GCP Logging Sink Modificationedit

Identifies a modification to a Logging sink in Google Cloud Platform (GCP). Logging compares the log entry to the sinks in that resource. Each sink whose filter matches the log entry writes a copy of the log entry to the sink’s export destination. An adversary may update a Logging sink to exfiltrate logs to a different export destination.

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: 100 (version history)

Added (Elastic Stack release): 7.10.0

Last modified (Elastic Stack release): 8.5.0

Rule authors: Elastic

Rule license: Elastic License v2

Potential false positivesedit

Logging sink modifications 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. Sink modifications from unfamiliar users or hosts should be investigated. If known behavior is causing false positives, it can be exempted from the rule.

Investigation guideedit


Rule queryedit

event.dataset:gcp.audit and
event.action:google.logging.v*.ConfigServiceV*.UpdateSink and
event.outcome:success

Threat mappingedit

Framework: MITRE ATT&CKTM

Rule version historyedit

Version 100 (8.5.0 release)
  • Formatting only
Version 7 (8.4.0 release)
  • Updated query, changed from:

    event.dataset:(googlecloud.audit or gcp.audit) and
    event.action:google.logging.v*.ConfigServiceV*.UpdateSink and
    event.outcome:success
Version 5 (7.13.0 release)
  • Formatting only
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:google.logging.v*.ConfigServiceV*.UpdateSink and
    event.outcome:success