.activitylogs and azure.activitylogs.operation_name:(
     "MICROSOFT.STORAGE/STORAGEACCOUNTS/BLOBSERVICES/CONTAINERS/BLOBS/MANAGEOWNERSHIP/ACTION" or
     "MICROSOFT.STORAGE/STORAGEACCOUNTS/BLOBSERVICES/CONTAINERS/BLOBS/MODIFYPERMISSIONS/ACTION") and
  event.outcome:(Success or success)

Framework: MITRE ATT&CKTM