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Description

The following analytic detects the creation of a Kubernetes node port service, an action that exposes a service to the external network. It identifies this behavior by monitoring Kubernetes Audit logs for creation of a Node Port service. This behavior is worth identifying for a SOC as it could potentially allow an attacker to access internal services, posing a significant threat to the integrity and security of the Kubernetes infrastructure. The impact of such an attack could be severe, leading to data breaches, service disruptions, or unauthorized access to sensitive information.

  • Type: Anomaly

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2023-12-13
  • Author: Patrick Bareiss, Splunk
  • ID: d7fc865e-b8a1-4029-a960-cf4403b821b6

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1204 User Execution Execution
Kill Chain Phase
  • Installation
NIST
  • DE.AE
CIS20
  • CIS 13
CVE 


1
2
3
4
5



`kube_audit` "objectRef.resource"=services verb=create requestObject.spec.type=NodePort 
| fillnull 
| stats count values(user.groups{}) as user_groups by kind objectRef.name objectRef.namespace objectRef.resource requestObject.kind requestObject.spec.type responseStatus.code sourceIPs{} stage user.username userAgent verb 
| rename sourceIPs{} as src_ip, user.username as user 
| `kubernetes_node_port_creation_filter`

Macros

The SPL above uses the following Macros:

:information_source: kubernetes_node_port_creation_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • user.groups{}
  • kind
  • objectRef.name
  • objectRef.namespace
  • objectRef.resource
  • requestObject.kind
  • requestObject.spec.type
  • responseStatus.code
  • sourceIPs{}
  • stage
  • user.username
  • userAgent
  • verb

How To Implement

The detection is based on data that originates from Kubernetes Audit logs. Ensure that audit logging is enabled in your Kubernetes cluster. Kubernetes audit logs provide a record of the requests made to the Kubernetes API server, which is crucial for monitoring and detecting suspicious activities. Configure the audit policy in Kubernetes to determine what kind of activities are logged. This is done by creating an Audit Policy and providing it to the API server. Use the Splunk OpenTelemetry Collector for Kubernetes to collect the logs. This doc will describe how to collect the audit log file https://github.com/signalfx/splunk-otel-collector-chart/blob/main/docs/migration-from-sck.md.

Known False Positives

unknown

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
49.0 70 70 Kubernetes node port creation from user $user$

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

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