Admission of containers with added capability is not minimized

Description

Containers run with a default set of capabilities as assigned by the Container Runtime. By default this can include potentially dangerous capabilities. With Docker as the container runtime the NET_RAW capability is enabled which may be misused by malicious containers. Ideally, all containers should drop this capability.

Fix - Buildtime

Terraform

resource "kubernetes_pod" "pass2" {
  metadata {
    name = "terraform-example"
  }

  spec {
    container {
      image = "nginx:1.7.9"
      name  = "example22"

      security_context {
        capabilities {
          add = []
        }
      }

      env {
        name  = "environment"
        value = "test"
      }

      port {
        container_port = 8080
      }

      liveness_probe {
        http_get  {
          path = "/nginx_status"
          port = 80

          http_header {
            name  = "X-Custom-Header"
            value = "Awesome"
          }
        }

        initial_delay_seconds = 3
        period_seconds        = 3
      }
    }

    dns_config {
      nameservers = ["1.1.1.1", "8.8.8.8", "9.9.9.9"]
      searches    = ["example.com"]

      option {
        name  = "ndots"
        value = 1
      }

      option {
        name = "use-vc"
      }
    }

    dns_policy = "None"
  }
}