Detection rules › Splunk

Kubernetes Scanner Image Pulling

Status
production
Severity
medium
Group by
host, kind, message, name, namespace, phase, reason, severity
Author
Patrick Bareiss, Splunk
Source
github.com/splunk/security_content

The following analytic detects the pulling of known Kubernetes security scanner images such as kube-hunter, kube-bench, and kube-recon. It leverages Kubernetes logs ingested through Splunk Connect for Kubernetes, specifically monitoring for messages indicating the pulling of these images. This activity is significant because the use of security scanners can indicate an attempt to identify vulnerabilities within the Kubernetes environment. If confirmed malicious, this could lead to the discovery and exploitation of security weaknesses, potentially compromising the entire Kubernetes cluster.

Known false positives

  • No false positives have been identified at this time.

MITRE ATT&CK coverage

TacticTechniques
Discovery

Rule body

name: Kubernetes Scanner Image Pulling
id: 4890cd6b-0112-4974-a272-c5c153aee551
version: 10
creation_date: '2021-08-24'
modification_date: '2026-05-13'
author: Patrick Bareiss, Splunk
status: production
type: TTP
description: The following analytic detects the pulling of known Kubernetes security scanner images such as kube-hunter, kube-bench, and kube-recon. It leverages Kubernetes logs ingested through Splunk Connect for Kubernetes, specifically monitoring for messages indicating the pulling of these images. This activity is significant because the use of security scanners can indicate an attempt to identify vulnerabilities within the Kubernetes environment. If confirmed malicious, this could lead to the discovery and exploitation of security weaknesses, potentially compromising the entire Kubernetes cluster.
data_source: []
search: |-
    `kube_objects_events` object.message IN ("Pulling image *kube-hunter*", "Pulling image *kube-bench*", "Pulling image *kube-recon*", "Pulling image *kube-recon*")
      | rename object.* AS *
      | rename involvedObject.* AS *
      | rename source.host AS host
      | eval phase="operate"
      | eval severity="high"
      | stats min(_time) as firstTime max(_time) as lastTime count
        BY host, name, namespace,
           kind, reason, message,
           phase, severity
      | `security_content_ctime(firstTime)`
      | `security_content_ctime(lastTime)`
      | `kubernetes_scanner_image_pulling_filter`
how_to_implement: You must ingest Kubernetes logs through Splunk Connect for Kubernetes.
known_false_positives: No false positives have been identified at this time.
references:
    - https://github.com/splunk/splunk-connect-for-kubernetes
finding:
    title: Kubernetes Scanner image pulled on host $host$
    entity:
        field: host
        type: system
        score: 50
analytic_story:
    - Dev Sec Ops
asset_type: Kubernetes
mitre_attack_id:
    - T1526
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: cloud
security_domain: network

Stages and Predicates

Stage 1: search

`kube_objects_events` object.message IN ("Pulling image *kube-hunter*", "Pulling image *kube-bench*", "Pulling image *kube-recon*", "Pulling image *kube-recon*")

Stage 2: rename

| rename object.* AS *

Stage 3: rename

| rename involvedObject.* AS *

Stage 4: rename

| rename source.host AS host

Stage 5: eval

| eval phase="operate"

Stage 6: eval

| eval severity="high"

Stage 7: stats

| stats min(_time) as firstTime max(_time) as lastTime count
    BY host, name, namespace,
       kind, reason, message,
       phase, severity

Stage 8: search

| `security_content_ctime(firstTime)`

Stage 9: search

| `security_content_ctime(lastTime)`

Stage 10: search

| `kubernetes_scanner_image_pulling_filter`

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
object.messagein
  • "Pulling image *kube-bench*"
  • "Pulling image *kube-hunter*"
  • "Pulling image *kube-recon*"
field:"object.message" kind:in
sourcetypeeq
  • kube:objects:events
field:"sourcetype" kind:eq value:"kube:objects:events"