GCP Pub/Sub Topic Creation

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Identifies the creation of a topic in Google Cloud Platform (GCP). In GCP, the publisher-subscriber relationship (Pub/Sub) is an asynchronous messaging service that decouples event-producing and event-processing services. A topic is used to forward messages from publishers to subscribers.

Rule type: query

Rule indices:

  • filebeat-*
  • logs-gcp*

Severity: low

Risk score: 21

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
  • Log Auditing

Version: 3 (version history)

Added (Elastic Stack release): 7.10.0

Last modified (Elastic Stack release): 7.11.2

Rule authors: Elastic

Rule license: Elastic License

Potential false positives

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Topic creations may be done by a system or network administrator. Verify whether the user email, resource name, and/or hostname should be making changes in your environment. Topic creations from unfamiliar users or hosts should be investigated. If known behavior is causing false positives, it can be exempted from the rule.

Investigation guide

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The GCP Filebeat module must be enabled to use this rule.

Rule query

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event.dataset:(googlecloud.audit or gcp.audit) and
event.action:google.pubsub.v*.Publisher.CreateTopic and
event.outcome:success

Threat mapping

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Framework: MITRE ATT&CKTM

Rule version history

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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:google.pubsub.v*.Publisher.CreateTopic and
    event.outcome:success