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Suspicious Container Runtime CLI Execution

Detects execution of container runtime CLI tools (ctr, crictl, nerdctl) with arguments indicating container creation, command execution inside existing containers, image manipulation, or host filesystem mounting. These tools interact directly with the container runtime socket, bypassing the Kubernetes API server, RBAC authorization, admission webhooks, pod security standards, and Kubernetes audit logging entirely. Attackers with host-level access may use these tools to create privileged ghost containers, exec into other pods to steal service account tokens and secrets, pull attacker-controlled images, and destroy evidence, all while remaining invisible to Kubernetes-level monitoring.

Rule type: eql
Rule indices:

  • logs-cloud_defend.process*

Rule Severity: medium
Risk Score: 47
Runs every:
Searches indices from: now-6m
Maximum alerts per execution: 100
References:

Tags:

  • Data Source: Elastic Defend for Containers
  • Domain: Container
  • OS: Linux
  • Use Case: Threat Detection
  • Tactic: Execution
  • Resources: Investigation Guide

Version: 1
Rule authors:

  • Elastic

Rule license: Elastic License v2

Review the full argv list and working directory. Confirm whether the session is interactive, whether the image or bundle referenced is trusted, and whether bind mounts or privileged flags target host paths such as /, /etc, or Docker sockets.

  • Reconstruct the container ID or snapshot key passed to tasks, snapshots, or content subcommands.
  • Correlate with file, network, and Kubernetes audit activity for pulls from unusual registries or subsequent pod changes.
  • Check whether the parent should legitimately be kubelet, containerd, or systemd on that host class.
  • If unauthorized, isolate the node, revoke credentials available to the session, and hunt for new privileged workloads or image imports.
process where host.os.type == "linux" and event.type == "start" and event.action == "exec" and
(
  (
    process.name in ("ctr", "crictl", "nerdctl") and
    (
      (process.args == "tasks" and process.args == "exec") or
      (process.args == "run" and process.args in ("--privileged", "--rm", "--mount", "--net-host", "--pid-host")) or
      (process.args == "snapshots" and process.args == "mount")
    )
  ) or
  (
    (process.executable like ("/dev/shm/*", "/tmp/*", "/var/tmp/*") or process.name : ".*") and
    process.args like ("*containerd.sock*", "*k8s.io*")
  )
) and
not process.parent.executable in (
  "/usr/bin/kubelet", "/usr/local/bin/kubelet",
  "/usr/bin/containerd", "/usr/sbin/containerd",
  "/lib/systemd/systemd", "/usr/lib/systemd/systemd", "/sbin/init"
)

Framework: MITRE ATT&CK

Framework: MITRE ATT&CK