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EKS clusters should have control plane audit logging enabled

EKS control plane audit logs record every request to the Kubernetes API server, including who made the request, what resource was affected, and whether it succeeded. Without these logs, you have no way to detect unauthorized kubectl commands, privilege escalation attempts, or misconfigurations in RBAC policies. Incident response becomes guesswork.

Each enabled log type costs roughly $0.50 per GB ingested into CloudWatch Logs, which is modest relative to the forensic value. Disabling audit logs to save a few dollars a month leaves a gap that compliance auditors will flag immediately.

Retrofit consideration

Enabling or changing control plane log types triggers a cluster update that can take several minutes, but does not cause downtime or node disruption.

Implementation

Choose the approach that matches how you manage Terraform.

Use the compliance.tf module to enforce this control by default. See get started with compliance.tf.

module "eks" {
  source  = "pcidss.compliance.tf/terraform-aws-modules/eks/aws"
  version = ">=21.0.0"

  include_oidc_root_ca_thumbprint = false
  name                            = "abc123"
  subnet_ids                      = ["subnet-abc123", "subnet-def456"]
  vpc_id                          = "vpc-12345678"
}


module "eks" {
  source  = "acscessentialeight.compliance.tf/terraform-aws-modules/eks/aws"
  version = ">=21.0.0"

  include_oidc_root_ca_thumbprint = false
  name                            = "abc123"
  subnet_ids                      = ["subnet-abc123", "subnet-def456"]
  vpc_id                          = "vpc-12345678"
}

If you use terraform-aws-modules/eks/aws, set the right module inputs for this control. You can later migrate to the compliance.tf module with minimal changes because it is compatible by design.

module "eks" {
  source  = "terraform-aws-modules/eks/aws"
  version = ">=21.0.0"

  include_oidc_root_ca_thumbprint = false
  name                            = "abc123"
  subnet_ids                      = ["subnet-abc123", "subnet-def456"]
  vpc_id                          = "vpc-12345678"
}

Use AWS provider resources directly. See docs for the resources involved: aws_eks_cluster.

resource "aws_eks_cluster" "this" {
  enabled_cluster_log_types = ["api", "audit", "authenticator", "controllerManager", "scheduler"]

  encryption_config {
    provider {
      key_arn = "arn:aws:kms:us-east-1:123456789012:key/12345678-1234-1234-1234-123456789012"
    }
    resources = ["secrets"]
  }

  name     = "pofix-abc123"
  role_arn = "arn:aws:iam::123456789012:role/example-role"

  vpc_config {
    endpoint_private_access = true
    subnet_ids              = ["subnet-abc123", "subnet-def456"]
  }
}

What this control checks

This control validates that the aws_eks_cluster resource enables the "audit" control plane log type. Depending on provider version and module design, this appears as either enabled_cluster_log_types or a nested logging/cluster_logging block. Valid EKS control plane log types are "api", "audit", "authenticator", "controllerManager", and "scheduler". To pass, the configured set must contain at least "audit". It fails when logging configuration is omitted entirely, when the enabled set is empty, or when other log types are present but "audit" is not.

Common pitfalls

  • Only audit vs all log types

    Setting enabled_cluster_log_types to ["api", "authenticator"] without "audit" fails this control. A common mistake: teams enable "api" thinking it captures audit events, but the api and audit streams are distinct in EKS. You need "audit" explicitly.

  • Provider schema differences for logging configuration

    Depending on provider version and module design, EKS logging appears as either enabled_cluster_log_types or a nested logging/cluster_logging block. Make sure your configuration actually enables "audit" and that your policy engine checks the schema your code uses.

  • CloudWatch log retention defaults to never expire

    EKS creates the log group with indefinite retention. Without a companion aws_cloudwatch_log_group resource for /aws/eks/<cluster>/cluster that sets a retention period, storage costs grow without bound. This doesn't affect the compliance check, but it will show up on your bill.

  • Log group must exist before cluster creation in some modules

    Pre-creating the CloudWatch log group to set encryption or retention is fine, but the name must match /aws/eks/<cluster-name>/cluster exactly. A mismatch means EKS silently creates its own unmanaged log group, and your KMS and retention settings are ignored.

Audit evidence

The primary evidence is the AWS Config rule eks-cluster-logging-enabled showing COMPLIANT for each cluster, or equivalent output from a CSPM tool. Supporting evidence is the CloudWatch Logs log group /aws/eks/<cluster-name>/cluster containing recent audit log streams, confirming logs are actively flowing. Console screenshots of the cluster's "Logging" tab under "Observability" can also demonstrate current state.

For periodic audits, a CloudTrail search for UpdateClusterConfig API calls with logging changes shows when logging was enabled or modified, which helps prove continuous compliance rather than point-in-time enablement.

Framework-specific interpretation

PCI DSS v4.0: Requirement 10 calls for logging all access to system components that may store, process, or transmit cardholder data. For EKS clusters in that scope, control plane audit logs are what examiners want to see: every API server request recorded with user identity, resource, and outcome.

Tool mappings

Use these identifiers to cross-reference this control across tools, reports, and evidence.

  • Compliance.tf Control: eks_cluster_control_plane_audit_logging_enabled

  • AWS Config Managed Rule: EKS_CLUSTER_LOG_ENABLED

  • Checkov Check: CKV_AWS_37

  • Powerpipe Control: aws_compliance.control.eks_cluster_control_plane_audit_logging_enabled

  • Prowler Check: eks_control_plane_logging_all_types_enabled

  • AWS Security Hub Control: EKS.8

  • KICS Queries: 37304d3f-f852-40b8-ae3f-725e87a7cedf, 66f130d9-b81d-4e8e-9b08-da74b9c891df

  • Trivy Check: AWS-0038

Last reviewed: 2026-03-09