A security team has deployed a runtime protection sensor as a DaemonSet in a Kubernetes cluster. However, after deployment, the sensor fails to send security events to the central CrowdStrike Cloud. The cluster nodes show no network connectivity issues. Which of the following is the most likely cause of the problem?

The most likely cause is a restrictive Kubernetes Network Policy. In Kubernetes, Network Policies control the flow of traffic at the pod level. If a default-deny egress policy is applied to the namespace where the CrowdStrike sensor DaemonSet is running, the sensor pods will be blocked from making outbound connections to the CrowdStrike Cloud (.crowdstrike.com on port 443). Since the problem statement confirms the underlying cluster nodes have network connectivity, the issue is isolated within the Kubernetes networking layer, making Network Policies the prime suspect for blocking the sensor's specific egress traffic.

B. The sensor DaemonSet is not using a privileged security context; restart with the --privileged flag enabled. A lack of privileged context would prevent the sensor from collecting runtime data from the host kernel, not from sending data it has already collected.
C. The container runtime (e.g., containerd or CRI-O) is misconfigured; reinstall Kubernetes to ensure proper integration. A misconfigured container runtime would likely cause widespread pod failures across the cluster, not a specific network communication issue for a single application.
D. The sensor lacks permissions to access container runtime data; check the Kubernetes RBAC settings. Kubernetes RBAC permissions grant access to the Kubernetes API for metadata enrichment, not for establishing external network connections to the CrowdStrike Cloud.

1. CrowdStrike, Falcon for Kubernetes Deployment Guide: The official deployment documentation specifies the network requirements for the Falcon sensor. It states, "The Falcon sensor must be able to connect to the CrowdStrike cloud over HTTPS (TCP port 443)... If you use network policies, you must create an egress policy that allows the Falcon sensor to connect to the CrowdStrike cloud." This directly supports that a missing or incorrect network policy is a common cause of communication failure. (Reference: Falcon for Kubernetes Deployment Guide, Section: "Network requirements").

2. Kubernetes Official Documentation, "Network Policies": The official Kubernetes documentation explains, "If there are any NetworkPolicy objects in a namespace that select a particular pod, that pod will reject any connections that are not allowed by at least one of those NetworkPolicy objects." This confirms that a network policy can block the sensor's required outbound traffic, even if the node's networking is functional. (Reference: kubernetes.io/docs/concepts/services-networking/network-policies/, Section: "The NetworkPolicy resource").