add falco operator plugin and custom rules

falco/operator-resources/custom-rules.yaml

@@ -0,0 +1,39 @@
+# Custom runtime detections for the portfolio baseline.
+# These rules supplement the default Falco rules and are intentionally scoped
+# to container activity for a clear admission-to-runtime demonstration.
+
+- list: sensitive_container_paths
+  items: [/etc/passwd, /etc/shadow, /etc/sudoers, /etc/ssh/sshd_config]
+
+- rule: Shell spawned in container
+  desc: A shell process was started inside a running container.
+  condition: spawned_process and container and proc.name in (bash, sh, ash, zsh, ksh, fish)
+  output: >-
+    Shell spawned in container
+    (user=%user.name user_uid=%user.uid shell=%proc.name command=%proc.cmdline
+    container_id=%container.id container_image=%container.image.repository
+    container_name=%container.name k8s_ns=%k8s.ns.name k8s_pod=%k8s.pod.name)
+  priority: WARNING
+  tags: [container, process, baseline]
+
+- rule: Sensitive file modified in container
+  desc: A process attempted to write a sensitive host-like file from a container.
+  condition: open_write and container and fd.name in (sensitive_container_paths)
+  output: >-
+    Sensitive file modified in container
+    (user=%user.name command=%proc.cmdline file=%fd.name
+    container_id=%container.id container_image=%container.image.repository
+    k8s_ns=%k8s.ns.name k8s_pod=%k8s.pod.name)
+  priority: ERROR
+  tags: [container, filesystem, persistence, baseline]
+
+- rule: Unexpected outbound connection from container
+  desc: A container opened a connection to a non-loopback address.
+  condition: evt.type=connect and container and not fd.sip in (127.0.0.1, 0.0.0.0)
+  output: >-
+    Outbound connection from container
+    (user=%user.name command=%proc.cmdline connection=%fd.name
+    container_id=%container.id container_image=%container.image.repository
+    k8s_ns=%k8s.ns.name k8s_pod=%k8s.pod.name)
+  priority: NOTICE
+  tags: [container, network, baseline]