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Description

The following analytic detects unauthorized access to Kubernetes by monitoring Kubernetes audit logs. It identifies anomalies in access patterns by segmenting and analyzing the source of requests. Unauthorized access is worth identifying for a SOC as it could indicate an attacker attempting to infiltrate the system. The impact of such an attack could be severe, potentially leading to unauthorized access to sensitive systems or data.

  • Type: Anomaly

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

  • Last Updated: 2023-12-07
  • Author: Patrick Bareiss, Splunk
  • ID: 9b5f1832-e8b9-453f-93df-07a3d6a72a45

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` verb=create responseStatus.reason=Forbidden 
| fillnull 
| stats count by objectRef.namespace objectRef.resource requestReceivedTimestamp requestURI responseStatus.code responseStatus.message sourceIPs{} stage user.groups{} user.uid user.username userAgent verb 
| rename sourceIPs{} as src_ip, user.username as user 
| `kubernetes_unauthorized_access_filter`

Macros

The SPL above uses the following Macros:

:information_source: kubernetes_unauthorized_access_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.

  • verb
  • requestReceivedTimestamp
  • requestURI
  • responseStatus.code
  • sourceIPs{}
  • user.groups{}
  • user.username
  • userAgent
  • verb
  • responseStatus.reason
  • responseStatus.status

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 Unauthorized access to Kubernetes 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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