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: 101 (version history)

Added (Elastic Stack release): 7.16.0

Last modified (Elastic Stack release): 8.6.0

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


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

Rule version historyedit

Version 101 (8.6.0 release)
  • Formatting only
Version 100 (8.5.0 release)
  • Formatting only
Version 3 (8.4.0 release)
  • Updated query, changed from:

    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)