You Trust Your Helm Charts — Here’s Why That’s a Huge Mistake That Could Lead to a Cloud Breach

Helm has revolutionized how Kubernetes applications are deployed. A single helm install can launch a fully functioning stack in seconds. But a new report by Microsoft Defender for Cloud reveals a disturbing truth: many Helm charts are insecure by default, and their convenience often comes at the cost of exposure.

The report, The Risk of Default Configuration: How Out-of-the-Box Helm Charts Can Breach Your Cluster, highlights how default configurations expose dashboards, APIs, and services to the internet — often without authentication or access control. What’s more alarming is that this risk isn’t limited to hobbyist tools: even security software — such as CrowdStrike’s Falcon Kubernetes Admission Controller (KAC) — can pose similar risks if misconfigured or deployed without hardening.

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📊 Microsoft’s Findings: Insecure Defaults Are Everywhere

Microsoft’s security researchers scanned GitHub repositories for common patterns like:

yamlCopyEdittype: LoadBalancer

These patterns often indicate that a Kubernetes service is exposed externally — which is fine for a web frontend, but dangerous for internal components like dashboards, databases, or control planes.

🔍 Key Findings from the Report:

1. Helm charts prioritize usability, not security.
   • Services are frequently exposed using LoadBalancer or NodePort.
   • Authentication and authorization are often absent or optional.
2. Open-source tools are often deployed directly into production.
   • Tools like Apache Pinot, Meshery, and Selenium Grid had publicly accessible dashboards with no login required.
3. Attackers are actively exploiting these defaults.
   • Microsoft observed real-world attacks where these exposed services were used for:
     • Remote code execution (RCE)
     • Data harvesting
     • Cluster persistence or lateral movement

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🧱 Real-World Example: Apache Pinot

• What it is: Real-time OLAP datastore
• Issue: Helm chart exposes pinot-controller and pinot-broker via LoadBalancer, unauthenticated
• Impact: Any remote IP can browse or query production data

🧪 Real-World Example: Meshery

• What it is: Service mesh manager for Kubernetes
• Issue: Default Helm deployment creates public-facing dashboard with open registration
• Impact: Unauthorized users can deploy workloads or run diagnostics

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🚨 Why Even Security Tools Need Scrutiny: CrowdStrike Falcon KAC

Even Helm charts from leading cybersecurity vendors aren’t immune. Consider the CrowdStrike Falcon KAC, a Kubernetes admission controller used to enforce workload policies and integrate with Falcon’s container visibility backend.

While secure by design in several aspects, it lacks some essential configuration defaults that Microsoft’s report warns about.

🔎 Security Analysis of Falcon KAC Helm Chart:

Feature	Behavior in Default Chart
Service Type	✅ Uses ClusterIP (internal-only)
NetworkPolicy	❌ Not defined — no traffic restrictions
Secrets Handling	⚠️ Uses standard K8s secrets; no vault integration
RBAC Scope	⚠️ Broad access for webhook components
Pod Isolation	✅ Uses securityContext for hardening

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🔐 What Could Go Wrong?

If a DevOps engineer adjusts the Falcon KAC service type to LoadBalancer (perhaps for debugging), and deploys in a cluster with no default NetworkPolicy:

• The webhook service could become publicly reachable.
• External actors could simulate pod creation requests or interfere with webhook operations.
• Combined with broad RBAC or weak secret management, this could lead to:
  • Unauthorized admission approvals or rejections
  • Remote code injection via manipulated pod specs
  • Complete cluster compromise

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🛡️ How to Mitigate: Recommendations from Microsoft + Community Best Practices

Risk Area	Microsoft Guidance	Action for Falcon KAC or Similar Charts
Service Exposure	Avoid LoadBalancer for internal services	Keep Falcon KAC on ClusterIP; use internal DNS only
Network Isolation	Apply NetworkPolicy to limit traffic	Define policy for Falcon namespace
Secrets Management	Use secure vaults or external managers	Replace K8s secrets with external store if possible
RBAC & Permissions	Enforce least privilege	Review ClusterRole/RoleBinding scopes
CI/CD Integration	Validate Helm via kubeaudit, OPA, etc.	Add checks to pipeline before deployment

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📂 Example: Secure NetworkPolicy for Falcon KAC

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: falcon-kac-ingress
  namespace: falcon-kac
spec:
  podSelector: {}
  policyTypes:
    - Ingress
    - Egress
  ingress:
    - from:
        - namespaceSelector:
            matchLabels:
              kubernetes.io/metadata.name: kube-system
  egress:
    - to:
        - ipBlock:
            cidr: <INSERT_CROWDSTRIKE_API_CIDR>

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🎯 Final Thought: Secure by Default Needs to Become the Standard

Microsoft’s report is a wake-up call: the Kubernetes ecosystem’s reliance on fast, reusable Helm charts is creating long-tail vulnerabilities. Helm maintainers and users alike must treat configuration as a security boundary. Whether you’re deploying an open-source dashboard or an enterprise-grade security tool like Falcon KAC — default does not mean safe.