Container Runtime CLI Execution with Suspicious Arguments
Description
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.
Query · eql
process where host.os.type == "linux" and event.type == "start" and event.action in ("exec", "executed") 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"
)
Implementation guide
Requires process execution telemetry with arguments from Elastic Defend (logs-endpoint.events.process*) and/or
Auditd Manager / Auditbeat (logs-auditd_manager.auditd-*, auditbeat-*).
Ensure exec-related auditing captures full argv for ctr, crictl, and nerdctl. See
https://docs.elastic.co/integrations/auditd_manager
Known false positives
- Platform automation, node bootstrap, and legitimate break-glass admin sessions may use these CLIs with overlapping arguments. Tune by parent process, user, or host role (worker vs bastion).
Analyst notes
Investigating Container Runtime CLI Execution with Suspicious Arguments
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.
Possible investigation steps
- Reconstruct the container ID or snapshot key passed to
tasks,snapshots, orcontentsubcommands. - 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.
Response and remediation
- If unauthorized, isolate the node, revoke credentials available to the session, and hunt for new privileged workloads or image imports.