detection-rules
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AWS CloudTrail Log Updated

Detects updates to an existing CloudTrail trail via UpdateTrail API which may reduce visibility, change destinations, or weaken integrity (e.g., removing global events, moving the S3 destination, or disabling validation). Adversaries can modify trails to evade detection while maintaining a semblance of logging. Validate any configuration change against approved baselines.

Rule type: query
Rule indices:

  • filebeat-*
  • logs-aws.cloudtrail-*

Rule Severity: low
Risk Score: 21
Runs every:
Searches indices from: now-6m
Maximum alerts per execution: ?
References:

Tags:

  • Domain: Cloud
  • Data Source: AWS
  • Data Source: Amazon Web Services
  • Data Source: AWS Cloudtrail
  • Use Case: Log Auditing
  • Resources: Investigation Guide
  • Tactic: Impact

Version: ?
Rule authors:

  • Elastic

Rule license: Elastic License v2

Disclaimer: This investigation guide was created using generative AI technology and has been reviewed to improve its accuracy and relevance. While every effort has been made to ensure its quality, we recommend validating the content and adapting it to suit your specific environment and operational needs.

AWS CloudTrail is a service that enables governance, compliance, and operational and risk auditing of your AWS account. It logs API calls and related events, providing visibility into user activity. Trail modifications can be used by attackers to redirect logs to non-approved buckets, drop regions, or disable valuable selectors. This rule identifies a modification on CloudTrail settings using the UpdateTrail API.

  • Actor and context
    • Check aws.cloudtrail.user_identity.arn, user_agent.original, source.ip; verify approved change.
  • Assess the modification
    • In aws.cloudtrail.request_parameters, note changes to:
      • S3BucketName, CloudWatchLogsLogGroupArn, KmsKeyId
      • IsMultiRegionTrail, IncludeGlobalServiceEvents
      • Event or insight selectors (management vs data events)
  • Correlate
    • Look for preceding StopLogging or following DeleteTrail.
    • Review concurrent IAM policy edits or role changes by the same actor.
  • Planned changes: Baseline drift during region onboarding or encryption rotation.
  • Automation: IaC pipelines updating trails as templates evolve.
  • If unauthorized
    • Revert to baseline; validate destination ownership and KMS policy.
    • Investigate time ranges where visibility may have been reduced.
  • Hardening
    • Constrain cloudtrail:UpdateTrail, require approvals, and monitor with AWS Config rules.
event.dataset: "aws.cloudtrail"
    and event.provider: "cloudtrail.amazonaws.com"
    and event.action: "UpdateTrail"
    and event.outcome: "success"

Framework: MITRE ATT&CK

Framework: MITRE ATT&CK