GCP Storage Bucket Permissions Modificationedit

Identifies when the Identity and Access Management (IAM) permissions are modified for a Google Cloud Platform (GCP) storage bucket. An adversary may modify the permissions on a storage bucket 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-gcp*

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
  • GCP
  • Continuous Monitoring
  • SecOps
  • Identity and Access

Version: 5 (version history)

Added (Elastic Stack release): 7.10.0

Last modified (Elastic Stack release): 7.13.0

Rule authors: Elastic

Rule license: Elastic License v2

Potential false positivesedit

Storage bucket 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 GCP Fleet integration, Filebeat module, or similarly structured data is required to be compatible with this rule.

Rule queryedit

event.dataset:(googlecloud.audit or gcp.audit) and
event.action:"storage.setIamPermissions" and event.outcome:success

Threat mappingedit

Framework: MITRE ATT&CKTM

Rule version historyedit

Version 5 (7.13.0 release)
  • Updated query, changed from:

    event.dataset:(googlecloud.audit or gcp.audit) and
    event.action:storage.setIamPermissions and event.outcome:success
Version 4 (7.12.0 release)
  • Formatting only
Version 3 (7.11.2 release)
  • Formatting only
Version 2 (7.11.0 release)
  • Updated query, changed from:

    event.dataset:googlecloud.audit and
    event.action:storage.setIamPermissions and event.outcome:success