Detection: Amazon EKS Kubernetes Pod scan detection

EXPERIMENTAL DETECTION

This detection status is set to experimental. The Splunk Threat Research team has not yet fully tested, simulated, or built comprehensive datasets for this detection. As such, this analytic is not officially supported. If you have any questions or concerns, please reach out to us at research@splunk.com.

Updated Date: 2024-05-29 ID: dbfca1dd-b8e5-4ba4-be0e-e565e5d62002 Author: Rod Soto, Splunk Type: Hunting Product: Splunk Enterprise Security

Description

The following analytic detects unauthenticated requests made against the Kubernetes Pods API, indicating potential unauthorized access attempts. It leverages the aws_cloudwatchlogs_eks data source, filtering for events where user.username is "system:anonymous", verb is "list", and objectRef.resource is "pods", with requestURI set to "/api/v1/pods". This activity is significant as it may signal attempts to access sensitive resources or execute unauthorized commands within the Kubernetes environment. If confirmed malicious, such access could lead to data compromise, unauthorized command execution, or lateral movement within the cluster.

1`aws_cloudwatchlogs_eks` "user.username"="system:anonymous" verb=list objectRef.resource=pods requestURI="/api/v1/pods" 
2| rename source as cluster_name sourceIPs{} as src_ip 
3| stats count min(_time) as firstTime max(_time) as lastTime values(responseStatus.reason) values(responseStatus.code) values(userAgent) values(verb) values(requestURI) by src_ip cluster_name user.username user.groups{} 
4| `security_content_ctime(lastTime)` 
5| `security_content_ctime(firstTime)` 
6| `amazon_eks_kubernetes_pod_scan_detection_filter`

Data Source

Name Platform Sourcetype Source Supported App
N/A N/A N/A N/A N/A

Macros Used

Name Value
aws_cloudwatchlogs_eks sourcetype="aws:cloudwatchlogs:eks"
amazon_eks_kubernetes_pod_scan_detection_filter search *
amazon_eks_kubernetes_pod_scan_detection_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1526 Cloud Service Discovery Discovery
KillChainPhase.EXPLOITAITON
NistCategory.DE_AE
Cis18Value.CIS_10

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting Value
Disabled true
Cron Schedule 0 * * * *
Earliest Time -70m@m
Latest Time -10m@m
Schedule Window auto
Creates Risk Event False
This configuration file applies to all detections of type hunting.

Implementation

You must install the AWS App for Splunk (version 5.1.0 or later) and Splunk Add-on forAWS (version 4.4.0 or later), then configure your AWS CloudWatch EKS Logs.Please also customize the kubernetes_pods_aws_scan_fingerprint_detection macro to filter out the false positives.

Known False Positives

Not all unauthenticated requests are malicious, but frequency, UA and source IPs and direct request to API provide context.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
tbd 25 50 50
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation Not Applicable N/A N/A N/A
Unit ❌ Failing N/A N/A N/A
Integration ❌ Failing N/A N/A N/A

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: GitHub | Version: 2