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Container security is the practice of securing containerized applications across their lifecycle, the image, the registry, the orchestrator (like Kubernetes), the running container, and the host, so a vulnerability or misconfiguration in any layer cannot be used to compromise the workload or the systems around it.
Container security is the practice of securing containerized applications across their lifecycle, the image, the registry, the orchestrator (like Kubernetes), the running container, and the host, so a vulnerability or misconfiguration in any layer cannot be used to compromise the workload or the systems around it.
NIST's SP 800-190, the standard reference, groups container risk into five areas: image, registry, orchestrator, container, and host. The recurring problems are vulnerable or bloated base images, untrusted or unauthenticated registries, an insecurely configured orchestrator, unbounded network access between containers, and the shared-kernel attack surface, where a container escape can reach the host and every other container on it.
Most container vulnerabilities enter through the base image and application dependencies. Scanning images for known vulnerabilities, and rebuilding on patched, minimal base images, catches the majority before they ship. A software bill of materials (SBOM) records what is inside each image so you can answer "are we affected" the next time a widely used component is found vulnerable.
Before a container runs, its configuration (privileges, mounted secrets, resource limits) and the orchestrator's admission policy decide how much damage a compromise could do. Least privilege here, no root and no privileged mode, and admission rules that reject non-compliant workloads, shrink the blast radius before anything is running.
At runtime, the questions are whether a container behaves as expected and how far it is exposed. Runtime protection watches for anomalous process, file, and network behavior, and network policy limits what a compromised container can reach. This is the layer image scanning cannot cover, because it is about behavior, not known vulnerabilities.
Kubernetes adds its own attack surface on top of the containers it runs: the API server, RBAC, secrets management, network policies, and workload configuration. Securing the cluster, least-privilege RBAC, network segmentation between namespaces, and hardened workload settings, matters as much as securing the images. A hardened image on a misconfigured cluster is still exposed.
latest tag instead of a specific digest).Fencer scans your container images and registry artifacts for known vulnerabilities and unpatched base images, and folds those findings into the same prioritized queue as your code, cloud, and application risk. That means an image vulnerability is ranked by whether the container is actually exposed and exploitable, not treated in isolation. Findings route into remediation, and Fencer re-scans to confirm the fix. Fencer focuses on image and artifact scanning as part of its broader cloud and application coverage; it is not a standalone runtime container-protection agent.
