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🛡️ AWS EKS Cluster allows unrestricted public traffic🟢

Logic​

Similar Policies​

  • Internal: dec-x-cffc7d8e

Similar Internal Rules​

RulePoliciesFlags
✉️ dec-x-cffc7d8e1

Description​

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Description​

Ensure the AWS EKS Kubernetes API server endpoint is not exposed to unrestricted public access. This endpoint provides the interface to your cluster's control plane. Permitting open access allows any IP to initiate connections.

Rationale​

Unrestricted public access expands your cluster's attack surface. Threat actors could probe the API server for vulnerabilities, enumerate resources, or launch denial-of-service attacks. By limiting access to authorized CIDR ranges (e.g., corporate networks, VPN gateways, or designated CI/CD environments), you enforce the principle of least privilege and reduce the risk of unauthorized access and workload compromise.

Impact​

When specifying approved CIDR blocks, include all addresses from which your worker nodes and (if applicable) Fargate pods will access the public endpoint. Omitting any required range may prevent legitimate cluster operations.

Audit​

This policy marks an AWS EKS Cluster as INCOMPLIANT when Endpoint Public Access is set to Enabled and Public Access CIDRs include 0.0.0.0/0.

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Remediation​

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Remediation​

From Command Line​

Execute the following command to restrict your EKS API server endpoint to approved CIDR ranges and enable private endpoint access. {{publicAccessCidrs}} is a single CIDR or comma-separated list. Note that CIDR blocks must exclude reserved addresses.

If you rely solely on the public endpoint, you must include every egress IP used by your VPC (for example, the NAT Gateway’s public IP) in publicAccessCidrs. Enabling the private endpoint simplifies traffic flow for internal components and reduces the need to enumerate VPC egress addresses.

aws eks update-cluster-config \
    --region {{region-name}} \
    --name {{cluster-name}} \
    --resources-vpc-config endpointPublicAccess=true,publicAccessCidrs="{{publicAccessCidrs}}",endpointPrivateAccess=true

