GCP Storage Bucket Permissions Modification

Elastic Stack Serverless Security

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: 5m

Searches indices from: None (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://cloud.google.com/storage/docs/access-control/iam-permissions

Tags:

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

Version: 7

Rule authors:

• Elastic

Rule license: Elastic License v2

event.dataset:gcp.audit and event.action:"storage.setIamPermissions" and event.outcome:success

Framework: MITRE ATT&CKTM

• Tactic:

  • Name: Defense Evasion
  • ID: TA0005
  • Reference URL: https://attack.mitre.org/tactics/TA0005/

• Technique:

  • Name: File and Directory Permissions Modification
  • ID: T1222
  • Reference URL: https://attack.mitre.org/techniques/T1222/