Sigma Rule Library

Kubernetes Potential Enumeration Activity

Detects potential Kubernetes enumeration or attack activity via the audit log. This includes the execution of common shells, utilities, or specialized tools like 'Rakkess' (access_matrix) and 'TruffleHog' via Kubernetes API requests. Attackers use these methods to perform reconnaissance (enumeration), secret harvesting, or execute code (exec) within a cluster.

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Detection logic

selection_status

responseStatus.code: ALLOW

selection_request_uri

requestURI|contains:
  - "%2fbin%2fash"
  - "%2fbin%2fbash"
  - "%2fbin%2fbusybox"
  - "%2fbin%2fdash"
  - "%2fbin%2fsh"
  - "%2fbin%2fzsh"
  - /bin/ash
  - /bin/bash
  - /bin/busybox
  - /bin/dash
  - /bin/sh
  - /bin/zsh
  - "%2fusr%2fbin%2fcurl"
  - "%2fusr%2fbin%2fkubectl"
  - "%2fusr%2fbin%2fperl"
  - "%2fusr%2fbin%2fpython"
  - "%2fusr%2fbin%2fwget"
  - /usr/bin/curl
  - /usr/bin/kubectl
  - /usr/bin/perl
  - /usr/bin/python
  - /usr/bin/wget

selection_request_user_agent

userAgent|contains:
  - access_matrix
  - trufflehog
  - azurehound
  - micro-scanner

Condition

selection_status and 1 of selection_request_*

Raw YAML

title: Kubernetes Potential Enumeration Activity
id: 597a7e84-187d-458b-9e4f-2f5a0e676711
status: experimental
description: |
    Detects potential Kubernetes enumeration or attack activity via the audit log.
    This includes the execution of common shells, utilities, or specialized tools like 'Rakkess' (access_matrix) and 'TruffleHog' via Kubernetes API requests.
    Attackers use these methods to perform reconnaissance (enumeration), secret harvesting, or execute code (exec) within a cluster.
references:
    - https://www.nccgroup.com/research/detection-engineering-for-kubernetes-clusters/
    - https://github.com/trufflesecurity/trufflehog
    - https://github.com/corneliusweig/rakkess
author: uniqu3-us3r
date: 2026-04-28
tags:
    - attack.execution
    - attack.discovery
    - attack.t1609
    - attack.t1613
logsource:
    product: kubernetes
    service: audit
detection:
    selection_status:
        responseStatus.code: 'ALLOW'
    selection_request_uri:
        requestURI|contains:
            # Shells Encoded
            - '%2fbin%2fash'
            - '%2fbin%2fbash'
            - '%2fbin%2fbusybox'
            - '%2fbin%2fdash'
            - '%2fbin%2fsh'
            - '%2fbin%2fzsh'
            # Shells Plain
            - '/bin/ash'
            - '/bin/bash'
            - '/bin/busybox'
            - '/bin/dash'
            - '/bin/sh'
            - '/bin/zsh'
            # Tools Encoded
            - '%2fusr%2fbin%2fcurl'
            - '%2fusr%2fbin%2fkubectl'
            - '%2fusr%2fbin%2fperl'
            - '%2fusr%2fbin%2fpython'
            - '%2fusr%2fbin%2fwget'
            # Tools Plain
            - '/usr/bin/curl'
            - '/usr/bin/kubectl'
            - '/usr/bin/perl'
            - '/usr/bin/python'
            - '/usr/bin/wget'
    selection_request_user_agent:
        userAgent|contains:
            - 'access_matrix'  # Rakkess
            - 'trufflehog'     # Secret scanning tool
            - 'azurehound'     # Azure/Cloud discovery
            - 'micro-scanner'  # Vulnerability scanning
    condition: selection_status and 1 of selection_request_*
falsepositives:
    - Authorized administrative maintenance via kubectl
    - Automated internal infrastructure monitoring and certificate rotation
    - Security-approved vulnerability or secret scanning in DevSecOps pipelines
level: medium

False positives

  • Authorized administrative maintenance via kubectl
  • Automated internal infrastructure monitoring and certificate rotation
  • Security-approved vulnerability or secret scanning in DevSecOps pipelines

References

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