Network policies define egress rules

ID: k8s-netpol-egress-rules

Severity: medium

Author: princechaddha

Tags: cloud,devops,kubernetes,devsecops,k8s,k8s-cluster-security

Description

Checks for network policies in Kubernetes that do not define egress rules, which can leave the network exposed to external threats.

YAML Source

id: k8s-netpol-egress-rules

info:
  name: Network policies define egress rules
  author: princechaddha
  severity: medium
  description: Checks for network policies in Kubernetes that do not define egress rules, which can leave the network exposed to external threats.
  impact: |
    Lack of egress rules in network policies can result in unrestricted outbound network traffic, which may allow data exfiltration or unauthorized access to external services.
  remediation: Define egress rules in all network policies to control outbound traffic from your Kubernetes pods, thereby reducing security risks.
  reference:
    - https://kubernetes.io/docs/concepts/services-networking/network-policies/
  tags: cloud,devops,kubernetes,devsecops,k8s,k8s-cluster-security

flow: |
  code(1);
  for (let policy of template.items) {
    set("policy", policy)
    javascript(1);
  }

self-contained: true
code:
  - engine:
      - sh
      - bash
    source: kubectl get networkpolicies --all-namespaces --output=json
    extractors:
      - type: json
        name: items
        internal: true
        json:
          - '.items[] | {policy: .metadata.name, egress: .spec.egress}'

javascript:
  - code: |
        let policyData = JSON.parse(template.policy);
        if (!policyData.egress || policyData.egress.length === 0) {
          let result = (`Network policy '${policyData.policy}' does not define egress rules.`);
          Export(result);
        }

    extractors:
      - type: dsl
        dsl:
          - response
# digest: 4b0a00483046022100f5b66ad83993ac53d96b185fe084956da4f39a3e8eaa67a860d924d34deb96a1022100f5aa41c75f483a4f13165022510835005277bbe223f96774b2740be52a106cc8:922c64590222798bb761d5b6d8e72950

Guide to check the vulnerabilities

This template is used to detect vulnerabilities in web applications. It can be used with the Nuclei tool to scan for specific patterns or behaviors.

$ nuclei -u "URL" -t "cloud/kubernetes/network-policies/k8s-netpol-egress-rules.yaml"

View on Github