Azure Blob Permissions Modificationedit

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: 5 minutes

Searches indices from: now-6m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

  • Elastic
  • Cloud
  • Azure
  • Continuous Monitoring
  • SecOps
  • Identity and Access

Version: 1

Added (Elastic Stack release): 7.16.0

Rule authors: Austin Songer

Rule license: Elastic License v2

Potential false positivesedit

Blob permissions may be modified by system administrators. Verify that the configuration change was expected. Exceptions can be added to this rule to filter expected behavior.

Investigation guideedit

## Config

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

Rule queryedit

event.dataset:azure.activitylogs and
azure.activitylogs.operation_name:( "MICROSOFT.STORAGE/STORAGEACC
OUNTS/BLOBSERVICES/CONTAINERS/BLOBS/MANAGEOWNERSHIP/ACTION" or "M
ICROSOFT.STORAGE/STORAGEACCOUNTS/BLOBSERVICES/CONTAINERS/BLOBS/MODIFYP
ERMISSIONS/ACTION") and event.outcome:(Success or success)

Threat mappingedit

Framework: MITRE ATT&CKTM