policy.yaml​

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Linked Framework Sections​

SectionSub SectionsInternal RulesPoliciesFlagsCompliance
💼 APRA CPG 234 → 💼 36d access management controls —only authorised users, software and hardware are able to access information assets (refer to Attachment B for further guidance);1414no data
💼 APRA CPG 234 → 💼 36e hardware and software asset controls —appropriate authorisation to prevent security compromises from unauthorised hardware and software assets;1616no data
💼 APRA CPG 234 → 💼 36f network design — to ensure authorised network traffic flows and to reduce the impact of security compromises;2930no data
💼 APRA CPG 234 → 💼 45 An understanding of plausible worst case scenarios can help regulated entities identify and implement additional controls to prevent or reduce the impact of such scenarios. One example is malware that infects computers and encrypts data, both on the infected computer and any connected storage, including (corporate) networks and cloud storage. Such attacks reinforce the importance of protecting the backup environment in the event that the production environment is compromised. Common techniques to achieve this include network segmentation, highly restricted and segregated access controls and network traffic flow restrictions.3537no data
💼 AWS Foundational Security Best Practices v1.0.0 → 💼 [EKS.1] EKS cluster endpoints should not be publicly accessible1no data
💼 Cloudaware Framework → 💼 Public and Anonymous Access116no data
💼 FedRAMP High Security Controls → 💼 AC-3 Access Enforcement (L)(M)(H)3784no data
💼 FedRAMP High Security Controls → 💼 AC-4 Information Flow Enforcement (M)(H)237105no data
💼 FedRAMP High Security Controls → 💼 AC-4(21) Physical or Logical Separation of Information Flows (M)(H)1163no data
💼 FedRAMP High Security Controls → 💼 AC-6 Least Privilege (M)(H)81179no data
💼 FedRAMP High Security Controls → 💼 AC-21 Information Sharing (M)(H)19no data
💼 FedRAMP High Security Controls → 💼 SC-7 Boundary Protection (L)(M)(H)10884no data
💼 FedRAMP High Security Controls → 💼 SC-7(3) Access Points (M)(H)19no data
💼 FedRAMP High Security Controls → 💼 SC-7(4) External Telecommunications Services (M)(H)49no data
💼 FedRAMP High Security Controls → 💼 SC-7(20) Dynamic Isolation and Segregation (H)20no data
💼 FedRAMP High Security Controls → 💼 SC-7(21) Isolation of System Components (H)37no data
💼 FedRAMP Low Security Controls → 💼 AC-3 Access Enforcement (L)(M)(H)84no data
💼 FedRAMP Low Security Controls → 💼 SC-7 Boundary Protection (L)(M)(H)49no data
💼 FedRAMP Moderate Security Controls → 💼 AC-3 Access Enforcement (L)(M)(H)84no data
💼 FedRAMP Moderate Security Controls → 💼 AC-4 Information Flow Enforcement (M)(H)189no data
💼 FedRAMP Moderate Security Controls → 💼 AC-4(21) Physical or Logical Separation of Information Flows (M)(H)63no data
💼 FedRAMP Moderate Security Controls → 💼 AC-6 Least Privilege (M)(H)679no data
💼 FedRAMP Moderate Security Controls → 💼 AC-21 Information Sharing (M)(H)19no data
💼 FedRAMP Moderate Security Controls → 💼 SC-7 Boundary Protection (L)(M)(H)768no data
💼 FedRAMP Moderate Security Controls → 💼 SC-7(3) Access Points (M)(H)19no data
💼 FedRAMP Moderate Security Controls → 💼 SC-7(4) External Telecommunications Services (M)(H)49no data
💼 NIST CSF v2.0 → 💼 DE.CM-01: Networks and network services are monitored to find potentially adverse events180no data
💼 NIST CSF v2.0 → 💼 DE.CM-09: Computing hardware and software, runtime environments, and their data are monitored to find potentially adverse events181no data
💼 NIST CSF v2.0 → 💼 ID.AM-03: Representations of the organization's authorized network communication and internal and external network data flows are maintained89no data
💼 NIST CSF v2.0 → 💼 PR.AA-05: Access permissions, entitlements, and authorizations are defined in a policy, managed, enforced, and reviewed, and incorporate the principles of least privilege and separation of duties133no data
💼 NIST CSF v2.0 → 💼 PR.DS-01: The confidentiality, integrity, and availability of data-at-rest are protected187no data
💼 NIST CSF v2.0 → 💼 PR.DS-02: The confidentiality, integrity, and availability of data-in-transit are protected160no data
💼 NIST CSF v2.0 → 💼 PR.DS-10: The confidentiality, integrity, and availability of data-in-use are protected184no data
💼 NIST CSF v2.0 → 💼 PR.IR-01: Networks and environments are protected from unauthorized logical access and usage123no data
💼 NIST SP 800-53 Revision 5 → 💼 AC-3 Access Enforcement15559no data
💼 NIST SP 800-53 Revision 5 → 💼 AC-3(7) Access Enforcement _ Role-based Access Control31no data
💼 NIST SP 800-53 Revision 5 → 💼 AC-4 Information Flow Enforcement3269123no data
💼 NIST SP 800-53 Revision 5 → 💼 AC-4(21) Information Flow Enforcement _ Physical or Logical Separation of Information Flows3763no data
💼 NIST SP 800-53 Revision 5 → 💼 AC-6 Least Privilege102372no data
💼 NIST SP 800-53 Revision 5 → 💼 AC-21 Information Sharing219no data
💼 NIST SP 800-53 Revision 5 → 💼 SC-7 Boundary Protection29493no data
💼 NIST SP 800-53 Revision 5 → 💼 SC-7(3) Boundary Protection _ Access Points19no data
💼 NIST SP 800-53 Revision 5 → 💼 SC-7(4) Boundary Protection _ External Telecommunications Services49no data
💼 NIST SP 800-53 Revision 5 → 💼 SC-7(9) Boundary Protection _ Restrict Threatening Outgoing Communications Traffic34no data
💼 NIST SP 800-53 Revision 5 → 💼 SC-7(11) Boundary Protection _ Restrict Incoming Communications Traffic37no data
💼 NIST SP 800-53 Revision 5 → 💼 SC-7(16) Boundary Protection _ Prevent Discovery of System Components37no data
💼 NIST SP 800-53 Revision 5 → 💼 SC-7(20) Boundary Protection _ Dynamic Isolation and Segregation20no data
💼 NIST SP 800-53 Revision 5 → 💼 SC-7(21) Boundary Protection _ Isolation of System Components37no data
💼 PCI DSS v3.2.1 → 💼 1.3.6 Place system components that store cardholder data in an internal network zone, segregated from the DMZ and other untrusted networks.15no data
💼 PCI DSS v4.0.1 → 💼 1.4.4 System components that store cardholder data are not directly accessible from untrusted networks.15no data
💼 PCI DSS v4.0 → 💼 1.4.4 System components that store cardholder data are not directly accessible from untrusted networks.15no data