Cisco Isovalent - Nsenter Usage in Kubernetes Pod
This analytic detects the execution of the nsenter utility from within a container, a technique often used for exploitation and container escape. Nsenter allows an attacker to enter the namespaces of another…
Description
This analytic detects the execution of the nsenter utility from within a container, a technique often used for exploitation and container escape. Nsenter allows an attacker to enter the namespaces of another process—such as the host's init process (PID 1)—and execute a shell or other binaries with elevated privileges. For example, an attacker may use docker exec to gain a shell in a container, enumerate the PID of a target container or the host, and then use nsenter to access all namespaces (mount, UTS, IPC, net, pid) of the host or another container. Example to escape to the host: `nsenter --target 1 --mount --uts --ipc --net --pid -- bash`. The WorkloadAncestorsBinary field is used to track the ancestry of the process, this is useful to understand the context of the nsenter usage. The options -m -u -n -i -p correspond to the various Linux namespaces. Adversaries exploit nsenter when pods are misconfigured with excessive privileges (e.g., privileged, hostPID, or broad hostPath mounts), enabling them to interact with the underlying node filesystem and processes. This can be an indicator of a container escape attempt or privilege escalation. Security teams should pay close attention to any nsenter invocation from within containers, especially outside of normal maintenance activity or in workloads with elevated privileges.
Detection logic
Detection requirements
- Platform
- ContainersLinuxmacOSWindows
The rule states no platform. This is derived from the ATT&CK technique it maps to.
- Log source category
- cisco_isovalent_process_exec
Known benign triggers
- It is highly unlikely that nsenter will be used in a legitimate way, investigate the alert in context to rule out benign operations.
MITRE ATT&CK mappings
0 exclusive techniques.This is coverage no other published rule has; it is not this rule's total technique count.
References
| Reference | Cited by |
|---|---|
| isovalent.com/blog/post/2021-11-container-escape/ | Only this detection cites it |
| kubehound.io/reference/attacks/CE_NSENTER/ | Only this detection cites it |
From the source
- At source
- Open at source
- Upstream identifier
- cd07120d-4265-481a-ba0f-3b91fbc5a02f
- Tagged by the source as
- Cisco Isovalent Suspicious ActivityEndpointendpointSplunk CloudSplunk EnterpriseSplunk Enterprise Securityendpoint
Licence
- Published under
- Apache License 2.0Read the licence
- Attribution
- Required
- Obtained under
- Apache-2.0Read the origin licence
Authorship
- Written by
- Published
- Aug 26, 2026
- Version
- 1