Network Policies in Kubernetes should be set up to prevent unrestricted communication between pods. The Deny-All rule ensures that no communication is allowed unless explicitly permitted, greatly reducing the attack surface.
Deny-All Policy: Set a Deny-All Network Policy in each namespace to block all traffic by default. This ensures that only allowed traffic is permitted, preventing unauthorized communication between pods.
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: deny-all
namespace: default # Should be created for all namespaces
spec:
podSelector: {}
policyTypes:
- Ingress
- Egress
Restrict Lateral Movement: The Deny-All policy stops lateral movement within the cluster by preventing compromised pods from accessing other pods or services without explicit permissions.
Namespace-Specific Policies: Avoid Global Network Policies, as they can lead to administrative confusion and unintended permissions. Namespace-specific policies ensure better control and clear security boundaries.
Management and Accountability: Assign responsibility for Network Policy management to specific team members, ensuring that policies are maintained and adjusted as needed.
By enforcing the Deny-All rule and only allowing explicitly defined communications, you can significantly enhance the security of your Kubernetes cluster, minimizing the risk of lateral attacks and protecting sensitive resources from unauthorized access.
