:warning: THIS IS A EXPERIMENTAL DETECTION

This detection has been marked experimental by the Splunk Threat Research team. This means we have not been able to test, simulate, or build datasets for this detection. Use at your own risk. This analytic is NOT supported.

Try in Splunk Security Cloud

Description

The following analytic identifies unauthenticated requests to Kubernetes cluster pods. It detects this activity by analyzing GCP Pub/Sub messages for audit logs where the response status code is 401, indicating unauthorized access attempts. This activity is significant for a SOC because it may indicate reconnaissance or scanning attempts by an attacker trying to identify vulnerable pods. If confirmed malicious, this activity could lead to unauthorized access, allowing the attacker to exploit vulnerabilities within the cluster, potentially compromising sensitive data or gaining control over the Kubernetes environment.

  • Type: Hunting

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

  • Last Updated: 2024-05-18
  • Author: Rod Soto, Splunk
  • ID: 19b53215-4a16-405b-8087-9e6acf619842

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1526 Cloud Service Discovery Discovery
Kill Chain Phase
  • Exploitation
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


1
2
3
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`google_gcp_pubsub_message` category=kube-audit 
|spath input=properties.log 
|search responseStatus.code=401 
|table sourceIPs{} userAgent verb requestURI responseStatus.reason properties.pod 
| `gcp_kubernetes_cluster_pod_scan_detection_filter`

Macros

The SPL above uses the following Macros:

:information_source: gcp_kubernetes_cluster_pod_scan_detection_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.

  • _time
  • category
  • responseStatus.code
  • sourceIPs{}
  • userAgent
  • verb
  • requestURI
  • responseStatus.reason
  • properties.pod

How To Implement

You must install the GCP App for Splunk (version 2.0.0 or later), then configure stackdriver and set a Pub/Sub subscription to be imported to Splunk.

Known False Positives

Not all unauthenticated requests are malicious, but frequency, User Agent, source IPs and pods will provide context.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
25.0 50 50 tbd

: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

source | version: 2