eks-iam-managed-policy-networking: Use AWS-managed policy to Manage Networking Resources

id: eks-iam-managed-policy-networking

info:
  name: Use AWS-managed policy to Manage Networking Resources
  author: princechaddha
  severity: high
  description: |
    Ensure that all Amazon EKS cluster node groups use the "AmazonEKS_CNI_Policy" managed policy to manage cloud networking resources effectively. This policy provides the necessary permissions to the Amazon VPC CNI Plugin for managing network interfaces.
  impact: |
    Without the AmazonEKS_CNI_Policy, the VPC CNI plugin cannot properly manage network interfaces, which will affect pod networking and communication within the EKS cluster.
  remediation: |
    Attach the AmazonEKS_CNI_Policy to the IAM role associated with your EKS node groups using either the AWS Console or AWS CLI.
  reference:
    - https://www.trendmicro.com/cloudoneconformity/knowledge-base/aws/EKS/eks-iam-managed-policy-networking.html
    - https://docs.aws.amazon.com/eks/latest/userguide/cni-iam-role.html
  tags: cloud,devops,aws,amazon,eks,aws-cloud-config

variables:
  region: "us-east-1"

flow: |
  code(1)
  for(let cluster of iterate(template.clusters)){
    set("cluster", cluster)
    code(2)
    for(let nodegroup of iterate(template.nodegroups)){
      set("nodegroup", nodegroup)
      code(3)
      code(4)
    }
  }

self-contained: true

code:
  - engine:
      - sh
      - bash
    source: |
      aws eks list-clusters --region $region --query 'clusters' --output json

    extractors:
      - type: json
        name: clusters
        internal: true
        json:
          - '.[]'

  - engine:
      - sh
      - bash
    source: |
      aws eks list-nodegroups --region $region --cluster-name $cluster --query 'nodegroups' --output json

    extractors:
      - type: json
        name: nodegroups
        internal: true
        json:
          - '.[]'

  - engine:
      - sh
      - bash
    source: |
      aws eks describe-nodegroup --region $region --cluster-name $cluster --nodegroup-name $nodegroup --query 'nodegroup.nodeRole' --output json

    extractors:
      - type: json
        name: rolearn
        internal: true
        json:
          - '.'

  - engine:
      - sh
      - bash
    source: |
      aws iam list-attached-role-policies --role-name $(echo $rolearn | cut -d'/' -f2) --query 'AttachedPolicies[*].PolicyArn' --output json

    matchers-condition: and
    matchers:
      - type: word
        words:
          - "arn:aws:iam::aws:policy/AmazonEKS_CNI_Policy"
        negative: true

      - type: word
        words:
          - "["

    extractors:
      - type: dsl
        dsl:
          - '"EKS node group " + nodegroup + " in cluster " + cluster + " does not have AmazonEKS_CNI_Policy attached to its IAM role"'
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